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关于复合材料的详细研究

第一章

1.简介

1.1前言

在现代材料工程中，复合材料是指一种利用纤维增强效用的基体材料。例如FRP（纤维增强塑料）一词通常是指热固性聚酯基体含有玻璃纤维。目前使用的复合材料在材料技术的方面具有突出优势，它拥有良好的性能和其成本也在可接受范围内，因此常被用于一些高指标的物体制作中如航天器[ 3 ]。为了增强商用和军用飞机的性能，航空航天工业正在不断推动改进高性能结构材料的发展。复合材料在当前和未来的航空航天部件中发挥着重要的作用。由于其独特的强度、刚度、密度比和优异的物理性能，使它在航空航天和航空航天的材料应用中显得十分重要。

复合材料结构的力学性能参数，如强度、刚度等参数的获得是一个耗时且困难的过程。测试通常是针对结构简单的材料。从这些测试中获得的数据与其他不同程度的结构形状中获得的数据相比更加简单和准确。先进的复合材料在军用结构、土木工程和航空航天工程等领域已经有了广泛的应用。

Detailed Study Of Composite Materials Engineering Essay

第一章-Chapter 1

1.简介-1 Introduction

1.1 Introduction

In modern materials engineering the term composite refers to a matrix material that is reinforced with fibres. For example the term FRP (fibre reinforced plastic) usually designates a thermosetting polyester matrix containing glass fibres. Composites that are being used now a day are at the prominent edge of materials technology, with performance and costs appropriate to ultra-demanding applications such as spacecraft [3]. To enhance the performance of commercial and military aircraft, the aerospace industry is constantly driving the development of improved high performance structural materials. Composite materials play a significant role in current and future aerospace components. Because of their unique strength and stiffness-to-density ratio and superior physical properties, composite materials are particularly important to aviation and aerospace application [2].

The mechanical testing of composite structure to obtain parameters such as strength and stiffness is a time consuming and difficult process. The testing is often done in small structures. The data gained from these tests are than related to any structural shape with varying degrees of simplicity and accuracy. Advanced composite materials have a wide range of application in military structures, civil engineering and aerospace engineering [5]. As the number and diversity of applications for fibre-reinforced composite materials rises, the need for new and improved test methods also rises [4]. Experimental valuation of the mechanical properties of composites for use in design and other areas has become ever more important. The determination of shear properties associated with composites is one of the most difficult tasks. The evaluation of shear properties is challenging because of the anisotropic nature and the nonlinear response of composite materials in shear [5].

Shear testing is usually executed to measure the in- plane shear modulus, in-plane shear strength or both [6]. An ideal shear test method should provide a region of pure and uniform shear and must be reproducible, it must not require any special equipment and it should provide the entire stress-strain response to failure from a single specimen. Many shear test methods have been developed for use with composite materials over the years; none of them completely satisfies all of these criteria. Four most commonly used in plane shear test methods for composite material laminates are ±45 tensile shear, rail shear, Iosipescu shear and V-notches rail shear [5]. The in plane shear test that is included in this project is two rail shear test method as per the ASTM (American Society for Testing Materials) standard, ASTM standard D 4255/D 4255M - 01 to be exact.

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