tailieunhanh - Mechanical Properties of Engineered Materials 2008 Part 11

Tham khảo tài liệu 'mechanical properties of engineered materials 2008 part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 10 Further Topics in Composites INTRODUCTION The introduction to composite deformation provided in the last chapter is adequate for the development of an intuitive understanding of composite deformation. However the simple expressions presented in the last chapter cannot be used easily in the analysis of multi-ply composites with plies of arbitrary orientation. Furthermore the models are only suitable for composites that contain simple reinforcement geometries and the rule-of-mixture expressions provide only moderately accurate estimates of composite strength and modulus. More advanced composites concepts are therefore needed to complement the introductory initial framework presented in Chap. 9. Following the brief introduction to the structure and deformation of composite materials in Chap. 9 this chapter presents further topics on composite deformation and design. The chapter is suitable for those that want to develop a more complete understanding of composites. It should probably be skipped in most undergraduate courses and even in some graduate courses. The chapter begins with systematic introduction to ply theory. This is done by first presenting a framework for the analysis of single composite plies before explaining the assembly of global stiff matrices for multiply composites. Composite design concepts are then discussed briefly along Copyright 2003 Marcel Dekker Inc. with composite failure criteria. The shear lag theory is also described before briefly discussing the experimental methods that are used for the measurement of the interfacial strengths of fiber-reinforced composite materials. UNIDIRECTIONAL LAMINATES Let us begin by considering the elastic deformation of a unidirectional ply Fig. . Typical plies in engineering composites mostly polymer matrix composites have thicknesses of mm and fiber volume fractions between and . The plies are also transversely isotropic orthothro-pic which means that the transverse properties