基于薄板弯曲蠕变模型, 对MSP（Modified Small Punch）蠕变试验进行了理论研究, 建立了材料蠕变应力指数n的评价公式. 采用有限元分析软件MARC对MSP蠕变试验进行了数值模拟, 将数值模拟采用的n值与评价结果n值进行了比较, 12Cr1MoV钢和含Cr9%的钨合金钢分别相差1.6%和2.7%; SUS304不锈钢的MSP蠕变试验结果与传统单轴拉伸蠕变实验结果相差仅为2.9%, 数值模拟结果的一致性与两种实验结果的吻合验证了理论公式的有效性. 在此基础上, 通过对多孔Si3N4陶瓷蠕变性能的研究, 发现多孔Si3N4陶瓷在温度为1000℃条件下不仅具有较好的延展性, 而且有较大的蠕变变形; 应用材料蠕变应力指数的理论公式, 得到了多孔Si3N4陶瓷材料的应力指数. 研究结果表明，MSP蠕变试验方法在非金属材料高温蠕变性能的评价上具有广阔的应用前景.
Theory research of MSP（Modified Small Punch）creep test was performed based on the thin plate bending creep model and the theory formula of creep stress exponent was established. A numerical study was carried out to simulate MSP creep tests by using the finite element software MARC. The creep stress exponent adopted in the numerical simulation was compared with the evaluation result. It is found that differences are 1.6% and 2.7% for 12Cr1MoV steel and tungsten-alloyed 9% Cr steel, respectively. The difference between the MSP creep test result of SUS304 stainless steel and the traditionally uniaxial creep test result is only 2.9%. The validity of the theory formula is verified by the consistency of numerical simulation results and by the excellent agreement with the experimental results. Based on the research of the creep properties of Si3N4 ceramic, it is found that there are both preferable ductibility and obvious creep deformation at 1000℃. The creep stress exponent of Si3N4 ceramic is obtained by using the theory formula. The results indicate that the MSP creep test method has wide application for the evaluation of high temperature creep properties of nonmetal materials.
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