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A probabilistic approach to evaluate dynamic and static strength of quasi-brittle materials through high-rate testing
International Journal of Mechanical Sciences ( IF 7.1 ) Pub Date : 2021-11-28 , DOI: 10.1016/j.ijmecsci.2021.106960
Grigory Volkov 1, 2 , Ivan Smirnov 1
Affiliation  

Results of mechanical tests, especially in dynamics, obtained under similar input conditions always have a statistical scatter. Currently, there is no generally accepted engineering approach to the correct assessment of critical stresses for a material under dynamic loads. For example, there is no clear understanding of how many specimens need to be tested to estimate a specific ultimate stress for a specific impact rate. The present study enhances the applicability of the randomized algorithm of Sign-Perturbed Sums to solve the mentioned problem of the dynamic strength evaluation under typical restrictions on experimental results such as few numbers of data points with unknown random noises. The combination of the incubation time criteria and this new probabilistic approach permits to estimate accurately material strength parameters: the critical failure stress and the incubation time with a given level of confidence. Comparative analysis of developing approach and different modifications of the scaling law obtained by Kimberly and Ramesh showed that both models are well agreed with empirically observed data. Experimental data of dynamic test on split Hopkinson pressure bars and a drop tower setup for different quasi-brittle materials are taken to demonstrate advantages of the new method. It is shown that incubation time of failure and critical stress values of certain materials can be estimated with a high level of confidence. These results can be used to optimize experimental studies and develop new standards for dynamic testing of materials.



中文翻译:

通过高速测试评估准脆性材料动态和静态强度的概率方法

在类似输入条件下获得的机械测试结果,尤其是动力学测试结果,总是具有统计上的分散性。目前,没有普遍接受的工程方法来正确评估材料在动态载荷下的临界应力。例如,对于需要测试多少个样本来估计特定冲击速率下的特定极限应力并没有明确的认识。本研究增强了符号扰动和的随机算法的适用性,以解决在实验结果的典型限制(例如具有未知随机噪声的数据点数量很少)下的动态强度评估的上述问题。孵化时间标准和这种新的概率方法相结合,可以准确估计材料强度参数:临界失效应力和具有给定置信度的孵化时间。Kimberly 和 Ramesh 获得的开发方法和标度定律的不同修改的比较分析表明,这两个模型与经验观察数据非常吻合。对分体式霍普金森压力棒的动态测试实验数据和不同准脆性材料的落塔装置进行了实验,以证明新方法的优势。结果表明,可以高可信度地估计某些材料的失效潜伏期和临界应力值。这些结果可用于优化实验研究并制定材料动态测试的新标准。Kimberly 和 Ramesh 获得的开发方法和标度定律的不同修改的比较分析表明,这两个模型与经验观察数据非常吻合。对分体式霍普金森压力棒的动态测试实验数据和不同准脆性材料的落塔装置进行了实验,以证明新方法的优势。结果表明,可以高可信度地估计某些材料的失效潜伏期和临界应力值。这些结果可用于优化实验研究并制定材料动态测试的新标准。Kimberly 和 Ramesh 获得的开发方法和标度定律的不同修改的比较分析表明,这两个模型与经验观察数据非常吻合。对分体式霍普金森压力棒的动态测试实验数据和不同准脆性材料的落塔装置进行了实验,以证明新方法的优势。结果表明,可以高可信度地估计某些材料的失效潜伏期和临界应力值。这些结果可用于优化实验研究并制定材料动态测试的新标准。对分体式霍普金森压力棒的动态测试实验数据和不同准脆性材料的落塔装置进行了实验,以证明新方法的优势。结果表明,可以高可信度地估计某些材料的失效潜伏期和临界应力值。这些结果可用于优化实验研究并制定材料动态测试的新标准。对分体式霍普金森压力棒的动态测试实验数据和不同准脆性材料的落塔装置进行了实验,以证明新方法的优势。结果表明,可以高可信度地估计某些材料的失效潜伏期和临界应力值。这些结果可用于优化实验研究并制定材料动态测试的新标准。

更新日期:2021-12-04
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