基于统一强度理论S-D材料组合筒的弹塑性极限分析

基于双剪统一强度理论对由拉压强度不同材料构成的组合筒的最优过盈配合以及弹塑性极限问题进行了研究，得到了组合筒的接触压力及最优接触压力、最优过盈量以及弹、塑性极限计算公式．与经典弹塑性分析解不同，所得到的解考虑了材料拉压强度的不同以及中间主应力的影响，并包含了两个双剪统一强度理论参数．为了比较方便，还基于库仑-摩尔屈服准则对由拉压强度不同材料构成的组合筒的弹塑性极限进行了分析．讨论了基于双剪统一强度理论所得解与基于库仑一摩尔屈服准则所得解及其他经典强度理论解的关系，分析了材料拉压强度的不同以及中间主应力的影响．

Elastic-plastic limit analysis of combination cylinders made of S-D effect materials based on unified strength theory

Multi-domain direct boundary element method (BEM) was applied to solve acoustic problem with an open structure. The theory and solver of multi-domain direct BEM were introduced in detail. Because of the arbitrary selectivity of the common fluid-fluid interaction boundary between the interior and exterior domains, the treatment technique of normal vectors at sharp corners and edges was validated using some numerical examples. Two kinds of spherical Helmholtz resonators were simulated. The resonance frequencies of these resonators computed using the multi-domain direct BEM agree with corresponding approximated theoretical results quite well.