基于裂纹闭合效应的高载迟滞预测模型修正
|
摘要
裂纹闭合效应通常是导致Ⅰ型裂纹扩展在高载作用下发生迟滞效应的主要因素之一.本文采用汽车薄板QSTE340TM材料,针对不同应力比,高载比条件下疲劳裂纹扩展行为进行了实验研究.论文通过断面分析,针对各参数对裂纹闭合效应的具体影响进行了分析讨论,认为裂纹作用区域随裂纹扩展而动态变化,从而提出了一种对有效应力强度因子幅的修正方法.通过在原有模型中引入幂函数形式的动态变量α,表征裂纹闭合效应的作用比例随裂纹长度的动态变化,取得了较好的效果.
The crack closure effect is usually considered as one of the primary causes of fatigue crack growth retardation due to overload in mode Ⅰ problem. This paper focused on experiment research on fatigue crack propagation under different stress ratios and overload ratios for QSTE340 TM automobile steel sheet. The fracture surface was investigated and the effect of different parameters on the crack closure was analysed. Considering that the crack influential region changes with the crack propagation, a modification to the effective stress intensity factor amplitude was proposed by introducing an exponential function named α, to characterize the change of the range of the crack closure effect due to the crack length change. The modified model agrees well with the experiment results.
The crack closure effect is usually considered as one of the primary causes of fatigue crack growth retardation due to overload in mode Ⅰ problem. This paper focused on experiment research on fatigue crack propagation under different stress ratios and overload ratios for QSTE340 TM automobile steel sheet. The fracture surface was investigated and the effect of different parameters on the crack closure was analysed. Considering that the crack influential region changes with the crack propagation, a modification to the effective stress intensity factor amplitude was proposed by introducing an exponential function named α, to characterize the change of the range of the crack closure effect due to the crack length change. The modified model agrees well with the experiment results.
引文
[1]吴昊,仲政,高玉魁.狭长缺口根部萌生的小裂纹扩展分析[J].力学季刊,2015,36(1):49-54.
[2]滕项铭,冯淼林.裂纹尖端疲劳塑性区研究[J].力学季刊,2011,32(3):418-426.
[3]陈特,杨凤鹏,兰天.恒扭对汽车薄板Ⅰ型疲劳裂纹扩展的影响[J].力学季刊,2017,38(4):772-779.
[4]WHEELER O E.Spectrum loading and crack growth[J].Journal of Basic Engineering,1972,94(1):181-186.
[5]ELBER W.Fatigue crack closure under cyclic tension[J].Engineering Fracture Mechanics,1970,2(1):37-45.
[6]MEHRZADI M,TAHERI F.A material sensitive modified wheeler model for predicting the retardation in fatigue response of AM60B due to an overload[J].International Journal of Fatigue,2013,55:220-229.
[7]SALVATI E,ZHANG H,FONG K S,et al.Fatigue and fracture behaviour of AZ31b Mg alloy plastically deformed by constrained groove pressing in the presence of overloads[J].Procedia Structural Integrity,2016,2:3772-3781.
[8]韩瑾,杨平,董琴.过载对于疲劳裂纹闭合效应的研究[J].武汉理工大学学报:交通科学与工程版,2017,41(5):854-858.
[9]张国勇,顾绍景,郭万林,等.一种基于约束因子的超载迟滞模型[J].航空学报,2011,32(6):1032-1039.
[10]SALVATI E,ZHANG H,FONG K S,et al.Separating plasticity-induced closure and residual stress contributions to fatigue crack retardation following an overload[J].Journal of the Mechanics and Physics of Solids,2017,98:222-235.
[11]PARIS P C,TADA H,DONALD J K.Service load fatigue damage-a historical perspective[J].International Journal of Fatigue,1999,21:S35-S46.
[12]DONALD K,PARIS P C.An evaluation ofΔKeff estimation procedures on 6061-T6 and 2024-T3aluminum alloys[J].International Journal of Fatigue,1999,21:S47-S57.
[13]SONG J,KANG J,KOO J.Proposal of modified(normalized)ASTM offset method for determination of fatigue crack opening load[J].International Journal of Fatigue,2005,27(3):293-303.
[14]ANTUNES F V,CASTANHEIRA F A,BRANCO R.A numerical analysis of the mechanisms behind plasticity induced crack closure:application to variable amplitude loadings[J].International Journal of Fatigue,2016,89:43-52.
[15]LêMINH B,MAITOURNAM M H,DOQUET V.A cyclic steady-state method for fatigue crack propagation:evaluation of plasticity-induced crack closure in 3D[J].International Journal of Solids and Structures,2012,49(17):2301-2313.
[2]滕项铭,冯淼林.裂纹尖端疲劳塑性区研究[J].力学季刊,2011,32(3):418-426.
[3]陈特,杨凤鹏,兰天.恒扭对汽车薄板Ⅰ型疲劳裂纹扩展的影响[J].力学季刊,2017,38(4):772-779.
[4]WHEELER O E.Spectrum loading and crack growth[J].Journal of Basic Engineering,1972,94(1):181-186.
[5]ELBER W.Fatigue crack closure under cyclic tension[J].Engineering Fracture Mechanics,1970,2(1):37-45.
[6]MEHRZADI M,TAHERI F.A material sensitive modified wheeler model for predicting the retardation in fatigue response of AM60B due to an overload[J].International Journal of Fatigue,2013,55:220-229.
[7]SALVATI E,ZHANG H,FONG K S,et al.Fatigue and fracture behaviour of AZ31b Mg alloy plastically deformed by constrained groove pressing in the presence of overloads[J].Procedia Structural Integrity,2016,2:3772-3781.
[8]韩瑾,杨平,董琴.过载对于疲劳裂纹闭合效应的研究[J].武汉理工大学学报:交通科学与工程版,2017,41(5):854-858.
[9]张国勇,顾绍景,郭万林,等.一种基于约束因子的超载迟滞模型[J].航空学报,2011,32(6):1032-1039.
[10]SALVATI E,ZHANG H,FONG K S,et al.Separating plasticity-induced closure and residual stress contributions to fatigue crack retardation following an overload[J].Journal of the Mechanics and Physics of Solids,2017,98:222-235.
[11]PARIS P C,TADA H,DONALD J K.Service load fatigue damage-a historical perspective[J].International Journal of Fatigue,1999,21:S35-S46.
[12]DONALD K,PARIS P C.An evaluation ofΔKeff estimation procedures on 6061-T6 and 2024-T3aluminum alloys[J].International Journal of Fatigue,1999,21:S47-S57.
[13]SONG J,KANG J,KOO J.Proposal of modified(normalized)ASTM offset method for determination of fatigue crack opening load[J].International Journal of Fatigue,2005,27(3):293-303.
[14]ANTUNES F V,CASTANHEIRA F A,BRANCO R.A numerical analysis of the mechanisms behind plasticity induced crack closure:application to variable amplitude loadings[J].International Journal of Fatigue,2016,89:43-52.
[15]LêMINH B,MAITOURNAM M H,DOQUET V.A cyclic steady-state method for fatigue crack propagation:evaluation of plasticity-induced crack closure in 3D[J].International Journal of Solids and Structures,2012,49(17):2301-2313.