Academic literature on the topic 'Space deformation techniques'
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Journal articles on the topic "Space deformation techniques"
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Yoshiyasu, Yusuke, and Nobutoshi Yamazaki. "Pose Space Surface Manipulation." International Journal of Computer Games Technology 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/596953.
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Example-based mesh deformation techniques produce natural and realistic shapes by learning the space of deformations from examples. However, skeleton-based methods cannot manipulate a global mesh structure naturally, whereas the mesh-based approaches based on a translational control do not allow the user to edit a local mesh structure intuitively. This paper presents an example-driven mesh editing framework that achieves both global and local pose manipulations. The proposed system is built with a surface deformation method based on a two-step linear optimization technique and achieves direct manipulations of a model surface using translational and rotational controls. With the translational control, the user can create a model in natural poses easily. The rotational control can adjust the local pose intuitively by bending and twisting. We encode example deformations with a rotation-invariant mesh representation which handles large rotations in examples. To incorporate example deformations, we infer a pose from the handle translations/rotations and perform pose space interpolation, thereby avoiding involved nonlinear optimization. With the two-step linear approach combined with the proposed multiresolution deformation method, we can edit models at interactive rates without losing important deformation effects such as muscle bulging.
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Sieger, Daniel, Sergius Gaulik, Jascha Achenbach, Stefan Menzel, and Mario Botsch. "Constrained space deformation techniques for design optimization." Computer-Aided Design 72 (March 2016): 40–51. http://dx.doi.org/10.1016/j.cad.2015.07.004.
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Aschieri, Paolo. "Deformation quantization of principal bundles." International Journal of Geometric Methods in Modern Physics 13, no. 08 (September 2016): 1630010. http://dx.doi.org/10.1142/s0219887816300105.
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We outline how Drinfeld twist deformation techniques can be applied to the deformation quantization of principal bundles into noncommutative principal bundles and, more in general, to the deformation of Hopf–Galois extensions. First, we twist deform the structure group in a quantum group, and this leads to a deformation of the fibers of the principal bundle. Next, we twist deform a subgroup of the group of automorphisms of the principal bundle, and this leads to a noncommutative base space. Considering both deformations, we obtain noncommutative principal bundles with noncommutative fiber and base space as well.
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Gasbarri, Paolo, Giovanni B. Palmerini, Giuliano Coppotelli, and Chiara Toglia. "Validation of attitude/deformation sensing techniques for space flexible manipulators." Acta Astronautica 64, no. 2-3 (January 2009): 212–21. http://dx.doi.org/10.1016/j.actaastro.2008.07.020.
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Robbins, J. W. "Geophysics 1990: Regional deformation and global tectonics from space geodetic techniques." Eos, Transactions American Geophysical Union 72, no. 14 (1991): 162. http://dx.doi.org/10.1029/90eo00125.
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Ilia, I., C. Loupasakis, and P. Tsangaratos. "ASSESSING GROUND SUBSIDENCE PHENOMENA WITH PERSISTENT SCATTERER INTERFEROMETRY DATA IN WESTERN THESSALY, GREECE." Bulletin of the Geological Society of Greece 50, no. 3 (July 27, 2017): 1693. http://dx.doi.org/10.12681/bgsg.11892.
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The main objective of the present study was to investigate ground subsidence in the wider area of Farsala, western Thessaly basin, by means of remote sensing techniques and to identify potential geo environmental mechanisms that contribute to the development of the observed surface fractures affecting the site. In this context, a set of Synthetic Aperture Radar (SAR) images, acquired in 1995-2003 by the European Space Agency (ESA) satellites ERS1 and ERS2 and processed with the Persistent Scatterer Interferometry (PSI) technique by the German Space Agency (DLR) during the Terrafirma project, were evaluated in order to investigate spatial and temporal patterns of deformation. Groundwater table levels of three water boreholes within the research area were processed providing the mean piezometric level drawdown and the mean annual drawdown rate. In addition, a quantitative comparison between the deformation subsidence rate and the thickness of the compressible sediments was also performed. The outcomes of the present study indicated a clear relationship in the subsidence deformation rate and the groundwater fluctuation and also a correlation between the depth of the bedrock and the deformation subsidence rate. Overall, the multitemporal SAR interferometry (DInSAR) data are proved as a valuable and suitable technique for increasing knowledge about the extent and the rate of the deformations in the current study area, proved to be affected with an increasing intensity.
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Li, Runguang, Youkang Wang, Xiaojing Liu, Shilei Li, Qing Tan, Wenjun Liu, Xing Fang, and Yan-Dong Wang. "Micromechanical behaviors related to confined deformation in pure titanium." MATEC Web of Conferences 321 (2020): 12018. http://dx.doi.org/10.1051/matecconf/202032112018.
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Confined deformation, e.g. mechanical twinning, shear banding, and Lüders banding, etc. was extensively observed in metals and alloys with low stacking-fault energies, especially under complex loadings, governing the mechanical properties. It is often accompanied with gradient microstructures to accommodate the stress concentrations. Understanding the micromechanical behaviors of structural materials having confined deformation is important for evaluating the structural stabilities of engineering components. Synchrotron-based techniques provide powerful tools for multiscale microstructural characterization owing to their good resolution in real/reciprocal space, fast data collection/processing and flexible application scenarios. In this paper, the synchrotron-based high-energy X-ray diffraction (HE-XRD) and microdiffraction (μXRD) techniques in combination with traditional characterization methods are used to reveal the deformational gradient structures/stresses under different loading modes in multiscale. The structure/stress gradients induced by laser shot peening treatment and the deformation twins generated during uniaxial tensile loading in pure titanium were systematically studied by HE-XRD and μXRD, in order to elucidate the accommodating role of the deformational structures subjected to various confined scenarios. The new finding regarding the micromechanical behaviors related to confined deformation contributes to the in-depth understanding of related complex deformation behaviors.
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Visentin, Silvia, Chiara Palermo, Martina Camerin, Luciano Daliento, Denisa Muraru, Erich Cosmi, and Luigi P. Badano. "Echocardiographic Techniques of Deformation Imaging in the Evaluation of Maternal Cardiovascular System in Patients with Complicated Pregnancies." BioMed Research International 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4139635.
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Cardiovascular diseases (CVD) represent the leading cause of maternal mortality and morbidity. Knowledge of CVD in women is constantly evolving and data are emerging that female-specific risk factors as complications of pregnancy are conditions associated with an increased risk for the long-term development of CVD. Echocardiography is a safe and effective imaging technique indicated in symptomatic or asymptomatic pregnant women with congenital heart diseases who require close monitoring of cardiac function. Deformation imaging is an echocardiographic technique used to assess myocardial function by measuring the actual deformation of the myocardium through the cardiac cycle. Speckle-tracking echocardiography (STE) is a two-dimensional (2D) technique which has been found to be more accurate than tissue Doppler to assess both left ventricular (LV) and right ventricular (RV) myocardial function. The use of 2D STE however might present some technical issues due to the tomographic nature of the technique and the motion in the three-dimensional space of the myocardial speckles. This has promoted the use of 3D STE to track the motion of the speckles in the 3D space. This review will focus on the clinical value of the new echocardiographic techniques of deformation imaging used to assess the maternal cardiovascular system in complicated pregnancies.
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Nurdin, A., N. W. Bressloff, A. J. Keane, and C. M. E. Holden. "Shape optimisation using CAD linked free-form deformation." Aeronautical Journal 116, no. 1183 (September 2012): 915–39. http://dx.doi.org/10.1017/s0001924000007351.
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AbstractFree-form deformation (FFD) is a method first introduced within the graphics industry to enable flexible deformation of geometric models. FFD uses an R3 to R3 mapping of a deformable space to the global Cartesian space to produce the geometry deformation. This method has been extensively used within the design optimisation field as a shape parameterisation technique. Typically it has been used to parameterise analysis meshes, where new design geometries are produced by deforming the original mesh. This method allows a concise set of design variables to be used while maintaining a flexible shape representation. However, if a computer aided design (CAD) model of the resulting geometry is required, reverse engineering techniques would need to be utilised to recreate the model from the deformed mesh. This paper extends the use of FFD within an optimisation routine by using FFD to directly parameterise a CAD geometry. Two methods of linking the FFD methods with the CATIA V5 CAD package are presented. Each CAD integration technique is then critiqued with respect to shape optimisation. Finally the set-up and initialisation of a case study is illustrated. The case study chosen is the aerodynamic optimisation of the wing-fuselage junction of a typical passenger aircraft.
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Govil, H., R. S. Chatterjee, K. Malik, P. Diwan, M. K. Tripathi, and S. Guha. "IDENTIFICATION AND MEASUREMENT OF DEFORMATION USING SENTINEL DATA AND PSINSAR TECHNIQUE IN COALMINES OF KORBA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-5 (November 19, 2018): 427–31. http://dx.doi.org/10.5194/isprs-archives-xlii-5-427-2018.
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<p><strong>Abstract.</strong> Natural Resources extraction for production of goods increases the stress on land and on the environment. Coal Mines are the primary source for energy production. This process increases the continuous deformation on land by disturbing equilibrium beneath the surface. Interferometry techniques have a capability to detect the minute deformation with millimetre precision on the ground using microwave SAR data. The study area covers the largest open cast coal mines of Asia. In this study for minute deformation identification, Persistent Scatterer Interferometry Synthetic Aperture Radar (PSInSAR) technique has been used. Research focuses on the application of PSInSAR technique for terrain deformation detection using 17 SAR scene of Korba, Chhattisgarh, India acquired by the Sentinel-1 satellite of European Space Agency. This technique is capable to monitor the minute deformation in the coal mines of Korba, Chhattisgarh, India. The results predicted that the area is deformed with the velocity up to 30 mm/year in the coal mines and surroundings areas. The PSInSAR technique with the Sentinel-1 data provides the proficient tool for deformation monitoring in coal mines of Korba.</p>
Dissertations / Theses on the topic "Space deformation techniques"
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Angelidis, Alexis, and n/a. "Shape modeling by swept space deformation." University of Otago. Department of Computer Science, 2006. http://adt.otago.ac.nz./public/adt-NZDU20060808.161349.
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In Computer Graphics, in the context of shape modeling on a computer, a common characteristic of popular techniques is the possibility for the artist to operate on a shape by modifying directly the shape�s mathematical description. But with the constant increase of computing power, it has become increasingly realistic and effective to insert interfaces between the artist and the mathematics describing the shape. While in the future, shape descriptions are likely to be replaced with new ones, this should not affect the development of new and existing shape interfaces. Space deformation is a family of techniques that permits describing an interface independently from the description. Our thesis is that while space deformation techniques are used for solving a wide range of problems in Computer Graphics, they are missing a framework for the specific task of interactive shape modeling. We propose such a framework called sweepers, together with a set of related techniques for shape modeling. In sweepers, we define simultaneous-tools deformation, volume-preserving deformation, topology-changing deformation and animated deformation. Our swept-fluid technique introduces the idea that a deformation can be described as a fluid. In fact, the sweepers framework is not restrained to shape modeling and is also used to define a new fluid animation technique. Since the motion of a fluid can be considered locally as rigid, we define a formalism for handling conveniently rigid transformations. To display shapes, we propose a mesh update algorithm, a point-based shape description and a discrete implicit surface, and we have performed preliminary tests with inverse-raytracing. Finally, our technique called spherical-springs can be used to attach a texture to our shapes.
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Armanjo, Jahanmehr. "The influence of microstructural deformations and defects on mechanical properties in cast aluminium components by using Digital Image Correlation Techniques (DICT)." Thesis, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28022.
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Digital image correlation techniques (DICT), a non-contact deformation measuring technique based on gray value digital images, have become increasingly used over the last years. By using the DIC technique during a tensile test, the deformation behavior of different engineering material under an applied load can be determined and analyzed. Digital images, acquired from a tensile test, can be correlated by using DICT software and from that the local or global mechanical properties can be calculated. The local or global mechanical properties determination of a flat test specimens are based on the displacements or changes in a previous stochastic sprayed or natural pattern. The used material for this purpose is cast silicon (Si) based aluminium (Al) component, designated as AlSi7Mg0.3 (Anticorodal-78 dv). The hypoeutectic Al- Si alloy is widely applicable for engine constructions, vehicle and aerospace constructions, shipbuilding, electrical engineering and constructions for food industry. There are many microstructural parameters in a binary system Al- Si alloys, which the mechanical properties can be depended on, for instance phase distribution, Secondary Dendrite Arm Spacing (SDAS), morphology of Si particles (Roundness) and microscopic defects or pores. All these parameters can contribute to enhance the proper mechanical performance (e.g. Strength and ductility) in the Al-Si cast components.
Book chapters on the topic "Space deformation techniques"
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Robbins, John W. "Regional Deformation and Global Tectonics from Space Geodetic Techniques." In Geophysics News 1990, 4–5. Washington, D.C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/sp029p0004.
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Robbins, John W., David E. Smith, and Chopo Ma. "Horizontal crustal deformation and large scale plate motions inferred from space geodetic techniques." In Contributions of Space Geodesy to Geodynamics: Crustal Dynamics, 21–36. Washington, D. C.: American Geophysical Union, 1993. http://dx.doi.org/10.1029/gd023p0021.
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Erman, Burak, and James E. Mark. "Segmental Orientation." In Structures and Properties of Rubberlike Networks. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195082371.003.0013.
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Segmental or molecular orientation refers to the anisotropic distribution of chain-segment orientations in space, due to the orienting effect of some external agent. In the case of uniaxially stretched rubbery networks, which will be the focus of this chapter, segmental orientation results from the distortion of the configurations of network chains when the network is macroscopically deformed. In the undistorted state, the orientations of chain segments are random, and hence the network is isotropic because the chain may undertake all possible configurations, without any bias. In the other hypothetically extreme case of infinite degree of stretching of the network, segments align exclusively along the direction of stretch. The mathematical description of segmental orientation at all levels of macroscopic deformation is the focus of this chapter. Segmental orientation in rubbery networks differs distinctly from that in crystalline or glassy polymers. Whereas the chains in glassy or crystalline solids are fully or partly frozen, those in an elastomeric network have the full freedom to go from one configuration to another, subject to the constraints imposed by the network connectivity. The orientation at the segmental level in glassy or crystalline networks is mostly induced by intermolecular coupling between closely packed neighboring molecules, while in the rubbery network intramolecular conformational distributions predominantly determine the degree of segmental orientation. The first section of this chapter describes the state of molecular deformation. In section 11.2, the simple theory of segmental orientation is outlined, followed by the more detailed treatment of Nagai and Flory. The chapter concludes with a discussion of infrared spectroscopy and the birefringence technique for measuring segmental orientation. For uniaxial deformation, the deformation tensor λ takes the form λ = diag(λ, λ-1/2, λ-1/2), where diag represents the diagonal of a square matrix, and λ is the ratio of the stretched length of the rubbery sample to its undeformed reference length. The first element along the diagonal of the matrix represents the extension ratio along the direction of stretch, which may be conveniently identified as the X axis of a laboratory-fixed frame XYZ. The other two elements refer to the deformation along two lateral directions, Y and Z.
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Kobayashi, Shiro, Soo-Ik Oh, and Taylan Altan. "Steady-State Processes of Extrusion and Drawing." In Metal Forming and the Finite-Element Method. Oxford University Press, 1989. http://dx.doi.org/10.1093/oso/9780195044027.003.0013.
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Except at the start and the end of the deformation, processes such as extrusion, drawing, and rolling are kinematically steady state. Steady-state solutions in these processes are needed for equipment design and die design and for controlling product properties. A variety of solutions for different conditions in extrusion and drawing have been obtained by applying the slip-line theory and the upper-bound theorems. Early applications of the finite-element method to the analysis of extrusion have been for the loading of a workpiece that fits the die and container, and for the extrusion of a small amount of it rather than extruding the workpiece until a steady state is reached. An exception is the work by Lee et al. for plane-strain extrusion with frictionless curved dies using the elastic-plastic finite-element method. In view of the computational efficiency, various numerical procedures particularly suited for the analysis of steady-state processes have been developed by several investigators. Shah and Kobayashi analyzed axisymmetric extrusion through frictionless conical dies by the rigid-plastic finite-element method. The technique involves construction of the flow lines from velocities and integration of strain-rates numerically along flow lines to determine the strain distributions. An improvement of the method was made by including friction at the die-workpiece interface. The steady-state deformation characteristics in extrusion and drawing were obtained as functions of material property, die-workpiece interface friction, die angle, and reduction. In kinematically transient or nonsteady-state forming problems, a mesh that requires continuous updating (Lagrangian) is used. In steady-state problems, a mesh fixed in space (Eulerian) is appropriate, since the process configuration does not change with time. For steady-state problems whose solutions depend on the loading history or strain history of the material, combined Eulerian-Lagrangian approaches are necessary. In deformation of rigid-plastic materials under the isothermal conditions, the solution obtained by the finite-element method is in terms of velocities and, hence, strain-rates. In the nonsteady-state processes, the effective strain-rates are added incrementally for each element to determine the effective strains after a certain amount of deformation.
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Erman, Burak, and James E. Mark. "Model Elastomers." In Structures and Properties of Rubberlike Networks. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195082371.003.0012.
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Until quite recently, there was relatively little reliable quantitative information on the relationship of stress to structure, primarily because of the uncontrolled manner in which elastomeric networks were generally prepared. Segments close together in space were linked irrespective of their locations along the chain trajectories, thus resulting in a highly random network structure in which the number and locations of the cross-links were essentially unknown. Such a structure is shown in figure 10.1. New synthetic techniques are now available, however, for the preparation of “model” polymer networks of known structure. More specifically, if networks are formed by end linking functionally terminated chains instead of haphazardly joining chain segments at random, then the nature of this very specific chemical reaction provides the desired structural information. Thus, the functionality of the cross links is the same as that of the end-linking agent, and the molecular weight Mc between cross-links and the molecular weight distribution are the same as those of the starting chains prior to their being end-linked. An example is the reaction shown in figure 10.2, in which hydroxyl-terminated chains of poly(dimethylsiloxane) (PDMS) are end-linked using tetraethyl orthosilicate. Characterizing the un-cross-linked chains with respect to molecular weight Mn and molecular weight distribution, and then carrying out the specified reaction to completion, gives elastomers in which the network chains have these characteristics; in particular, a molecular weight Mc between cross-links equal to Mn, a network chain-length distribution equal to that of the starting chains, and cross-links having the functionality of the end-linking agent. It is also possible to use chains having a known number of potential cross-linking sites placed as side chains along the polymer backbone, so long as their distribution is known as well. Because of their known structures, such model elastomers are now the preferred materials for the quantitative characterization of rubberlike elasticity. Such very specific cross-linking reactions have also been shown to be useful in the preparation of liquid-crystalline elastomers. Trifunctional and tetrafunctional PDMS networks prepared in this way have been used to test the molecular theories of rubber elasticity with regard to the increase in non-affineness of the network deformation with increasing elongation.
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Erman, Burak, and James E. Mark. "Networks Having Multimodal Chain-Length Distributions." In Structures and Properties of Rubberlike Networks. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195082371.003.0015.
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As was mentioned in chapter 10, end-linking reactions can be used to make networks of known structures, including those having unusual chain-length distributions. One of the uses of networks having a bimodal distribution is to clarify the dependence of ultimate properties on non-Gaussian effects arising from limited-chain extensibility, as was already pointed out. The following chapter provides more detail on this application, and others. In fact, the effect of network chain-length distribution, is one aspect of rubberlike elasticity that has not been studied very much until recently, because of two primary reasons. On the experimental side, the cross-linking techniques traditionally used to prepare the network structures required for rubberlike elasticity have been random, uncontrolled processes, as was mentioned in chapter 10. Examples are vulcanization (addition of sulfur), peroxide thermolysis (free-radical couplings), and high-energy radiation (free-radical and ionic reactions). All of these techniques are random in the sense that the number of cross-links thus introduced is not known directly, and two units close together in space are joined irrespective of their locations along the chain trajectories. The resulting network chain-length distribution is unimodal and probably very broad. On the theoretical side, it has turned out to be convenient, and even necessary, to assume a distribution of chain lengths that is not only unimodal, but monodisperse! There are a number of reasons for developing techniques to determine or, even better, control network chain-length distributions. One is to check the “weakest link” theory for elastomer rupture, which states that a typical elastomeric network consists of chains with a broad distribution of lengths, and that the shortest of these chains are the “culprits” in causing rupture. This is attributed to the very limited extensibility associated with their shortness that is thought to cause them to break at relatively small deformations and then act as rupture nuclei. Another reason is to determine whether control of chain-length distribution can be used to maximize the ultimate properties of an elastomer. As was described in chapter 10, a variety of model networks can be prepared using the new synthetic techniques that closely control the placements of crosslinks in a network structure.
Conference papers on the topic "Space deformation techniques"
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Scott, Mark I., Mitra N. Sexton, David M. Stubbs, and Ab Hashemi. "Thermal Deformation Prediction and Measurement of Space Optical Systems." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80174.
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A computational and experimental study of the thermal and thermally induced deformation of a plano mirror undergoing mW heat loading was performed to verify the capability to model the response of a representative imaging optic on the Space Interferometry Mission (SIM) spacecraft. Novel state of the art experimental and computational techniques provided milliKelvin and picometer precision in temperature and deformation prediction and experimental measurement. Mirrors of two different substrates, initially at ambient temperature under vacuum, were subjected to a thermal loading profile representing flight-like and overdrive thermal disturbance conditions. The experimental setup measured milliKelvin level temperature changes and picometer level deformation responses. I-deas / TMG was used to generate an integrated model to predict milliKelvin level changes in temperature of the mirror and picometer level deformation responses of the mirror surface. This paper focuses on the thermally induced deformation modeling and correlation to experimental data for the optical system. Comparison between experimental results and computational models for the deformation aspects of the test agreed well for the fused silica test mirror. In particular for the flight-like regime of primary interest, agreement between the experimental deformations and computational deformation results was within 18%. However the experimental results for the deformation of the Zerodur mirror presented challenges in prediction by the computational models. This is partly attributed to the low value of Zerodur CTE which affects numerical precision and partly due to non-homogeneity of the CTE which is neither modeled nor measured. Bi-material affect of coating was also investigated and found to be a potential source of discrepancy. Further studies regarding computational methods for Zerodur deformation are planned.
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Sexton, Mitra N., Mark I. Scott, David M. Stubbs, and Ab Hashemi. "Integrated Thermal Deformation Modeling and Measurement of Space Optical Systems." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72816.
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A computational and experimental study of the thermal, response and thermally induced deformation of a circular plano mirror (101.6 mm in diameter) undergoing mW heat loading was performed to verify the capability to model the response of a representative imaging optic on the Space Interferometry Mission (SIM) spacecraft. Novel state of the art experimental and computational techniques provided milliKelvin and picometer precision in temperature and deformation prediction and experimental measurement. Mirrors of two different substrates, initially at ambient temperature, were subjected to nominal thermal loading profiles of three 5 hour steps of 12 mW, 54 mW, and 295 mW respectively, representing flight-like and overdrive thermal disturbance conditions. The experimental setup measured milliKelvin level temperature changes using the mKTMS (milliKelvin Temperature Measurement System) instrument and picometer level deformation responses using the CoPHI (Common Path Heterodyne Interferometer) instrument. I-deas/TMG was used to generate an integrated model to predict milliKelvin level temperature changes of the mirror and picometer level deformation responses of the mirror surface. This paper focuses on the thermal modeling and correlation to thermal experimental data of the optical system. Comparison between experimental results and computational models for the thermal aspects of the test show good agreement for the two test mirror materials, fused silica and Zerodur. In particular for the flight-like regime of primary interest, agreement between the experimental temperatures and computational thermal results was within 14%.
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Zhao, Yanbing, and Haixiao Liu. "Key Techniques in Simulating Comprehensive Anchor Behaviors by Large Deformation Finite Element Analysis." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61348.
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With the application of innovative anchor concepts and advanced technologies in deepwater moorings, anchor behaviors in the seabed are becoming more complicated, such as 360-degree rotation of the anchor arm, gravity installation of anchors with high soil strain rate, and keying and diving (or penetration) of anchors. As a very important component of the installation or mooring system, anchor line connects the anchor and the anchor handling vessel (AHV) or floating moored platform. With moving of the AHV or platform, anchor line produces a space movement, and forms a reverse catenary shape and even a three-dimensional profile in the soil. Numerical analysis on the behaviors of anchor lines and deepwater anchors requires techniques that can deal with large strains and deformations of the soil, track changes in soil strength due to soil deformation, strain rate and strain softening effects, appropriately describe anchor-soil friction, and construct structures with connector elements to conform to their characteristics. Being an effective tool of large deformation finite element analysis, the coupled Eulerian-Lagrangian (CEL) method is advantageous in handling geotechnical problems with large deformations, where a traditional Lagrangian analysis is coupled with an Eulerian phase of material advection. This paper gives an overview of several key techniques in the CEL analysis of comprehensive behaviors of deepwater anchors, including construction of the embedded anchor line and the anchor line in the water, installation of gravity installed anchors (GIAs), keying or diving of drag anchors and GIAs, and implementation of the omni-directional arm of GIAs. Numerical probe tests and comparative studies are also presented to examine the robustness and accuracy of the proposed techniques. The aim of this paper is to provide a numerical framework to analyze the comprehensive behaviors of anchor lines and deepwater anchors.
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Awazu, Shigeru, Satoshi Matsumoto, and Yutaka Abe. "Study on Nonlinear Deformation Behaviors of Electrostatic Levitating Liquid Drop." In ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37193.
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Under the micro-gravity environment in space, it is possible to hold a liquid drop without using container. The electrostatic levitation is one of the containerless processing techniques. Using this technique, thermo-physical properties of extreme high temperature molten metals have been measured. For example, the surface tension and viscosity have been estimated from the resonance frequency and the damping constant respectively with an oscillating drop method. This method is based on theoretical equations derived under linear approximations. However, an actual levitating drop includes nonlinear effects. Nonlinear effects should be taken into account for highly precise measurements of physical properties, but it is unknown experimentally. The purpose of the present study is to investigate nonlinear effects of a levitating liquid drop from fluid-dynamic point of view. In the present study, at first, axisymmetric oscillation was applied to a liquid drop levitated by electrostatic force and the oscillation frequency was related to the oscillation amplitude. Next, the rotation in the horizontal direction was applied. The drop deformation and the dependence of resonance frequency on rotational angular velocity were investigated. These experimental results agreed with theoretical predictions.
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Yeh, Tsung-Pin, and Judy M. Vance. "Applying Virtual Reality Techniques to Sensitivity-Based Structural Shape Design." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/dac-3765.
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Abstract Virtual reality (VR) provides a design space consisting of three-dimensional computer images where participants can interact with these images using natural human motions in real time. In the field of engineering design, prototyping and design verification have provided the initial application areas for VR. The research presented in this paper takes the scenario one step further by incorporating free-form deformation techniques and sensitivity analysis into the virtual world such that the designer can easily implement analysis-based shape design of a structural system where stress considerations are important. NURBS-based free-form deformation (NFFD) methods and direct manipulation techniques are used as the interface between the VR interaction and the finite element model. Sensitivity analysis is used to allow the designer to change the design model and immediately view the effects without performing a re-analysis. An engine connecting rod is analyzed to demonstrate how virtual reality techniques can be applied to structural shape design.
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Liauzun, Ce´dric. "Aeroelastic Response to Gust Using CFD Techniques." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30153.
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A numerical method to predict the aeroelastic response of an aircraft to a gust is assessed. It is based on the use of CFD techniques to compute accurately the aerodynamic fields. Gust models are then implemented as a field of grid deformation speed, that depends on both space and time. The numerical method has been first validated for a 2D Naca12 airfoil embedded in an inviscid flow and submitted to a sharp edged gust, by comparisons with results presented by Zaide et al. It has afterwards been validated in the case of a 3D wing submitted to a harmonic gust in the subsonic domain by comparisons with computations using the Doublet Lattice Method. After the validation step, the method has been used first to investigate the influence of the aerodynamic nonlinearities that occurs in the transonic domain, and at last to compute the aeroelastic responses of wings to gust excitations.
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Fialko, Sergiy, and Viktor Karpilowskyi. "Spatial thin-walled reinforced concrete structures taking into account physical nonlinearity in SCAD software. Rod finite element." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.086.
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This paper considers a spatial frame bar finite element for modeling reinforced concrete beams and columns. Both concrete and reinforcement are described by the equations of the deformation theory of plasticity and the theory of plastic flow. Degradation of concrete during cracking is modeled by the descending branch of the σ – ε diagram (the deformation theory of plasticity), as well as the compression of the yield surface and its displacement in the space of principal stresses (the plastic flow theory). The longitudinal reinforcement is considered discretely. It is assumed that there is no reinforcement slipping in concrete. The paper provides the results of the studies that reveal the causes of computational instability related to the presence of a descending branch of the σ – ε diagram for concrete, and proposes ways to overcome it. The reliability of the obtained results is confirmed by comparing them with the results of experimental studies performed by other researchers, as well as with the results of numerical solutions obtained by the particle method. This paper also provides an example of the nonlinear analysis of the fragment of a multi-storey building from the SCAD Soft collection of problems (www.scadsoft.com).
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Miyoshi, K., K. W. Street, and R. L. Vander Wall. "Contact and Surface Problems in Adhesion, Friction, Indentation, and Cavitation Erosion Related to Space and Aeronautics Lubrication." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63253.
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This paper presents fundamental studies and observations of the adhesion, friction, deformation, and fracture behavior of solid surfaces undergoing solid-to-solid contact and liquid-to-solid contact. Emphasis is on the basic material and structural characteristics, as well as the surface effects, in the tribological phenomena. First, the adhesion and friction behaviors of smooth, atomically clean surfaces of solid-solid couples in a clean environment are presented, and the friction mechanisms are described in terms of surface energy and ductility. The roles of interface species (dispersed carbon nanotubes as well as contaminant and oxide layers) are also considered. The importance of surface analytical techniques used both to understand the phenomena and mechanisms of adhesion, friction, deformation, and fracture and to define the associated problems is addressed. Secondly, deformation behavior of single crystals, such as MgO, subjected to hardness indentation and cavitation erosion is discussed. How the deformation behavior relates to crystal orientation and distribution of dislocations is explained. Thirdly, crack patterns in ceramics, such as diamond, generated by spherical indenters under normal loading are discussed in relation to the structures, impurities, and properties of the ceramics.
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Koohestani, Afshin, and John P. T. Mo. "The Application of Image Correlation in Order to Define Chatter During Milling of Titanium." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87289.
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Self-excited vibration or chatter is the main barrier against milling process. Many techniques have been proposed in order to detect chatter during milling. However, they have some limitations in detection of chatter or using in industry. This paper addresses if can detect chatter during milling process using image correlation. Image correlation is a method of tracking and image registration for 2D and 3D measurements of changes in images. This method is often used to measure any deformation, displacement, or define any changes during an engineering process. At this research, Poincaré sections are plotted for milling system by reconstruction of phase space. Then, variation of Poincaré maps is measured and parameterized by image correlation technique using Pearson coefficient.
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Al-Rubaiai, Mohammed, Ryohei Tsuruta, Taewoo Nam, Umesh Gandhi, and Xiaobo Tan. "Direct Printing of a Flexible Strain Sensor for Distributed Monitoring of Deformation in Inflatable Structures." In ASME 2019 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/smasis2019-5713.
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Abstract Inflatable structures provide significant volume and weight savings for future space and soft robotic applications. Structural health monitoring (SHM) of these structures is essential to ensuring safe operation, providing early warnings of damage, and measuring structural changes over time. In this paper, we propose the design of a single flexible strain sensor for distributed monitoring of an inflatable tube, in particular, the detection and localization of a kink should that occur. Several commercially available conductive materials, including 3D-printing filaments, conductive paint, and conductive fabrics are explored for their strain-sensing performance, where the resistance change under uniaxial tension is measured, and the corresponding gauge factor (GF) is characterized. Flexible strain sensors are then fabricated and integrated with an inflatable structure fabric using screen-printing or 3D-printing techniques, depending on the nature of the raw conductive material. Among the tested materials, the conductive paint shows the highest stability, with GF of 15 and working strain range of 2.28%. Finally, the geometry of the sensor is designed to enable distributed monitoring of an inflatable tube. In particular, for a given deformation magnitude, the sensor output shows a monotonic relationship with the location where the deformation is applied, thus enabling the monitoring of the entire tube with a single sensor.