This paper presents a simple damage-gradient based elastoplastic model with non linear isotropic hardening in order to regularize the associated initial and boundary value problem (IBVP). Using the total energy equiva...This paper presents a simple damage-gradient based elastoplastic model with non linear isotropic hardening in order to regularize the associated initial and boundary value problem (IBVP). Using the total energy equivalence hypothesis, fully coupled constitutive equations are used to describe the non local damage induced softening leading to a mesh independent solution. An additional partial differential equation governing the evolution of the non local isotropic damage is added to the classical equilibrium equations and associated weak forms derived. This leads to discretized IBVP governed by two algebric systems. The first one, associated with equilibrium equations, is highly non linear and can be solved by an iterative Newton Raphson method. The second one, related to the non local damage, is a linear algebric system and can be solved directly to compute the non local damage variable at each load increment. Two fields, linear interpolation triangular element with additional degree of freedom is terms of the non local damage variable is constructed. The non local damage variable is then transferred from mesh nodes to the quadrature (or Gauss) points to affect strongly the elastoplastic behavior. Two simple 2D examples are worked out in order to investigate the ability of proposed approach to deliver a mesh independent solution in the softening stage.展开更多
To reproduce the premature rupture process of metal sheet subjected to laser irradiation with subsonic airflow,which is an interesting phenomenon observed in the experiments given by Lawrence Livermore National Labora...To reproduce the premature rupture process of metal sheet subjected to laser irradiation with subsonic airflow,which is an interesting phenomenon observed in the experiments given by Lawrence Livermore National Laboratory,a coupled numerical model considering the interaction and evolution of metal elastoplastic deformation and aerodynamic pressure profile is presented.With the thermal elastoplastic constitutive relationship and failure criterion,the simulated failure modes and dynamic rupture process are basically consistent with the experimental results,indicating plastic flow and multiple fracturing is the main failure mechanism.Compared with the case of non-airflow,subsonic airflow not only accelerates deformation,but also turns the bugle deformation,plastic strain and rupture mode into asymmetric.展开更多
文摘This paper presents a simple damage-gradient based elastoplastic model with non linear isotropic hardening in order to regularize the associated initial and boundary value problem (IBVP). Using the total energy equivalence hypothesis, fully coupled constitutive equations are used to describe the non local damage induced softening leading to a mesh independent solution. An additional partial differential equation governing the evolution of the non local isotropic damage is added to the classical equilibrium equations and associated weak forms derived. This leads to discretized IBVP governed by two algebric systems. The first one, associated with equilibrium equations, is highly non linear and can be solved by an iterative Newton Raphson method. The second one, related to the non local damage, is a linear algebric system and can be solved directly to compute the non local damage variable at each load increment. Two fields, linear interpolation triangular element with additional degree of freedom is terms of the non local damage variable is constructed. The non local damage variable is then transferred from mesh nodes to the quadrature (or Gauss) points to affect strongly the elastoplastic behavior. Two simple 2D examples are worked out in order to investigate the ability of proposed approach to deliver a mesh independent solution in the softening stage.
基金supported by the National Natural Science Foundation of China (11472276, 11332011, and 11502268)the National Defense Basic Scientific Research Program of China (JCKY2016130B009)
文摘To reproduce the premature rupture process of metal sheet subjected to laser irradiation with subsonic airflow,which is an interesting phenomenon observed in the experiments given by Lawrence Livermore National Laboratory,a coupled numerical model considering the interaction and evolution of metal elastoplastic deformation and aerodynamic pressure profile is presented.With the thermal elastoplastic constitutive relationship and failure criterion,the simulated failure modes and dynamic rupture process are basically consistent with the experimental results,indicating plastic flow and multiple fracturing is the main failure mechanism.Compared with the case of non-airflow,subsonic airflow not only accelerates deformation,but also turns the bugle deformation,plastic strain and rupture mode into asymmetric.
