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研究了微孔金属薄膜的微观变化和阻尼性能,采用扫描电镜(SEM)原位观察实验方法对带孔金属薄膜微观结构和阻尼进行分析。分析得到:交变载荷拉伸加载过程中微纳米孔缺陷试件经历了微裂纹萌生、微裂纹扩展及多孔裂纹重叠等一系列变化过程,而卸载过程中,微裂纹逐渐消失。同时得出金属薄膜应变滞后于应力周期性变化的规律,并求出损耗因子为0.00442。结果表明:在交变载荷作用下,微孔附近微裂纹的萌生、扩展及多孔处裂纹叠加变化促使外载荷的机械能以热能形式散失,是金属薄膜具有一定的阻尼减振性能的原因之一。
The microscopic changes and damping properties of microporous metal thin films were studied. The microstructure and damping of metal films with holes were analyzed by scanning electron microscopy (SEM) in situ observation. The results show that a series of changes of microcrack initiation, microcrack propagation and porous crack overlap occur during the tensile loading of alternating load. However, the microcracks gradually disappear during unloading. At the same time, we get the rule that the strain of the metal thin film changes with the periodicity of stress, and find the loss factor of 0.00442. The results show that under the action of alternating load, the initiation and propagation of microcracks in the vicinity of micropores and the superposition of cracks in the pores cause the mechanical energy of the external load to dissipate as heat energy, which is one of the reasons for the damping performance of the metal thin film.