摘要
为了研究挤压筒结构的疲劳破坏情况,根据循环应力状态及破坏时局部发生塑性变形的特点,认为挤压筒的疲劳失效属于低周疲劳(LCF)。建立挤压筒热-机械耦合数值模型,施加热载荷、装配载荷以及工作载荷,进行瞬态热-结构静力学分析并找出结构可能发生破坏的危险点。绘制此危险点的应力历程曲线及循环应力-应变曲线。使用诺伯修正公式对局部应力-应变的关系作近似估算。代入由结构几何形状和材料确定的LCF参数,计算危险点的局部应力与应变。基于局部应力应变情况,使用兰德格拉夫损伤公式计算结构发生疲劳破坏的载荷循环次数,结果表明,计算得出的载荷循环次数与挤压筒内衬的实际服役寿命一致。
In order to study the fatigue failure of extrusion cylinder structure,according to its cyclic stress state and the characteristics of local plastic deformation during failure,it was considered that the fatigue failure of extrusion cylinder belonged to the low cycle fatigue(LCF),and the thermo-mechanical coupling numerical model of extrusion cylinder was established.Then,the thermal load,assembly load and working load were applied to perform transient thermal-structure static analysis and find the dangerous point where the structure was damaged,and the stress history curve and cyclic stress-strain curve of the danger point were plotted.Furthermore,the local stress-strain relationship was estimated by using Norbert correction formula,and the local stress and strain at the danger point were calculated by substituting LCF parameters determined by the structural geometry and material.Finally,based on the local stress and strain conditions,the number of load cycles at which the fatigue failure of the structure occurred was calculated by using Landgraf damage formula.The re-sult shows that the calculated number of load cycles is consistent with the actual service life of extrusion cylinder lining.
作者
苏芳
王晓国
任银银
周改丽
Su Fang;Wang Xiaoguo;Ren Yinyin;Zhou Gaili(Technology Center,Taiyuan Heavy Industry Co.,Ltd.,Taiyuan 030024,China;Technology Center,TZ(Tianjin)Binhai Heavy Machinery Co.,Ltd.,Tianjin 300452,China)
出处
《锻压技术》
北大核心
2025年第7期192-197,共6页
Forging & Stamping Technology
基金
天津市科技领军(培育)企业认定及支持项目(20YDLZGX00290)
天津市“项目+团队”重点培养专项(XC202050)。
关键词
挤压筒
热-机械载荷
低周疲劳
过盈装配
局部应力-应变法
extrusion cylinder
thermo-mechanical load
low cycle fatigue
interference assembly
local stress-strain method
