EBookClubs

Read Books & Download eBooks Full Online

EBookClubs

Read Books & Download eBooks Full Online

Book Effects of Prior Aging at 274 Degree C in Argon on Inelastic Deformation Behavior of PMR 15 Polymer at 288 Degreee C Experiment and Modeling

Download or read book Effects of Prior Aging at 274 Degree C in Argon on Inelastic Deformation Behavior of PMR 15 Polymer at 288 Degreee C Experiment and Modeling written by and published by . This book was released on 2010 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inelastic deformation behavior of PMR-15 neat resin, a high-temperature polymer, was investigated at 288 deg C. The experimental program was designed to explore the influence of strain rate on loading and unloading behaviors. In addition, the effect of prior strain rate on creep, relaxation, and recovery responses was evaluated. The material exhibits positive, nonlinear strain rate sensitivity in monotonic loading. The creep, relaxation, and recovery responses are significantly influenced by prior strain rate. The experimental data were modeled using the Viscoplasticity Based on Overstress for Polymers (VBOP) theory. The effects of prior aging in argon at 274 deg C on the time (rate)-dependent behavior of the PMR-15 polymer were evaluated in a series of stress and strain controlled experiments. Several of the VBO material parameters were expanded as functions of prior aging time. The resulting model was used to predict the behavior of PMR-15 subjected to prior aging at 274 deg C for 2000h. The effects of aging at 274 deg C were compared to previous research in which aging was conducted at 288 deg C.

Book Extension of Viscoplasticity Based on Overstress to Capture the Effects of Prior Aging on the Time Dependent Deformation Behavior of a High temperature Polymer

Download or read book Extension of Viscoplasticity Based on Overstress to Capture the Effects of Prior Aging on the Time Dependent Deformation Behavior of a High temperature Polymer written by Amber J. W. McClung and published by . This book was released on 2008 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Physical and Chemical Aging Effects in PMR 15 Neat Resin

Download or read book Physical and Chemical Aging Effects in PMR 15 Neat Resin written by JE. Kamvouris and published by . This book was released on 1997 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study was to determine whether a shifting approach can be used to account for both chemical and physical effects during long-term aging of high temperature polyimide thermoset polymers, such as the commercial material PMR-15. Stress relaxation curves measured after aging at 316°C for times up to 800 h could be shifted to form a master curve. The horizontal shift factors were found to increase with increasing aging time, consistent with a reduction in molecular mobility that occurs as a result of either physical aging or increased cross-linking. There was a correlation between the vertical shift factors and cure related chemical changes that cause Tg to increase and mass to decrease. Aging effects were partially reversed by heating the aged specimen above its glass transition temperature, indicating that a large portion of the aging is physical in nature. Specimens aged in nitrogen had a larger reversible component than specimens aged in air.

Book Longtime Durability of PMR 15 Matrix Polymer at 204 260 288 and 316 C

Download or read book Longtime Durability of PMR 15 Matrix Polymer at 204 260 288 and 316 C written by and published by . This book was released on 2001 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Longtime Durability of Pmr 15 Matrix Polymer at 204 260 288 and 316 C

Download or read book Longtime Durability of Pmr 15 Matrix Polymer at 204 260 288 and 316 C written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Isothermal weight loss studies at the Glenn (Lewis) Research Center were conducted at four temperatures (204, 260, 288, and 316 C) with specimens of varied geometric shapes to investigate the mechanisms involved in the thermal degradation of PMR-15. Both neat resin behavior and composite behaviors were studied. Two points of interest in these studies are the role(s) of oxygen in the mechanisms involved in the thermo-oxidative degradation of these composite materials and the dimensional changes that occur during their useable lifetime. Specimen dimensional changes and surface layer growth were measured and recorded. It was shown that physical and chemical changes take place as a function of time and location in PMR-15 neat resin and composites as aging takes place in air at elevated temperatures. These changes initiate at the outer surfaces of both materials and progress inward following the oxygen as it proceeds by diffusion into the central core of each material. Microstructural changes cause changes in density, material shrinkage (strains), glass transition temperature, dimension, dynamic shear modulus, and compression properties. These changes also occur slowly dividing the polymer material into two distinct parts: a visibly undamaged core section between two visibly damaged surface layers. The surface layer has a significant effect on compression properties of thinner specimens, but the visibly undamaged core material controls these properties for specimens having eight or more plies. It was demonstrated that there are three different mechanisms involved in the degradation of PMR-15 during aging at elevated temperatures. These are a weight gain, a small weight fraction bulk material weight loss, and a large mass fraction weight loss concentrated at the surface of the polymer or composite. At the higher temperatures (260 C and above), the surface loss predominates. Below 260 C, the surface loss and the bulk core loss become more equivalent. Between 175 and 260 C,

Book Isothermal Aging Effects on Pmr 15 Resin

Download or read book Isothermal Aging Effects on Pmr 15 Resin written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-22 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specimens of PMR-15 polyimide neat resin were aged in air at temperatures of 288, 316, and 343 C. Weight losses and dimensional changes were monitored during the course of the exposure time. Physical changes were also observed by optical and electron microscopy. It was found that polyimide polymer degradation occurred within a thin surface layer that developed and grew during thermal aging. The cores of the polymer specimens were protected from oxidative degradation, and they were relatively unchanged by the thermal treatment. Surface cracking was observed at 343 C and was probably due to an interaction between voids and stresses that developed in the surface layer. Bowles, Kenneth J. and Jayne, Douglas and Leonhardt, Todd A. Glenn Research Center RTOP 510-01-50...

Book Long Term Durability of Polymeric Matrix Composites

Download or read book Long Term Durability of Polymeric Matrix Composites written by Kishore V. Pochiraju and published by Springer Science & Business Media. This book was released on 2011-09-25 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-Term Durability of Polymeric Matrix Composites presents a comprehensive knowledge-set of matrix, fiber and interphase behavior under long-term aging conditions, theoretical modeling and experimental methods. This book covers long-term constituent behavior, predictive methodologies, experimental validation and design practice. Readers will also find a discussion of various applications, including aging air craft structures, aging civil infrastructure, in addition to engines and high temperature applications.

Book Polymer Matrix Composites and Technology

Download or read book Polymer Matrix Composites and Technology written by Ru-Min Wang and published by Elsevier. This book was released on 2011-07-14 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Book Unified Constitutive Laws of Plastic Deformation

Download or read book Unified Constitutive Laws of Plastic Deformation written by A. S. Krausz and published by Elsevier. This book was released on 1996-05-31 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-technology industries using plastic deformation demand soundly-based economical decisions in manufacturing design and product testing, and the unified constitutive laws of plastic deformation give researchers aguideline to use in making these decisions. This book provides extensive guidance in low cost manufacturing without the loss of product quality. Each highly detailed chapter of Unified Constitutive Laws of Plastic Deformation focuses on a distinct set of defining equations. Topics covered include anisotropic and viscoplastic flow, and the overall kinetics and thermodynamics of deformation. This important book deals with a prime topic in materials science and engineering, and will be of great use toboth researchers and graduate students. - Describes the theory and applications of the constitutive law of plastic deformation for materials testing - Examines the constitutive law of plastic deformation as it applies to process and product design - Includes a program on disk for the determination and development of the constitutive law of plastic deformation - Considers economical design and testing methods

Book Composite Materials

Download or read book Composite Materials written by Krishan K. Chawla and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on the relationship between structure and properties, this is a well-balanced treatment of the mechanics and the materials science of composites, while not neglecting the importance of processing. This updated second edition contains new chapters on fatigue and creep of composites, and describes in detail how the various reinforcements, the materials in which they are embedded, and of the interfaces between them, control the properties of the composite materials at both the micro- and macro-levels. Extensive use is made of micrographs and line drawings, and examples of practical applications in various fields are given throughout the book, together with extensive references to the literature. Intended for use in graduate and upper-division undergraduate courses, this book will also prove a useful reference for practising engineers and researchers in industry and academia.

Book Innovations in Biomedical Engineering

Download or read book Innovations in Biomedical Engineering written by Marek Gzik and published by Springer Nature. This book was released on 2022-05-31 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest developments in the field of biomedical engineering and includes practical solutions and strictly scientific considerations. The development of new methods of treatment, advanced diagnostics or personalized rehabilitation requires close cooperation of experts from many fields, including, among others, medicine, biotechnology and finally biomedical engineering. The latter, combining many fields of science, such as computer science, materials science, biomechanics, electronics not only enables the development and production of modern medical equipment, but also participates in the development of new directions and methods of treatment. The presented monograph is a collection of scientific papers on the use of engineering methods in medicine. The topics of the work include both practical solutions and strictly scientific considerations expanding knowledge about the functioning of the human body. We believe that the presented works will have an impact on the development of the field of science, which is biomedical engineering, constituting a contribution to the discussion on the directions of development of cooperation between doctors, physiotherapists and engineers. We would also like to thank all the people who contributed to the creation of this monograph—both the authors of all the works and those involved in technical works.

Book Hard X ray Photoelectron Spectroscopy HAXPES

Download or read book Hard X ray Photoelectron Spectroscopy HAXPES written by Joseph Woicik and published by Springer. This book was released on 2015-12-26 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.

Book The Shock Absorber Handbook

Download or read book The Shock Absorber Handbook written by John C. Dixon and published by John Wiley & Sons. This book was released on 2008-02-28 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every one of the many millions of cars manufactured annually worldwide uses shock absorbers, otherwise known as dampers. These form a vital part of the suspension system of any vehicle, essential for optimizing road holding, performance and safety. This, the second edition of the Shock Absorber Handbook (first edition published in 1999), remains the only English language book devoted to the subject. Comprehensive coverage of design, testing, installation and use of the damper has led to the book's acceptance as the authoritative text on the automotive applications of shock absorbers. In this second edition, the author presents a thorough revision of his book to bring it completely up to date. There are numerous detail improvements, and extensive new material has been added particularly on the many varieties of valve design in the conventional hydraulic damper, and on modern developments such as electrorheological and magnetorheological dampers. "The Shock Absorber Handbook, 2nd Edition" provides a thorough treatment of the issues surrounding the design and selection of shock absorbers. It is an invaluable handbook for those working in industry, as well as a principal reference text for students of mechanical and automotive engineering.