考虑拉压强度差效应的厚壁圆筒承载能力分析

应用双剪统一强度理论，考虑材料的拉压异性和同性，推导了在内压力和轴力联合作用下的厚壁圆筒的塑性极限载荷表达式．在该表达式中，当反映中间主应力效应的系数取不同的值时，就能得到按Tresca屈服准则、线性逼近的Mises屈服准则和双剪应力屈服准则的计算结果，并且绘制了在相应准则下的极限应力线图．从而可知：在三维应力状态下，应用该理论，可以获得极限载荷分析的精确解；极限载荷线图与三种屈服准则的屈服曲线是相吻合的；计算的结果可以用于拉压异性和同性的材料，为工程应用提供了理论依据．

PLASTIC LOADBEARING CAPACITY ANALYSES OF THICK WALLED TUBE CONSIDERING THE EFFECT OF DIFFERENT STRENGTH IN TENSION AND COMPRESSION

In the paper, the limit load formulae for a thick-walled tube with different strength in tension and compression state are derived based on the twin shear unified strength theory, under the action of an inner pres- sure and axial force. In these formulae, the results with Tresca criterion, linear approximate Mises criterion and twin shear stress yield criterion can be obtained with dif- ferent coefficient values reflecting the middle main stress effect, and limit loading curves for different yielding crite- rions are plotted. Therefore, accurate solutions for limit loads can be obtained with this theory under the three- dimensional state; the limit loading diagram is consistent to yielding curves of twin shear stress, Mises and Tresca criterions; these formulae can be used for the material with differentia strength in tension and compression state.