Deformation and Adhesion of Soft Composite Systems for Bio-inspired Adhesives and Wrinkled Surface Fabrication

Deformation and Adhesion of Soft Composite Systems for Bio-inspired Adhesives and Wrinkled Surface Fabrication
Author: Michael Imburgia
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:

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The study of soft material deformation and adhesion has broad applicability to industries ranging from automobile tires to medical prosthetics and implants. When a mechanical load is imposed on a soft material system, a variety of issues can arise, including non-linear deformations at interfaces between soft and rigid components. The work presented in this dissertation embraces the occurrence of these non-linear deformations, leading to the design of functional systems that incorporate a soft elastomer layer with application to bio-inspired adhesives and wrinkled surface fabrication. Understanding the deformation of a soft elastomer layer and how the system loading and geometry influence non-linear mechanical transitions, including interfacial failure and surface buckling, are crucial for predicting the performance of the mechanical system. This dissertation focuses on three soft composite systems of particular interest: (1) a multi-component, multiple adhesive contact surface device that allows for control of reversible adhesive force with geometric arrangement, (2) a confined isolated shear contact and an elastomeric coating, where the deformation and adhesion scale with the degree of confinement, and (3) a thin film lamination technique involving a soft substrate, where surface wrinkles are created and tuned in a continuous manner by controlling interfacial strains via applied contact load and substrate curvature. We first study the deformation and adhesion of a multi-component fabric-elastomer system with multiple adhesive contacts, or "digits". We conduct lap adhesion experiments in a model three digit system, finding that increasing angular spacing between adhesive digits increases system compliance and attenuates adhesive force capacity. To describe these findings we develop several relationships between system loading, materials properties, and geometry. We develop an equation which describes the relationship of system compliance with individual digit compliance and angular spacing between adhesive digits that agrees well with experimental data. Additionally, we derive equations for adhesive force capacity in a multiple adhesive contact system that agree well with experimental data. These explicit equations not only relate angular spacing with force capacity, but include critical strain energy release rate, digit compliance, and contact area. The equations derived and verified in this study will lead to more complex adhesive device design, as well as provide a foundation for studying the biomechanics of animals that use adhesion for locomotion. Next, we examine the deformation and adhesion of a rigid punch contacting and shearing a thin elastic coating. Using experiment we find that increasing confinement leads to a decrease in compliance and an increase in adhesive force capacity. We develop an explicit, semi-empirical equation with the help of finite element analysis to describe the influence of confinement ratio on shear compliance. This derived equation agrees with our experimental data, with the exception of a few data points that deviate due to a pronounced normal force component. Additionally, we derive an equation for adhesive force capacity as a function of confinement, elastic coating modulus, and critical strain energy release rate. We find experimentally that an increase in adhesive force capacity was largely dictated by an increase in confinement, with some additional contributions attributed to dissipative processes confined to the adhesive crack tip. These equations will serve as a guide for decoupling the contributions of geometry and materials parameters to adhesive force in systems involving a thin elastic layer. Lastly, we develop a fabrication technique that transforms the existing manufacturing process of film lamination to create tunable wrinkled surfaces in a thin film/soft elastomer composite. We conduct experiments to find that the process parameters of applied contact load and roller curvature can be used to control wrinkle aspect ratio. Our experimental results convey that increasing applied contact load and decreasing roller radius lead to an increase in wrinkle amplitude. Using both experimental results and finite element analysis, we develop a relation between wrinkle aspect ratio and the process parameters of applied contact load and roller curvature. This explicit equation allows us to predict the change in wrinkle amplitude for a given materials system as process parameters are tuned using our modified film lamination technique. Wrinkled surface technology has been envisioned in many applications ranging from optoelectronics to enhanced adhesives. The technique presented here to tune wrinkle size in a continuous process can lead to the large scale manufacturing of these previously proposed wrinkling technologies.

Fabric and Soft Materials Composites for Bio-Inspired Adhesives and Prosthetics

Fabric and Soft Materials Composites for Bio-Inspired Adhesives and Prosthetics
Author: Daniel R. King
Publisher:
Total Pages:
Release: 2015
Genre:
ISBN:

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Adhesives have long been designed around a trade-off between adhesive strength and releasability. Within this spectrum, specialized materials have been designed to maximize adhesive ability for a given application. To overcome this trade-off, a new adhesive paradigm is required. Biologically inspired adhesives have been of interest over the past two decades, because organisms are seen using their adhesive pads to achieve high adhesive forces, while maintaining releasability and reusability. Many biological organisms possess microscopic fibrillar features on their toe-pads, which enables climbing. While much effort has been spent attempting to mimic these features, ultimately high force capacities have not been achieved. Recently, a new framework has been introduced which states that a specific surface morphology is not necessary for creating high force capacity, easy release adhesives. This framework states that for shear adhesives to achieve high force capacity, the ratio of contact area to compliance in the loading direction, A/C, must be increased. In this thesis we focus on expanding this framework to quantitatively understand both compliance and area, for a wide range of adhesive materials and geometries, and across a wide range of substrates with varying roughness. To increase the functionality of high strength, reusable adhesives, we have developed a new adhesive configuration which supports normal loading as well as shear loading. Finally, we expand to a new field, biological prosthetic materials, and develop fabric-based composites which are extremely tough, strong, and flexible, while containing water. The foundation of the work presented in this thesis is based upon an analytical model developed to calculate the compliance of fabricated adhesives (Chapter 2). Combining this knowledge with the previously developed scaling theory allows a high degree of accuracy in calculating force capacity. While this method works well for smooth surfaces such as glass, it assumes that the nominal pad area is equal to the true area of contact, which is not true on rough surfaces. A model is developed to calculate the true area of contact based on surface roughness and adhesive materials properties (Chapter 3). The results of this model demonstrate that there is an optimum pad modulus for any given surface roughness to achieve maximum stress capacity. In some situations, high strength and easy release adhesives are required in normal loading situations. We develop a new adhesive configuration which enables shear adhesives to support normal loads (Chapter 4). This method results in a six-fold increase in normal force capacity. This provides tolerance in adhesives applications, greatly improving the commercial utility of these adhesives. Finally, we use techniques learned from the fabrication of adhesives to develop composites from polyampholyte gels and glass fiber fabrics (Chapter 5). These materials exhibit enhanced properties over the controls, including extremely high toughness and strength, while maintaining flexibility and containing water. A general mechanism is explained that results in these improved properties, opening up opportunities to develop enhanced composites from fabrics and soft materials in other fields.

Bio-inspired Polymers

Bio-inspired Polymers
Author: Nico Bruns
Publisher: Royal Society of Chemistry
Total Pages: 613
Release: 2016-10-14
Genre: Science
ISBN: 1782626662

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Many key aspects of life are based on naturally occurring polymers, such as polysaccharides, proteins and DNA. Unsurprisingly, their molecular functionalities, macromolecular structures and material properties are providing inspiration for designing new polymeric materials with specific functions, for example, responsive, adaptive and self-healing materials. Bio-inspired Polymers covers all aspects of the subject, ranging from the synthesis of novel polymers, to structure-property relationships, materials with advanced properties and applications of bio-inspired polymers in such diverse fields as drug delivery, tissue engineering, optical materials and lightweight structural materials. Written and edited by leading experts on the topic, the book provides a comprehensive review and essential graduate level text on bio-inspired polymers for biochemists, materials scientists and chemists working in both industry and academia.

Adhesive Bonding of Aircraft Composite Structures

Adhesive Bonding of Aircraft Composite Structures
Author: Welchy Leite Cavalcanti
Publisher: Springer
Total Pages: 350
Release: 2021-06-04
Genre: Technology & Engineering
ISBN: 9783319928098

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This book is open access under a CC BY 4.0 license. It presents the results of the ComBoNDT European project, which aimed at the development of more secure, time- and cost-saving extended non-destructive inspection tools for carbon fiber reinforced plastics, adhered surfaces and bonded joints. The book reports the optimal use of composite materials to allow weight savings, reduction in fuel consumptions, savings during production and higher cost efficiency for ground operations.

Advanced Healthcare Materials

Advanced Healthcare Materials
Author: Ashutosh Tiwari
Publisher: John Wiley & Sons
Total Pages: 421
Release: 2014-05-09
Genre: Technology & Engineering
ISBN: 1118773683

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Offers a comprehensive and interdisciplinary view of cutting-edge research on advanced materials for healthcare technology and applications Advanced healthcare materials are attracting strong interest in fundamental as well as applied medical science and technology. This book summarizes the current state of knowledge in the field of advanced materials for functional therapeutics, point-of-care diagnostics, translational materials, and up-and-coming bioengineering devices. Advanced Healthcare Materials highlights the key features that enable the design of stimuli-responsive smart nanoparticles, novel biomaterials, and nano/micro devices for either diagnosis or therapy, or both, called theranostics. It also presents the latest advancements in healthcare materials and medical technology. The senior researchers from global knowledge centers have written topics including: State-of-the-art of biomaterials for human health Micro- and nanoparticles and their application in biosensors The role of immunoassays Stimuli-responsive smart nanoparticles Diagnosis and treatment of cancer Advanced materials for biomedical application and drug delivery Nanoparticles for diagnosis and/or treatment of Alzheimers disease Hierarchical modelling of elastic behavior of human dental tissue Biodegradable porous hydrogels Hydrogels in tissue engineering, drug delivery, and wound care Modified natural zeolites Supramolecular hydrogels based on cyclodextrin poly(pseudo)rotaxane Polyhydroxyalkanoate-based biomaterials Biomimetic molecularly imprinted polymers

Polymer Matrix Composites and Technology

Polymer Matrix Composites and Technology
Author: Ru-Min Wang
Publisher: Elsevier
Total Pages: 570
Release: 2011-07-14
Genre: Technology & Engineering
ISBN: 0857092227

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Given such properties as low density and high strength, polymer matrix composites have become a widely used material in the aerospace and other industries. Polymer matrix composites and technology provides a helpful overview of these materials, their processing and performance.After an introductory chapter, part one reviews the main reinforcement and matrix materials used as well as the nature of the interface between them. Part two discusses forming and molding technologies for polymer matrix composites. The final part of the book covers key aspects of performance, including tensile, compression, shear and bending properties as well as impact, fatigue and creep behaviour.Polymer matrix composites and technology provides both students and those in industry with a valuable introduction to and overview of this important class of materials. Provides a helpful overview of these materials, their processing and performance incorporating naming and classification of composite materials Reviews the main reinforcement and matrix materials used as well as the nature of the interface between them including damage mechanisms Discusses forming and molding technologies for polymer matrix composites outlining various techniques and technologies

Continuum Micromechanics

Continuum Micromechanics
Author: P. Suquet
Publisher: Springer
Total Pages: 352
Release: 2014-05-04
Genre: Technology & Engineering
ISBN: 3709126622

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This book presents the most recent progress of fundamental nature made in the new developed field of micromechanics: transformation field analysis, variational bounds for nonlinear composites, higher-order gradients in micromechanical damage models, dynamics of composites, pattern based variational bounds.

Shape Memory Polymers

Shape Memory Polymers
Author: Jinlian Hu
Publisher: Smithers Rapra
Total Pages: 326
Release: 2014-05-27
Genre: Science
ISBN: 1909030333

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Shape-memory polymers (SMP) are a unique branch of the smart materials family which are capable of changing shape on-demand upon exposure to external stimulus. The discovery of SMP made a significant breakthrough in the developments of novel smart materials for a variety of engineering applications, superseded the traditional materials, and also influenced the current methods of product designing. This book provides the latest advanced information of on-going research domains of SMP. This will certainly enlighten the reader to the achievements and tremendous potentials of SMP. The basic fundamentals of SMP, including shape-memory mechanisms and mechanics are described. This will aid reader to become more familiar with SMP and the basic concepts, thus guiding them in undergoing independent research in the SMP field. The book also provides the reader with associated challenges and existing application problems of SMP. This could assist the reader to focus more on these issues and further exploit their knowledge to look for innovative solutions. Future outlooks of SMP research are discussed as well. This book should prove to be extremely useful for academics, R&D managers, researcher scientists, engineers, and all others related to the SMP research.

Lonely Planet USA

Lonely Planet USA
Author: Lonely Planet
Publisher: Lonely Planet
Total Pages: 2126
Release: 2018-04-01
Genre: Travel
ISBN: 1787019519

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Lonely Planet: The world’s leading travel guide publisher Lonely Planet USA is your passport to the most relevant, up-to-date advice on what to see and skip, and what hidden discoveries await you. Gaze into the mile-deep chasm of the Grand Canyon, hang 10 on an iconic Hawaiian wave, or let sultry southern music and food stir your soul; all with your trusted travel companion. Get to the heart of the USA and begin your journey now! Inside Lonely Planet USA Travel Guide: Colour maps and images throughout Highlights and itineraries help you tailor your trip to your personal needs and interests Insider tips to save time and money and get around like a local, avoiding crowds and trouble spots Essential info at your fingertips - hours of operation, phone numbers, websites, transit tips, prices Honest reviews for all budgets - eating, sleeping, sight-seeing, going out, shopping, hidden gems that most guidebooks miss Cultural insights give you a richer, more rewarding travel experience - including history, art, literature, cinema, music, architecture, politics, landscapes, national parks, wildlife, cuisine and wine Covers New England, New York, the Mid-Atlantic, Florida, the South, Great Lakes, Great Plains, Texas, Rocky Mountains, Southwest, Pacific Northwest, California, Alaska, Hawaii, and more eBook Features: (Best viewed on tablet devices and smartphones) Downloadable PDF and offline maps prevent roaming and data charges Effortlessly navigate and jump between maps and reviews Add notes to personalise your guidebook experience Seamlessly flip between pages Bookmarks and speedy search capabilities get you to key pages in a flash Embedded links to recommendations' websites Zoom-in maps and images Inbuilt dictionary for quick referencing The Perfect Choice: Lonely Planet USA, our most comprehensive guide to the USA, is perfect for both exploring top sights and taking roads less traveled. About Lonely Planet: Lonely Planet is a leading travel media company and the world’s number one travel guidebook brand, providing both inspiring and trustworthy information for every kind of traveller since 1973. Over the past four decades, we’ve printed over 145 million guidebooks and grown a dedicated, passionate global community of travellers. You’ll also find our content online, on mobile, video and in 14 languages, 12 international magazines, armchair and lifestyle books, ebooks, and more. Important Notice: The digital edition of this book may not contain all of the images found in the physical edition.