A double scalar elastic damage constitutive model of ice materials

Abstract

The constitutive model of material is the basis of structural analysis and is extremely important. In order to improve the analysis accuracy of the novel ice structure, a double scalar elastic damage constitutive model of ice materials including plain ice and fiber-reinforced ice (FRI) based on continuum damage theory and fracture mechanics is established in this study. The modified Ottosen equivalent strain criterion which can consider the comprehensive mechanical properties of compression, tension and shear is used as the damage initiation criterion and the internal variable of damage evolution. Based on the uniaxial compressive and tensile experiments, the two damage evolution laws of tensile and compressive damage with the modified Ottosen equivalent strain criterion as the internal variables are established. A unified weighted damage evolution function is constructed by the strain decomposition in the principal strain space. Based on the strain equivalent assumption, a complete damage constitutive model is established, which can consider the properties of ice materials at different temperatures and fiber contents. The energy regularization of crack bond model in fracture mechanics is adopted and the softening behavior of materials is described through fracture energy and stress-crack width relationship instead of the relationship between stress and strain, which solves the problem of mesh dependence in finite element analysis. The damage constitutive model is integrated into the large-scale finite element analysis software ABAQUS through the user-defined material subroutine (UMAT), and the establishment of the numerical model is realized, which can be conveniently used for numerical simulation of ice structures. Finally, the proposed damage constitutive model is evaluated according to the comparison between the results of finite element analysis and the results of uniaxial compression, uniaxial tension and four-point bending beam experiments. The results show that the damage constitutive model can well describe the stress-strain nonlinear behavior and capture the basic failure mode of ice materials. This study will lay a foundation for the refined analysis of ice structures.