双轴载荷下含沿厚度方向贯穿裂纹平板的极限载荷分析

Analysis on Limit Load for Plates with Extended Cracks along Thickness Direction under Biaxial Loading

目前在结构完整性评定标准中,对含缺陷构件的加载条件往往从实际的多轴载荷简化为单轴载荷进行评定,但是国内外学者研究发现平行于裂纹面的载荷对评定结果可能存在较大影响。本文针对含沿厚度方向贯穿裂纹的平板,基于Tresca屈服准则,推导出在与裂纹面垂直方向拉弯组合和与裂纹面平行方向轴向力的双轴载荷作用下的极限载荷表达式,并通过m_(1L)-n_(1L)和m1Ln_(2L)关系图得到屈服线,探讨了与裂纹面平行方向轴向力对极限载荷的影响,即忽视σ2始终会高估极限载荷值,但是当以拉/压应力为主时,若0≤λ_2≤2/(1-β)时高估程度不明显,若λ_2>2/(1-β)或λ_2<0时高估程度较为明显。

The loading conditions of defective components are usually simplified to uniaxial loading from the actual muhiaxial loading in existing structural integrity assessment criteria. However, the study of domestic and foreign scholars found that load parallel to the crack surface may have a greater impact on the assessment results. A global limit load solution for plates with extended cracks along thickness direction under combined biaxial force/stress and through-thickness bending moment is derived based on Tresca criterion, yield lines has been gotten by the m1L-n1L and m1L-n2L graphs. The influence of biaxial loading on defective components has been discussed. The results show that if the load parallel to the crack sur- face is ignored, the limit loads will always be overestimated. When tension/compression stress is dominated, if meeting the conditions of 0≤λ2≤2/（1-β）, overestimated degree is not obvious, but if meeting the conditions of λ2 〉 2/（ 1 -β） or A2 〈0,overestimated degree is obvious.