| 基于裂纹闭合效应的高载迟滞预测模型修正 |
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| 引用本文： | 陆云超,杨凤鹏,陈特.基于裂纹闭合效应的高载迟滞预测模型修正[J].上海力学,2019,40(1):64-71. |
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| 作者姓名： | 陆云超 杨凤鹏 陈特 |
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| 作者单位： | 上海交通大学 船舶海洋与建筑工程学院,上海,200240;上海交通大学 船舶海洋与建筑工程学院,上海,200240;上海交通大学 船舶海洋与建筑工程学院,上海,200240 |
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| 基金项目： | 国家自然科学基金;国家自然科学基金 |
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| 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.
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| 关 键 词： | 裂纹疲劳扩展 高载迟滞 裂纹闭合效应 有效应力强度因子幅 |
A Modification of Overload Retardation Model Based on Crack Closure Effect |
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| LU Yunchao,YANG Fengpeng,CHEN Te.A Modification of Overload Retardation Model Based on Crack Closure Effect[J].Chinese Quarterly Mechanics,2019,40(1):64-71. |
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| Authors: | LU Yunchao YANG Fengpeng CHEN Te |
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| Affiliation: | (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China) |
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| Abstract: | 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 QSTE340TM 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. |
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| Keywords: | fatigue crack growth overload crack closure effective stress intensity factor range |
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