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小冲杆试验(Small Punch Test,SPT)技术是一种新型微试样试验技术,通过极少量材料就能得到材料的许多力学性能。本文以压力容器常用钢材Q345R为研究对象,通过ABAQUS有限元软件模拟小冲杆试验过程,得到了小冲杆试样最先失效单元的应力三轴度;然后根据ASME防止局部失效的应变限制准则中求解多轴应变极限的方法,对小冲杆试验的等效断裂应变进行了研究。研究结果表明:基于ASME应变限制准则的等效断裂应变具有较大的保守性,作者所提出的修正应变限制准则参数的方法是可行的。此外,小冲杆试样的尺寸效应对等效断裂应变也有重要影响,使得计算的等效断裂应变比有限元模拟的应变值小。
The Small Punch Test (SPT) technology is a new type of micro-sample test technique that provides many mechanical properties of a material with a very small amount of material. In this paper, Q345R, a commonly used steel for pressure vessels, was taken as the research object. The ABAQUS finite element software was used to simulate the small punch test process, and the stress triaxiality of the first failed unit was obtained. Then, In the method of solving the multiaxial strain limit, the equivalent rupture strain of the small punch test was studied. The results show that the equivalent fracture strain based on the ASME strain limit criterion is conservative. The method proposed by the author to correct the strain limit criterion parameters is feasible. In addition, the size effect of the small punch sample also has an important effect on the equivalent fracture strain, making the calculated equivalent fracture strain smaller than that of the finite element simulation.