Abstract:Efforts are made to grasp the probability information of the stress strain relationship.Firstly,a class of mesoscopic damage mechanics models of concrete is listed to understand the mesoscopic damage evolution characteristics of concrete material.Then the Karhunen-Loeve orthogonal decomposition is adopted to simulate the stochastic field mentioned in the former model.Based on the generalized probability density evolution method (PDEM),probability density function (PDF) of stress strain relationship in unaxial loading condition and its evolution are provided.In the end,the comparison between the theoretical and experimental results verifies that the probability density evolution process of constitutive relationship for concrete material can be obtained from this method.