压剪复合加载下聚丙烯屈服行为的实验研究

为研究聚丙烯在压剪复合加载下的变形行为和屈服规律,设计了一种压剪复合加载的试件(Shear-Compression Specimen,SCS),分析其构型参数对变形行为的影响,并分别对倾斜角度为5°,15°,30°,45°,60°的SCS进行了准静态加载实验,对SCS压缩变形过程中测量区的压缩应力和剪切应力的演化规律进行了分析。结果发现:聚丙烯在压剪复合加载下屈服规律受静水压影响明显,偏离von-Mises屈服准则;而Hu-Pae屈服准则可较好地描述聚丙烯在不同压剪复合加载条件下的屈服规律。此外,对加载速率影响屈服的规律进行研究,发现聚丙烯在压剪复合加载下的屈服行为具有应变率敏感性。

Experimental study on yield behavior of polypropylene under compression and shear composite loading

In order to study the deformation behavior and yield pattern of polypropylene subjected to compression and shear composite loading, a kind of shear-compression specimen (SCS) was designed to analyze the effect of specimen configuration parameters on the deformation behavior. Quasi-static loading experiment of SCS with a tilt angle of 5°/15°/30°/45°/60° was carried out respectively. The evolution of compressive stress and shear stress in SCS measured area during compression and deformation was analyzed. Experimental results show that the yield rule of polypropylene under compression and shear composite loading is obviously influenced by hydrostatic pressure, which deviates from von-Mises yield criterion. While Hu-Pae yield criterion can better describe the yield pattern of polypropylene subjected to different compression and shear composite loading. In addition, the influence of loading rate on yield pattern was also studied. It is found that the yield behavior of polypropylene subjected to compression and shear composite loading is sensitive to strain rate.