Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781721090105 Category : Languages : en Pages : 116
Book Description
The durability of polymer matrix composites exposed to harsh environments is a major concern. Surface degradation and damage are observed in polyimide composites used in air at 125 to 300 C. It is believed that diffusion of oxygen into the material and oxidative chemical reactions in the matrix are responsible. Previous work has characterized and modeled diffusion behavior, and thermogravimetric analyses (TGAs) have been carried out in nitrogen, air, and oxygen to provide quantitative information on thermal and oxidative reactions. However, the model developed using these data was not able to capture behavior seen in isothermal tests, especially those of long duration. A test program that focuses on lower temperatures and makes use of isothermal tests was undertaken to achieve a better understanding of the degradation reactions under use conditions. A new low-cost technique was developed to collect chemical degradation data for isothermal tests lasting over 200 hr in the temperature range 125 to 300 C. Results indicate complex behavior not captured by the previous TGA tests, including the presence of weight-adding reactions. Weight gain reactions dominated in the 125 to 225 C temperature range, while weight loss reactions dominated beyond 225 C. The data obtained from isothermal tests was used to develop a new model of the material behavior. This model was able to fully capture the behavior seen in the tests up to 275 C. Correlation of the current model with both isothermal data at 300 C and high rate TGA test data is mediocre. At 300 C and above, the reaction mechanisms appear to change. Attempts (which failed) to measure non-oxidative degradation indicate that oxidative reactions dominate the degradation at low temperatures. Based on this work, long term isothermal testing in an oxidative atmosphere is recommended for studying the degradation behavior of this class of materials. Patekar, Kaustubh A. Glenn Research Center NAS3-2054; RTOP 714-04-40
Author: Kaustubh Ashok Patekar Publisher: ISBN: Category : Languages : en Pages : 210
Book Description
The durability of polymer matrix composites exposed to harsh environments is a major concern. Surface degradation and damage are observed in polyimide composites used in air at 125-300°C. It is believed that diffusion of oxygen into the material and oxidative chemical reactions in the matrix are responsible. Previous work has characterized and modeled diffusion behavior, and thermogravimetric analyses (TGAs) have been carried out in nitrogen, air, and oxygen to provide quantitative information on thermal and oxidative reactions. However, the model developed using these data was not able to capture behavior seen in isothermal tests, especially those of long duration. A test program that focuses on lower temperatures and makes use of isothermal tests was undertaken to achieve a better understanding of the degradation reactions under use conditions. A new, low-cost technique was developed to collect chemical degradation data for isothermal tests lasting over 200 hours in the temperature range 125-300° C. Results indicate complex behavior not captured by the previous TGA tests, including the presence of weight-adding reactions. Weight gain reactions dominated in the 125-225°C temperature range, while weight loss reactions dominated beyond 225°C. The data obtained from isothermal tests was used to develop a new model of the material behavior. This model was able to fully capture the behavior seen in the tests up to 275°C. Correlation of the current model with both isothermal data at 300°C and high rate TGA test data is mediocre. At 300°C and above, the reaction mechanisms appear to change. Attempts (which failed) to measure non-oxidative degradation indicate that oxidative reactions dominate the degradation at low temperatures. Based on this work, long term isothermal testing in an oxidative atmosphere is recommended for studying the degradation behavior of this class of materials.
Author: Kishore V. Pochiraju Publisher: Springer Science & Business Media ISBN: 1441993088 Category : Technology & Engineering Languages : en Pages : 681
Book Description
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.
Author: Tom Proulx Publisher: Springer Science & Business Media ISBN: 1441997946 Category : Technology & Engineering Languages : en Pages : 394
Book Description
This the third volume of six from the Annual Conference of the Society for Experimental Mechanics, 2010, brings together 56 chapters on Time-Dependent Constitutive Fracture and Failure. It presents early findings from experimental and computational investigations on Time Dependent Materials including contributions on Thermal and Mechanical Characterization, Coupled Experimental and Computational Analysis of Fracture Path Selection, Procedures for Mixed Mode Fracture Testing of Bonded Beams, and Experimental Study of Voids in High Strength Aluminum Alloys.
Author: Rod Martin Publisher: Elsevier ISBN: 1845694937 Category : Technology & Engineering Languages : en Pages : 543
Book Description
Ageing of composites is a highly topical subject given the increasing use of composites in structural applications in many industries. Ageing of composites addresses many of the uncertainties about the long-term performance of composites and how they age under conditions encountered in service.The first part of the book reviews processes and modelling of composite ageing including physical and chemical ageing of polymeric composites, ageing of glass-ceramic matrix composites, chemical ageing mechanisms, stress corrosion cracking, thermo-oxidative ageing, spectroscopy of ageing composites, modelling physical and accelerated ageing and ageing of silicon carbide composites. Part two examines ageing of composites in transport applications including aircraft, vehicles and ships. Part three reviews ageing of composites in non-transport applications such as implants in medical devices, oil and gas refining, construction, chemical processing and underwater applications.With its distinguished editor and international team of contributors, Ageing of composites is a valuable reference guide for composite manufacturers and developers. It also serves as a source of information for material scientists, designers and engineers in industries that use composites, including transport, chemical processing and medical engineering. Addresses many of the uncertainties about the long-term performance of composites and how they age under conditions encountered in service Reviews processes and modelling of composite ageing including chemical ageing mechanisms and stress corrosion cracking Discusses ageing of composites in both transport and non-transport applications ranging from aircraft to implants in medical devices
Author: Celine A Mahieux Publisher: Elsevier ISBN: 0080531059 Category : Technology & Engineering Languages : en Pages : 323
Book Description
Thanks to their low density and tailored properties, polymer matrix composites are attractive candidates for a large number of industrial applications ranging from aerospace to transportation and energy. However, the behaviour of polymer-based materials is strongly affected by a number of environmental factors. Environmental Degradation in Industrial Composites provides vital information on the effects of environmental factors such as temperature, liquid and gas exposure, electrical fields and radiations, and how micro- and micromechanical calculations during design and manufacture must take these effects into account. The book concludes with reviews on standard and specific testing methods for the various environmental factors and their combinations, helping mechanical/materials engineers and specifiers to predict possible changes due to environmental conditions. Each chapter is supplemented by industrial case studies to help in the understanding of degradation of composites in real life situations.This book will help you to...* Understand how environmental factors lead to degradation effects in polymer matrix composite structures* Build these factors into calculations when predicting the part performance and lifetime of structures* Compare real-life situations from case studies with your predicted results* Predict probable composite behaviour with greater accuracy This book will help you to...* Understand how environmental factors lead to degradation effects in polymer matrix composite structures* Build these factors into calculations when predicting the part performance and lifetime of structures* Compare real-life situations from case studies with your predicted results* Predict probable composite behaviour with greater accuracy
Author: Antonio Carvalho Filho Publisher: CRC Press ISBN: 0429807171 Category : Science Languages : en Pages : 360
Book Description
Durability of Industrial Composites offers numerical and quantitative solutions to long-term composite failures that are useful to practicing engineers, researchers, and students. All modes of laminate long-term failure are contemplated, with resin toughness and environmental conditions considered. The book develops a simple unified equation to compute the load-dependent durability of laminates under the simultaneous action of cyclic and static loads. The load-independent durability and residual life of equipment immersed in corrosive chemicals are also discussed. The book presents a full discussion of the elusive strain-corrosion mode of failure as well as a complete solution to the durability issue of underground sanitation pipes. The currently accepted durability parameters of HDB, Sb and Sc are discarded as incorrect and replaced with the appropriate threshold parameters. The entirely new concept of the "anomalous failure" is fully discussed and solved. The effects of overpressure and spike strains, as well as of the operating temperature and moisture, are quantitatively evaluated and illustrated in numerical examples.
Author: Composite Materials Handbook – 17 (CMH-17) Publisher: SAE International ISBN: 1468604953 Category : Technology & Engineering Languages : en Pages : 778
Book Description
The first volume of this six-volume compendium contains guidelines for determining the properties of polymer matrix composite material systems and their constituents, as well as the properties of generic structural elements, including test planning, test matrices, sampling, conditioning, test procedure selection, data reporting, data reduction, statistical analysis, and other related topics. Special attention is given to the statistical treatment and analysis of data. Volume 1 contains guidelines for general development of material characterization data as well as specific requirements for publication of material data in CMH-17. The primary purpose of this volume of the handbook is to document industry best-practices for engineering methodologies related to testing, data reduction, and reporting of property data for current and emerging composite materials. It is used by engineers worldwide in designing and fabricating products made from composite materials. The Composite Materials Handbook, referred to by industry groups as CMH-17, is a six-volume engineering reference tool that contains thousands of records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. CMH-17 provides information and guidance necessary to design, analyze, fabricate, certify and support end items using composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair.
Author: National Aeronautics and Space Administration (NASA)
Author: 
Author: Kaustubh Ashok Patekar
Author: Kishore V. Pochiraju
Author: Thomas S. Gates
Author: Tom Proulx
Author: Rod Martin
Author: Celine A Mahieux
Author: Antonio Carvalho Filho
Author: Composite Materials Handbook – 17 (CMH-17)