Papers by Author: Jing Zhang

Abstract: In order to study the dynamic responses of stiffened plate under underwater contact explosions, the FEM code LS-DYNA is used to discuss the problem, six different stiffened plates are included. The stiffened plate’s distortion, the size of crevasses in the numerical simulation are analyzed. The position where the maximum plastic strain appears, the effective stress and acceleration are also described. It is revealed that the deformation of stiffened plate is different with the position of the stiffener, but the stiffener can harmonize and reduce the deformation of plate, and the whole structure will be more safety when it is subjected to explosions. So the research of this paper can be help to the design of steel structure explode resistance.

Abstract: The damage of thin steel plate subjected to contact explosions was a very complex nonlinear process. The initial crevasse of plate subjected to contact explosions had influence upon the whole damage process, so the critical damage study was significant on the anti-explosion of ship structure. In virtue of the wave solution of the plate plastic dynamic response and the dynamic fracture theory, the critical blasting charge was derived theoretically when onset of initial circumferential crack namely critical damage happened. And the expression of critical deformation was also obtained. Lastly the results calculated using proposed method was compared with numerical simulation and the experiment in the published literature, which were almost coincided. It could be seen that the present method could perfectly solve the critical damage of thin plate under contact explosions theoretically, and provide references for defensive engineering.

Abstract: The reliability of ship defensive structure subjected to underwater contact explosions is important both in theory and engineering. Because of the complex response of structure under explosions in which the fluid-structure-interaction should be considered, the problem under discussion could not be solved by analytical method. The Monte Carlo combined with FEM method is used to solve this problem in this paper. The samples of basic random variables that are dynamite density, the elastic modulus and ultimate strength of plate material are generated by the random number generate program. Then, with these samples, the simulations of multilayer plate-shell structure subjected to underwater contact explosions are done by LS-DYNA, and the maximum stress of each plate is obtained, which should be validated to obey the normal distribution. Based on the intensity rule, the destroy index is introduced in this paper, then the destroy probability of each plate and system are calculated using the basic theory of reliability.