双向应力场对HDPE1158管材力学性能的影响

Effect of shearing-drawing two-dimensional compound stress field on mechanical properties of HDPE1158 pipes

利用自行设计制造的剪切拉伸双向复合应力场挤管装置制备了高密度聚乙烯管材;研究了剪切拉伸双向复合应力场对管材力学性能的影响,并对管材的微观结构进行了观察分析。结果表明:剪切拉伸双向复合应力场能同时改善管材轴向和周向的力学性能,其轴向拉伸强度最大提高36.6%,轴向拉伸模量最大提高47.4%;周向拉伸强度最大提高54.6%,周向拉伸模量最大提高140.7%;且周向性能的增强效果更明显。扫描电子显微镜照片显示,自增强管材内部由高度取向的微纤结构及二次取向结晶且串晶互锁结构组成。

Self-reinforced high density polyethylene（HDPE） DMDY1158 pipes were produced by shearing-drawing two-dimensional compound stress field pipe-extrusion equipment developed by the authors. The effect of shearing-drawing two-dimensional compound stress field on the mechanical properties of these pipes and their microstructure were studied in this paper. The results show that the field can improve the axial and circular mechanical properties of these pipes. The increment of axial and circular strength is up to 36.6% and 54.6%, respectively; and the increment of axial and circular modulus is up to 47.4% and 140.7%, respectively. So the self-reinforcement of circular properties is more obvious. The scanning electronic microscope（SEM） photos show that the microstructure of the self-reinforced pipes is composed of microfibril oriented finely and twice-oriented-crystallization interlocking shish-kebab structure.