前言 一般力学性能测试大多是研制适当的夹具使试样承受所要求应力,并测出相应应变。随着测试技术的发展,引伸计已成为测试应变的必不可少的测试仪器。 近年来,我国有些材料试验机研究、制造单位生产了一些引伸计,有些使用单位根据各自的不同需要也研制了各种不同类型的引伸 Preface The general mechanical properties of the test are mostly developed appropriate fixture so that the sample withstand the required stress and measured the corresponding strain. With the development of testing technology, extensometer has become an indispensable test instrument for testing strain. In recent years, some materials testing machine research and manufacturing units in our country have produced some extensometers. Some units have also developed various types of extensometers according to their different needs