新型Bell实验法环境应力开裂测试装置

Testing Equipment for Characterizing Environmental Stress Cracking Resistance Based on the Modified Bell Testing Method

自主设计并搭建了自动刻痕装置和压弯装置,提高了刻痕质量和测试结果的可重复性,同时采用改进的Bell实验方法对高密度聚乙烯材料的环境应力开裂行为进行了系统实验研究。结果表明,试剂浓度、刻痕偏移量、刻痕倾斜角度、刻痕刀片厚度的改变均会对环境应力开裂时间产生较大的影响;裂纹起裂位置既不在试样弯曲变形最大的中间位置,也不在刻痕边缘,而是在距离刻痕边缘约6.38 mm的位置。

The Bell test method has been modified through designing automatic notching device and bending device.By doing so the quality of the notch has been improved significantly and the variation of the testing results has been reduced.The modified test method has been applied to investigate the ESC behavior of high density polyethylene.The results show that the failure time is affected by the solvent concentration,notch offset distance,notch inclination angle and blade thickness.Furthermore,it is observed that the crack initiation occurs neither in the middle position nor at the edge of the notch,but at a position about 6.38 mm from the edge of the notch.