混凝土材料冲击压缩试验中的一些问题

Some Problems in the Test of Concrete under Impact Compressive Loading

本文简要介绍了在大直径(Φ74mm)直锥变截面式SHPB实验装置上进行混凝土试件冲击压缩实验方法,以及实验过程中出现的试件应力均匀性问题.对于由方波加载造成的试件内应力波反射次数不够,导致应力分布不均匀的问题,我们提出了波形整形的思想,将矩形波改造成三角波,增加试件破坏前的应力作用时间以获得应力均匀;对于由杆与试件接触不平引起的应力分布不均,我们设计了万向头加以消除.在此基础上进行了一系列试验并得出了一些结论.

The principle and the method of test on concrete specimen under impact compressive loading conducted on largediameter modified right cone variable crosssection SHPB are introduced in this paper, problems of stress homogeneity in the process of test are also presented. The thought of waveform shaping is put forward to solve the problem of nonuniform stress distribution caused by less reflections within specimen due to rectangular wareform loading, where triangular waveform is used to lengthen loading time to obtain uniform stress distribution within specimen before its failure; Gimbal device is designed to solve the problem of nonuniform stress distribution caused by uneven contact between the interface of bar and specimen. Some conclusions are derived from a series of tests on concrete.