Rozprawy doktorskie na temat „Damping”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Damping.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Damping”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Olsen, Mary W., i Deborah Young. "Damping Off". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011. http://hdl.handle.net/10150/144802.
Pełny tekst źródłaStreszczenie:
2 pp.Originally published: 1998
Damping off is caused by several different fungi under different environmental conditions. The fungi include Pythium, Rhizoctonia solani, and Thielaviopsis basicola. This article discusses the symptoms, environmental conditions, diseases, prevention and control methods for the damping-off caused by fungi.
2
Rappeline, Peter Frederick. "The microstructural basis of damping in high damping alloys". Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/27132.
Pełny tekst źródła
3
Penetrante, Wendel D. "Calculating required substructure damping to meet prescribed system damping levels". Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FPenetrante.pdf.
Pełny tekst źródłaStreszczenie:
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2007.Thesis Advisor(s): Joshua Gordis. "June 2007." Includes bibliographical references (p. 73-74). Also available in print.
4
Prandina, Marco. "Spatial damping identification". Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533930.
Pełny tekst źródła
5
Dew, Dwight D. "Strain dependent damping characteristics of a high damping manganese-copper alloy". Thesis, Monterey, California: U.S. Naval Postgraduate School, 1986. http://hdl.handle.net/10945/22121.
Pełny tekst źródła
6
Labonnote, Nathalie. "Damping in Timber Structures". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18168.
Pełny tekst źródłaStreszczenie:
Key point to development of environmentally friendly timber structures, appropriate to urban ways of living, is the development of high-rise timber buildings. Comfort properties are nowadays one of the main limitations to tall timber buildings, and an enhanced knowledge on damping phenomena is therefore required, as well as improved prediction models for damping. The aim of this work has consequently been to estimate various damping quantities in timber structures. In particular, models have been derived for predicting material damping in timber members, beams or panels, or in more complex timber structures, such as floors. Material damping is defined as damping due to intrinsic material properties, and used to be referred to as internal friction. In addition, structural damping, defined as damping due to connections and friction in-between members, has been estimated for timber floors. The thesis consists of six main parts. The first part is entitled “Contexts”, and is composed of four chapters. A general overview of the wood material and its structural use in buildings is presented in Chapter 1. Chapter 2 gives a thorough literature review on comfort properties of (timber) floors. Chapter 1 and Chapter 2 serve as justifications for the motivation of this work, expressed in Chapter 3, and the aim of the work, expressed in Chapter 4. The next part “Backgrounds” briefly describes the basic theories used along the thesis, for the analytical studies (Chapter 5), the experimental studies (Chapter 6), and the numerical studies (Chapter 7). The part “State of the art” is a general literature review on damping (Chapter 8). A particular accent is set on the derivation of various damping prediction models. The “Research” part summarizes the original research work. Chapter 9 briefly presents the background and main findings for each study, and Chapter 10 concludes and proposes suggestions for further research. The studies are detailed in four journal papers, which are integrally reported in the “Publications” part. Paper I focuses on the evaluation of material damping in timber beam specimens with dimensions typical of common timber floor structures. Using the impact test method, 11 solid wood beams and 11 glulam beams made out of Norway Spruce (Picea Abies) were subjected to flexural vibrations. The tests involved different spans and orientations. A total of 420 material damping evaluations were performed, and the results are presented as mean values for each configuration along with important statistical indicators to quantify their reliability. The consistency of the experimental method was validated with respect to repeatability and reproducibility. General trends found an increasing damping ratio for higher modes, shorter spans, and edgewise orientations. It is concluded from the results that material damping is governed by shear deformation, which can be expressed more conveniently with respect to the specific mode shape and its derivatives. Paper II deals with the prediction of material damping in Timoshenko beams. Complex elastic moduli and complex stiffness are defined to derive an analytical model that predicts the hysteretic system damping for the whole member. The prediction model comprises two parts, the first related to bending, and the second related to shear. Selected experimental damping evaluations from Paper I are used to validate the model and obtain fitted values of loss factors for two types of wood. The good agreement of the derived model with experimental data reveals an efficient approach in the prediction of material damping. In Paper III, a semi-analytical prediction model of material damping in timber panels is described. The approach is derived from the strain energy method and input is based on loss factors, which are intrinsic properties of the considered materials, together with material properties and mode shape integrals, whose calculation can easily be implemented in most finite element codes. Experimental damping evaluations of three types of timber panels are performed. These are particleboards, oriented strand board panels and structural laminated veneer panels. Fair goodness-of-fit between the experimental results and the prediction models reveals an efficient approach for the prediction of material damping in timber panels with any boundary conditions, knowing only the loss factors and the mode shapes. In Paper IV, dynamic properties of two timber floors are experimentally evaluated by impact method. Each floor uses one specified type of connectors, either screws or nails. A numerical model is developed using constrained degrees-of-freedom for the modeling of connectors. Numerical analyses have been performed, and show good agreement with experimental results. A procedure is written using the commercial finite element software Abaqus to predict material damping from a strain energy approach. Estimation of structural damping is performed as the difference between the experimentally evaluated total damping and the predicted material damping. The contribution from floor members to material damping is extensively investigated, and the needs for better prediction of damping are discussed. Specific details of some aspects of the work are included in the “Appendix” part.
7
Messalti, Mansour. "Viscoelastic damping of beams /". Online version of thesis, 1988. http://hdl.handle.net/1850/10414.
Pełny tekst źródła
8
André, Samuel. "Optimization of Valve Damping". Thesis, Linköpings universitet, Fluida och mekatroniska system, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-104862.
Pełny tekst źródłaStreszczenie:
Öhlins CES Technologies in Jönköping have in the last 30 years been developing control valves for semi active suspension systems used in the car industry. The system, marketed by Öhlins under the brand name CES (Continuously controlled Electronic Suspension), enables a wide working range and ability to adapt to the current road conditions. By controlling the valve in different ways there are also possibilities to decide on a specfic damper characteristic such as sport or comfort. The CES valve is working as a pilot controlled pressure regulator and is continuously controlled with help of an electro magnet. The CES valve is mounted in a uniflow damper which in turn guarantees the flow through the valve to go in only one direction independently ofdamper stroke direction. The rst part of the thesis investigates the damping characteristics in the latest model of the CES valve (i.e the CES8700). A simulation model is made to approximate the damping in the solenoid plunger. Questions that are answered are: How is damping dened, what creates damping in the valve, how large is the damping, what parameters aect the damping. The second part of the thesis investigates new and already prototyped damping concepts with help of simulation. This has been done in order to optimize the valve damping and in turn the damper performance. The simulation results show that the valve dynamics can be improved but often at the expense of a slower valve.
9
Hsu, Yi-Chu. "Damping treatments for microstructures /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/7054.
Pełny tekst źródła
10
Muratani, Keiichi, Satoshi Kito, Yoshito Itoh, Yasuo Kitane i Paramashanti. "Experimental investigation of aging effect on damping ratio of high damping rubber bearing". 土木学会, 2011. http://hdl.handle.net/2237/18847.
Pełny tekst źródła
11
MORENO, FRANCO OLMO ALONSO. "The Shape of Damping: Optimizing Damping Coefficients to Improve Transparency on Bilateral Telemanipulation". Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/939640.
Pełny tekst źródłaStreszczenie:
This thesis presents a novel optimization-based passivity control algorithm for hapticenabled bilateral teleoperation systems involving multiple degrees of freedom. In particular, in the context of energy-bounding control, the contribution focuses on the implementation of a passivity layer for an existing time-domain scheme, ensuring optimal transparency of the interaction along subsets of the environment space which are preponderant for the given task, while preserving the energy bounds required for passivity. The involved optimization problem is convex and amenable to real-time implementation. The effectiveness of the proposed design is validated via an experiment performed on a virtual teleoperated environment.
The interplay between transparency and stability is a critical aspect in haptic-enabled bilateral teleoperation control. While it is important to present the user with the true impedance of the environment, destabilizing factors such as time delays, stiff environments, and a relaxed grasp on the master device may compromise the stability and safety of the system. Passivity has been exploited as one of the the main tools for providing sufficient conditions for stable teleoperation in several controller design approaches, such as the scattering algorithm, timedomain passivity control, energy bounding algorithm, and passive set position modulation.
In this work it is presented an innovative energy-based approach, which builds upon existing time-domain passivity controllers, improving and extending their effectiveness and functionality.
The set of damping coefficients are prioritized in each degree of freedom, the resulting transparency presents a realistic force feedback in comparison to the other directions. Thus, the prioritization takes effect using a quadratic programming algorithm to find the optimal values for the damping.
Finally, the energy tanks approach on passivity control is a solution used to ensure stability in a system for robotics bilateral manipulation. The bilateral telemanipulation must maintain the principle of passivity in all moments to preserve the system’s stability. This work presents a brief introduction to haptic devices as a master component on the telemanipulation chain; the end effector in the slave side is a representation of an interactive object within an environment having a force sensor as feedback signal. The whole interface is designed into a cross-platform framework named ROS, where the user interacts with the system. Experimental results are presented.
12
Biggerstaff, Janet M. "Vibrational Damping of Composite Materials". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3204578.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed April 3, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 218-224).
13
Dwivedi, Tashi. "Aerodynamic damping in lateral buffeting". Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9204.
Pełny tekst źródłaStreszczenie:
Using the balanced cantilever method of erection, the cable-stayed bridge during its critical construction phase resembles a long overhanging cantilever structure. This type of structure is particularly vulnerable to wind-induced buffeting instabilities because of its low natural frequencies and low overall stiffness. In the past, the critical buffeting case for both vertical and horizontal excitation was assumed to occur when the wind was incident perpendicular to the bridge's axis. Recent observations in some cable-stayed bridges during construction revealing higher lateral responses at yaw angles other than perpendicular have triggered interest in the lateral vibration case. Buffeting instabilities are affected mainly by the aerodynamic damping term. Experimental research for the vertical aerodynamic damping resulted in the cosine approximation. In the absence of available experimental data for lateral vibration, the cosine approximation is extended from the vertical case and assumed to be valid for the lateral aerodynamic term. The experimental section of this thesis attempts to clarify the validity of the cosine approximation for the lateral aerodynamic damping case. Cantilever-type section models are triggered into vibration under various wind speeds and over a range of yaw angles, the aerodynamic damping is calculated, and the results are studied.
14
Graves, Kynan E., i kgraves@swin edu au. "Electromagnetic energy regenerative vibration damping". Swinburne University of Technology, 2000. http://adt.lib.swin.edu.au./public/adt-VSWT20060307.120939.
Pełny tekst źródłaStreszczenie:
This thesis documents a PhD level research program, undertaken at the Industrial
Institute Swinburne, Swinburne University of Technology between the years of 1997
and 2000. The research program investigated electromagnetic energy regenerative
vibration damping; the process of recovering energy from damped, vibrating systems.
More specifically, the main research objective was to determine the performance of
regenerative damping for the application of vehicle suspension systems. This question
emerged due to the need for continuous improvement of vehicle efficiency and the
potential benefits possible from the development of regenerative vehicle suspension. It
was noted, at the outset of this research, that previous authors had undertaken research
on particular aspects of regenerative damping systems. However in this research, the
objective was to undertake a broader investigation which would serve to provide a
deeper understanding of the key factors.
The evaluation of regenerative vibration damping performance was achieved by
developing a structured research methodology that began with analysing the overall
requirements of regenerative damping and, based on these requirements, investigated
several important design aspects of the system. The specific design aspects included an
investigation of electromagnetic machines for use as regenerative damping devices. This
analysis concentrated on determining the most promising electromagnetic device
construction based on its damping and regeneration properties. The investigation then
proceeded to develop an 'impedance-matching' regenerative interface, in order to control
the energy flows in the system. This form of device had not been previously developed
for electromagnetic vibration damping, and provided a significant advantage in
maximising energy regeneration while maintaining damping control. The results from
this analysis, when combined with the issues of integrating such a system in vehicle
suspension, were then used to estimate the overall performance of regenerative damping
for vehicle suspension systems.
The methodology and findings in this research program provided a number of
contributing elements to the field, and provided an insight into the development of
regenerative vehicle systems. The findings revealed that electromagnetic regenerative
vibration damping may be feasible for applications such as electric vehicles in which
energy efficiency is a primary concern, and may have other applications in similar
vibrating systems.
15
Gilmore, Keith. "Precession Damping in Itinerant Ferromagnets". Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/gilmore/GilmoreK1207.pdf.
Pełny tekst źródłaStreszczenie:
Precession damping in metallic ferromagnets had been assumed to result from the spinorbit interaction. While several theories of spin-orbit damping had been postulated, no convincing numerical comparisons to data existed. We selected one promising theory and performed first-principles numerical calculations of damping for bulk iron, cobalt, and nickel. Comparison of minimal calculated and measured damping rates demonstrated a 70 % agreement for nickel, 60 % for iron, and 40 % for cobalt. We then relaxed the initial constraint of a universal electron-lattice scattering rate by allowing the scattering rate to be spin dependent. The spin dependent lifetime ratio was equated to the ratio of the spin resolved density of states at the Fermi level. This modification improved the agreement to 95 % for nickel, 70 % for iron, and 47 % for cobalt. With this level of agreement, we next constructed a simple effective field explanation for the damping process. As the magnetization rotates, the energy of the spin system gets pushed out of equilibrium and this excitation is quenched by electron-lattice scattering. The energy of the spin system changes by two mechanism: the energies of the states change and transitions to excited states occur. The first mechanism had previously been described within the effective field picture as producing a breathing of the Fermi surface. As the magnetization precesses, the spin-orbit energy of each state changes leading to expansions and contractions of the Fermi surface that are periodic with the precession. To expand this metaphor, we have dubbed the second effect of transitions to excited states as a bubbling of the Fermi sea. In this picture, individual electrons across the Fermi surface undergo larger excitations. Finally, we investigated the dependence of the damping rate on the density of states and the spin-orbit coupling parameter. We found that the damping due to the breathing effect was roughly proportional to the density of states while damping from the bubbling terms correlated strongly with the density of states squared. By tuning the spin-orbit parameter we found that the breathing terms were proportional to the spin-orbit parameter cubed while the bubbling terms went as the spin-orbit parameter squared.
16
Nadampalli, Ravi Varma. "Interface Damping: Characterization and Implementation". Licentiate thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93413.
Pełny tekst źródłaStreszczenie:
Material damping in a structure is well defined and documented. However, dissipation due to mechanical contact (surface contact) in a complex built-up structure is not as well represented, in particular in large scale noise and vibration simulations. The present work is dealing with the understanding of the physical behaviour of losses that take place at such complex interfaces. The objective is to investigate, if, these mechanical loss phenomena can be modelled using linear response simulation techniques and implemented using commercially available finite element software. In a first step, the losses at the interfaces were experimentally investigated using an experimental setup capable of in-vacuo conditions. Following this, the second step was aimed at different ways of representing the proposed boundary conditions in a linear response simulation of a built-up structure. Two different approaches were studied, one using a continuous surface approach and one using a discrete element method.QC 20120424
17
Kandil, Mohamed Abdelhadi. "On rotor internal damping instability". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421790.
Pełny tekst źródła
18
Lord, Charles. "Damping effects of debonded composites". Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577524.
Pełny tekst źródłaStreszczenie:
Numerical simulations and analytical models are increasingly being sought for the design and behaviour prediction of composite materials. The use of high-performance composite materials is a growing area particularly in civilian and defence related applications. This growth demands the understanding and ability to predict how these materials will behave under their exposed environments. In this thesis, the displacement behaviour of naturally debonded composites (NDCs) from out-of-plane bending conditions is investigated. A detailed experimental programme is conducted to ascertain the phenomenological behaviours of these systems from steady-state responses for forced harmonic loading and freevibrations. The stiffness and energy dissipation behaviour are examined and a finite element (FE) model describing their behaviour is developed. Using the FE model, the experimental programme is extended through simulations and analytical models are developed to predict the displacement response behaviour. Through the exploitation of the analytical models, a linearisation is used to extract the bulk effective material properties and a constitutive model is developed to describe multi-layered 0JDCs that are reduced to a single layer describing their steady-state responses. The friction between each of the layers is included in the analytical model and is shown to have distinct behaviour for these types of composites. Acceptable agreement is observed between the analytical model predictions, the FE model and the experiments. It is well known that prevention of failure for vibratory exposed structures is a continuing challenge and that although the characterisation of damping in vibrating structures has long been an active area of research in structural dynamics, it is usually limited to experimental data. As the exploitation of lighter and more efficient structures is becoming more prevalent, the need for alternative damping materials and systems is overwhelmingly necessary. The use of NDCs poses as a viable candidate for rectifying some of these challenges, particularly since they can be designed with high levels of accuracy as opposed to a rough estimation as with many damping systems. From this work it is shown that layered NDCs have the ability to dissipate large amounts of energy from exploiting their frictional interfaces. There are many areas that NDCs could serve to be useful as damping systems.
19
Ayllon, Rolando. "Cyclotron Damping in Magnetized Plasmas". Thesis, Umeå universitet, Institutionen för fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-99662.
Pełny tekst źródłaStreszczenie:
The aim of this thesis was to study the cyclotron damping in magnetized plasmas using a different approach to the dielectric tensor that is the stardard way to study this case. In this approach given we deduce a set of coupled differential equations that give us the evolution of the electric field and the distribution function. The system of coupled equations can not be solved analitically, that is why we have found numerical solutions. The algorithm we used to obtain the numerical solutions is the staggered leap-frog method that common used in problems involving electromagnetic fields. We have studied two cases where we consider two different initial conditions for our distribution function in the velocity space. In the first example we used ˜g(t = 0, v_n) = 0. In this case we found that the electric field decays exponentially and there is phase mixing in the evolution of the distribution function. As second example we used as initial condition the expression ˜g(t = 0, v_n) = E_n/(iv_n −\gamma). In this case the phase mixing is less pronounced compared to the first example, and the electric field start growing until the oscillations of the distribution function start to become important, then the electric field start to decay slowly.
20
Bolter, J. D. "Active damping of framework vibrations". Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382018.
Pełny tekst źródła
21
Simeone, Luigi. "Nonlinear damping in energy harvesters". Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/426890/.
Pełny tekst źródłaStreszczenie:
Energy harvesting from ambient vibration has become an attractive topic in the recent years. Initial studies aimed to maximise the performance of small linear device for different excitation scenarios. These devices were assumed to be located in hostile and inaccessible environments and be able to provide energy for low powered sensors. Due to the limited size of the energy harvesters, however, the amount of power produced was small. More recently, many researchers have considered using nonlinear stiffness to improve the performance of these devices. This thesis, however, focuses on the use of nonlinear damping in energy harvesters. Nonlinear damping may be unwanted and introduced as the mechanism of the harvester, but can also be deliberately introduced to improve the dynamic range of the harvester. Typically ambient vibration generates a relative displacement between the suspended mass and the base in an energy harvester, which induces an electromotive force (EMF) in a circuit that is used to harvest electrical energy. It is possible to introduce nonlinear mechanical damping by having a circuit with a nonlinear resistance. Specifically, a load, in which the current is a third-power function of the voltage is compared with an equivalent linear load for three kinds of excitation such as harmonic, random white noise and random bandlimited noise. According to the numerical and analytical results, the cubic load provides more harvested power at resonance at low levels when compared to an equivalent linear load at the same level of excitation. As the frequency bandwidth of a random excitation becomes wider, to the limit of white noise, as the power generated by the cubic converges to the linear case. Electromagnetic transducer energy harvesters usually adopt a conversion mechanism of motion, such as ball screw or rack and pinion, which introduce a source of loss such as friction. Static friction is then added to the model and this is shown to affect the harvested power at low input levels. Another proposed strategy consists of adjusting the electric load according to the input level, which can also enlarge the dynamic range of performance of energy harvested compared to a device with constant load. To demonstrate the effectiveness of the level-dependent load, an energy harvesting device was designed and manufactured, which comprised of an oscillating beam sprung to the base, and attached to a generator. Across the terminals of the generator, an electric resistance is mounted and the voltage measured is used to compute the harvested power. Experiments are conducted by exciting the harvested with a harmonic input at resonance via a shaker. A level-dependent load and a constant load were separately tested; with results that are in good agreement with the simulations, it is shown that by adjusting the load according to the input level, the harvested power is increased compared to a linear constant load.
22
Gutierrez, Homero L. (Homero Luis). "Damping formulations in substructure synthesis". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/47363.
Pełny tekst źródła
23
Wu, Jiun-Yan 1972. "Extracting damping ratios using wavelets". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8618.
Pełny tekst źródłaStreszczenie:
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (leaves 87-88).
The focus of this work is to evaluate the accuracy of methods for extracting damping ratios with respect to: three extraction methods, different damping ratios, added noisy data, separated modes and close modes. To achieve this goal, a simulated analytical signal is analyzed by estimating the modal parameters. The simulated analytic signal is useful because the exact values are known and the characteristic of the FRF can be varied in order to observe how the accuracy of damping ratios is affected. Results show that the Continuous Wavelet Transform method gives the most accurate estimations even for data corrupted by the noise. The Complex Exponential method presents better results in the cases with higher modes and higher damping ratios without the noise. Wavelet Packet method and Continuous Wavelet Transform method are more suitable in the cases for extracting lower damping ratios than those for higher damping ratios even for data corrupted by the noise. And in general, the estimation results are more accurate in the cases with separated modes than those with close modes.
by Jiun-Yan Wu.
M.Eng.
24
Gessel, David Jacob. "Impulse damping in structural materials". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/49583.
Pełny tekst źródła
25
Anasavarapu, Srikantha Phani. "Damping identification in linear vibration". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615994.
Pełny tekst źródła
26
Adhikari, Sondipon. "Damping models for structural vibration". Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620975.
Pełny tekst źródła
27
Bajalan, Hamid. "Damping in zinc-based alloys". Thesis, Aston University, 1993. http://publications.aston.ac.uk/15271/.
Pełny tekst źródłaStreszczenie:
The damping behaviour of the cold chamber pressure-die-casting alloy: M3, ZA8, ZA27, ZM11, Cosmal, Supercosmal and newly developed ZA27H1 and ZA27H2 was investigated at room temperature and elevated temperatures of up to 90 degrees C. The damping properties of the alloys were established at all temperatures. Formulas were established to predict damping properties of each alloy at any given temperature. The prediction formulae were found to be very accurate. All of the experimental alloys were heterogenous with varying microstructure and grain size; this was the major contribution and dominated the damping properties of the alloys. Super cosmal and ZA27 possessed the highest tensile strength but ZA27H1, ZA27H2 and ZM11 showed the highest damping properties. The relationship between microstructure and damping capacity of all alloys was also examined using back-scattered electron on the SEM. Further more detailed examinations of the microstructures of alloys ZM11, Cosmal and Supercosmal were carried out on the transmission electron microscope in order to establish the phases present in all alloys. These helped to obtain the mechanism of damping in the experimental alloys. The main damping mechanism in most of the experimental alloys was due to grain-boundary-sliding. Micro structural examinations also revealed the absence of -phase in the Cosmal and Supercosmal. This was thought to be due to a change in solid solubility of the alloys, which could have been caused by the addition of Si.
28
West, Ray A. "Damping of elastic-viscoelastic beams /". Online version of thesis, 1992. http://hdl.handle.net/1850/11111.
Pełny tekst źródła
29
Ehnes, Charles W. "Damping in stiffener welded structures". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FEhnes.pdf.
Pełny tekst źródła
30
Nygren, Björn. "Angle Damping in Bundle Adjustment". Thesis, Umeå universitet, Institutionen för fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160547.
Pełny tekst źródłaStreszczenie:
Bundle Adjustment is a common fine-tuning step used in photogrammetry. It uses different types of parameters, some of which can be considered to be almost linear while others can be considered to be highly nonlinear, e.g. the rotational parameters. However, in the Bundle Adjustment process all parameters are treated equal. In concert with a poor initial estimate, this might cause Bundle Adjustment to diverge. In this report, two novel methods based on the damped Gauss-Newton with Armijo linesearch, modified by giving rotational parameters a special treatment, are tested. These methods, Clamped Alpha and Linear Exponential Search, are compared to Gauss-Newton with Armijo linesearch, as well as to the undamped Gauss-Newton method, also known as the Gauss-Markov method. Parameter sweeps over different perturbation levels for the angular parameters show that each of the three damped methods outperform the Gauss-Newton method. Notably, the Clamped Alpha method also outperforms the other two damped methods, with as much as 16 times as many convergent cases for a given perturbation level. Meanwhile, the average number of iterations is increased by only 1.8 times that of the Gauss-Newton with Armijo linesearch. The results add to existing research arguing for the use of damped methods in Bundle Adjustment. In particular, the simple and cheap Clamped Alpha method is potentially attractive for problems where the uncertainty of the camera angles is significant. While the Clamped Alpha method show promising results, it should be noted that the experiments in this study are on synthetic data. In order to solidify these results, further investigations into the performance of Clamped Alpha using real-world data should be conducted.
31
Bolduc, Maxime. "Acquiring statistical energy analysis damping loss factor for complex structures with low to high damping characteristics". Thèse, [S.l. : s.n.], 2007. http://savoirs.usherbrooke.ca/handle/11143/1801.
Pełny tekst źródła
32
Ting-Kong, Christopher. "Design of an adaptive dynamic vibration absorber". Title page, contents and abstract only, 1998. http://thesis.library.adelaide.edu.au/adt-SUA/public/adt-SUA20010220.212153.
Pełny tekst źródła
33
Barsallo, Pacheco Nilma Rosa. "Material and Damping Characterization of Discretized Adhesive Tapes in Cantilever Beams undergoing Free and Forced Vibration". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64357.
Pełny tekst źródłaStreszczenie:
The work is focused in investigating the effectiveness of discretized damping tapes applied to a cantilever beam subjected to free and forced vibrations. The work is divided into three main sections. First, we performed material characterization of the viscoelastic (VE) pressure sensitive adhesive layer of the damping tapes. To do so, we designed a novel quad shear specimen to measure shear storage and loss moduli, and tan delta from dynamic mechanical analyzer measurements. Second, the optimal discretization length for different damping tapes was experimentally determined and analytically verified using linear viscoelasticity and basic strength of materials and vibrations principles. These results showed a mean to improve the damping of a structure without increasing the weight of the added damping layer. Third, a nonlinear analysis was performed for cantilever beams with damping layers subjected to parametric excitation. Comparison of the response amplitude of the parametrically excited beam was performed for different discretization lengths, and system identification of the nonlinear parameters was carried out. The effects of large deflections of a beam under parametric excitation were analyzed; large deflections were found to induce localized buckling of the stiff constraining layer of the damping tape that would invalidate some of the assumptions and analytical solutions that do not take such phenomena into account.Master of Science
34
Bournine, Hadjila. "Bolted friction columns for structural damping". Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555725.
Pełny tekst źródłaStreszczenie:
Over the last three decades, friction damping has been proved to be very efficient for vibration mitigation. The designs developed so far are either bracing mechanisms or friction joints. The aim of this thesis is to investigate the feasibility of friction columns for vibration damping. A friction column is composed of two steel beams bolted together allowing dynamic friction to occur at the interface. The mechanism has been proved to dissipate a large amount of the vibration energy. The energy dissipated by friction depends on both the bolt tension forcing the beams together and the relative displacement at the interface. Therefore, a model relating the relative displacement at the interface to the deflection of the friction column was developed and experimentally investigated. The results assisted in defining a hysteretic friction-slip model and the conditions causing the stick and slip transitions. The results showed that the damping in the friction column could be improved up to ten. times its inherent viscous damping when the bolts tension is properly optimised. The presence of friction in the column does not only affect its damping properties but also its stiffness. A model depicting the effect of friction on the dynamics of the column was derived from first principles and experimentally validated. The friction column was then placed in a frame context. Despite the fact that both ends of the friction column were restrained, the relative displacement at the interface was large. This is due to the non monotonic nature of the modeshapes during lateral vibration. This also increases the friction force magnitude which allows the column to slip at higher bolt tensions and lower deflection magnitudes compared to the cantilever. This proved that friction columns can provide valuable damping and prevent irreversible damage to the structure . •.
35
Kitching, Kevin John. "Semi-active damping of heavy vehicles". Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/265419.
Pełny tekst źródłaStreszczenie:
This thesis is concerned with the use of semi-active suspensions in heavy vehicles to improve ride and reduce road damage. An introduction into the subject is given in chapter 1 and a review of the relevant literature is presented at the beginning of each main chapter. The development and modelling of a prototype, continuously variable semi-active damper for heavy vehicles is described in chapter 2. A proportional valve is used to generate the variable damping coefficient and the detrimental effects of the oil flow forces acting on the valve spool are studied. The force tracking performance of the damper is then examined for simple input conditions and the compliance of the hydraulic fluid is found to have a strong influence upon the response of the damper. The different vehicle and road models used in the thesis are described in chapter 3. In chapter 4, the performance of the prototype damper is investigated under realistic operating condition using a Hardware-in-the-Loop (HiL) test rig, with a single wheel station vehicle model. The prototype damper displays a phase lag of approximately 20ms between the demanded and achieved damping force. The semi-active suspension is found to be most effective in reducing the body accelerations relative to an optimum non-linear passive suspension. A theoretical investigation into the reduction of road damage through the use of active and semi-active suspensions is described in chapter 5. The relative performance of four linear state feedback control strategies is examined. The potential for reducing road damage by using a controller which directly regulates various measures of road damage is also studied. Significant improvements are predicted for the three controllers which assume the road inputs to the vehicle are correlated. However, these benefits are shown to diminish as the vehicle speed is reduced. It is concluded that the control of the dynamic tyre forces is an effective means by which to regulate road damage. Theoretical predictions of the benefits from wheelbase preview control are measured experimentally in chapter 6, using the prototype semi-active damper in a half-car HiL rig with a planar two axled heavy vehicle model. The benefits of preview control using the prototype semi-active damper are found to be less than theoretically possible due to the phase lag between the demanded and achieved damping force of the prototype damper. The final section of chapter 6 shows that the performance of the prototype damper can be improved further by having a theoretical simulation running ahead of the HiL vehicle. The theoretical simulation is used to predict the demanded damper force for the HiL vehicle and thereby compensate for the phase lag in the prototype damper. Conclusions and recommendations for further work are presented in chapter 7.
36
Ganguli, ABHIJIT. "Chatter reduction through active vibration damping". Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210980.
Pełny tekst źródłaStreszczenie:
The aim of the thesis is to propose active damping as a potential control strategy for chatter instability in machine tools.The regenerative process theory explains chatter as a closed loop interaction between the structural dynamics and the cutting process. This is considered to be the most dominant reason behind machine tool chatter although other instability causing mechanisms exist.
The stability lobe diagram provides a quantitative idea of the limits of stable machining in terms of two physical parameters: the width of contact between tool and the workpiece, called the width of cut and the speed of rotation of the spindle. It is found that the minimum value of the stability limit is proportional to the structural damping ratio for turning operations. This important finding provides the motivation of influencing the structural dynamics by active damping to enhance stability limits of a machining operation.
A direct implementation of active damping in an industrial environment may be difficult. So an intermediate step of testing the strategy in a laboratory setup, without conducting real cutting is proposed. Two mechatronic "Hardware in the Loop" simulators for chatter in turning and milling are presented, which simulate regenerative chatter experimentally without conducting real cutting tests. A simple cantilever beam, representing the MDOF dynamics of
the machine tool structure constitutes the basic hardware part and the cutting process is simulated in real time on a DSP board. The values of the cutting parameters such as spindle speed and the axial width of cut can be changed on the DSP board and the closed loop interaction between the structure and the cutting process can be led to instability.
The demonstrators are then used as test beds to investigate the efficiency of active damping, as a potential chatter stabilization strategy. Active damping is easy to implement, robust and does not require a very detailed model of the structure for proper functioning, provided a collocated sensor and actuator configuration is followed. The idea of active damping is currently being implemented in the industry in various metal cutting machines as part of the European Union funded SMARTOOL project (www.smartool.org), intended to propose smart chatter control technologies in machining operations.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
37
Vlassenbroek, Alain. "Radiation damping in High Resolution NMR". Doctoral thesis, Universite Libre de Bruxelles, 1993. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212811.
Pełny tekst źródła
38
Sun, Jia. "Rotating Structure Modeling and Damping Measurements". Licentiate thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31161.
Pełny tekst źródłaStreszczenie:
The structural damping is of importance to suppress the vibration amplitude of compressor blades rotating at high angular velocity under a high cycle impact. To avoid the appearance of the high cycle fatigue (HCF), damping materials may be applied to the compressor blades. To quantify the effect while using damping materials, a numerical tool needs to be developed for the damping prediction of a dynamic rotating blade. This thesis is divided into two parts: Paper A develops a dynamic model of a rotating blade and Paper B a damping structure model including measurements. In Paper A, a dynamic rotating blade model is developed by using a plate model at an arbitrary stagger angle. Hamilton’s principle is applied to derive a system of equations of motion and the corresponding boundary conditions. Numerical simulation is implemented to perform eigenfrequency analysis by the Extended Galerkin method. In addition, parametric analysis is performed with respect to rotation speed and stagger angle, respectively. Results show a good agreement with those of the finite element method. Finally, forced response analysis is determined for two cases; a point force and a distribution force, using a proportional damping model. In Paper B, unconstrained and constrained damping techniques are applied to increase the structural damping of the blades, including measurement and modeling results. Two specimens, titanium and stainless steel, are treated by aluminum oxide and epoxy coating material. Measurement results show that both treatments give damping increase, where aluminum oxide is more effective for damping improvement than the corresponding epoxy treatment. The unconstrained damping layer model is used to predict the total material damping of the combined structure as well as the material damping of coating layer. Furthermore, the constrained-layer model is used to optimize the damping configuration. Two compressor blades in titanium and stainless steel are tested in air and vacuum. One reason is being that the radiation loss factor increases the total damping comparing with that under vacuum condition. The calculation of radiation loss factor is performed to match the measurement data. Finally, increased material damping decreases peak stress and therefore increases the life time of the compressor blades.QC 20110311
39
Pelletier, Michel 1964. "Adaptive damping control for robotic teleoperation". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55621.
Pełny tekst źródła
40
Awang, Jusoh. "Active damping of DC power networks". Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559484.
Pełny tekst źródłaStreszczenie:
The research involves devising new control and compensation methods for DC power distribution systems containing power electronics loads with constant power characteristic. A compensation method called an active damping network is examined, which utilises capacitor and inductor energy storage elements and high frequency switching devices. This network is controlled to behave as a small-signal resistor so that any instabilities in the power distribution system due to the interaction between interconnected sub-systems will be damped and eliminated successfully. This method is studied and analysed in detail. The system was designed and simulated, and was verified by experimental results. The results show that stable operation is achieved of a small-scale power distribution system that contains power electronic loads with constant power characteristics such as DC-DC converters and electrical drives.
41
Algozzini, Lee. "MULTIFUNCTIONAL NANOCOMPOSITES FOR HIGH DAMPING PERFORMANCE". Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4454.
Pełny tekst źródłaStreszczenie:
Composite structures for aerospace and wind turbine applications are subjected to high acoustic and vibrational loading and exhibit very high amplitude displacements and thus premature failure. Materials with high damping or absorbing properties are crucially important to extend the life of structures. Traditional damping treatments are based on the combinations of viscoelastic, elastomeric, magnetic, and piezoelectric materials. In this work, the use of carbon nanofibers (CNFs) in the form of interconnected self-supportive paper as reinforcement can significantly improve damping performance. The interfacial friction is the primary source of energy dissipation in CNF paper based nanocomposites. The approach entailed making CNF paper by filtration of well-dispersed nanofibers under controlled processing conditions. The CNF paper was integrated into composite laminates using modified liquid composite molding processes including Resin Transfer Molding (RTM) and Vacuum Assisted Resin Transfer Molding (VARTM). The rheological and curing behaviors of the CNF-modified polymer resin were characterized with Viscometry and Differential Scanning Calorimetry (DSC). The process analysis in mold filling and pressure distribution was conducted using Control Volume Finite Element Method (CVFEM) in an attempt to optimize the quality of multifunctional nanocomposites. The mold filling simulation was validated with flow visualization in a transparent mold. Several tests were performed to study the damping properties of the fabricated composites including Dynamic Mechanical Analysis (DMA) and piezoceramic patch based vibration tests. It was found that the damping performance was significantly enhanced with the incorporation of carbon nanofibers into the composite structures.M.S.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical, Materials and Aerospace Engineering
42
Wong, Seck Jiong. "Thermoelastic damping in MEMS ring resonators". Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431849.
Pełny tekst źródła
43
Zhu, Jianfeng. "Vibration suppression by using magnetic damping". Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440844.
Pełny tekst źródła
44
Antler, Natania. "Passive damping of a LIGO mirror". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51612.
Pełny tekst źródłaStreszczenie:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.Includes bibliographical references (p. 75-76).
There may be largely untapped source of information about our cosmic surroundings in the form of gravitational radiation, predicted by Einstein's theory of General Relativity. If detected, gravitational waves (GWs) could become a valuable means to study astrophysical events. The Laser Interferometer Gravitational-Wave Observatory (LIGO) has built detectors to search for these GWs. In essence, these detectors are several kilometer long Michelson interferometers with Fabry-Perot cavities in the arms. In order to detect gravitational waves, LIGO must be sensitive to relative displacements on the order of 10-18 m. Advanced LIGO, a detector upgrade, is projected to achieve a tenfold increase in sensitivity through a wide range of new technologies and techniques. One proposed change is to increase the laser power in the cavities from ~10 W to ~180 W. There is concern that with this increased radiation pressure, optical modes in the cavity may overlap with acoustic modes of the mirrors and excite mechanical motion. If such a parametric instability occurs, it will disrupt the operation of the interferometer. In this thesis I test a method to passively damp the acoustic modes of the mirror, using a mass-spring damper. The damper can be modeled as a piezoelectric "spring" (PZT) connected to a seismic mass. The damper can lose energy from both mechanical motion, and motion of charge through a resistor across the PZT.
(cont.) I built a small Michelson interferometer to measure the acoustic modes of an Initial LIGO mirror, excited by an electrostatic drive, while it hung as a pendulum in vacuum. For a 6.6 kHz mode of the mirror, I found that the quality factor, or Q, of the mirror decreased from (7.7 ± 0.1) x 105 to (6.2 ± 0.1) x 103 when the damper was added. The addition of a resistor across the PZT reduced the Q below the measurement threshold.
by Natania Antler.
S.B.
45
Young, Joseph Y. J. 1968. "Squeeze-film damping for MEMS structures". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/34334.
Pełny tekst źródła
46
Marsh, Eric Russell. "An integrated approach to structural damping". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37726.
Pełny tekst źródła
47
Dody, Thibault Alexandre. "Damping optimization using transfer function criteria". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82709.
Pełny tekst źródłaStreszczenie:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 84-85).
Seismic performance has become a key point in the design of every type of structures. Even the simplest buildings need protection in areas of high seismic activity.However,there is no method defined!by codes or general knowledge to help engineers make choices about the design of seismic protection devices. Even!though several theories to optimize the use of devices have been developed, there is little practical application in!structural engineering. The purpose of this paper is first to settle on the elements that can be used to protect structures. By looking at their effects on structures, it was found that dampers are the easiest to use in an optimization process. After describing the need of progress in the field of earthquake protections, this paper focuses on the impact of additional damping in a 2-D frame. Finally, the method developed by Izuru Takewaki was studied and implemented. By looking at the limitation of the interstory drift, the algorithm produced the optimal distribution of the damping. In order to estimate the performance of! the method, the results were compared to empirical damping distributions. A complete program was developed in order to apply the optimization method to a wide range of custom 2-D frames.
by Thibault Alexandre Dody.
M.Eng.
48
PENG, WU, i Sebastian Levin. "Chatter Vibration Damping in Parting Tools". Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16798.
Pełny tekst źródła
49
Ely, Paul T. "Internal Damping Rates of Construction Cranes". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36524.
Pełny tekst źródłaStreszczenie:
The conveyance of payloads by construction cranes generates pendulations of the payload. This research provides a critical design parameter for the development of a device that aids in reduction of these pendulations. Previous research developed a tuned mass damping system, that effectively attenuated the energy of a pendulating payload. In order to be effective the internal damping rate of the tuned mass damper must be at least twice that of the system to be damped. Prototypes of a tuned mass damping system have achieved damping rates between 6 and 12 %, making cranes with damping rates below 3% attractive. This research indicates that the internal damping rate of construction cranes is on the order of one percent, suggesting that a tuned mass damping system could be retrofitted to today's construction cranes.
This thesis is an investigation of the internal damping rates of construction cranes. Three hydraulic and two lattice boom cranes were tested. The motion of pendulating payloads was modeled after a simple pendulum. The internal damping rate was calculated using logarithmic decrement technique. Light to medium duty cranes were tested with loads similar to those used in duty cycle operations. Damping tests were performed both perpendicular and parallel to the mast of the crane. Values were calculated from data extracted from videos of a payload oscillating over a measurement scale.
A FMC Link Belt 25-ton hydraulic crane was tested at 6.4 % of capacity and displayed damping rates between 0.25 and 0.6 %. A 50-ton FMC Link Belt was tested at 10 % of capacity and had damping rates of 0.18 % for both tests. The third hydraulic crane was a 60-ton P&H T-600XL. The test parallel to the mast was performed at 6 % of capacity having a damping rate of 0.22 %. The test-performed perpendicular to the mast was at 3.5 % of capacity with a damping rate of 0.65 %.
Two lattice boom cranes with capacities of 70 and 100 tons were tested. The 70-ton LIMA 778c's damping rates were 0.06 and 1.3 percent. This test was performed at 15 % of capacity. The 100-ton Link Belt LS318 was tested at 6.8 % of capacity and had damping rates between 0.07 and 0.08 percent.Master of Science
50
Aumjaud, Pierre. "Vibration damping of lightweight sandwich structures". Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/20730.
Pełny tekst źródłaStreszczenie:
Honeycomb-cored sandwich structures are widely used in transport for their high strength-to-mass ratio. Their inherent high stiffness and lightweight properties make them prone to high vibration cycles which can incur deleterious damage to transport vehicles. This PhD thesis investigates the performance of a novel passive damping treatment for honeycomb-cored sandwich structures, namely the Double Shear Lap-Joint (DSLJ) damper. It consists of a passive damping construct which constrains a viscoelastic polymer in shear, thus dissipating vibrational energy. A finite element model of such DSLJ damper inserted in the void of a hexagonal honeycomb cell is proposed and compared against a simplified analytical model. The damping efficiency of the DSLJ damper in sandwich beams and plates is benchmarked against that of the Constrained Layer Damper (CLD), a commonly used passive damping treatment. The DSLJ damper is capable of achieving a higher damping for a smaller additional mass in the host structure compared to the optimised CLD solutions found in the literature. The location and orientation of DSLJ inserts in honeycomb sandwich plates are then optimised with the objective of damping the first two modes using a simple parametric approach. This method is simple and quick but is not robust enough to account for mode veering occurring during the optimisation process. A more complex and computationally demanding evolutionary algorithm is subsequently adopted to identify optimal configurations of DSLJ in honeycomb sandwich plates. Some alterations to the original algorithm are successfully implemented for this optimisation problem in an effort to increase the convergence rate of the optimisation process. The optimised designs identified are manufactured and the modal tests carried out show an acceptable correlation in the trends identified by the numerical simulations, both in terms of damping per added mass and natural frequencies.