广义平均形状改变能密度断裂准则及应用  

Generalized Averaged Deviator Strain Energy Density Criterion and Its Application

作　　者：黄如旭[1] 万正权[1] HUANG Ruxu;WAN Zhengquan(State Key Laboratory of Deep-sea Manned Vehicles,China Ship Scientific Research Center,Wuxi 214082,Jiangsu,China)

机构地区：[1]中国船舶科学研究中心深海载人装备国家重点实验室,江苏无锡214082

出　　处：《力学季刊》2021年第1期178-186,共9页Chinese Quarterly of Mechanics

基　　金：海军装备预研项目(3020503010101)。

摘　　要：基于形状改变能为材料起裂扩展控制参量的物理事实及裂纹尖端断裂控制区能量平均概念,提出了计及裂纹尖端应力场特征级数展开奇异项和常数项的广义平均形状改变能密度(GADSED)准则,建立了Ⅰ-Ⅱ-Ⅲ混合型裂纹断裂判据计算式,为工程结构疲劳断裂评估提供了新选择.基于提出的GADSED准则,系统分析了T应力对裂纹断裂判据的影响,结果表明:当参数|Bα|数值相同时:负值T应力的Ⅰ-Ⅱ混合型裂纹更易起裂扩展,正值T应力的KⅠf值高于负值T应力的KⅠf值,正负T应力的KⅡf值相同;T应力在区间0<Bα<0.45时增大了KⅠf值(3%以内),T应力降低了KⅡf值.根据GADSED准则完成了双轴疲劳载荷平板表面Ⅰ型裂纹扩展寿命预报,结果表明:基于GADSED准则的裂纹扩展寿命预报值约为传统方法预报值的40.7%,可为工程实际评估提供借鉴.A new energy-based mixed mode criterion called generalized averaged deviator strain energy density(GADSED)criterion considering both the singularity terms and the constant term T-stress is proposed in this paper based on the deviator strain energy and averaged energy concept.The fracture onset criterion of theⅠ-Ⅱ-Ⅲmixed mode crack was then given.The effect of T-stress on the fracture behavior of the modeⅠ,modeⅡand mixed modeⅠ-Ⅱcrack was investigated thoroughly based on GADSED criterion.The results show that fracture is more likely to happen when the T-stress is negative at a given parameter|Bα|for the mixed modeⅠ-Ⅱcrack,and T-stress has a positive effect on KⅠf when 0<Bα<0.45 for modeⅠcrack while it reduces the KⅡf for modeⅡcrack.The crack growth life of the plate surface modeⅠcrack under the biaxial load was predicted based on the traditional criterionΔKⅠand the proposed GADSED criterion.The results show that the crack growth life predicted by GADSED criterion is about 40.7%of that predicted by traditional method,providing reference for practical engineering evaluation.

关 键 词：T应力 平均形状改变能 断裂准则 混合型裂纹 

分 类 号：O346.1[理学—固体力学]