巨型压机C型机架的疲劳寿命预测研究  

Study on fatigue life prediction for C-type frame of huge pressure machine

作　　者：黄宁[1] 杨建湘[1] 李素云[1] 

机构地区：[1]贺州学院机械与电子工程学院,广西贺州542899

出　　处：《锻压技术》2016年第5期136-141,共6页Forging & Stamping Technology

基　　金：贺州学院博士基金启动项目(HZUBS201303);贺州市科技开发项目(贺科能1408013);广西高校科研项目(KY2015ZD128)

摘　　要：针对循环拉伸载荷下光滑件的尺寸效应不显著和大型零件难于进行原型疲劳试验,给出了利用小试样试验去预测大型零件疲劳寿命的分析方法。首先,基于疲劳模拟试验建立模拟缩比模型,引入缺口试样尺寸系数。其次,引入表征尺寸变化对疲劳性能影响的特征参量,利用两种材料(45钢,Q235)的几何相似试样(K_t=2,K_t=3)疲劳寿命试验结果,获得缺口试样尺寸系数经验公式。同时兼顾尺寸、应力集中和表面状况之间的相互影响,建立了拉伸载荷下的疲劳综合修正系数模型,并用一算例验证了其有效性。最后,在名义应力法的基础上,应用该模型对大型C型板材料的S-N曲线进行修正,成功地预测出C型板的疲劳寿命。该方法符合实际情况,使疲劳寿命估算更合理,可用于评估拉伸作用下的大型零件疲劳评估。For insignificant size effect of smooth specimen under cyclic tensile load and difficulty in the fatigue test for large-scale component,fatigue life prediction method for large-scale component was presented by experiments of small samples. Firstly,simulate-scale model was created based on fatigue simulation test,and size coefficient of notched-sample was introduced. Secondly,characteristic parameter that represents the influences of size change condition on fatigue properties was introduced,and an empirical size coefficient formula was obtained by utilizing the tested fatigue life results of geometrically similar specimens（ Kt= 2,Kt= 3） made in two kinds of materials（ Steel 45,Q235）. Simultaneously considering interaction of size,stress concentration and surface quality,a fatigue comprehensive correction factor model was proposed,and its validity was proved. Finally,on the basis of the nominal stress method,fatigue life of largescaled C-type plate was successfully predicted after modifying S-N curve of plate material through fatigue comprehensive correction factor model. This method was in well accordance with the practical situation,and fatigue life prediction was more reasonably. Furthermore,this method provided a new way for fatigue assessment of large-scale component under tension.

关 键 词：疲劳寿命 模拟缩比模型 缺口试样尺寸系数 疲劳综合修正系数 名义应力法 C型板 

分 类 号：TH114[机械工程—机械设计及理论]