Dissertations / Theses on the topic 'Hypervelocity impact'
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Gardner, David John. "Hypervelocity impact morphology." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294316.
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Thurber, Andrew. "Investigations of Hypervelocity Impact Physics." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/95298.
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Spacecraft and satellites in orbit are under an increasing threat of impact from orbital debris and naturally occurring meteoroids. While objects larger than 10 cm are routinely tracked and avoided, collisions inevitably occur with smaller objects at relative velocities exceeding 10 km/s. Such hypervelocity impacts (HVI) create immense shock pressures and can melt or vaporize aerospace materials, even inducing brief plasmas at higher speeds. Sacrificial shields have been developed to protect critical components from damage under these conditions, but the response of many materials in such an extreme event is still poorly understood.
This work presents the summary of computational analysis methods to quantify the relevant physical mechanisms at play in a hypervelocity impact. Strain rate-dependent behavior was investigated using several models, and fluid material descriptions were used to draw parallels under high shear rate loading. The production and expansion of impact plasmas were modeled and compared to experimental evidence. Additionally, a parametric study was performed on a multitude of possible material candidates for sacrificial shield design, and new shielding configurations were proposed.
A comparison of material models indicated that the Johnson-Cook and Steinberg-Cochran-Guinan-Lund metallic formulations yielded the most consistent results with the lowest deviation from experimental measures in the strain rate regime of interest. Both meshless Lagrangian and quasi-Eulerian meshed schemes approximated the qualitative and quantitative characteristics of HVI debris clouds with average measurable errors under 5%. While the meshless methods showed better resolution of interfaces and small details, the meshed methods were shown to converge faster under several metrics with fewer regions of spurious instability.
Additionally, a new technique was introduced using hypothetical viscous fluids to approximate debris cloud behavior, which showed good correlation to experimental results when such models were constructed using the shear rates seen in hypervelocity impacts. Formulations using non-Newtonian fluids showed additional capability in approximating solid behavior, both quantitatively and qualitatively. Such fluid models are significant, in that they reproduced the qualitative and quantitative characteristics of evolving debris clouds with better fidelity than purely hydrodynamic models using inviscid fluids. This indicates that while inertial effects can dominate overdriven shock phenomena, neglecting shear forces invariably introduces errors; such forces can instead be simplistically approximated via viscous models. The viscous approximation also allowed for a successful scaling analysis using dimensionless Pi terms, which was unfeasible using solid constitutive relations.
Attempts to model plasma dynamics saw success in the simulation of a laser ablation-driven flyer plate by using a hot gas with solid initial conditions; similar strategies were used to analyze plasma production in hypervelocity impacts with reasonable correlation to experimental measurements. Lastly, the analysis of bumper material candidates showed that metals with a low density such as beryllium and magnesium yield a higher specific energy and momentum reduction of incident projectiles with lower weight requirements than a similarly constructed bumper using aluminum. Investigations of bumpers using a combination of materials and variations in microstructure showed promise in increasing weight-normalized efficacy. Through these computational models, the parameters which influence damage and debris in hypervelocity impacts are more critically understood.PHD
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Milner, Daniel. "Laboratory simulations of oceanic hypervelocity impact events." Thesis, University of Kent, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445726.
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Mann, Joanna. "The hypervelocity impact related aspects of Panspermia." Thesis, University of Kent, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269100.
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Evans, S. T. "Hypervelocity impact studies on the Giotto comet Halley mission." Thesis, University of Kent, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233399.
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Tsembelis, Kostantinos. "Elevated temperature measurements during a hypervelocity impact process." Thesis, University of Kent, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285978.
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Campbell, J. "Lagrangian hydrocode modelling of hypervelocity impact on spacecraft." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266986.
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Stucky, Michael S. "Analysis of the NASA shuttle hypervelocity impact database." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FStucky.pdf.
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Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, September 2003.Thesis advisor(s): Eric Christiansen, Rudy Panholzer, Dan Bursch. Includes bibliographical references (p. 75-76). Also available online.
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Ryan, Shannon, and shannon ryan@studentems rmit edu au. "Hypervelocity Impact Induced Disturbances on Composite Sandwich Panel Spacecraft Structures." RMIT University. Aerospace, Mechanical & Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080808.092240.
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The next generation of European scientific satellites will carry extremely sensitive measurement devices that require platform stability orders of magnitude higher than current missions. It is considered that the meteoroid and space debris (M/SD) environment poses a risk to the success of these missions as disturbances induced by the impact of these particles at hypervelocity may degrade the platform stability below operational requirements. In this thesis, disturbances induced by the impact of M/SD particles at hypervelocity on a representative scientific satellite platform have been investigated. An extensive experimental impact test program has been performed, from which an empirical ballistic limit equation (BLE) which defines the conditions of structural perforation for composite sandwich panel structures with CFRP facesheets and aluminium honeycomb cores (CFRP/Al HC SP) has been defined. The BLE is used to predict impact conditions capable of inducing the different excitation modes relevant for a SP sandwich panel structure, enabling a significant reduction in the time and expense usually required for calibrating the protective capability of a new structural configuration. As experimental acceleration facilities are unable to cover the complete range of possible in-orbit impact conditions relevant for M/SD impact risk assessment, a Hydrocode model of the representative CFRP/Al HC SP has been constructed. A series of impact simulations have been performed during which the local impact-induced disturbance has been measured. The numerical disturbance signals have been validated via comparison with experimental disturbance measurements, and subsequently subject to a characterisation campaign to define the local elastic excitation of the SP structure equivalent to that induced by impact of a M/SD particle at hypervelocity. The disturbance characterisation is made such that it is applicable as an excitation force on a global satellite Finite Element (FE) model, allowing propagation of impact-induced disturbances throughout the complete satellite body to regions of critical stability (i.e. measurement devices). The disturbance induced upon measurement devices by M/SD impacts at both near- and far-body locations can then be made, allowing the threat to mission objectives to be assessed.
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Pasini, Luna. "Panspermia : the survival of micro-organisms during hypervelocity impact events." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/67564/.
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The possible spread of life between planetary bodies has significant implications for any future discoveries of life elsewhere in the solar system, and for the origin of life on Earth itself. Litho-Panspermia proposes that life can survive the shock pressures associated with giant impacts which are sufficiently energetic to eject life into space. As well as this initial ejection, life must also survive the impact onto another planetary surface. The research presented shows that the micro-organisms Nannochloropsis oculata phytoplankton and tardigrade Hypsibius dujardini can be considered as viable candidates for panspermia. Using a Two-Stage Light Gas Gun, shot programmes were undertaken to impact frozen organisms at different velocities to simulate oceanic impacts from space. It is demonstrated that the organisms can survive a range of impact velocities, although survival rates decrease significantly at higher velocities. These results are explained in the context of a general model for survival after extreme shock, showing a two-regime survival with increasing shock pressure which closely follows the pattern observed in previous work on the survival of microbial life and spores exposed to extreme shock loading, where there is reasonable survival at low shock pressures, but a more severe lethality above a critical threshold pressure (a few GPa). Hydrocode modelling is then used to explore a variety of impact scenarios, and the results are compared with the experimental data during a thorough analysis of potential panspermia scenarios across the universe. These results are relevant to the panspermia hypothesis, showing that extreme shocks experienced during the transfer across space are not necessarily sterilising, and that life, could survive impacts onto other planetary bodies, thus giving a foothold to life on another world.
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Olsen, Gregory Dana. "Experimental investigation into catastrophic failure of pressure vessels due to hypervelocity impact /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008411.
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Wilk, Jakob [Verfasser], and Thomas [Akademischer Betreuer] Kenkmann. "Shatter cones in hypervelocity impact experiments: Structure, formation and comparison to natural impact craters." Freiburg : Universität, 2017. http://d-nb.info/1220225657/34.
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Tanner, William Graydon. "Meteoroids and space debris hypervelocity impact penetrations : the role of hydrocodes." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319235.
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Huneault, Justin. "Development of an implosion-driven hypervelocity launcher for orbital debris impact simulation." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117206.
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The ability to soft-launch projectiles to velocities exceeding 10 km/s is of interest for a number of scientific fields, including orbital debris impact testing. Current soft-launch technologies have reached a performance plateau below this operating range. In the implosion-driven launcher (IDL) concept, explosives are used to linearly implode a pressurized steel tube, thereby dynamically compressing a light driver gas to significantly higher pressures and temperatures than typical light-gas launchers. As a result, the IDL has the potential to significantly outperform current state of the art hypervelocity launchers. This work will focus on establishing an understanding of the critical design parameters of the IDL with the goal of improving the velocity potential of the launcher. For this purpose, a computational gasdynamics solver capable of simulating the internal ballistics of the IDL has been developed. The elevated pressure and temperature in the driver gas lead to a number of non-ideal effects during the launch cycle, including expansion of the launcher walls, convective heat transfer, and gas leakage, which have a significant effect on launcher performance. These effects have been simulated by coupling the gasdynamics solver to loss models. Specifically, a structural hydrocode has been developed to provide a realistic model of reservoir and launch tube expansion, which has been identified as the main source of performance loss in the launch cycle. The complete internal ballistics solver will be used in conjunction with classical internal ballistics theory and experimental results, in order to gain valuable understanding of the key design parameters of the launcher and improve the design of the McGill IDL. This analysis has led to the development of an IDL capable of launching a 0.1-g projectile to 9.1 km/s.La capacité d'accéléré des projectiles à des vitesses au-delà de 10 km/s est d'intérêt pour de nombreuses applications, incluant la protection contre les débris spatiaux. La performance des lanceurs hyper-vitesse de pointe n'est pas capable de rejoindre ces vitesses. Le lanceur à implosion utilise des explosifs pour comprimer un gaz léger de façon dynamique, afin d'atteindre des pressions et des températures beaucoup plus élevés que des lanceurs hyper-vitesse typiques. Pour cette raison, le lanceur à implosion à le potentiel de surpasser la performance de tout autre lanceur. Ce travail mettra l'accent sur l'établissement d'une compréhension des paramètres de conception critiques du lanceur à implosion dans le but d'améliorer la performance du lanceur. A cet effet, un code capable de simuler la balistique interne du lanceur a été développé. La pression et la température élevées dans le gaz causent plusieurs pertes durant le cycle de lancement, y compris l'expansion des parois du lanceur, le transfert de chaleur par convection, et les fuites de gaz. Ces pertes ont un effet important sur la performance du lanceur. Les modèles utilisés pour simuler ces pertes sont aussi présentés. Le code complet sera utilisé en conjonction avec la théorie classique de la balistique interne ainsi que des résultats expérimentaux afin d'amélioré le lanceur. Cette analyse a conduit à l'élaboration d'un lanceur à implosion capable d'accéléré un projectile de 0,1 g à 9,1 km/s.
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Taylor, Emma Ariane. "Experimental and computational study of hypervelocity impact on brittle materials and composites." Thesis, University of Kent, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264769.
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Retrieval and analysis of space-exposed surfaces from Low Earth Orbit (LEO) can lead to an improved understanding of the space debris and micrometeoroid particulate environment. A large volume of data has been accumulated from analysis of space-exposed ductile materials, including the LDEF satellite. The Hubble Space Telescope (HST) and EURECA solar arrays provide a large, new source of information on the LEO particulate flux. Below a certain crater diameter, these solar arrays are equivalent to semi-infinite brittle material targets and thus the impact crater fluxes are analogous to impact fluxes on returned lunar rocks and Apollo/Gemini windows. An extensive shot programme has been executed onto glass, aluminium and spacecraft honeycomb (used as exterior spacecraft wall and solar array support structure). The data supplement the large database of brittle material hypervelocity impact tests used in this thesis. These data have been used to (i) develop new, target-dependent, empirically-determined brittle material damage equations, (ii) derive a conversion factor between the brittle material ,) conchoidal diameter( D, and the ballistic limit in aluminium for a particular exposure and shielding history (Fmax)a, nd (iii) investigatet he ballistic limit of spacecrafth oneycomb. In addition, the response of brittle materials to, hypervelocity impact has been explored via hydrocode modelling, including the implementation and validation of the Johnson-Holmquist brittle material model at velocities beyond the experimental calibration regime. The converted semi-infinite brittle material fluxes from the HST and EURECA solar arrays have been directly compared with both an experimentally-measured LDEF mean flux and a modelled flux prediction for meteoroids (excluding space debris). The solar array fluxes are in good agreement with the LDEF data and modelling results for F. greater than 20-30 μm. Below this value of F,,,, the data do not reproduce the space debris flux enhancement shown by LDEF. ll
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Giblin, Ian. "Development and use of software for the analysis of hypervelocity impact experiments." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238765.
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Kalinski, Michael E. "Hypervelocity impact analysis of International Space Station Whipple and Enhanced Stuffed Whipple Shields." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FKalinski.pdf.
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Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, Dec. 2004.Thesis Advisor(s): Eric Christiansen, Terry R. McNelley. Includes bibliographical references (p. 275-276) Also available online.
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Yano, Hajime. "The physics and chemistry of hypervelocity impact signatures on spacecraft : meteoroids and space debris." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262370.
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Marroquin, Salvador Michael Deivi. "Hypervelocity Impact of Spherical Aluminum 2017-T4 Projectiles on Aluminum 6061-T6 Multi-Layered Sheets." Thesis, Mississippi State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10642662.
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With the growing threat of orbital debris impacts to space structures, the development of space shielding concepts has been a critical research topic. In this study, numerical simulations of the hypervelocity impact response of stacked aluminum 6061-T6 sheets were performed to assess the effects of layering on penetration resistance. This work was initially motivated by set of experimental tests where a stack of four aluminum sheets of equal thickness was observed to have a higher hypervelocity ballistic resistance than a monolithic aluminum sheet with the same total thickness. A set of smoothed particle hydrodynamic simulations predicted a 40% increase in the ballistic limit for a 6-layer target compared to a monolithic sheet. In addition, the effect of variable sheet thickness and sheet ordering on the impact resistance was investigated, while still maintaining a constant overall thickness. A set of thin layers in front of a thick layer generally lead to a higher predicted ballistic limit than the inverse configuration. This work demonstrates an increase in the performance of advanced space shielding structures associated with multi-layering. This suggests that it may be possible to dramatically improve the performance of such structures by tailoring the material properties, interfaces, and layering concepts.
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New, James Stephen Oliver. "The design, construction and hypervelocity impact testing of a prototype orbital debris and interplanetary dust detector." Thesis, University of Kent, 2018. https://kar.kent.ac.uk/68472/.
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The constant bombardment of millimeter and submillimeter interplanetary dust and orbital debris particles on spacecraft and other space assets leads to long term degradation of exposed surfaces and systems. In the past, post-flight surface analysis on the Space Shuttle provided regular data on these small particles in low Earth orbit. The accumulation of data provided by the characterisation of these particles is required for the development, and updating, of orbital debris environment models, which are essential to predict the conditions in space that can significantly a↵ect the design, operation and cost of spacecraft. Since the retirement of the Space Shuttle program in 2011, there has been very little new data generated. Consequently, there is now an increasing need for additional information on the characteristics of interplanetary dust and orbital debris for both commercial and research purposes. Dedicated dust detectors, rather than post-flight data collection from collision damage, have successfully demonstrated the potential for characterising particles in the past, and provide the most likely method of analysis going forward. However, current versions have a number of limitations and there is an opportunity to make significant advancements in the next generation of detectors. Designing, testing and analyzing improved detector systems was the primary focus of this research. Interplanetary dust and orbital debris properties of specific interest include; flux, size, velocity, trajectory, kinetic energy, density and mass. Although previously flown detectors are capable of measuring a number of these parameters, no previous detector has integrated the capacity to measure all of them simultaneously. This thesis describes concepts for a detector capable of collecting, processing and transmitting back the data for all of the parameters listed above and in real time, which is a significant advancement on current state-of-the-art detectors. Prototypes were designed incorporating selected adaptations of previous detectors, utilising the basic principle of sequential detection gates. Proof-of-concept experiments were conducted on the prototypes using the light gas gun at the University of Kent in order to replicate orbital impacts with simulated space particles in the laboratory. Algorithms written in Python were developed for the five subsystems to analyse data collected by PVDF sensors on each of the three detection gates, and to directly calcu- late the flux, velocity, trajectory, diameter and kinetic energy of particles interacting with the prototypes. In turn, these results were used to derive mass and density. The characteristics of particles calculated by the subsystems during the experiments were compared with their known properties in order to quantify the accuracy of each mea- surement. The velocity, trajectory and diameter calculations had an average confidence within 6.5%, 0.5% and 10.0%, respectively. Measurement of the kinetic energy was accurate to ⇠26.0 %, which is regarded as a significant step forward. Additionally, the experiments provided evidence that flux models can be accurately measured for par- ticles larger than 50μm. The prototypes designed and validated in this research can be used as templates for future detectors capable of providing real-time data on the characteristics of interplanetary dust and orbital debris. These data will contribute directly to the design of future instrumentation and assist the development of more detailed environment models with both commercial and research applications.
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Bettella, Alberto. "Generation and propagation of vibrations on satellite structures and planetary bodies after hypervelocity impacts." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425965.
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Hyper-Velocity-Impacts (HVI) are a common problem in the space environment. They especially concern space missions, in terms of:
Potential damage to spacecrafts and satellites Collisional evolution of small and large bodies of the Solar System.
This thesis focuses on the effect of such impacts, through the analysis of the vibration field generated by HVI on both of the aforementioned cases.
Referring to the first point, i.e. the HVI-induced disturbances on spacecraft internal components, a wide experimental campaign has been performed on targets representative of S/C structures, making it possible to measuring and reproducing the HVI-induced vibration field on the selected targets. The aim of this activity was to acquire data on transient waves generated after an HVI and propagating from the impact point. Such disturbances have been evaluated in from of acceleration signals.
The invaluable information achievable from such an activity is related to the HVI ability of loading structures up to frequencies that are normally not explored in the standard practice for mechanical dynamic testing. These loads can damage electronic components and sensors mounted on S/C.
An experimental campaign on structural components represents a unique mean of collecting data about the transient behaviour of spacecraft components subjected to HVI threat. The Study is relevant to both "simplified" (i.e. simple plates and sandwich panels made by Aluminium alloy and composite materials) and "complex" (i.e. structural assemblies including joints) targets, hit by projectiles in the range 0.6 - 2.3 mm at velocity from 2 to 5 km/s.
The test-case selected for the experimental activity is the GOCE satellite, whose mission main objective is to measure the Earth's gravity field modelling the geoid with extremely high accuracy and spatial resolution. To do this, it will carry a gradiometer that is sensitive to disturbances, like the one generated by HVI. For this reason, the assessment of the vibration field that propagates after an HVI is fundamental.
As a conclusion, the activity on spacecraft structures resulted in the creation of an extensive database of the disturbance field generated and propagated by HVI on simple and complex assemblies, even highlighting the dependence of the structural response from the mass and velocity of the impacting debris. The disturbance was quantified computing SRS spectra of the measured acceleration signals.
This activity made also possible to evaluate the momentum transferred by the projectiles to the impacted targets. This measurement was necessary to validate the numerical technique used to extrapolate the experimental results to structures and impact conditions different from those achievable at laboratory scale with the existing hypervelocity facilities [28].
Moreover, to investigate in detail the typical features of transient disturbances, a dedicated study was implemented on the application of Wavelet Transform (WT) to the sampled acceleration signal on aluminium simple plates and honeycomb sandwich panels. WT was used to explore the complex wave generation and propagation behaviour inside these targets, thanks to its ability of identifying the following wave features: speed of propagation, type, dispersion properties and frequency content. This work led to a better understanding of the origin of disturbance field due to HVI, demonstrating that WT technique may be used to analyse the elementary constituents of transitory signals.
Referring to the second point, i.e. the study of the collisional evolution of minor bodies of the Solar System, several numerical simulations were carried out to study the wave propagation on planetary-like objects.
HVI characterize the evolutional story of all the small and large bodies of the Solar System. For this reason, the goal of simulations on porous materials (concrete was used as test-case in this thesis) was to obtain a better comprehension of the impact processes and to provide a tool to validate the results of numerical models, through the analysis of wave generation and propagation on different materials. The results of this activity aimed also to contribute to the data interpretation of the ground and space based observations, in particular in view of space missions such as Smart1, MarsExpress, VenusExpress, BepiColombo, Cassini-Huygens, Rosetta, Dawn.
Impact experiments to investigate craterization and catastrophic disruption on planetary objects are limited due to scale effect (i.e. size of the targets, Earth gravity environment, actual performance of the modern hypervelocity facilities). Therefore, a possible method used to study the impact processes is to perform numerical simulations with hydrocodes. The main issue with these tools is the unknown response of materials to high velocity impacts, pressures of several MPa and shock wave propagation. The validation of such models implies to test with the available impact facilities small-scale targets representative of real asteroids and to match experiments and numerical simulations. Waves propagating within the impacted target can be used in the assessment of such numerical models, through the comparison of waves features like: speed, frequency and reflections.
In this thesis the possibility to use an accelerometer to measure waves propagation in concrete spheres (representative of porous targets) and to identify wave features with WT is explored. For this reason, SPH (smooth particles hydrocode) simulations have been carried out on a small-scale concrete sphere to better understand the propagation of shock waves and to evaluate the load effects due to the accelerometer mass. Results show that this measurement is possible, even if it is necessary to perform it with a highly sensitive measurement chain.
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Xia, Kang. "Numerical characterization of the mechanical properties of graphene and graphene-based structures." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/102705/1/Kang_Xia_Thesis.pdf.
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This project thoroughly investigated the deformation mechanisms of graphene and graphene-based structures under various loading conditions. The work extends and enhances the existing knowledge and understanding of graphene and graphene-based structures, which will shed lights on the facilitation of their engineering applications. All delineated models and theoretical analysis methods established in this study are also applicable to future studies on other nanostructures.
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Barilaro, Leonardo. "Measurement techniques for assessing and reducing the risk posed by Micrometeoroid and Orbital Debris to Space vehicles." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3425452.
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In recent years a new risk for Earth-orbiting spacecraft started to emerge: space debris.
This term describes any man-made object in orbit around Earth that no longer has a useful purpose.
The present work describes measurement techniques for assessing and reducing the risk posed by Micrometeoroid and Orbital Debris (MMOD) to space vehicles.
The main research areas are:
• Impacts phenomenology, risk assessment methodology, and design methods;
• Experimental methods (i.e. acceleration techniques and diagnostic instrumentation);
• Engineering models (i.e. measurements of the effects of the MMOD and derivation of damage equations).
Related to these areas, the objectives and personal contributions are presented regarding:
• Hypervelocity facility developments, i.e. improvements of the CISAS (Center of Studies and Activities for Space) ‘G. Colombo’ two stage light gas gun (LGG) and a design study about 2 single stage LGGs, for the CISAS HVI (hypervelocity impacts) facility and for the Cranfield University, UK;
• Experimental activity for impacts’ study, where instruments for the ejecta characterization and the primary impact detection were developed;
• Derivation of damage equations, this led to the definition of new Ballistic Limit Equations statistically based that give a new scenario for MMOD shields’ design in the future. These equations are developed to define impact conditions (i.e. particle size, particle density, impact velocity, and impact angle) that result in threshold failure of specific spacecraft components or subsystems.
The main objectives of the research were met and they led to the:
• Gasdynamical study and sabot stopping system design for a new CISAS single stage Light Gas Gun;
• Impact chamber and sabot stopping system design for the Cranfield University (UK) single stage LGG;
• High pressure section and supporting structure design for a new CISAS two stage LGG;
• Design and evolution of an instrument for ejecta characterization;
• Design of an instrument for primary impact measurements;
• Development of a methodology to derive damage predictor equations statistically based for Cosmo-Skymed satellites ;
• Development of a methodology to derive ballistic limit equations statistically based for inflatable structures.Negli ultimi anni un nuovo rischio ha iniziato ad emergere per i veicoli spaziali orbitanti attorno alla Terra: i detriti spaziali. Questo termine descrive oggetti di origine umana in orbita attorno alla Terra che non hanno più uno scopo utile. Il presente lavoro descrive tecniche di misura per stimare e ridurre il rischio creato da micrometeoriti e detriti spaziali (MMOD) ai veicoli spaziali. Le principali aree di ricerca sono: • Fenomenologia dell’impatto, metodologia per la stima del rischio, metodi di progettazione; • Metodi sperimentali (ossia tecniche di accelerazione e strumentazione per la diagnostica); • Modelli ingegneristici (ossia misure degli effetti dei MMOD e derivazione delle equazioni di danno). Gli obiettivi e i contributi personali legati a queste aree di ricerca sono presentati relativamente a: • Sviluppo della strumentazione del laboratorio per la simulazione di impatti iperveloci presso il CISAS (Centro Interdipartimentale Studi ed Attività Spaziali) “G. Colombo”, ossia evoluzione del cannone bistadio a gas leggero e progettazione relativa a componenti di due cannoni monostadio a gas leggero, uno per il CISAS e uno per la Cranfield University, UK; • Attività sperimentale relativa allo studio degli impatti, dove sono stati sviluppati strumenti per la caratterizzazione di ejecta e per il rilevamento di impatti primari; • Derivazione delle equazioni di danno, questo ha portato allo sviluppo di nuove Equazioni di Limite Balistico, aventi base statistica e che forniscono un nuovo scenario riguardo il futuro della progettazione di scudi per i MMOD. Queste equazioni sono sviluppate per definire le condizioni di impatto (ossia diametro e densità del detrito, velocità e angolo di impatto) che risultano per il valore di soglia relativo al fallimento di uno specifico componente o sottosistema di un veicolo spaziale. I principali obiettivi di questa ricerca sono stati raggiunti e hanno portato a: • Studio gasdinamico e progettazione del sistema ferma sabot per un nuovo cannone monostadio a gas leggero per il laboratorio per impatti iperveloci presso il CISAS; • Progettazione della camera per gli impatti e del sistema ferma sabot per il cannone monostadio a gas leggero presso la Cranfield University, UK; • Progettazione della sezione ad alta pressione e della struttura di supporto per il nuovo cannone bistadio a gas leggero presso il CISAS; • Progettazione ed evoluzione di uno strumento per la caratterizzazione di ejecta; • Progettazione di uno strumento per misure relative a impatti primari; • Sviluppo di una metodologia per derivare equazioni di danno su base statistica per i satelliti Cosmo-Skymed; • Sviluppo di una metodologia per derivare equazioni di limite balistico su base statistica per strutture inflatable.
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Grey, Ivan David Serafim Simon. "Hypervelocity impacts on ice." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342161.
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Bertrand, Aubert. "Comportement de matériaux carbonés sous sollicitations dynamiques intenses : analogie entre irradiations lasers et impacts hypervéloces." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0065/document.
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L’étude des impacts hypervéloces (IHV) est essentielle dans de nombreux domaines tels que l’aérospatial, la cosmologie ou l’armement. Pour les reproduire en laboratoire, il est usuel d’utiliser des lanceurs à gaz ou à poudre. Toutefois, ce type de moyen se limite à des vitesses d’impact de l’ordre de 10 km/s pour des projectiles millimétriques. Afin d’étudier des vitesses plus élevées, il faut se tourner vers des moyens alternatifs. Dans cette étude, nous démontrons qu’une analogie est possible entre irradiations laser et IHV. Pour parvenir à ce résultat, des données expérimentales ont été obtenues sur le lanceur HERMES et sur l’installation laser GCLT. Deux matériaux cibles ont été considérés : l’aluminium 6061-T6 et l’EDM3, un graphite poreux. Par simulation numérique, nous avons caractérisé spatialement et temporellement les champs de pression générés en surface des cibles par un projectile et par un laser. Cela nous a permis de proposer et de valider une procédure permettant de lier IHV et essais laser. Pour finir, une campagne expérimentale été réalisée sur l’installation laser du LULI2000 afin d’étudier des vitesses d’impact pouvant atteindre 32 km/sThe study of hypervelocity impacts (HVI) is essential in many fields such as aerospace, cosmology or defense. To reproduce them in laboratory, it is usual to use gas or powder launchers. However, this type of facility is limited to impact velocities under 10 km/s for projectiles of millimeter size. In order to study higher velocities, it is necessary to consider alternative means. In this study, we demonstrate that an analogy is possible between laser irradiations and HVI. To do this, experimental data were obtained on the HERMES launcher and the GCLT laser facility. Two target materials were considered: 6061-T6 aluminum and EDM3, a porous graphite. By numerical simulation, we spatially and temporally characterized the pressure fields generated on the surface of the targets by a projectile and a laser. It allowed us to propose and validate a procedure to link HVI and laser shots. Finally, an experimental campaign was carried out on the LULI2000 laser facility to study impact velocities up to 32 km/s
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Baron, John Michael. "Microparticle hypervelocity impacts on satellites in low-Earth orbit." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308822.
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Morris, Andrew James Wulfric. "Laboratory studies of hypervelocity impacts on solar system analogues." Thesis, University of Kent, 2015. https://kar.kent.ac.uk/50707/.
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Impact cratering and asteroid collisions are major processes throughout the Solar System. Although previous collision-related impact investigations exist (Flynn et al. 2015, Holsapple et al. 2002 and Burchell et al. 1998 are good examples), in the works covering this broad range of investigation, the targets are non-rotating (for the purposes of catastrophic disruption) and different temperature conditions are not considered (for impact cratering). Accordingly, I present experimental processes and data, regarding hypervelocity impact experiments into analogues of (1) rotating asteroids and (2) temperature dependant terrestrial planetary rock. During the course of this work, it was necessary to develop new apparatus and new experimental techniques such as three separate target holders to aid in both catastrophic disruption and heated impact projects, a 3-dimensional model analysis of craters and a completely new, statistically robust, technique to determine a complete crater profile called the KDM method where KDM is Kinnear-Deller-Morris. The main result from this work showed that during an asteroid impact collision where the asteroid is not rotating, the impact energy density for catastrophic disruption is Q*static = 1442 ± 90 J kg-1. However, when the target asteroid was rotating, the condition Q*rotation = 1097 ± 296 J kg-1. The mean value of Q* had thus reduced, but the spread in the data on individual experiments was larger. This leads to two conclusions. The mean value for Q*, based on measurements of many impacts, falls, due to the internal forces acting in the body which are associated with the rotation. This energy term reduction means that the amount of energy to instigate catastrophic disruption is lower and that a rotating asteroid is effectively weaker upon impact than a stationary asteroid. However, the spread in the results indicates that this is not a uniform process, and an individual result for Q* for a rotating or spinning target may be spread over a large range. For the temperature related impacts, as the targets were heated to approximately 1000 K, the target rocks showed an impact dependence more similar to a plastic phase-state than to solidus, due to being held close to temperatures associated with semi-plastic phases. Basalt impact craters displayed this relationship greatest with crater sizes becoming smaller at the higher temperature ranges but larger in the colder brittle solidus temperatures, partly explained in experiments by increased spallation.
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Avdellidou, Chrysoula. "Hypervelocity impacts in the Solar System : an experimental investigation on the fate of the impactor." Thesis, University of Kent, 2016. https://kar.kent.ac.uk/54994/.
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Collisions is one of the most important processes in the Solar System that have played a significant role in its evolution for 4.5 Gy. They are responsible for the formation of asteroid families, craters and regolith production on bodies surfaces. Moreover they pose a hazard for our planet's environment, human civilisation and space assets. Impacts have shaped the asteroids and their surfaces and recently there are indications that they are also responsible for the creation of multi-lithology asteroids. The effectiveness of this process lies, apart from the collisional speed and angle, on the physical parameters of both the target and the impactor. A plethora of laboratory experiments are devoted to study the outcome of impacts, from low speeds of a few m/s to greater speeds of several km/s. In addition space missions; such as Deep Impact (NASA) in the past and AIDA (ESA/NASA) hopefully in the near future, are aiming to perform hyper-velocity impact experiments at large scales. Although there is advance in our understanding of crater formation, target fragmentation and ejecta speeds, however the fate of the impactor is still very poorly constrained. Experiments so far were focused using materials not directly relevant to the composition of asteroids. We start an investigation for the impactors' fate, by using lithological projectiles that impacted three different types of targets with different material and bulk porosities. For this experimental campaign was used the Light Gas Gun (LGG) of the Impact Group at the University of Kent. The study was focused on three main topics: i) the fragmentation of the impactor, ii) the implantation of exogenous material onto the target and iii) the inspection of the final state of the projectile.\\ This Thesis is divided in six Chapters. The first two, Chapters 1 and 2, are giving a review of recent advances of small bodies studies, the importance of collisions in the Solar System, and a brief description of the laboratory impact experiments, providing the current state of research on the fate of projectiles. Some open questions lead to the explanation of the aim of this study. In Chapter 3 are described the series of experiments performed, explaining the analysis methods were developed and the way that the main topics of fragmentation, implantation and characterisation of the impactor were studied. All the results for each one of these topics, along with the difficulties during the experimental procedure are provided in Chapter 4. In Chapter 5 we discuss the results giving the implications, attempting to place the outcome in the big picture of the small bodies collisions. In the last Chapter 6 there is a summary of this work, providing also possible future ideas for the continuation of this study.
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Watters, Wesley Andrés 1976. "Hypervelocity impacts and the evolution of planetary surfaces and interiors." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/46806.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 227-234).
The thesis consists of five studies relating impact processes to the evolution of planetary interiors as well as impact structures on planetary surfaces. Chapter 2 is concerned with developing methods for estimating the amount of heat deposited deep in terrestrial mantles by large impacts. Chapter 3 makes use of these results to compute the consequences of impact-related thermal buoyancy perturbations in numerical models of subsolidus convection. Among the important results of this work is a relation for the time-scale on which a buoyancy anomaly flattens and spreads before it is halted by convective downflows, as well as a condition that indicates for what perturbation magnitudes and Rayleigh numbers the flow is significantly slowed at a global scale. Chapter 4 describes a structural model of Endurance Crater in Meridiani Planum on Mars, which is constrained by observations gathered by the MER-B Opportunity rover. These results reveal new insights about the planform shape of the crater excavation flow, as well as the connection between crater shape and pre-existing structures in target materials. The study presented in chapter 5 relates the planimetric shape of simple impact craters on Mars (D < 5 km) to the geological targets in which they form, as well as rim diameter. Planform crater shape is characterized by a suite of morphometric parameters, including Fourier harmonic amplitudes and phase angles, as well as measures of deviation from radial symmetry and convexity.
(cont.) In addition to finding the morphometric dependence on target properties, this work has illuminated prominent transitions between different cratering regimes, and contains a measure of the global distribution of planform elongation azimuths - which may relate to impact azimuth and provide an estimate of Mars' past obliquity variations. Finally, Chapter 6 describes a stochastic-kinematic model of the interaction between the excavation front and fractures in the target, which replicates many of the observations obtained in Chapter 5.
by Wesley Andrés Watters.
Ph.D.
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Seisson, Gabriel. "Etude expérimentale et théorique de l'endommagement du graphite sous sollicitation dynamique - Application aux impacts hypervéloces." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2014. http://www.theses.fr/2014ESMA0015/document.
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Les matériaux composites sont très utilisés dans diverses applications et sont parfoissoumis à des impacts hypervéloces (IHV), notamment dans le domaine spatial. La taille des impacteursétant proche de celle des torons de fibres, les simulations mésoscopiques ont tout leurintérêt mais nécessitent des modèles numériques aboutis pour chaque sous-Constituant. Le graphiteétant souvent utilisé comme matrice ou fibres, nous avons étudié son comportement dynamique.Ainsi, des expériences de pénétration et de cratérisation ont été menées sur un isographite poreux.L’analyse post-Mortem des cibles, associée à des calculs d’ordre de grandeur, apporte un éclairagenouveau sur la phénoménologie des impacts et fournit des renseignements utiles à la simulationnumérique. Un modèle pour matériaux poreux et fragiles, implémenté dans un code de dynamiquerapide, est utilisé. Basé en partie sur des propriétés statiques, il a été progressivement testé sur deschocs plans. Son utilisation pour la simulation des IHV donne de bons résultats. Toutefois, il convenaitde le valider en s’affranchissant du comportement du projectile. Pour cela, une campagne dechocs lasers a été menée. Des diagnostics in-Situ ont été utilisés et leur corrélation avec des analysespost-Mortem a permis l’identification de différents modes d’endommagement des cibles. Finalement,bien que l’équivalence entre IHV et chocs lasers ne soit pas démontrée, ces derniers se sont montréscomplémentaires en suggérant de futures évolutions du modèle numériqueComposite materials are widely used in various applications and may be submittedto hypervelocity impacts (HVI), such as in the aerospace field. The size of the impactors beingclose to that of a strand of fibers, mesoscopic simulations are of great interest but they need reliablenumerical models for each meso-Constituent. Graphite often being used as fiber or matrix,we studied its dynamic behavior. Penetration and craterization experiments have been conductedonto porous isotropic graphite. Post-Mortem analysis of targets, associated to order-Of-Magnitudecalculations, sheds a new light on the phenomenology of impacts and brings useful informationfor numerical simulation. A model for porous and brittle materials, implemented into a hydrocode,is used. Partially based on static mechanical properties, it has been progressively tested on planeshocks. Its use for simulating HVI gives satisfying results. Nevertheless, it was necessary to validateit by disregarding the projectile behavior. In that purpose, a campaign of laser-Driven shocks hasbeen conducted. In-Situ diagnostics have been simultaneously used and their correlation with postmortemanalysis allowed the identification of different damaging regimes of the targets. Finally,although the equivalence between HVI and laser-Driven shocks is not proved, the latter turned outto be complementary, suggesting the future evolutions of the numerical model
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Shrine, Nicholas Robert George. "Laboratory investigation of oblique hypervelocity impacts with relevance to in situ meteoroid and space debris detectors." Thesis, University of Kent, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301828.
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Wickham-Eade, Jamie E. "Fragmentation of carbon-bearing projectiles and the effects on their Raman spectra due to hypervelocity impacts." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/66264/.
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The term hypervelocity refers to something that is travelling at speeds in excess of a few km/s. Impacts within the Solar System generally occur at these speeds, hence they are referred to as Hypervelocity Impacts. Typical impact speeds in the Solar System depends on their location. Within the main asteroid belt, the average impact speed is generally considered to be 5 km/s. Moving to impacts on Earth, the Moon and Mars, an asteroid average impact speed is approximately 22, 19 and 9 km/s respectively. Move to the outer Solar System and the average impact speed on Pluto is thought to be approximately 2 km/s Generally, research into hypervelocity impacts looks into cratering and the ejecta from these craters. However, the fate of the projectile is relatively neglected. Hence, this topic was explored in this thesis. To achieve this, experiments were performed using the University of Kent's two-stage light gas gun. Along with a mechanical effect on the projectile material, the propagating shock wave can cause effects on the molecular structure. This can be investigated using Raman Spectroscopy, which is an inelastic scattering effect resulting from the laser light interaction with the molecules of the sample. By comparing a before and after spectrum of an impacted material, it is possible to determine the effects of shock pressure. An important biomarker is carbon. The Raman spectra of carbon often contain a D (disorder) and G (graphite/order) band. The amplitude and area ratios of these two bands denote the structural organisation of the carbon-bearing materials. Impacting these materials can affect the Raman spectra. Changes in the spectra can reflect the effect shock pressures have had on the molecular structure of the material. Firstly, the mechanical effect of a hypervelocity impact was investigated for basalt and shale. The materials were filed into 1.5 mm cubes. These cubes were then fired into water at speeds up to 6.13 km/s (peak shock pressure of 30.9 GPa). The water was then filtered through a 0.1 um filter membrane and a scanning electron microscope used to image the entire filter paper. ImageJ was then used to analyse the fragments. From this, information on the morphology, cumulative fragment size distribution, survival percentage and the energy density at the catastrophic disruption threshold are obtained. Catastrophic disruption is where the shock wave of an impact is sufficiently intense that the largest fragment is equal to or less than 50% of the original mass of the body (exactly 50% is the threshold limit). Over 400,000 fragments were measured per shot, providing fragment sizes down to 10^-3 of the original projectile size. When excluding the partially disrupted projectiles (impacts not sufficient enough to surpass the catastrophic disruption threshold limit), the average semi-minor to semi-major axis ratio (b/a) for basalt and shale were 0.58 +/- 0.16 and 0.59 +/- 0.14 respectively. This suggests that the difference in morphology does not have an effect on this ratio at higher impact speeds. From the results an estimate of percentage survival at Pluto, the Moon, in the asteroid belt and on Mars is 76 +/- 11 %, 39 +/- 8 %, 17 +/- 5 % and 10 +/- 4 % respectively. It was found that for basalt and shale the catastrophic disruption energy density was (24.0 +/- 2.1) x 10^4 and (9.4 +/- 5.0) x 10^4 J/kg respectively. The work then moved on to investigating the effect of the shock upon the fragments of the projectile. An additional material (graphite) was used with basalt and shale. The materials were shot using the same method used to investigate the mechanical effect of the hypervelocity impact. Pre-shot the projectile was mapped using a 532 nm laser in a Raman spectrometer. These spectra were then compared to the spectra of 40 separate randomly chosen fragments in each shot. From this, it is possible to determine the shock pressure effects of the impact. Although no trends were identified positive shifts were observed for the D band peak position for basalt and shale, the G band peak position of basalt experienced a positive shift while graphite experienced both a positive and negative shift. Additionally, the G band width for basalt and shale experienced an absolute narrowing of 12.2% and 8.1% respectively, while graphite exhibited an absolute broadening of 17.6%. Overall, all the materials displayed an increased structural disorder after impact, as suggested by plotting the Raman spectra R1 and R2 values. These are ratios of the D and G band amplitudes (R1) and the bands' areas (R2). Furthermore, it was found from this work that there is a possibility of misinterpreting a sample when attempting to determine whether it is biotic carbon if from a shocked environment. The samples were also subjected to static pressure up to a maximum pressure of 3.59 GPa using a diamond anvil cell, and heating/cooling (temperature range 173 to 773 K) using a Linkam temperature stage. This was done in order to ascertain the effects of flash heating upon Raman spectra during hypervelocity impacts. It was found that the effects of temperature are mostly opposite to the effect of shock and static pressure on a carbon Raman spectrum. Increasing static pressure led to the G band peak position for shale and graphite shifting a total of 19.2 and 15.0 cm^-1, at 3.48 and 3.23 GPa respectively. In contrast, for shale and graphite the D and G band peak position were shifted to lower wavenumbers at high temperature (>300 K), and to higher wavenumbers at low temperature (< 300 K). Finally, the capture effect upon olivine as a constituent of a mineral assemblage was also investigated. These capture effects are shock pressures ≤300 MPa (Trigo-Rodriguez et al. 2008) and heating to over 1,000 °C for a brief period of a microsecond (Naguchi et al. 2007, Leroux 2012, see). Ground carbonaceous chondrite (CR2) was red at approximately 6.1 km s⁻¹ (Stardust collection speeds) into aerogel in order to investigate the capture effects. Three examples of shifted olivine spectra were observed. An estimate of the shift for the peaks P1 and P2 (the main two peaks seen in olivine spectra) for the three spectra are 1.21, 1.56 and 1.48 cm⁻¹ and 1.81, 3.40 and 3.21 cm⁻¹, both to lower wavenumbers, respectively. The capture effects exhibited by olivine when contained within a mineral assemblage were found to be less than those when the olivine was a single grain. In summary, the work in this thesis was undertaken in order to understand the hypervelocity impact effects upon the projectile. This is reasonably straight forward for the mechanical effects, however, the shock effects upon the carbon Raman bands were more complex. The most significant is the natural variation in the raw sample spectra. Despite this, it is possible to observe the effects of shock pressure upon the carbon D and G bands.
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Michel, Yann. "Phénomène d'impact à haute vitesse sur cibles minces fragiles : application au projet de laser mégajoule et à la problématique des débris spatiaux." Toulouse 3, 2007. http://www.theses.fr/2007TOU30034.
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Les propriétés de transparence des verres les rendent souvent indispensables pour des systèmes optiques, mais leur incapacité à subir de grandes déformations les rend spécialement sensibles aux impacts à grande vitesse. L'objectif de cette thèse est de caractériser et de modéliser les dommages et l'éjection de matière induits par ces impacts sur des cibles minces monolithiques (EPA LMJ) ou multicouches (cellules solaires). Une partie importante de ce travail est consacrée à la caractérisation expérimentale du comportement sous choc de la silice fondue et des dommages subis par des cibles minces de verre sous impacts tridimensionnels (VProj £ 3. 5km/s). L'expertise de ces cibles et les méthodes originales de collecte et de caractérisation dynamique de la matière éjectée ont permis de mieux comprendre les mécanismes intervenant lors d'impacts à grandes vitesse sur des verres. Cette partie aboutit à la réalisation de développements enrichissant le modèle de comportement dérivé par Johnson & Holmquist et implémenté dans le code LS-DYNA. Ce modèle, couplé avec la méthode SPH, permet de reproduire les effets de fragmentation et de densification permanente sous choc. La seconde partie de ce travail présente l'utilisation des développements et des modèles numériques réalisés pour évaluer les performances balistiques, les dommages, et les caractéristiques d'éjection de matière des EPA et des cellules solaires. Les simulations numériques 3D ont permis de fixer les limites actuelles de l'outil numérique à l'intérieur desquelles ses capacités de prédiction ont été utilisées pour déterminer la durée de vie des cibles EPA pour divers projectilesDue to its optical properties, glass is often essential for optical systems but its inability to undergo large deformations makes it particularly sensitive to high velocity impacts (HVI). The objective of this PhD consist in characterising and modelling damages and matter ejection induced by such impacts on thin monolithic targets (LMJ Disposable Debris Shields, DDS) or multilayered targets (solar cells). An important effort is dedicated to experimental activities including characterisation of fused silica behaviour under shock loadings and of damages induced by 3D HVI (VProj £ 3. 5km/s) on thin brittle targets. SEM and metrological analyses of impacted targets as well as innovating characterisation methods of ejected clouds allowed a better understanding of ejection processes. This phenomenological observation led to improvements of the LS-DYNA Johnson-Holmquist material model (JH-2). This modified model has been coupled with an SPH method and allows to reproduce effects of fragmentation and permanent densification under planar shock loadings. The 2nd part of this work presents the results of 3D modelling activity corresponding to CNES & CEA applications. It has been performed to assess ballistic performances (spallation & perforation), to reproduce damages and matter ejection observed on DDS and solar cells. 3D numerical simulations allowed to identify actual limitations of the code which provides satisfying results for damaging and ejection phenomenology for the range 0-5 km/s. The modelling tool has been used to predict ballistic limits and ejection tendencies due to impact on 2 mm DDS involving various projectiles (shape, material, velocity) in the validated range
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Mullen, Steven. "Analysis of hypervelocity impacts on the thermal blankets of the ultra heavy cosmic ray experiment from the long duration exposure facility." Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267412.
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Raffray, Yoann. "Comportement dynamique sous choc laser de verres métalliques base zirconium : D'une étude macroscopique pour des impacts hypervéloces à une étude microscopique sur la piste de changements structuraux." Electronic Thesis or Diss., Université de Rennes (2023-....), 2023. http://www.theses.fr/2023URENS100.
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La constante augmentation du nombre de petits débris spatiaux (≈1 mm) motive l’étude du comportement sous choc de matériaux innovants pour renforcer les blindages des structures spatiales actuellement utilisées. De précédentes études ont mis en lumière le potentiel des verres métalliques base zirconium comme matériaux de blindage lors d’expérience d’impacts hypervéloces sur une configuration de type Whipple. Dans ces travaux sur le comportement dynamique de verres métalliques du système ZrCuAl, nous avons fait le choix d’utiliser des lasers de puissance comme générateur de chocs plutôt que des lanceurs notamment pour atteindre des vitesses de déformation plus élevées (> 2×10⁷ s⁻¹) et, surtout, plus représentatives de celles générées lors d’impacts de débris spatiaux hypervéloces. Des campagnes expérimentales sur les installations du Laboratoire pour l’Utilisation des Lasers Intenses et du CEA ont permis : de compléter les courbes d’Hugoniot de verres métalliques massiques et sous forme de rubans ; de mettre en évidence une évolution de la limite à rupture avec la vitesse de déformation atteignant 13,6 GPa, soit presque 7 fois la valeur en quasi-statique ; d’observer de la cristallisation sous choc de la composition Zr₅₀ Cu₄₀ Al₁₀ avec des mesures de DRX sous choc ; et enfin de construire une équation d’état basée sur le modèle de Mie-Grüneisent référencée à l’isotherme de BirchThe constant augmentation of small sizes space debris (≈1 mm) incites the study of innovative materials behaviour under shock compression to reinforce the actual space structure shields. Previous studies have highlighted the potential of Zirconium-based metallic glasses as shielding components with hypervelocity impact experiments on a Whipple shield configuration. In this work on the dynamic behaviour of metallic glasses from the ZrCuAl system, we have chosen to use high-power lasers as shock generator rather than launchers, in particular to achieve higher strain rates (> 2×10⁷ s⁻¹) and, above all, more representative of those generated during hypervelocity impacts of space debris. Experimental campaigns on Laboratoire pour l’Utilisation des Lasers Intenses and CEA facilities have made it possible to: complete the Hugoniot curves for bulk metallic glasses and ribbons metallic glasses; to highlight an evolution of the spall strength with the strain rate reaching 13.6 GPa, i.e. almost 7 times the quasi-static value; to observe crystallisation of Zr₅₀ Cu₄₀ Al₁₀ composition with XRD measurements under shock compression; and finally to build an equation of state based on Mie-Grüneisen’s model considering the Birch’s isotherm formulation as a reference
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Osinski, Gordon Richard. "Hypervelocity impact into sedimentary targets: Process and products." Thesis, 2004. http://hdl.handle.net/1882/163.
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This investigation focuses on two well-preserved impact structures developed in sedimentary target rocks: the ~23.5 Ma old Haughton structure, Canada, and the ~14.5 Ma old Ries structure, Germany. The aim of this study was to investigate the effects of hypervelocity impact into sedimentary targets. The study reveals that a series of different impactites are present at Haughton, the bulk of which comprise a groundmass of impact-generated melts (calcite + silicate glass ± anhydrite). Thus, carbonates, evaporites, sandstones, and shales underwent shock melting during the Haughton impact event. The shock melting of impure carbonates resulted in the generation of Mg–Ca–Si-rich melts that crystallized calcite during rapid cooling. The residual melt quenched to Mg–Si-rich glass. These impactites should, therefore, be classified as clast-rich impact melt rocks or impact melt breccias, and not clastic matrix breccias as previously held. Ries surficial suevites are reinterpreted as clast-rich impact melt rocks or impact melt breccias. Four main types of impact melt glass are present, in contrast to previous studies that recognized only one type. These results are at odds with the current, generally accepted, definition of suevite. Given that the Ries is the original type occurrence of ‘suevite’, some redefinition of the term suevite may be in order. Furthermore, it is clear that sedimentary rocks, as well as crystalline rocks, were shock melted during the Ries impact event. The results of this study are, therefore, incompatible with previous models in which the zone of melting is restricted to the crystalline basement. It is apparent that impact melting in sedimentary targets is much more common than previously thought. Furthermore, there is no unequivocal evidence for the decomposition of carbonates or evaporites at any terrestrial impact site. Many previous assumptions about the response of sedimentary rocks during hypervelocity impact events are, therefore, incorrect. The products of impact into sedimentary targets may appear very different from those developed in crystalline targets. However, microscopic imaging and analysis suggests that these seemingly different lithologies may be genetically equivalent. Thus, the apparent ‘anomaly’ between the amount of impact melt rocks formed in sedimentary and crystalline targets may be due to a misinterpretation of the rock record.
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Lamberson, Leslie Elise. "Dynamic Optical Investigations of Hypervelocity Impact Damage." Thesis, 2010. https://thesis.library.caltech.edu/5888/1/Lamberson_Thesis_FINAL.pdf.
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One of the prominent threats in the endeavor to develop next-generation space assets is the risk of space debris impact in earth’s orbit and micrometeoroid impact damage in near-earth orbit and deep space. To date, there is no study available which concentrates on the analysis of dynamic crack growth from hypervelocity impacts on such structures, resulting in their eventual catastrophic degradation. Experiments conducted using a unique two-stage light-gas gun facility have examined the in situ dynamic fracture of brittle polymers subjected to this high-energy-density event. Optical techniques of caustics and photoelasticity, combined with high-speed photography up to 100 million frames per second, analyze crack growth behavior of Mylar and Homalite 100 thin plates after impact by a 1.8 mm diameter nylon 6-6 right cylindrical slug at velocities ranging from 3 to 7 km/s (7000–15500 mph). Crack speeds in both polymers averaged between 0.2 and 0.47 cR, the Rayleigh wave speed (450–1000 mph). Shadow spots and surrounding caustics reveal time histories of the dynamic stress intensity factor, as well as the energy release rate ahead of the mode-I, or opening, crack tips. Results indicate that even under extreme impact conditions of out of-plane loading, highly localized heating, and energetic impact phenomena involving plasma formation and ejecta, the dynamic fracture process occurs during a deformation regime dominated by in-plane loading. These findings imply that the reliability of impacted, thin-walled, plate and shell space structures, idealized by the experimental configuration investigated, can be predicted by the well defined principles of classical dynamic fracture mechanics.
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Smith, James Pope. "Hypervelocity impact on strain-rate sensitive shielded plates." Thesis, 1993. http://hdl.handle.net/1911/13785.
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A ballistic limit equation for hypervelocity impact on thin plates is derived analytically. This equation applies to cases of impulsive impact on a plate that is protected by a multi-shock shield, and is valid in the range of velocity above 6 km/s. Experimental tests were conducted at the NASA Johnson Space Center on square aluminum plates. Comparing the center deflections of these plates with the theoretical deflections of a rigid-plastic plate subjected to a blast load, one determines the dynamic yield strength of the plate material. The analysis is based on a theory for the expansion of the fragmented projectile and on a simple failure criterion. Curves are presented for the critical projectile radius versus the projectile velocity, and for the critical plate thickness versus the velocity. These curves are in good agreement with curves that have been generated empirically.
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Cruz, Banuelos Jose Santiago. "Ballistic limit equation for hypervelocity impact on composite-orthotropic materials." Thesis, 2004. http://hdl.handle.net/1911/18618.
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Two new ballistic limit equations for hypervelocity impact on homogeneous and composite-orthotropic materials have been developed for a velocity range above 6 km/s. The methodology used to develop the ballistic limit equations involves Kirchhoff's plate theory for a two plate fundamental structure comprising a shield and back plate. The Boundary Element Method is used to calculate the deformation and the moments when the load, is uniformly distributed over a circular area of the back plate, and is applied quickly so that the momentum transferred to the loaded area is equal to twice the momentum of the original projectile. The Von Mises yield criterion is used to account for elastic-plastic deformations into homogeneous materials and the Tsai-Hill yield criterion is used to account for elastic-plastic deformations into composite-orthotropic materials. The ballistic limit equations developed are compared with existing ballistic limit equations based on empirical and semi empirical formulations. It can be seen that our results are in good agreement with experimental measurements of spherical projectiles impacted on a two-plate shield at hypervelocity.
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Mihaly, Jonathan Michael. "Investigation of Hypervelocity Impact Phenomena Using Real-time Concurrent Diagnostics." Thesis, 2013. https://thesis.library.caltech.edu/7869/1/Mihaly_Jonathan_2013_thesis.pdf.
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Hypervelocity impact of meteoroids and orbital debris poses a serious and growing threat to spacecraft. To study hypervelocity impact phenomena, a comprehensive ensemble of real-time concurrently operated diagnostics has been developed and implemented in the Small Particle Hypervelocity Impact Range (SPHIR) facility. This suite of simultaneously operated instrumentation provides multiple complementary measurements that facilitate the characterization of many impact phenomena in a single experiment. The investigation of hypervelocity impact phenomena described in this work focuses on normal impacts of 1.8 mm nylon 6/6 cylinder projectiles and variable thickness aluminum targets. The SPHIR facility two-stage light-gas gun is capable of routinely launching 5.5 mg nylon impactors to speeds of 5 to 7 km/s. Refinement of legacy SPHIR operation procedures and the investigation of first-stage pressure have improved the velocity performance of the facility, resulting in an increase in average impact velocity of at least 0.57 km/s. Results for the perforation area indicate the considered range of target thicknesses represent multiple regimes describing the non-monotonic scaling of target perforation with decreasing target thickness. The laser side-lighting (LSL) system has been developed to provide ultra-high-speed shadowgraph images of the impact event. This novel optical technique is demonstrated to characterize the propagation velocity and two-dimensional optical density of impact-generated debris clouds. Additionally, a debris capture system is located behind the target during every experiment to provide complementary information regarding the trajectory distribution and penetration depth of individual debris particles. The utilization of a coherent, collimated illumination source in the LSL system facilitates the simultaneous measurement of impact phenomena with near-IR and UV-vis spectrograph systems. Comparison of LSL images to concurrent IR results indicates two distinctly different phenomena. A high-speed, pressure-dependent IR-emitting cloud is observed in experiments to expand at velocities much higher than the debris and ejecta phenomena observed using the LSL system. In double-plate target configurations, this phenomena is observed to interact with the rear-wall several micro-seconds before the subsequent arrival of the debris cloud. Additionally, dimensional analysis presented by Whitham for blast waves is shown to describe the pressure-dependent radial expansion of the observed IR-emitting phenomena. Although this work focuses on a single hypervelocity impact configuration, the diagnostic capabilities and techniques described can be used with a wide variety of impactors, materials, and geometries to investigate any number of engineering and scientific problems.
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DeBord, John 1986. "Evaluation of Hypervelocity Gold Nanoparticles for Nanovolume Surface Mass Spectrometry." Thesis, 2012. http://hdl.handle.net/1969.1/148083.
Full textAbstract:
Impacts of high kinetic energy massive gold clusters (~ 500 keV Au400+4) exhibit significantly enhanced secondary ion yields relative to traditional atomic or polyatomic primary ions (e.g. Au3 and C60). The one-of-a-kind instrument used to generate these hypervelocity nanoparticles (~2 nm diameter, ~30 km/s) and monitor emissions from their impacts (SIMS) is described in detail for the first time.
The projectile range of 520 keV Au400+4 is measured to be ~20 nm in amorphous carbon and projectile disintegration is observed at the exit of carbon foils as thin as 5 nm. These experiments were performed by monitoring carbon cluster ions emitted from both sides of a foil impacted by the projectile. Surprisingly, clusters emitted in the forward direction are larger than those emitted backward. The composition of the mass spectra is shown to depend on both the thickness of the foil and the size of the projectile.
Secondary ion yields for a variety of materials including peptides, lipids, drugs, polymers, inorganic salts, and various small molecules have been measured and molecular ion yields for many of these species exceed unity. Multiplicity measurements show that up to seven molecular ions of leucine-enkephalin (YGGFL) can be detected from the impact of a single projectile. SI yields measured with ~500 keV Au400+4 are generally one to two orders of magnitude greater than those obtained with 130 keV Au3+ and 50 keV C60+ projectiles.
The high molecular ion yields observed suggest the internal energies of ions emitted from massive cluster impacts are relatively low. In order to address this hypothesis, a novel method for measuring secondary ion internal energies was developed using a series of benzylpyridinium salts. Using this method, the internal energies were measured to be ~0.19 eV/atom, which is a factor of five less than that seen in atomic-SIMS.
Sample metallization is shown to be ineffective for further increasing secondary ion yields with Au400, despite observations from previous molecular dynamic simulations. Coincidence mass spectrometry is applied to nanometric chemical segregations found on samples coated with thin layers of gold and silver. It is possible to measure the surface coverages of the metallic and underlying organic layers using mass spectrometry in a non-imaging mode.
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Espinoza, Magana Nancy. "Evaluation of superelastic nitinol as a shielding material for hypervelocity impact." Thesis, 1999. http://hdl.handle.net/1911/17262.
Full textAbstract:
Superelastic Nitinol Shape Memory Alloy (SMA) as a shielding material for hypervelocity impact is investigated. Impact peak pressures from Rankine-Hugoniot equations and empirical figures of merit, which give a general evaluation of this material as a nickel titanium alloy, have been derived. Superelastic Nitinol was impacted at oblique and normal incidence using a two-stage light-gas gun and was evaluated as an intermediate layer in the Stuffed Whipple configuration and as bumper in the Whipple configuration. Its performance during oblique impacts is better than that of Kevlar and Al2024-T3. Superelastic SMA can dissipate impact energy through a martensitic phase transformation and through plastic yielding. Differential scanning calorimeter studies demonstrated that stress induced Martensite (SIM) is present in the hypervelocity impacted samples. Optical metallography and electron microscopy studies confirm the presence of SIM.
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Smith, James Conrad Pope. "The use of shock physics to predict the mechanics of hypervelocity impact." Thesis, 2000. http://hdl.handle.net/1911/19557.
Full textAbstract:
Shielding of spacecraft is a concern in the design of modern space vehicles. Due to unplanned spacecraft failures and naturally occurring planetary matter, the space environment is littered with orbital debris. This orbital debris poses a real threat to the safety of humans in space and the structural integrity and mission success of spacecraft. Debris shields mitigate the damage caused by debris impacting objects at hypervelocity. An effective shield shocks the incoming projectile, causing the projectile to break and expand. The expansion causes the projectile's momentum to be spread over a larger volume, thereby decreasing its potential to damage. A model is developed to estimate the velocity, shape, and mass distribution of debris clouds that are produced by the impact of a projectile on a bumper at hypervelocity. Models are developed for both normal and oblique impact in terms of the material and geometrical properties of the projectile and target. The model utilizes the Hugoniot shock equations to predict the states of stress and velocity in the projectile and bumper.
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Shivarama, Ravishankar Ajjanagadde. "Hamilton's equations with Euler parameters for hybrid particle-finite element simulation of hypervelocity impact." Thesis, 2002. http://wwwlib.umi.com/cr/utexas/fullcit?p3108510.
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YANG, ZHAN-KUI, and 楊瞻魁. "Helical TEA-CO2 laser and simulation of hypervelocity impact by laser-generated impulse." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/90684453335296085049.
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Whitney, James Pliny III. "A method to determine the ballistic limits of shielded plates subjected to hypervelocity impact." Thesis, 1992. http://hdl.handle.net/1911/13659.
Full textAbstract:
Ballistic limit curves are determined by using experimental and theoretical results for the permanent deformation of a plate subjected to an impact load. The experiments have been performed on shielded plates of various thicknesses and materials at the Hypervelocity Impact Research Laboratory of NASA JSC. Comparison of the theoretical and experimental deformations allows one to determine the dynamic yield strength of the plate material. It is assumed that the shields can be replaced by a single equivalent shield, and that the debris cloud produced by the impact expands according to the theory of Swift. A strain criterion is imposed and ballistic limit equations describing the critical projectile radius and the critical backwall thickness are derived. The corresponding curves are plotted for the case of the most damaging impact conditions. Comparison is made with empirical limit curves that are available in the literature.
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Buettner, Douglas J. "Hypervelocity spectroscopy from impacts in polymeric materials." Thesis, 1991. http://hdl.handle.net/1957/38073.
Full textAbstract:
Stacked sheets of polyethylene terephthalate andpolystyrene provide a means
for recovering projectiles travelling at hypervelocities. The transparency of these
multiple diaphragms is utilized so that light generated from hypervelocity impacts
can be studied.
A method for gathering visible as well as ultraviolet light from less
transparent polymer foams has been confirmed. Distinct spectral characteristics
as well as a blackbody temperature can now be used as tools for characterizing the
response of polymer foams to hypervelocity impact.
The identification of newly discovered excited atomic transitions from the
incident projectile suggests a method for observing the thermal history of the
projectile as it progresses through the capture medium.Graduation date: 1991
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Eller, Michael. "Surface mapping based on the correlated emission of ions and electrons from hypervelocity C60 impacts." Thesis, 2012. http://hdl.handle.net/1969.1/148366.
Full textAbstract:
High resolution mapping of molecular species, specifically sub-micrometer spatial resolution mapping, is at the forefront of recent interest in Secondary Ion Mass Spectrometry (SIMS). Large projectiles, e.g. C60, Au400, display high quasi-molecular ion yields with reduced fragment ion yields compared to atomic or polyatomic projectiles. However, the application of large projectiles in a sub-micrometer beam is hampered by limitations in source brightness and angular emission characteristics which are incompatible with tight focusing. An alternate approach to a focused beam is to reduce the beam intensity to less than 1000 impacts per second (referred to as the event-by-event mode) and localize each projectile impact via an electron emission microscope. The characterization and performance of such an instrument for localizing individual projectile impacts of 15-75keV C60 with sub-micrometer spatial resolution are described here.
The quest for localizing single cluster impacts requires an understanding of the relationship between SI and electron emissions. It was found that electron emission is observed independently of the number or type of secondary ion emitted for flat homogeneous samples. The independence of ion and electron emission confirms the rationale for using the emitted electrons to localize individual projectile impacts. Further investigation of electron emission revealed that the electron yield is characteristic of the class of sample investigated (e.g. metal, organic, semiconductor). The electron yield was found to depend on the size and topology of the sample. Additionally, the electron yield increases with increasing projectile velocity.
The use of the novel instrumentation presented here, necessitated the development of custom acquisition and analysis software. The analysis of co-emitted species from nano-metric dimensions is enhanced with the ability to perform multiple coincidence/anti-coincidence calculations. New concepts were implemented for integrating localization and mass spectrometry via software solutions for image analysis and localization and subsequently correlation between emitted ions and electrons. The result is software and instrumentation capable of generating ion maps with sub-micrometer spatial resolution.
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Seram, Sai Bhargavi. "Use of SPH and Lagrangian meshing technique to assess damage area in bumper shields impacted by hypervelocity space debris." Thesis, 2007. http://hdl.handle.net/10057/1171.
Full textAbstract:
Space debris are objects in Earth’s orbit consisting of fragments of spent rocket stages, non-functional satellites, and parts like fasteners, paint chips and other waste materials in the lower earth orbits (LEO) (200 – 2000 km/s) traveling at hypervelocity with maximum speeds of 16 km/s. These objects can cause considerable damage to spacecraft structure, the Space Shuttle and the International Space Station which are orbiting around the earth at altitudes of 300 to 500 km/s in the LEO. Damage occurs when the debris traveling at hypervelocity impact (HVI) the spacecraft structure. Hence there is necessity to not only develop spacecraft with good shielding, but also develop a means of spacecraft pressure wall repair. A NASA EPSCoR grant for designing a portable friction stir welder to repair the hypervelocity impact damage caused was the driving force for this thesis topic. A detailed understanding of the extent of damage to the spacecraft shielding system was necessary to understand repair requirements expected for the design of a space-bound Friction Stir Welder. A spacecraft shielding system can consist of a double bumper shielding system placed ahead of the pressure wall. The current goal of this study was to determine the damage area of the pressure wall, using the new grid less Smoothed Particle Hydrodynamics (SPH) meshing techniques and the regular Lagrangian meshing technique. The approach was to model and validate the damage area due to the HVI against existing test data, and to conduct a parametric study for various impactor shapes, velocities and impact scenarios. The software tools used for modeling were PATRAN for the Lagrangian models and LS-Prepost for SPH modeling. The simulation was analyzed in LS-DYNA, a non-linear finite element dynamic analyzer. Simulations were initially conducted using a spherical projectile; later parametric studies were conducted with varied impactor shapes. The materials for the plate and impactor were alloys of Al (6061-T6, l100-O, 2024-T4). It was observed that the model developed using SPH meshing technique generated the debris cloud as in the actual impact scenario, unlike the Lagrangian meshing technique which had problems with mesh tangles. Hence the SPH technique provided a potential means of predicting pressure wall damage due to HVI.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.