The hardness tester is applicable to measure micro hardness of micro & thin specimen , etc . , and determine micro hardness of fraglie materials , such as glass , ceramic , agate , etc . , being the ideal hardness testing instrument for scientific research institution , enterprise and quality inspection department to perform research and detection 硬度计适用于测量微小、薄形试件、表面渗镀层等试件的显微硬度和测定玻璃、陶瓷、玛瑙、宝石等脆性材料的显微硬度，是科研机构、企业及质检部门进行研究和检测的理想硬度测试仪器。
At present , there is no one effective numerical computing technology come to deal with that the mechanics model of material transfers from continuum to non - continuum . our main research work is to try to improve dem to finish the work . no matter at domestic or overseas , the pre - processed and post processed of discrete element method is a weakness 鉴于目前还没有一种有效的数值计算方法来对冲击载荷下脆性材料从连续体转变为非连续体的整个动态破坏过程进行仿真模拟，我们的主要研究工作就是尝试改良dem法来完成这项工作。
In the present thesis , researches on the micro - mechanisms and the macro - mechanical models of fcp in high ductility - , low ductility - and brittle materials , including metals , ceramics and polymers , are briefly summarized . furthermore , systematic investigation is made on the general fcp pattern , the fcp micro - mechanisms , the mechanical models and the intrinsic - and extrinsic factors affecting fcp by using the approach combining the analysis and the experiments . finally , an almost perfect formula for fcp is developed 本文系统地分析和总结了中外文献对高塑性材料、低塑性材料和脆性材料，包括金属材料、高分子材料和陶瓷材料的疲劳裂纹扩展微观机制和宏观力学模型的研究结果，进而采用理论分析与实验研究相结合的方法，从微观和宏观两个方面对疲劳裂纹扩展的一般规律、影响因素、微观机制、力学条件和宏观规律及其定量理论进行了深入的研究，给出了为实验结果所验证的接近完善的疲劳裂纹扩展表达式。
It has better physical mechanical properties than ordinary concrete except for compressive resistance . it can make ordinary concrete that is a kind of brittle material be changed into a kind of compound material that has better plasticity . its main working mechanism is to improve the brittleness of ordinary concrete by using short fibers that are scattered equably 除抗压强度外,它的各项物理力学性能都比普通混凝土有显著的改善和提高,使原属于脆性材料的混凝土变为具有一定塑性性质的复合材料,其主要工作机理是利用均匀分散的短钢纤维来改善普通混凝土的脆性。
Jqa series of electropneumatic machine have various funtions such as punching , winding , extending and riveting . they have unique efficiency in rivet joint of tubular rivets and brittleness material . these electropneumatic machines are ments in realizing the automation and mechanization of the electronics , instruments , clocks & watches and toys industries as well as other trades Jqa系列气压机能冲孔、折弯、拉伸、铆接，尤其是对空心铆钉的铆接、脆性材料的铆合具有特效的功能，是电子、仪表、钟表、玩具等行业实现自动化、机械化的理想设备。
Based on the damage evolution formation depicted by kachanov of brittle materials in unitary stress state , in this dissertation , the constitutive equation of nonlinear damage material is given , macroscopically , on the assumption that damage variable is exponential relation to strain , d = ( gy i k ) " , where g is the shear module , k is the damage module and the y is the effective strain , d is damage variable and n is hardening exponent 在kachanov描述的一维应力状态下的脆性材料的损伤演化模型的基础上，文中给出非线性损伤材料的本构方程，唯象地假设损伤变量与应变成幂次关系， d ~ * = ( g / k ) ~ n ，其中g为剪切模量， k为损伤模量，为有效应变因子， d为损伤变量， n为硬化指数。
It can make ordinary concrete that is a kind of brittle material be changed to a kind of compound material that has better plasticity . its main working mechanism is to improve the brittleness of ordinary concrete by using short fibers that are scattered equably . because short fibers have higher dragging resistance and ordinary concrete has higher crushing strength in the process of stressing , every technical property of fiber - reinforced concrete is improved greatly 钢纤维混凝土是近年来发展起来的一种新型建筑材料，是在普通混凝土中掺入适量的钢纤维而形成的可浇筑、可喷射成型的一种新型复合材料，除抗压强度外，它的各项物理力学性能都比普通混凝土有显著的改善和提高，使原属于脆性材料的混凝土变为具有一定塑性性质的复合材料，其主要工作机理是利用均匀分散的短钢纤维来改善普通混凝土的脆性。
