黏弹材料动态纳米压入过程的尺度效应

Indentation Size Effect of Viscoelastic Polymers by Dynamic Nanoindentation

提出柔度因子分析法表征压入尺寸效应(ISE),通过聚甲基丙烯酸甲酯(PMMA)及热塑性聚氨酯(TPU)的动态纳米压痕试验,探讨黏弹材料动态压入过程中的压入尺度效应及其影响因素。结果表明,Berkovich针尖对黏弹材料进行纳米压痕动态测试时,主载荷是压入尺度效应产生与否的决定因素,频率对此影响较小,谐振载荷控制方式影响甚微;测试材料存在一临界值,当压入深度大于其临界值时,动态纳米压痕测试获得的黏弹材料参数与传统的动态力学分析(DMA)试验结果基本一致。

Flexibility factor analysis was proposed for exploring the indentation size effect （ISE） of viscoelastic polymers, and the influencing factors of ISE were analyzed by dynamic nanoindentation for PMMA and thermoplastic polyurethane （TPU）. It was found that the carrier load was the key factor of ISE of linear viscoelastic materials in dynamic nanoindentation using Berkovich tip, and the harmonic load control methods have little influence on ISE. The viscoelastic performances by dynamic nanoindentation agree with the dynamic mechanical analysis（DMA） results as the carrier displacement was larger than the critical value.