Дисертації з теми "Soft Material Mechanics"
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Jin, Lihua. "Mechanical Instabilities of Soft Materials: Creases, Wrinkles, Folds, and Ridges." Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13064983.
Повний текст джерелаEngineering and Applied Sciences
Zhang, Li Ying Grace. "Fatigue and integrity of hard ceramics and coatings using the soft impressor technique." Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363272.
Повний текст джерелаHockings, Nicholas. "Material and mechanical emulation of the human hand." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720651.
Повний текст джерелаHuang, Shan. "Nano-chemo-mechanics of advanced materials for hydrogen storage and lithium battery applications." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42710.
Повний текст джерелаKramer, Rebecca Krone. "Soft Active Materials for Actuation, Sensing, and Electronics." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10368.
Повний текст джерелаEngineering and Applied Sciences
Lin, Gaojian. "Instability driven reconfigurable soft materials: mechanics and functionality." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/508542.
Повний текст джерелаPh.D.
Mechanical instability, a deformation mode involving abrupt switching between two distinct equilibrium structural configurations, has historically been viewed as a failure mechanism in engineering and materials science. Since the pioneering work in harnessing spontaneous buckling for surface micro-patterning in 1998, tremendous research interest has focused to utilize, rather than avoid, buckling instability in soft materials at small scale for achieving unique properties and multifunctionality. The benefit of small-scale bucking instability in soft materials and structures lies in the reversible dynamic tunability of the buckled structural or surface configuration in response to different external stimuli, which enables the coupling of structural or surface reconfiguration with dynamically tunable properties, such as mechanical, optical, wetting, and electrical properties. In this dissertation, I explore the fundamental mechanics and functionality of surface-based buckling and hierarchical wrinkling on substrates in multifunctional opto-electronic devices and smart windows. I will first explore the benefits of classical plate buckling in soft materials. The challenge lies in the intrinsic indeterminate characteristics of buckling in terms of its buckling orientation, which could lead to geometric frustration and random global structures. To address this challenge, I introduce cuts-based geometrical imperfection to guide the deterministic buckling in arrays of parallel active polymeric plates on rigid substrates. After introducing patterned cuts, the originally random phase-shifted buckling transits to a prescribed buckling with controllable phases. The design principle for cut-directed deterministic buckling in plates is revealed through both mechanics model and finite element simulation. By harnessing cut-directed buckling for controllable contacts and interactions in buckled parallel plates, I demonstrate the array of parallel plates as a multifunctional platform for selectively steering the electronic and optical pathways on demand, as well as the potential application in design of mechanical logic gates. I then explore the hierarchical wrinkling of thin films on soft substrates via sequential wrinkling for design of a potential multifunctional smart window with combined structural color and water droplet transport control. The self-similar hierarchical wrinkles with both nanoscale and microscale features are generated on a pre-strained poly(dimethylsiloxane) (PDMS) elastomer through sequential strain release and multi-step oxygen plasma treatment. I exploit the criteria for generating self-similar hierarchical wrinkles through both simplified theoretical model and experiments. I show that the hierarchically wrinkled elastomer displays both opaqueness and iridescent structural color. I further show its ability in control of water droplet transport on demand through mechanical stretching and release. I further extend the study of self-similar hierarchical wrinkling to the dynamic wetting behavior of multiscale self-similar hierarchical wrinkled surfaces on PDMS substrates through combined plasma and ultraviolet ozone (UVO) treatment. The generated surface structure shows an independently controlled dual-scale roughness with level-1 small-wavelength wrinkles resting on level-2 large-wavelength wrinkles, as well as accompanying orthogonal cracks. By tuning the geometry of hierarchical wrinkles, I explore the small degree of wetting anisotropy in hierarchical wrinkled surfaces, defined as the contact angle difference between the parallel and perpendicular directions to the wrinkle grooves through both experimental characterization (confocal fluorescence imaging) and theoretical analyses. I find that the measured larger apparent contact angle than the theoretically predicted Wenzel contact angle is attributed to the three-phase contact line pinning effect of both wrinkles and cracks, which generates energetic barriers during the contact line motion. I reveal that the observed small degree of wetting anisotropy in the hierarchical wrinkled surfaces arises from the competition between orthogonal wrinkles and cracks in the contact line pinning.
Temple University--Theses
Liu, Qihan. "Mechanics and Physics of Soft Materials." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493423.
Повний текст джерелаEngineering and Applied Sciences - Engineering Sciences
Perera, M. Mario. "Dynamic Soft Materials with Controllable Mechanical Properties." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595847753887897.
Повний текст джерелаSalahshoor, Pirsoltan Hossein. "Nanoscale structure and mechanical properties of a Soft Material." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/924.
Повний текст джерелаBhattacharjee, Tirthankar. "Cohesive Zone Modeling of Tearing in Soft Materials." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1313765176.
Повний текст джерелаGeri, Michela. "Dynamics and rheology of soft phase-change materials." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121885.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 325-353).
Many industrial processes involve multicomponent or composite materials in which one component can undergo a phase transition leading to the appearance of a solid phase dispersed in a liquid-like continuous phase. Examples of soft phase-change materials can be found in a variety of applications from food products (e.g., organogels, casein gels and gelatin), pharmaceutical products (e.g., tissue mimicking phantoms and encapsulating agents), cosmetics (e.g., foundations and lipsticks), and in the oil and gas industry, where formation of paraffin waxes and clathrate hydrates represent major issues for upstream production and flow assurance.
Historically, phase-changing materials have been exploited for their unique thermal properties in energy storage applications, however soft solids and complex fluids that undergo phase transformation have broader impact in industrial and biomedical applications because of the dramatic changes in mechanical properties that result from the conditions across the phase transition. Typically, these soft phase-change materials are part of the broader class of elasto-visco-plastic materials, showing both viscoelasticity at small deformations and plasticity at large deformations. However, their material properties are greatly influenced by the specific processing conditions during formation, such as temperature and applied deformation, leading to a thermo-rheological complexity that still poses major challenges for their experimental and theoretical characterization.
In this Thesis, we develop novel experimental protocols and theoretical frameworks to characterize and describe the complex rheological behavior of soft phase-changing materials, under both linear and non-linear deformations. We focus mainly on two types of materials that are of major importance in the oil and gas industry: paraffin gels, as model waxy crude oils, and clathrate hydrate suspensions. In the limit of small deformations, we are usually interested in measuring the frequency response of the material as it evolves, or mutates, over time. Current state-of-the-art techniques have major limitations in providing both time- and frequency-resolution primarily due to the type of input signals used. To overcome this, we develop a robust excitation signal that allows us to perform time-resolved mechanical spectroscopy of fast mutating systems. Inspired by the biosonar signals of bats and dolphins, we introduce a joint frequency- and amplitude- modulated chirp signal.
Combining experiments and numerical simulations, we show that there exists an optimized range of amplitude modulation that minimizes the estimation error while reducing the total acquisition time by almost two orders of magnitude. With this new technique, which we call the Optimally Windowed Chirp (or OWCh), we then explore the phase transition during gelation of a series of mutating, phase-changing materials, including casein gels, gelatin and paraffin gels. To address large, non-linear deformations, we start from a thorough investigation of the steady state and transient response of paraffin gels under shear. We develop a robust protocol that enables us to systematically extract the main rheological features including the thermokinematic memory (i.e. the effect of thermal and shear history on the rheological behavior of the gel) and thixotropy (i.e. the time-dependent behavior under constant applied deformation).
We show that these features can be understood in terms of microstructural rearrangements of the underlying solid particle network, which can be quantified through differential scanning calorimetry, birefringence imaging and rheometry. Based on this understanding, we present a constitutive framework that captures all of the different features while respecting thermodynamic and objectivity constraints. We also investigate mechanical instabilities that may arise during rheological measurements. Combining ultrasonic image velocimetry and rheometry, we show that both shear banding and slip can take place during steady shear below a critical value of the shear rate. However, the thixotropic nature of these materials precludes the banding instability from growing in the sheared region of the gap, ensuring that the measured stress response corresponds to the real bulk behavior. Finally, we study the visco-plastic response of clathrate hydrate suspensions.
To do so, we develop a novel method to robustly control their formation, which so far has been a major issue in experimental studies due to uncontrolled nucleation and growth of hydrate crystals. Our method, based on the use of "frozen emulsions", decreases the induction time by orders of magnitude while guaranteeing that all the water droplets initially frozen into ice particles are converted into hydrate particles. Rheological measurements for different water volume fractions and shear rates reveal that the macroscopic rheological response is again governed by rearrangements of the microstructure; however, due to the very strong interparticle forces (which are the result of a continuous sintering process) the microstructure evolves towards a fully connected network that behaves as a porous solid structure.
Incorporating this limit into our theoretical model, we show that the framework developed for softer interparticle interaction can also capture the macroscopic plastic response of hydrate suspensions. The results from this Thesis have the potential to impact many industrial processes that involve soft phase-change materials, such as flow assurance and oil extraction, thermal energy storage, gas transport and storage, and other processes where the dynamics of gelation are used to control the rheological properties of the ultimate product.
by Michela Geri.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
Tegeler, Lisa Jan. "Mechanics and materials issues in processing and flexibility of soft contact lenses." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/38071.
Повний текст джерелаMcNally, Lisa M. "Mechanical and biological properties of novel denture soft lining materials." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520186.
Повний текст джерелаKim, Yoonho S. M. Massachusetts Institute of Technology. "Printing ferromagnetic domains in soft materials : mechanism, modeling, and applications." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118709.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 61-63).
Soft materials capable of transforming between three-dimensional (3D) shapes have applications in areas as diverse as flexible electronics, soft robotics, and biomedicine. This thesis introduces a method of printing ferromagnetic domains in soft materials that yield fast transformation between complex 3D shapes via magnetic actuation. This approach is based on direct ink writing of an elastomer composite containing hard ferromagnetic microparticles. By applying a magnetic field to the dispensing nozzle while printing, we make the particles reoriented along the applied field direction to impart patterned magnetic polarity to printed filaments. This method allows us to design ferromagnetic domains in 3D-printed soft materials encoded with complex programmed shapes. A mathematical model based on a continuum mechanics framework is developed to predict such complex transformation of printed structures under the applied magnetic fields. For this computational model, a constitutive law is developed to describe the behavior of soft materials incorporating hard ferromagnetic microparticles under applied magnetic fields. The capability to quantitatively predict the shape changes enables designing a set of previously inaccessible modes of transformation such as remotely controlled 3D auxetic behaviors in an extremely fast and fully reversible manner via magnetic actuation. The actuation speed and power density of the printed soft materials with programmed ferromagnetic domains are orders of magnitude greater than existing 3D-printed active materials. Diverse functions derived from the fast and complex shape changes such as reconfigurable soft electronics, interaction with quickly moving objects, rolling-based locomotion and delivery of drug pills, and a horizontal leap of a 3D auxetic structure.
by Yoonho Kim.
S.M.
Liang, Heyi. "Rational Design of Soft Materials through Chemical Architectures." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1573085345744325.
Повний текст джерелаPisani, R. "Footwear and soft ground interaction." Thesis, University of Salford, 2002. http://usir.salford.ac.uk/2170/.
Повний текст джерелаFiorenza, Roberta Maria. "Mechanism of Formation of Soft Particles in Biodiesel Fuel Blends." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-275685.
Повний текст джерелаDen stora miljöpåverkan relaterad till användningen av fossilt bränsle har drivit övergången till förnybara alternativ. Fossil diesel kan numera ersättas av biodiesel, härledd av vegetabiliska oljor och fetter, oftast används som biodieselblandningar. Vissa nackdelar är emellertid relaterade till användningen av detta biobränsle, bland annat bildandet av avlagring i injektorer och filter som orsakar en minskning av motorprestanda eller motorfel. Detta projekt fokuserar på analysen av mekanismen för bildning av mjuka partiklar i biodieselavlagring. Dessa partiklar består huvudsakligen av karboxylmetall tvålar och hittades i biodieselmotorer efter användning av åldrad biobränsle med föroreningar, såsom motorolja. Rollen för kortkedjiga fettsyror (SCFA) har undersökts, tillsammans med användning av tre olika kalciumkomponenter, för att analysera bildningsmekanismen för kalciumtvålar. Experimentellt åldring av testbränslen B10 och B100 på labbet utfördes, och i vissa fall bubblades en inert gas för att avlägsna de bildade SCFA. Kalcium komponenter, nämligen kalciumoxid, kalciumkarbonat och motorolja, tillsattes för att undersöka bildningen av mjuka partiklar. Jonkromatografi, pH-mätningar, NMR- spektroskopi och oxidations stabilitetstester har utförts på det flytande testbränslet för att verifiera närvaron och effekten av SCFA, medan FTIR-spektroskopi och GC/MS-analyser användes för att verifiera närvaron av kalciumtvålar i sedimentet och i lösning. I motsats till förväntningarna visades det att närvaron av SCFA i bränslet inte är grundläggande för bildandet av karboxyltvål. Dessutom resulterar de olika kalciumkomponenterna i olika mängder och strukturer av metalltvålar i sediment och i lösning.
Ying, Min. "A Soft-Body Interconnect For Self-Reconfigurable Modular Robots." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/234.
Повний текст джерелаButcher, Annabel Louise. "Deformation and fracture of soft materials for cartilage tissue engineering." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277890.
Повний текст джерелаGaballa, Mohamed Abdelrhman Ahmed. "Nonlinear multiphasic mechanics of soft tissue using finite element methods." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184837.
Повний текст джерелаBufi, Nathalie. "Identification of soft tissue material constants using tailored finite element model based regressions." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104874.
Повний текст джерелаLe développement d'outils efficaces pour la caractérisation des propriétés mécaniques des tissus mous est nécessaire. La connaissance du module d'Young et du coefficient de Poisson est essentielle à la modélisation du comportement mécanique et à l'estimation des champs de contraintes et de déplacements. L'objectif de cette étude est de mettre en oeuvre une méthode indirecte permet- tant d'identifier les constantes de matériau de tissus mous à partir de données expérimentales, pour des échantillons de forme et de composition variables. L'approche retenue est la résolution d'un problème inverse sur-déterminé. Des simulations par éléments finis en trois dimensions ont été réalisées, modélisant un corps homogène de matériau élastique linéaire isotrope. Les résultats de ces simulations ont été confrontés au champ de déplacement mesuré sur la surface d'échantillons en tension simple, par des techniques de corrélation d'image. Les constantes du matériau sont identifiés lorsque la différence entre le champ de déplacement mesuré et calculé atteint un minimum. La faisabilité de cette méthode a été vérifiée dans le cas de tests de tension simple sur des cordes vocales de porc. Les paramètres identifiés ont été comparés à des données publiées dans la littérature. Cette méthode peut être développée et appliquée à une grande variété de tissus mous.
Kalcioglu, Zeynep Ilke. "Mechanical behavior of tissue simulants and soft tissues under extreme loading conditions." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79558.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 157-168).
Recent developments in computer-integrated surgery and in tissue-engineered constructs necessitate advances in experimental and analytical techniques in characterizing properties of mechanically compliant materials such as gels and soft tissues, particularly for small sample volumes. One goal of such developments is to quantitatively predict and mimic tissue deformation due to high rate impact events typical of industrial accidents and ballistic insults. This aim requires advances in mechanical characterization to establish tools and design principles for tissue simulant materials that can recapitulate the mechanical responses of hydrated soft tissues under dynamic contact-loading conditions. Given this motivation, this thesis studies the mechanical properties of compliant synthetic materials developed for tissue scaffold applications and of soft tissues, via modifying an established contact based technique for accurate, small scale characterization under fully hydrated conditions, and addresses some of the challenges in the implementation of this method. Two different engineered material systems composed of physically associating block copolymer gels, and chemically crosslinked networks including a solvent are presented as potential tissue simulants for ballistic applications, and compared directly to soft tissues from murine heart and liver. In addition to conventional quasistatic and dynamic bulk mechanical techniques that study macroscale elastic and viscoelastic properties, new methodologies are developed to study the small scale mechanical response of the aforementioned material systems to concentrated impact loading. The resistance to penetration and the energy dissipative constants are quantified in order to compare the deformation of soft tissues and mechanically optimized simulants, and to identify the underlying mechanisms by which the mechanical response of these tissue simulant candidates are modulated. Finally, given that soft tissues are biphasic in nature, atomic force microscopy enabled load relaxation experiments are utilized to develop approaches to distinguish between poroelastic and viscoelastic regimes, and to study how the anisotropy of the tissue structure affects elastic and transport properties, in order to inform the future design of tissue simulant gels that would mimic soft tissue response.
by Zeynep Ilke Kalcioglu.
Ph.D.
Shan, Sicong. "Planar Soft Functional Periodic Structures Exploiting Instabilities and Large Deformation." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845411.
Повний текст джерелаEngineering and Applied Sciences - Engineering Sciences
Mosier, Aaron P. "Microfluidic-assisted atomic force microscopy for the mechanical characterization of soft biological materials." Thesis, State University of New York at Albany, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3566554.
Повний текст джерелаViable methods for bacterial biofilm remediation require a fundamental understanding of biofilm mechanical properties and their dependence on dynamic environmental conditions. Mechanical test data, quantifying elasticity or adhesion, may be used to perform physical modeling of biofilm behavior, thus enabling the development of novel remediation strategies. To achieve real-time, dynamic measurements of these properties, a novel analysis platform consisting of a microfluidic flowcell device has been designed and fabricated for in situ analysis using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The flowcell consists of microfluidic channels for biofilm establishment that are then converted into an open architecture, laminar flow channel for AFM measurement in a liquid environment. Computational fluid dynamics (CFD) was used to profile fluid conditions within the device during biofilm establishment. The validity of the AFM nanoindentation measurement mechanism was confirmed in the context of the system through the elastic characterization of several non-living reference materials. Force-mode AFM was used to measure the elastic properties of mature Pseudomonas aeruginosa PAO1 biofilms and observe a dynamic response to a chemical antagonist. Elastic moduli ranging from 0.58 to 2.61 kPa were determined for the mature biofilm, which fall within the range of moduli previously reported by optical, rheometric, and microindentation techniques. A modified version of the flowcell was employed to perform similar elastic characterization of mouse submandibular glands (SMGs), demonstrating the adaptability of the system to perform ex situ analyses of a broader set of biological materials. These results demonstrate the validity of the microfluidic flowcell system as an effective platform for future investigations of the mechanical and morphological response of biofilms and other soft biomaterials to dynamic environmental conditions.
Meem, Asma Ul Hosna. "On the Mechanics and Dynamics of Soft UV-cured Materials with Extreme Stretchability for DLP Additive Manufacturing." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1628358191573142.
Повний текст джерелаOwino, Vivianne. "Structural Analysis of Soft-Hard Material Interface in an Ant Neck Joint." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376947061.
Повний текст джерелаWang, Zhixin. "Polydimethylsiloxane Mechanical Properties Measured by Macroscopic Compression and Nanoindentation Techniques." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3402.
Повний текст джерелаNguyen, Van Tang. "Nanostructured soft-hard magnetic materials with controlled architecture." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1007.
Повний текст джерелаAmong currently investigated rare-earth-free magnets, ferromagnetic τ-MnAl is a highly potential candidate as having promising intrinsic magnetic properties. In my thesis, Mn(Fe)AlC was synthesized by mechanical alloying method. Effects of carbon on microstructure and magnetic properties were systematically investigated. It was found that high purity of τ-MnAl(C) could be obtained at 2 at.% C doping, showing clearly stabilizing effect of carbon. Mn54.2Al43.8C2 has the best magnetic properties: magnetization at 2T M2T = 414 kAm-1, remanent magnetization Mr = 237 kAm-1, coercivity HC = 229 kAm-1, and |BH|max = 11.2 kJm-3. HC increased inversely with the crystallite size of τ phase and proportionally with C content. Moreover, first principle calculation showed both stabilizing effect and preferable interstitial positions of carbon in tetragonal τ-MnAl. Mn51-xFexAl47C2 (x= 0.25, 0.5, 1, 2, 4, 6) alloys were also synthesized by mechanical alloying method, showing high purity of τ phase up to 2 at.% Fe doping. Adding of Fe on MnAl(C) reduced both magnetization and TC but likely increased slightly HC. 57Fe Mössbauer spectrometry at 300K was used to probe local enviroment in ε-, τ-, β-, and γ2-MnFeAl(C). In which, γ2-, ε-, and β-MnFeAl(C) exhibited a quadrupolar structure while τ -Mn50.5Fe0.5Al47C2 spectrum showed a rather complex magnetic hyperfine splitting. The interaction between Fe and Mn examined by in-field Mössbauer measurement at 10 K and 8 T showed a non-collinear magnetic structure between Fe and Mn with different canting angles at different sites. Hyperfine field of MnFeAl alloy calculated by Win2k supported both magetic properties and Mossbauer results
Van, der Westhuizen Artho Otto. "Impact response of a continuous fibre reinforced thermoplastic from a soft bodied projectile." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80095.
Повний текст джерелаAFRIKAANSE OPSOMMING: Saamgestelde materiale het baie gewilde materiale in die lugvaart- en motor industrië geword as gevolg van die gewigsbesparende voordele wat dit inhou. Kostes en ander verwerkingsprobleme het tradisioneel die wydverspreide gebruik van spesifiek termoplasties-versterkte vesels in hierdie areas verhinder. Baie van die vervaardigingsprobleme (spesifiek lang siklusse) is aangespreek met die aanvang van termoplastiese matriks materiaal soos Polyphenolien Sulfied (PPS). Hierdie materiaal voldoen ook aan die lugvaart-industrie se brand-, rook- en giftigheidstandaarde. Termoplastiese saamgestelde materiale kan byvoorbeeld gevind word op komponente in vliegtuie se binneruimtes en ook die voorste rand van die vlerke. Hierdie komponente is hoogs vatbaar vir impakskade. Die hoë sterkte en styfheid tot gewig verhoudings van saamgestelde materiale laat toe vir dun materiaal dwarssnitte. Komponente is dus kwesbaar vir uit-vlakkige impak beladings. Saamgestelde materiale kan ook intern deur hierdie beladings beskadig word en kan nie met die blote oog waargeneem kan word nie. Dit is dus nodig om die skade weens hierdie beladings tydens normale gebruik akkuraat te voorspel. Verder sal dit nuttig wees om die struktuur se gedrag te bepaal in toepassings waar byvoorbeeld passasier veiligheid krities is, soos op vliegtuig ruglenings tydens noodlandings. In hierdie studie is die potensiële vervaardigingsvoordele van termoplastiese saamgestelde materiale gedemonstreer. Daarbenewens is 'n uit-vlakkige impak deur 'n sagte liggaam herbou in 'n laboratorium omgewing. Die primêre doelwit van hierdie studie was om die impak numeries te modelleer. Vervaardigingsvoordele van `n vesel versterkte termoplastiese laminaat is gedemonstreer deur die vervaardiging van 'n konkawe, agt laag laminaat uit 'n vooraf gekonsolideerde geweefde doek. Die totale verwerkingstyd van die plat laminaat na 'n konkawe laminaat was minder as vyf minute. 'n Eenvoudige plat laminaat en 'n konkawe laminaat is onderwerp aan 'n lae snelheid impak deur 'n sagte projektiel. Die impak is gemodelleer deur die evaluering van drie modelleringsmetodes vir die saamgestelde paneel. Die evalueringskriteria het o.a. ingesluit of laminaat se volle gedrag suksesvol gemodelleer kon word met behulp van slegs 2D dop elemente. Die reaksie van die saamgestelde paneel en gepaardgaande faling is met wisselende vlakke van sukses deur die drie geëvalueerde modelle voorspel. Die faling van tussen-laminêre bindings (verwys na as delaminasie) kon nie deur enige van die modelle voorspel word nie. Twee van die modelle het egter in-vlak faling met redelike akkuraatheid voorspel.
ENGLISH ABSTRACT: Due to weight saving advantages composite materials have become a highly popular material in the aerospace and automotive industries. Traditionally processing difficulties and costs have been a barrier to widespread composite material use in these industries. With the advent of thermoplastic matrix materials such as Polyphenoline Sulphide (PPS) the processing difficulties (especially long cycle times) experienced with traditional thermosetting resins can be addressed while maintaining aerospace Fire-Smoke and Toxicity (FST) approval. Thermoplastic composites can for example be found on aircraft interior components and leading edges of the wings. These areas are highly susceptible to impact damage. The high strength- and stiffness to weight ratios of composites allows for thin material cross sections. This leaves the components vulnerable to out-of-plane impact loads. Composite materials may also be damaged internally by these loads, leaving the damage undetectable through visual inspections. It may therefore be necessary to predict the amount of damage a component would sustain during normal operation. Additionally, it would be useful to predict structural response of these materials in applications where passenger safety is crucial, such as aircraft seat backrests during emergency landings. In this study the potential processing benefits of thermoplastic composite materials were demonstrated. Additionally an out-of-plane impact from a soft bodied projectile was reconstructed in a laboratory environment. The primary objective was to numerically model the impact event. Processing benefits of thermoplastics were demonstrated by producing a single curvature eight layered laminate from a pre-consolidated woven sheet. The total processing time from flat panel to a single curvature panel was below five minutes. A simple flat laminate and a single curvature laminate were subjected to a low velocity drop weight impact load from a soft bodied projectile. These impact events were modelled by evaluating three modelling methods for the composite panel structural response and damage evolution. Part of the evaluation criteria included whether laminate failure could be modelled successfully using only 2D shell elements. The response of the composite panel and accompanying failure were predicted with varying levels of success by the three evaluated models. The failure of interlaminar bonds (referred to as delamination) could not be predicted by either model. However two of the models predicted in-plane failure with reasonable accuracy.
Bruton, Jared Thomas. "Packing Sheet Materials Into Cylinders and Prisms Using Origami-based Approaches." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5998.
Повний текст джерелаFincan, Mustafa. "Assessing Viscoelastic Properties of Polydimethylsiloxane (PDMS) Using Loading and Unloading of the Macroscopic Compression Test." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5480.
Повний текст джерелаPetekkaya, Ali Tolga. "In Vivo Indenter Experiments On Soft Biological Tissues For Identification Of Material Models And Corresponding Parameters." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610071/index.pdf.
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s) effect and anisotropic response were examined. By using the results of the relaxation and creep tests, parameters of the Prony series capable of modelling these data were determined. With this study, some important conclusions regarding the soft biological tissues were drawn and thus the behaviors of the soft biological tissues were better understood. Besides, the difficulties inherent to in-vivo tests were recognized and actions to reduce these difficulties were explained. Finally, clean experimental data, to be used in the computer simulations, were obtained.
Pelegrini, Leandro. "Influência do tempo de moagem por mecâno-síntese nas propriedades da liga magnética Fe-3%Si-0,75%P aplicada em núcleos de máquinas elétricas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/72911.
Повний текст джерелаThe present work aims to study, obtaining and characterization of Fe-Si-P soft magnetic alloy produced by conventional powder metallurgy intended for the future application in electrical machines cores, currently manufactured by sheet metal forming. The alloy Fe-3%Si-0,75%P was chosen based on previous tests. To obtain the alloy was used mechanical alloying route with different milling times: 1 h, 3 h and 9 h, and the material without milling for comparison. In the sequence, the specimens were uniaxially cold compacted at 600 MPa followed by sintering at 1150 ° C in an atmosphere of argon. The analysis of the influence of milling time on the physical, mechanical, magnetic and electric properties of the sintered material was the central goal of this work. The physical properties characterization showed a reduction in the bulk apparent density of the milled powder, an increase in particle size distribution and reduction thereof with increasing milling time. As regards magnetic properties, it was observed that the milled material for 3 hours showed the best results of saturation induction (1.15 T), despite the increase in the coercivity as expected due to the inherent mechanical alloying process. Furthermore, the X-ray diffraction detected the alloy formation through the solid solution of P and Si elements in the ferrite matrix. The metallographic analysis showed the decrease in grain size with increasing milling time. Finally, were performed a simulation prototype for analysis of material performance in order to future implement. This, held by finite element method on a synchronous generator core with NdFeB permanent magnets, resulting in a flux density (1.95 T) for the material with 3h of milling and a torque of only 13% lower compared to conventional generator produced with cores of electric steel sheet.
Usu, Kerem. "Identification Of Soft Tissue Mechanical Material Model And Corresponding Parameters From In Vivo Experimental Data By Using Inverse Finite Element Method." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609885/index.pdf.
Повний текст джерелаChang, Hong. "Hydraulic Fracturing in Particulate Materials." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4957.
Повний текст джерелаTanguy, Francois. "Debonding mechanisms of soft adhesives : toward adhesives with a gradient in viscoelasticity." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01021169.
Повний текст джерелаKaminuza, Irénée. "Thermal and chemical analysis of carbonaceous materials: diesel soot and diesel fuel reactor deposits." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/16911.
Повний текст джерелаLefranc, Maxime. "Fracture properties of Soft Materials : From Linear Elastic Fracture to damage at the microscopic scale." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112028/document.
Повний текст джерелаOur novel experimental approach consists in studying fracture mechanics of soft materials, mainly polymer and colloidal gels, which have microstructures with large typical length scales. This increase in the microscopic length scale will consequently increase the typical size of the process zone and make its observation easier with standard microscopy techniques (optical or confocal).To do so, we designed a novel experimental device to study crack propagation in such soft materials. This experiment enables us to grow a unique crack in a controlled way in a soft specimen and to look at the crack tip at high magnification for crack velocities between 1 µm/s and 1cm/s. Working on physical polymer gels, we analysed the crack shape and crack displacement fields (using Digital Image Correlation) at large and intermediate scales for various velocities. We realized there was a separation of scales between the scale at which LEFM applies, the scale at which elastic nonlinearities emerge and the scale at which dissipation occurs. This last scale could not be investigated with the polymer gel. Recent experiments on colloidal gels, which have a microscopic length scale bigger than the one of polymer gels, show that we are able to probe damage at the microstructural scale
Manisha. "Evaluation of thermal stresses in planar solid oxide fuel cells as a function of thermo-mechanical properties of component materials." Texas A&M University, 2008. http://hdl.handle.net/1969.1/86039.
Повний текст джерелаSiéfert, Emmanuel. "Inflating to shape : from soft architectured elastomers to patterned fabric sheets." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS018.
Повний текст джерелаIn this thesis at the interface between geometry and mechanics, we aim at developing, studying and programming slender morphing inflatables structures. A first strategy consists in manufacturing elastomeric plates embedding a network of channels, which expand, when inflated, mainly perpendicular to their local orientation, similarly to simple elastic tubes. Playing with both the orientation and density of channels, we control the direction and intensity of the in-plane homogenized ``growth", in general incompatible with a flat geometry. The structure spontaneously buckles and adopts a shape which minimizes its elastic energy. For very thin slender bodies, this reduces to follow the target metric induced by inflation. We then study the inflation of structures made of two superimposed inextensible thin sheets, sealed together along a specific line network. Starting with flat curved ribbons, we observe and rationalize the surprising overcurvature upon inflation by maximizing the inner volume given the inextensibility constraint. We finally extend our investigation to two-dimensional structures and control the in-plane contraction upon inflation, which occurs perpendicular to the seam?s direction. We program the morphing of such stiff inflatable structures and investigate their mechanics
Chafetz, Jared Richard. "A Novel Fiber Jamming Theory and Experimental Verification." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2102.
Повний текст джерелаKukatla, Harish C. "A Study of Strain Elastography Under a Normal Tensile Testing Condition." Youngstown State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1296334599.
Повний текст джерелаDarvish, Shadi. "Thermodynamic Investigation of La0.8Sr0.2MnO3±δ Cathode, including the Prediction of Defect Chemistry, Electrical Conductivity and Thermo-Mechanical Properties". FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3653.
Повний текст джерелаStanciu, Cristina Daniela. "Matériaux magnétiques doux Fe-Si de hautes performances obtenus par mécanosynthèse." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY020/document.
Повний текст джерелаFe-Si alloys are known for combining excellent magnetic properties with good electric characteristics (high resistivity). In this context we sought to develop materials with a relatively high Si content, often difficult to obtain and shape industrially.In this thesis, soft magnetic Fe-Si alloys with high Si content (4.5, 6.5, 10 and 15 wt. %) were successfully obtained in nanocrystalline state by mechanical alloying and annealing. The formation of the alloy was studied by X-ray and neutron diffraction, Mossbauer spectroscopy and thermomagnetic analysis. DSC technique was used in order to study the powder’s thermal stability. Magnetisation measurements were also made in order to characterise their magnetic performances. The milling duration necessary for the formation of the alloy was determined for each Si content. For low milling times, annealing leads to the formation of the Fe3Si compound. Once the alloy is formed by mechanical milling, the effect of the annealing is only to reduce the second order stress induced in the powder by the milling process. Si addition leads to the decrease of the alloy’s Curie temperature from 770 °C for pure Fe to 725 °C for a 4.5 wt. % Si and down to 550 °C if the Si content increases to 15 wt. %. For low milling times, a gap between the magnetisation of the as-milled alloy and of the milled and subsequently annealed one is due to the formation of the Fe3Si compound during annealing which has a lower magnetisation than that of the αFe (Si) solid solution. For longer milling durations, annealing at 400 °C for 4 hours has no effect on the saturation magnetisation value. By increasing the Si content, the Fe-Si alloy’s saturation magnetisation decreases.Fe-Ni alloys whose composition is close to Ni3Fe (commonly known as Permalloys) have better magnetic properties, but a resistivity well inferior to that of Fe-Si alloys. Therefore, a combination of the properties of these 2 alloy classes of soft magnetic materials into a composite seems to be an attractive route. The previously obtained Fe-Si alloys were used for the preparation of Permalloy/Fe-Si composite powders by mechanical milling. Milling leads to the formation of composite powder particles with a stratified aspect. Milling of the Fe-Si and Ni3Fe alloys for 4 hours does not lead to the formation of new phases, but a subsequent annealing at 900 °C results in the formation of a Ni-Fe-Si alloy. Saturation magnetisation of the composite increases with increasing of the Fe-Si content, but milling duration seems to have no effect on it.A preliminary study was made on the elaboration of Ni3Fe/Fe-Si composite compacts obtained by spark plasma sintering, aiming to preserve the nanocrystalline state by lower sintering temperatures. The influence of the sintering temperature and temperature holding duration on the structure, density, resistivity and magnetic properties of the compacts is discussed. Temperatures of up to 750 °C for minimal holding duration or a maintain at the temperature of 700 °C for a duration of up to 2 minutes does not lead to a diffusion of the alloys’ elements. Increasing of the sintering temperature or duration leads to larger crystallite sizes, but they remain in the nano domain for the studied temperatures. The compacts’ density increases with temperature and sintering duration. Resistivity, on the other hand decreases when increasing the aforementioned parameters. The effect of the Fe-Si content is to decrease the density and at the same time increase the compacts’ resistivity. Magnetic permeability is reduced with increasing sintering temperature and duration, as well as when decreasing of the Ni3Fe content. High temperature and long maintaining duration leads to an increase of magnetic losses. Coercive field is also influenced by sintering parameters by the effect they have on the crystallite size
Ramirez, Arias José Luis. "Development of an artificial muscle for a soft robotic hand prosthesis." Thesis, Paris 10, 2016. http://www.theses.fr/2016PA100190/document.
Повний текст джерелаIn the field of robotic hand prosthesis, the use of smart and soft materials is helpful in improving flexibility, usability, and adaptability of the robots, which simplify daily living activities of prosthesis users. However, regarding the smart materials for artificial muscles, technologies are considered to be far from implementation in anthropomorphic robotic hands. Therefore, the target of this thesis dissertation is to reduce the gap between smart material technologies and robotic hand prosthesis. Five central axes address the problem: i)identification of useful grasping gestures and reformulation of the robotic hand mechanism, ii) analysis of human muscle behavior to mimic human grasping capabilities, iii) modeling robot using the hybrid model DHKK-SRQ for the kinematics and the virtual works principle for dynamics, iv) definition of actuation requirements considering the synergy between prehension conditions and robot mechanism, and v) development of a smart material based actuation system.This topics are addressed in four chapters:1. Human hand movement analysis toward the hand prosthesis requirements2. Design and modeling of the soft robotic hand ProMain-I3. Mechatronic assessment of Prosthetic hand4. Development of an artificial muscle based on smart materials
Czarnecki, Jarema S. "Engineered carbon-based scaffolds for hard and soft tissue repair, reconstruction or regeneration." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1386953861.
Повний текст джерелаVillanova, Julie. "Détermination des contraintes résiduelles dans les matériaux céramiques pour SOFC : mesures multi-échelles et influence des cycles d'oxydo-réduction." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2010. http://tel.archives-ouvertes.fr/tel-00582358.
Повний текст джерелаDavis, Andrew Scott. "Temperature Induced Deflection of Yttria Stabilized Zirconia Membranes." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338369600.
Повний текст джерелаSILVA, MAVIAEL J. da. "Desenvolvimento de selantes vitrocerâmicos para uso em SOFC pertencentes ao sistema BAS (BaO-Alsub(2)0sub(3)-SiOsub(2)) modificados com Bsub(2)Osub(3)." reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23655.
Повний текст джерелаMade available in DSpace on 2015-04-10T16:38:07Z (GMT). No. of bitstreams: 0
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Bohec, Pierre. "Étude du comportement hors-équilibre du cortex cellulaire." Phd thesis, Université Paris-Diderot - Paris VII, 2012. http://tel.archives-ouvertes.fr/tel-00870466.
Повний текст джерела