In-plane Bending Behavior of a Two-ply Composite PDF Download

Author: John T. Murphy
Publisher:
ISBN:
Category :
Languages : en
Pages : 122

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Author: Hassan Abdullah Alshahrani
Publisher:
ISBN:
Category :
Languages : en
Pages : 178

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Composite materials are increasingly replacing metals for many modern structures used in the aerospace and automotive industry. Textile composites are favored due to their superior forming capabilities to produce complex shapes. However, the formability of a textile composite is limited by failure modes, such as wrinkling, which remain challenging issues during the forming process. The ability to accurately predict wrinkles and ultimately prevent them during the forming process is highly desirable for process optimization in an industrial environment. The success or failure of composite formation is determined by the properties of the material that is undergoing the deformation. A significant amount of time and effort has been devoted to characterizing and modeling these properties. Therefore, to predict those defects, a thorough understanding of the deformation behavior of textile-woven prepregs is required. Out-of-plane bending is one of the deformation mechanisms that govern the appearance of wrinkles during composite forming. This thesis therefore presents an experimental, theoretical, and numerical study on the out-of-plane bending behavior of woven out-of-autoclave prepregs with application in forming simulations.Within this thesis, a new test method for characterizing the bending behavior of prepreg materials at forming conditions was developed based on a vertical cantilever test associated with a linear actuator and load cell. This test method allowed for sufficient control of the deflection shape, testing rates, and processing temperatures within the range of the thermosetting resin. Investigations for out-of-plane bending behavior and viscoelastic behavior in the forming process conditions were undertaken using the developed test method. Through the cantilever beam theory, where the prepreg yarn is composed of two external viscoelastic polymer plies with a linear elastic ply, a theoretical model is proposed to estimate the bending stiffness over a range of processing conditions. A new approach for considering the testing rate and temperature with respect to a reference value is also established. Experimental tests were carried out to estimate the model parameters and to validate the proposed model. The predicted bending stiffness was found to be in a good agreement with experimental values at selected conditions. However, there were slight differences due to the complexity of the undulation in the woven fabric structure. Then, a finite element model for the bending behavior of multilayered prepregs was developed by considering the actual bending behavior of the material. The prepreg ply was modeled by incorporating the characterized behavior of intra-ply shear and inter-ply friction. The effect of stacking sequences on out-of-plane bending deformation during the forming process was studied experimentally and numerically. Moreover, the feasibility of using a viscoelastic approach and its application in forming simulations were analyzed.Finally, a series of real forming experiments using a double diaphragm process were carried out to investigate the formability of textile out-of-autoclave thermoset prepregs over complex geometry for aerospace applications. A one-step procedure was used for both the forming and curing processes using the same experimental setup. A finite element model was developed to simulate the double diaphragm forming process, with consideration for the diaphragm material properties at forming conditions. In addition, important considerations, such as local fiber compressive stresses, shear angle distributions, and stacking lay-up sequences, were analyzed to identify the potential causes of wrinkles in the formed parts. The resulting knowledge from the modeling methodology allowed the designers to reliably choose the appropriate stacking sequences and suitable process parameters for complex structures prior to conducting expensive trial and error tests.

Author: Srinivasan Sridharan
Publisher: Elsevier
ISBN: 1845694821
Category : Technology & Engineering
Languages : en
Pages : 787

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Given such advantages as low weight compared to strength and toughness, laminated composites are now used in a wide range of applications. Their increasing use has underlined the need to understand their principal mode of failure, delamination. This important book reviews key research in understanding and preventing delamination.The first part of the book reviews general issues such as the role of fracture mechanics in understanding delamination, design issues and ways of testing delamination resistance. Part two describes techniques for detecting and characterising delamination such as piezoelectric sensors, the use of lamb waves and acoustic emission techniques. The next two sections of the book discuss ways of studying and modelling delamination behaviour. The final part of the book reviews research on delamination behaviour in particular conditions such as shell and sandwich structures, z-pin bridging and resin bonding.With its distinguished editor and international team of contributors, Delamination behaviour of composites is a standard reference for all those researching laminated composites and using them in such diverse applications as microelectronics, aerospace, marine, automotive and civil engineering. - Reviews the role of fracture mechanics in understanding delamination, design issues and ways of testing delamination resistance - Discuss ways of studying and modelling delamination behaviour - A standard reference for all those researching laminated composites

Author: P.K. Mallick
Publisher: CRC Press
ISBN: 1482277735
Category : Technology & Engineering
Languages : en
Pages : 1262

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Book Description
Offers information on the fundamental principles, processes, methods and procedures related to fibre-reinforced composites. The book presents a comparative view, and provides design properties of polymeric, metal, ceramic and cement matrix composites. It also gives current test methods, joining techniques and design methodologies.

Author: M. W. Hyer
Publisher: DEStech Publications, Inc
ISBN: 193207886X
Category : Technology & Engineering
Languages : en
Pages : 718

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Book Description
Updated and improved, Stress Analysis of Fiber-Reinforced Composite Materials, Hyer's work remains the definitive introduction to the use of mechanics to understand stresses in composites caused by deformations, loading, and temperature changes. In contrast to a materials science approach, Hyer emphasizes the micromechanics of stress and deformation for composite material analysis. The book provides invaluable analytic tools for students and engineers seeking to understand composite properties and failure limits. A key feature is a series of analytic problems continuing throughout the text, starting from relatively simple problems, which are built up step-by-step with accompanying calculations. The problem series uses the same material properties, so the impact of the elastic and thermal expansion properties for a single-layer of FR material on the stress, strains, elastic properties, thermal expansion and failure stress of cross-ply and angle-ply symmetric and unsymmetric laminates can be evaluated. The book shows how thermally induced stresses and strains due to curing, add to or subtract from those due to applied loads.Another important element, and one unique to this book, is an emphasis on the difference between specifying the applied loads, i.e., force and moment results, often the case in practice, versus specifying strains and curvatures and determining the subsequent stresses and force and moment results. This represents a fundamental distinction in solid mechanics.

Author: Christos Kassapoglou
Publisher: John Wiley & Sons
ISBN: 1119957060
Category : Technology & Engineering
Languages : en
Pages : 303

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Book Description
Design and Analysis of Composite Structures enables graduate students and engineers to generate meaningful and robust designs of complex composite structures. Combining analysis and design methods for structural components, the book begins with simple topics such as skins and stiffeners and progresses through to entire components of fuselages and wings. Starting with basic mathematical derivation followed by simplifications used in real-world design, Design and Analysis of Composite Structures presents the level of accuracy and range of applicability of each method. Examples taken from actual applications are worked out in detail to show how the concepts are applied, solving the same design problem with different methods based on different drivers (e.g. cost or weight) to show how the final configuration changes as the requirements and approach change. Provides a toolkit of analysis and design methods to most situations encountered in practice, as well as analytical frameworks and the means to solving them for tackling less frequent problems. Presents solutions applicable to optimization schemes without having to run finite element models at each iteration, speeding up the design process and allowing examination of several more alternatives than traditional approaches. Includes guidelines showing how decisions based on manufacturing considerations affect weight and how weight optimization may adversely affect the cost. Accompanied by a website at www.wiley.com/go/kassapoglou hosting lecture slides and solutions to the exercises for instructors.

Author: Holm Altenbach
Publisher: Springer Science & Business Media
ISBN: 3662085895
Category : Technology & Engineering
Languages : en
Pages : 487

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Book Description
Laminate and sandwich structures are typical lightweight elements with rapidly ex panding application in various industrial fields. In the past, these structures were used primarily in aircraft and aerospace industries. Now, they have also found ap plication in civil and mechanical engineering, in the automotive industry, in ship building, the sport goods industries, etc. The advantages that these materials have over traditional materials like metals and their alloys are the relatively high specific strength properties (the ratio strength to density, etc). In addition, the laminate and sandwich structures provide good vibration and noise protection, thermal insulation, etc. There are also disadvantages - for example, composite laminates are brittle, and thejoining of such elements is not as easy as with classical materials. The recycling of these materials is also problematic, and a viable solution is yet to be developed. Since the application of laminates and sandwiches has been used mostly in new technologies, governmental and independent research organizations, as well as big companies, have spent a lot of money for research. This includes the development of new materials by material scientists, new design concepts by mechanical and civil engineers as well as new testing procedures and standards. The growing de mands of the industry for specially educated research and practicing engineers and material scientists have resulted in changes in curricula of the diploma and master courses. More and more universities have included special courses on laminates and sandwiches, and training programs have been arranged for postgraduate studies.

Author: Hal F. Brinson
Publisher: Springer
ISBN: 1489974857
Category : Science
Languages : en
Pages : 488

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This book provides a unified mechanics and materials perspective on polymers: both the mathematics of viscoelasticity theory as well as the physical mechanisms behind polymer deformation processes. Introductory material on fundamental mechanics is included to provide a continuous baseline for readers from all disciplines. Introductory material on the chemical and molecular basis of polymers is also included, which is essential to the understanding of the thermomechanical response. This self-contained text covers the viscoelastic characterization of polymers including constitutive modeling, experimental methods, thermal response, and stress and failure analysis. Example problems are provided within the text as well as at the end of each chapter. New to this edition: · One new chapter on the use of nano-material inclusions for structural polymer applications and applications such as fiber-reinforced polymers and adhesively bonded structures · Brings up-to-date polymer production and sales data and equipment and procedures for evaluating polymer characterization and classification · The work serves as a comprehensive reference for advanced seniors seeking graduate level courses, first and second year graduate students, and practicing engineers

Author: Daniel Gay
Publisher: CRC Press
ISBN: 1000634574
Category : Technology & Engineering
Languages : en
Pages : 646

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Book Description
For decades, Composite Materials: Design and Applications has guided readers on the efficient design of structural composite parts and has illustrated challenges encountered in modern engineering practice. The fourth edition of this perennial best-seller retains its pedagogical structure, featuring a technical level that rises in difficulty as the text progresses, while allowing each part to be explored independently, but has been updated to mirror recent advances and developments in manufacturing processes and applications. Gives numerous examples of the pre-sizing of composite parts, processed from industrial cases and reworked to highlight key information Provides a design method to define composite multilayered plates under loading, along with all numerical information needed for implementation Includes test cases for the validation of computer software using finite elements Proposes original study of composite beams of any section shapes and of transverse shear behavior of laminates, leading to technical formulations that are not found in the literature Reflects the latest manufacturing processes and applications in the aerospace, automotive, naval, wind turbine, and sporting goods industries, and now features new details on the recycling of composites and additive manufacturing Offers new coverage of ceramic-matrix composites and new concepts for design of laminates, including Double-Double and tapered laminates by means of Tsai homogenization This book serves as a textbook for advanced students studying composite materials design, as well as a handy reference for industry professionals working with composite materials.

Author: Peng Wang
Publisher: Elsevier
ISBN: 0443215790
Category : Technology & Engineering
Languages : en
Pages : 667

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Advanced Structural Textile Composites Forming: Characterization, Modeling, and Simulation comprehensively describes the influence of fiber/fabric architectures and properties on composites forming, along with their deformability and structural optimization, covering the latest advances in the composites forming field. Part one reviews textile reinforcement architectures and discusses the forming behaviors of important 2D and 3D fabrics. Part two discusses numerical models to conduct simulation analysis of different structural composites forming at mesoscopic and macroscopic scales, in particular, 3D preforms with through-the-thickness yarns. Part three looks at the latest developments in the relationship between forming and other steps in composite manufacturing, such as resin injection, and automated fiber placement (AFP) and the effects on certain mechanical properties, such as structural damage and impact resistance. The book will be an essential reference for academic researchers, industrial engineers and materials scientists working with the manufacture and design of fiber-reinforced composite materials. - Describes the influence of the fiber/fabric architectures and properties on composites forming, along with their deformability and structural optimization - Provides numerical modeling and simulation of different fiber-reinforced composites forming at mesoscopic and macroscopic scales, in particular, reinforcements with discontinue fibers, and 3D preforms with through-the-thickness yarns - Discusses cutting edge topics such as resin injection, and automated fiber placement (AFP) and the effects of forming results on mechanical properties such as structural damage and impact resistances