球压痕试验法评价金属材料的强度

Strength Evaluation of Metal Materials by Spherical Indentation Test Method

通过单次压痕试验与有限元模拟相结合的方法,结合反向分析方法与模拟退火粒子群算法,从获得的载荷-深度曲线加载部分提取材料的塑性参数,基于Ludwig硬化模型预测了不同金属材料的强度,并与单轴拉伸试验结果进行对比。结果表明:模拟得到的载荷-深度曲线与试验得到的几乎重合,二者的相对误差小于0.5%,说明模拟退火粒子群算法可有效地从压痕载荷-深度曲线中提取出金属材料的塑性参数;基于Ludwig硬化模型,利用反向分析方法从压痕载荷-深度曲线中提取的真应力-真塑性应变曲线不是唯一的,但从真应力-真塑性应变曲线计算得到的强度具有明显的收敛趋势;采用压痕试验得到不同金属材料的强度均接近于由拉伸试验得到的,屈服强度与抗拉强度的最大相对误差分别为5.9%,4.3%,说明采用压痕试验法可以准确地评价金属材料的强度。

The plastic parameters of materials were extracted from the loading part of load-depth curves obtained by coupling single indentation test and finite element simulation,and combining inverse method and simulated annealing particle swarm optimization.The strength of different metal materials was estimated on the basis of Ludwig hardening model and compared with the results obtained by uniaxial tensile test.The results show that the load-depth curves obtained by simulation almost coincided with those obtained by tests,and the relative error was less than 0.5%,indicating that plastic parameters could be extracted from indentation load-depth curves by simulated annealing particle swarm optimization.The true stress-true plastic strain curves extracted from indentation load-depth curves by inverse method based on Ludwig hardening model were not unique,but obvious convergence tendency of the strength estimated from the extracted true stress-true plastic strain could be observed.The strength of different metal materials obtained by the indentation tests was close to that obtained by tensile tests;the biggest relative errors of the yield strength and tensile strength were 5.9% and 4.3%,respectively,indicating that the strength of the metal materials could be evaluated accurately by indentation test method.