Q345R拉伸过载作用下裂纹扩展行为的影响因素研究

发布时间：2018-07-10 18:36

本文选题：拉伸过载 + 过载比　；参考：《机械工程学报》2015年18期

【摘要】：针对部件服役过程中,在常幅循环加载中引入单个拉伸过载作用的行为,研究过载比、应力比和试样厚度对单个拉伸过载后的裂纹扩展行为和疲劳寿命产生的影响。采用Q345R标准紧凑拉伸试样为研究对象,开展不同过载比、应力比和厚度条件下,在常幅加载过程中引入单个拉伸过载作用下疲劳裂纹扩展行为的试验。试验结果表明:在保持应力比、过载比和试样厚度中的任意两个条件一致的情况下,过载比越大,迟滞效应越明显;应力比越高,迟滞效应越弱;试样厚度增加,迟滞效应减弱。利用半幅降载勾线法,研究由过载引起的沿试样厚度方向的裂纹扩展形貌的变化,并一定程度上解释了厚度效应对过载行为的影响。根据试验和分析结果,对于Q345R在实际服役过程中的寿命评定起重要作用。
[Abstract]:The effects of overload ratio, stress ratio and specimen thickness on the crack propagation behavior and fatigue life of a single tensile overload are studied. Using Q345R standard compact tensile specimen as the research object, the fatigue crack propagation behavior under the condition of different overload ratio, stress ratio and thickness under constant amplitude loading was studied under the action of single tensile overload. The test results show that when the stress ratio, overload ratio and any two conditions in the thickness of the specimen are the same, the hysteresis effect becomes more obvious with the increase of the overload ratio, the higher the stress ratio, the weaker the hysteresis effect and the thickness of the specimen. The hysteresis effect is weakened. The variation of crack growth morphology along the specimen thickness caused by overload is studied by using the half amplitude load reduction hook line method, and the effect of thickness effect on the overload behavior is explained to a certain extent. According to the experimental and analytical results, Q345R plays an important role in evaluating the life of Q345R in actual service.
【作者单位】：浙江工业大学机械工程学院;浙江工业大学过程装备及其再制造教育部工程研究中心;
【基金】：国家自然科学基金(51175469) “十二五”国家科技支撑计划(2011BAK06B02-03) 浙江省重点科技创新团队自主设计(2010R50001-19)资助项目
【分类号】：TG142.1

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