多轴载荷对含埋藏椭圆裂纹平板极限载荷的影响  

Influence of Multiaxial Loading on Limit Load of Plates with Embedded Elliptical Cracks

作　　者：吕原君[1,2] 杨建国[1,3] 雷月葆[1,3] 高增梁[1,3] 

机构地区：[1]浙江工业大学化工机械设计研究所,浙江杭州310032 [2]浙江工业职业技术学院电气电子工程学院,浙江绍兴312000 [3]过程装备及其再制造教育部工程研究中心,浙江杭州310032

出　　处：《压力容器》2015年第2期40-47,共8页Pressure Vessel Technology

基　　金：国家十二五科技支撑计划项目(2011BAK06B03);浙江省公益类重点项目(2014C23001)

摘　　要：极限载荷是含缺陷结构完整性评定的主要参量,极限载荷的计算是否正确十分重要。在多轴应力条件下,目前通用的评定计算中一般只考虑与裂纹面垂直方向的应力σ1,忽略与裂纹面平行方向的载荷σ2,这可能会给极限载荷的计算带来误差。针对含中心埋藏椭圆裂纹的平板,推导出在双轴拉/压载荷与单轴弯矩共同作用下的极限载荷解,并通过三维有限元计算结果进行了验证。探讨了多轴载荷对极限载荷的影响,当σ1为正时,若σ2<0,忽视σ2会过高估计极限载荷;若σ2≥0,当σ2/σ1小于一特定值,忽视σ2会低估极限载荷,反之,忽视σ2也会过高估计极限载荷。Limit load is a major parameter in integrity assessment of engineering structures containing de-fects and its calculation is very important for the integrity assessment.Only the stress σ1 that is perpendic-ular to the crack plane is considered for calculating the limit load and J integral of structures under mul-tiaxial loading,while the stress σ2 that is parallel to the crack plane is ignored.It may results in the devia-tion of the limit load.The limit load expressions of plates with central embedded elliptical cracks under combined loading have been deduced based on Mises yield criterion.The loading are tensile /compressive stress in dual-axis and bending moment applied at the centroid of the end sections of the plate.The de-duced results have been validated using 3D elastic plastic finite element method（FEM）.The influence of multiaxial loading on limit load is discussed.When the stress σ1 is positive,limit loads will be overestima-ted ignoring σ2 for the case with σ2 〈0.While for the case with σ2≥0,the limit loads will be underesti-mated when σ2 /σ1 is less than a certain value,and the limit loads will be overestimated when σ2 /σ1 is higher than a certain value,if ignoring σ2 .

关 键 词：多轴载荷影响 中心埋藏椭圆裂纹 平板 极限载荷 

分 类 号：TH123[机械工程—机械设计及理论] TB301[一般工业技术—材料科学与工程]