一种新的低周疲劳损伤累积模型及试验验证

摘要

基于连续介质损伤力学理论,依据疲劳损伤的加载参数与损伤变量之间的不可分割性等特点,建立了一种新的低周疲劳损伤累积模型。经过对00Cr17Ni14Mo2钢和2.25Cr1Mo钢的低周疲劳试验数据的分析,得到了相应的疲劳损伤累积模型。将该模型与不同的损伤累积模型相比较,结果表明：该累积模型的计算结果与试验结果能更好地一致,能更真实地反映损伤的非线性累积过程。该累积模型考虑了损伤和应变的耦合作用以及平均应力、疲劳极限对其的影响,且物理意义明确,具有一定的实用价值。%Based on the theory of continuum damage mechanics,a new low cycle fatigue damage model was established,which combined the unseparable characteristics of the damage variables and loading parameters.Through the analysis of test data of the low cycle fatigue damage of steel 00Cr17Ni14Mo2 and 2.25Cr1Mo,the fatigue damage evolution equations under different plastic strain amplitudes were acquired,which are in good agreement with the experimental results.While the constants of new low cycle fatigue damage model were obtained by fitting,two fatigue damage evolution equations of steel 00Cr17Ni14Mo2 and 2.25Cr1Mo were given respectively.And comparing with several fatigue damage accumulation models,the results show that except linear damage accumulation model,the rest of the models could reflect the nonlinear damage accumulation process of material.The new model established herein accords the experimental results best,which truly reflects the nonlinear damage accumulation process,and takes the coupling of damage and strain,fatigue limit,mean pressure into consideration.Therefore,the new damage model has a clear physical meaning and practical value.