高密度聚乙烯力学性能试验研究

Experimental study on mechanical properties of high density polyethylene

在两种低温条件下对高密度聚乙烯(PE100)进行了单轴拉伸试验,材料的拉伸屈服强度与最大拉伸强度相等,随着温度的降低,材料的拉伸屈服强度和弹性模量增大,拉伸屈服应变和拉伸断裂应变减小,温度的降低使得材料的延性变差。在动态(冲击)压缩试验中,材料随着应变率的增大,压缩名义屈服应力线性增大,压缩名义屈服应变总体上减小,弹性模量逐渐增大,材料应力应变关系曲线与弹塑性材料相似;在动态(冲击)拉伸试验中,材料随着应变率的增大,拉伸屈服强度线性增大,拉伸屈服应变在总体上有减小的趋势,弹性模量逐渐增大;通过回归分析给出了力学性能参数与应变率的关系式。动态(冲击)压缩和拉伸条件下,不同应变率所获得的压缩名义屈服强度和动态拉伸屈服强度在大小上差别不大,弹性模量也较为接近。

Uniaxial tensile tests are carried out on high density polyethylene(PE100)under two low temperature conditions.The tensile yield strength of the material is equal to the maximum tensile strength.The tensile yield strength and the elastic modulus of the material increase,the tensile yield strain and the tensile fracture strain decrease,the ductility of the material deteriorates with the decrease of temperature.In dynamic(impact)compression test,the nominal yield stress increases linearly,the nominal yield strain decreases on the whole and the elastic modulus increases gradually with the increase of strain rate,and the stress-strain curve of the material is similar to that of elastic-plastic material.In dynamic(impact)tensile test,the tensile yield strength increases linearly,the tensile yield strain decreases on the whole,and the elastic modulus increases gradually with the increase of strain rate.The relationship between mechanical properties and strain rate is given by regression analysis.Under dynamic(impact)compression and tension conditions,the compressive nominal yield strength and the dynamic tensile yield strength obtained by different strain rates have a little difference in size,and the elastic modulus is also close.