Parallel blast simulation of nonlinear dynamics for concrete retrofitted with steel plate using multi-solver coupling

The blast damage behaviors for concrete panels retrofitted with steel plates exposed to blast loading are investigated. In order to enhance the reliability of the simulation results, the equation of state, strength, and failure model of materials are implemented in an explicit analysis program, AUTODYN. In particular, the implemented formulation includes the rate-dependent plasticity and damage softening; the non-linear strain and strain-rate hardening and non-linear strain softening. Furthermore, simplified and idealized 2D axis-symmetry, 3D, and parallel 3D simulations are compared in order to achieve accurate and efficient computation running times using multi-solver coupling method. Comparing the 2D axis-symmetry and 3D models, 2D model is stiffer and has a smaller deflection than the 3D models by geometries of retrofit material. The result of 3D numerical simulation becomes mesh size dependent, because of the explosive characteristics and mechanical properties of concrete. The parallel 3D simulation shows good scalability up to 15 processors and can be simulated at very high speed-up, while still consuming a reasonable amount of run times. Also, the retrofitted concrete panels are compared to the non-retrofitted concrete panel; maximum deflection and maximum deflection ratio are reduced by 1 mm, 3 mm, and 5 mm thick steel plates, scabbing can be prevented by retrofitted with steel plates. The simulation result shows good agreement with the experimental result. Finally, discussion on the numerical results with respect to code criteria and damage localization in retrofitted concrete panels is presented.