基于应变能密度的疲劳-蠕变裂纹扩展行为描述  

Fatigue-Creep Cracks Growth Behavior Description Based on Strain Energy Density

作　　者：于强[1,2] 罗云蓉[1,2] 付磊[1,2] 张应迁[1,2] 

机构地区：[1]四川理工学院,四川自贡643000 [2]过程装备与控制工程四川省高校重点实验室,四川自贡643000

出　　处：《热加工工艺》2015年第12期60-63,共4页Hot Working Technology

基　　金：四川省教育厅项目(13ZA0129);过程装备与控制工程四川省高校重点实验室基金(GK201205);四川理工学院校级基金(2012PY15);材料腐蚀与防护四川省重点实验室基金(2012CL10;2013CL07);四川理工学院教改项目(JG-1502)

摘　　要：为准确描述疲劳-蠕变裂纹的扩展行为,选取材料在一个循环周次内吸收的应变能密度增量为材料的损伤变量。将加、卸载阶段的裂纹扩展量与保载期的裂纹扩展量叠加,导出了基于有效应变能密度的疲劳-蠕变裂纹扩展速率表达式。该表达式不仅与载荷的循环周次相关,而且还与材料的疲劳-蠕变速率相关。将1Cro10Mo Ni VNb N合金在600梯形应力波加载下的裂纹扩展速率实验值与该表达式的计算值相比较,结果基本吻合。该公式合理解释了某些合金材料的疲劳-蠕变裂纹扩展的部分行为特征。In order to get an accurate description of growth behavior of fatigue-creep cracks, a damage variable described by stain energy density increment within a cycle was chosen. The crack length increment of loading and unloading process and constant stress process was overlayed. The formula of fatiguecreep cracks growth rate based on stain energy density can be derived. The formula is related to the load cycle as well as fatigue-creep strain rate. The calculated values of cracks growth rate have a good agreement with experiment values under stress with trapezoidal waveform of 1Cro10MoNiVNbN superalloys at 600℃. A part of features of superalloys＇ growth behavior of creep-fatigue cracks could be properly explained by the formula

关 键 词：应变能密度 疲劳-蠕变 裂纹扩展速率 

分 类 号：O346.2[理学—固体力学]