论文部分内容阅读
通过压缩具有一定倾斜角(0°,10°,15°,20°和25°)试件和双剪切模型试件,实现了单轴压缩、压缩-剪切复合应力以及纯剪切三种应力状态,得到PMMA(聚甲基丙烯酸甲酯)在相应应力状态下的应力-应变曲线,同时对不同应力状态下试件的破坏模式进行了分析。结果表明:在不同受力环境中材料的强度和破坏的机理不同;同单轴压缩状态下相比,材料在压缩-剪切复合应力状态下屈服极限、强度极限以及破坏应变均不同程度的增大,呈现明显的“剪切增强”现象。单轴压缩与压缩-剪切应力状态下试件的破坏模式均为在试件短对角面上出现明显的剪切屈服带,由应力分析得出试件剪应力在短对角面上达到最大,引起在此平面上分子链间滑动从而产生应变软化形成剪切屈服带;双剪切试件的破坏模式为与剪切面呈45°的斜面。
Uniaxial compression, compressive-shear composite stress and pure shear were achieved by compressing specimens with a certain angle of inclination (0 °, 10 °, 15 °, 20 ° and 25 °) and double shear model The stress-strain curves of PMMA (polymethylmethacrylate) under the corresponding stress state are obtained, and the failure modes of the specimens under different stress states are also analyzed. The results show that the strength and failure mechanism of the material are different in different stress environments. Compared with the uniaxial compression state, the yield stress, the ultimate strength and the failure strain of the material increase in different degrees under the compressive-shear stress state Large, showing a clear “shear enhancement ” phenomenon. The uniaxial compression and compressive-shear stress conditions of the specimen failure mode are obvious shear yield zone in the short diagonal surface of the specimen, the stress analysis shows that the specimen shear stress on the short diagonal surface Maximum, resulting in sliding in the plane between the molecular chains to produce strain softening to form shear yield zone. The failure mode of the double-shear specimen is a slope of 45 ° with respect to the shear plane.