压头形状对高分子材料压痕和刮擦行为影响的实验研究

Experimental investigation on the effect of indenter shape on indentation and scratching behaviour of polymer materials

针对聚丙烯PP和聚甲基丙烯酸甲酯PMMA,本文开展了系统的压痕与刮擦实验,研究了压头形状对高分子材料压痕与刮擦过程中变形和失效的影响,探讨了高分子材料压痕和刮擦响应的应力集中敏感性。压痕实验结果表明:不同压头形状下,PP压入硬度均随载荷增加而小幅减小;而不同压头下PMMA的压入硬度变化不大。两种材料维氏压头压入硬度均小于圆锥形压头压入硬度。刮擦实验结果表明:不同压头形状下PP与PMMA的刮擦变形和失效形式不同,且压头形状对两种材料刮擦时的切向力和刮擦深度有一定的影响。

The indentation and scratch experiments are carried out systematically for polypropylene(PP)and polymethylmethacrylate(PMMA),to explore the influence of the indenter shape on the indentation and scratch behaviours of polymer materials,and analyze the stress concentration sensitivity of the indentation and scratch response of polymer materials.The results of indentation tests show that under different indenter shapes,the hardness of PP decreases slightly with the increase of the load.The hardness of PMMA changes a little.The indentation hardness values of PP and PMMA using Vickers indenter are larger than those using conical indenter.The results of scratch tests indicate that the scratch deformation and damage behaviours of PP and PMMA are different due to different indenter shapes.The indenter shapes also influence the tangential force and the scratch depth.