准静态压缩应力-应变曲线测量方法的探索

本文介绍了用应变片直接测量材料的准静态应力-应变曲线的试验研究。在MTS810材料试验机上分别对93W、G50、砂浆等几种材料进行了准静态压缩试验。由于仪器的系统误差不能由MTSCod规准确的得到材料的真实的弹性变形。为此在试件的中部贴应变片得到材料的弹性变形,塑性变形仍旧由MTSCod规记录,从而得到试样的真实的应变,准确获得准静态压缩应力-应变曲线。试验结果表明:在试件中部贴应变片的方法能够准确得到该材料的杨氏模量;在试件两端垫块的刀口上安置Cod规可得到材料的应力应变曲线。两者的合理组合即可得到准确而完整的准静态压缩应力-应变曲线。试验中还发现准静态实验中试件的断面加工不平,偏心压缩等都会影响E的准确测量。

Investigation on the Method of Measuring Quasi-Static Compression Stress-Strain Curve

Experiments of using strain gage to measure the quasi-static stress-strain curve of materials directly were introduced. A variety of compression experiments on 93W,G50,concrete etc, are carried out under quasi-static loading on MTS 801. The strain gage is used for direct measurement of elastic strain, since the elastic strain of the samples is so small, it can not be measured with MTS Cod gage. The plastic strain is still obtained by MTS Cod gage, and the overall quasi-static stress-strain relation of the material is achieved. The experiment results show that the accurate modulus can be acquired by the strain gage placed on the middle of samples, and the overall strain can be obtained by combining the elastic and plastic part. The accurate quasi-static compressive stress-strain relations can be got by reasonable combination of the two curves above. It is found that the accuracy of modulus is also affected by the declining section or eccentric compressing.