【摘要】 测定了有机玻璃的抗裂纹增长因子K_1C与材料组份、拉力机夹头速度的关系。发现增塑剂和交联剂对抗裂纹性能的影响,可从聚合物分子运动能力对裂纹端点塑性屈服过程的影响说明。在对断面形态、断面层厚度、折光指数以及K_1C值与拉力机夹头速度关系研究之后,认为用“撕布”模式和次级断裂模式分别解释慢裂纹、快裂纹扩展过程中的实验现象是合适的。更多还原

【Abstract】 The relationships between crack propagation resistant factor K10, the compositions of PMMA organic glasses, and cross-head rates of clamps were determined by conducting tensile testing of centrical notched samples. It was observed by experiments that influence of plasticizers and cross-linking agents on crack propagation resistant properties of organic glasses may be explained by molecular motion which influences plastic yielding process near crack tip. The two different crack propagation processes of organic glasses, i.e. slow and fast crack propagation processes, were studied. By studying the morphology, the refractive index, the thickness of fracture surface layers and the relationships of K1c values with cross-head rates of clamps, we are convinced that a "tearing cloth" fracture model for slow crack propagation and secondary fracture model for fast crack propagation of organic glasses may be used to explain all phenomenons which were observed in this experiments. It is interested to observe that every secondary fracture shower on banded structure surface is corresponding to one parabola.更多还原