Tham khảo tài liệu 'mechanics analysis composite materials episode 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 7 ENVIRONMENTAL SPECIAL LOADING AND MANUFACTURING EFFECTS Properties of composite materials as well as properties of all structural materials are affected by environmental and operational conditions. Moreover for polymeric composites this influence is more pronounced than for conventional metal alloys because polymers are more sensitive to temperature moisture and time than metals. There exists also a specific feature of composites associated with the fact that they do not exist apart from composite structures and are formed while these structures are fabricated. As a result material characteristics depend on the type and parameters of the manufacturing process . unidirectional composites made by pultrusion hand lay-up and filament winding can demonstrate different properties. This section of the book is concerned with the effect of environmental loading and manufacturing factors on mechanical properties and behavior of composites. . Temperature effects Temperature is the most important of environmental factors affecting the behavior of composite materials. First because polymeric composites are rather sensitive to temperature and have relatively low thermal conductivity. This combination of properties allows US on one hand to use these materials in structures subjected to short-term heating and on the other hand requires US to perform analysis of these structures with due regard to temperature effects. Second there exist composite materials . carbon-carbon and ceramic composites that are specifically developed for the operation under intense heating and materials like mineral-fiber composites that are used to form heatproof layers and coatings. And third fabrication of composite structures is usually accompanied with more or less intensive heating . for curing or carbonization and the further cooling induces thermal stresses and strains to calculate which we need to attract equations of thermal conductivity and thermoelasticity that are .
