考虑剪胀的线性软化柱形孔扩张问题

从常规试验成果出发，用弹性软化－残余塑性三线性应力应变模型来模拟应力应变软化关系曲线；用三折线来模拟体积应变、小主应变与大主应变的关系曲线。采用双剪统一强度理论的屈服函数形式，推导并给出了柱形孔扩张时，应力场、应变场、位移场和最终扩张压力计算时所需公式和计算求解步骤。最后，通过对某一算例的计算求解，与弹脆塑性模型作了对比，着重分析了不同软化模式对应力场和位移场的影响。

ON EXPANSION OF CYLINDRICAL CAVITY WITH LINEAR SOFTENING AND SHEAR DILATATION BEHAVIOUR

Based on conventional test results,trilinear elastic-strain-softening-residual- plastic model is used to simulate stress-strain softening curve, trilinear curves to simulate the relation curves of volumetric strain, minor principal strain and major principal strain. By using the field function with the form of twin shear stress unified strength theory ,the formulas and procedure are given to calculate the stress, strain, displacement fields and final pressure of cylindrical cavity expansion. Anexample is used to compare the model with the elastic-brittle-plastic model, where the focus is on the effect on the stress, strain fields from different strain softening models.