2.5.2.4. Bilinear Isotropic HardeningThis option (BISO) uses the von Mises yield criteria coupled with an isotropic work hardening assumption. The material behavior is described by a bilinear stress-strain curve starting at the origin with positive stress and strain values. The initial slope of the curve is taken as the elastic modulus of the material. At the specified yield stress (C1), the curve continues along the second slope defined by the tangent modulus C2 (having the same units as the elastic modulus). The tangent modulus cannot be less than zero nor greater than the elastic modulus. 这是ansys帮助文件里的一段话,请注意最后一句,剪切模量不能小于零,不能大于弹性模量。也就是说0<tangent modulus C2< elastic modulus 但在我图中剪切模量(tangent modulus C2)是大于弹性模量(elastic modulus)的,当我按照这种模式输入参数后,应力应变曲线也是可以graph的,见我的附件。但是在进行计算的时候他会提示你错误,剪切模量(tangent modulus C2)已经大于弹性模量(elastic modulus),然后不能进行计算。