Papers by Author: Shan Wang

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.

Abstract: Based on the characteristics of loading condition of ship structure in service and the degeneration of the strength under fatigue and corrosion, the random time-variant model of ship hull section modulus was set up using the theory of random process. Then the time-variant reliability was analyzed with the method of up-crossing analysis and parallel system reliability. This method could not only present successive decrease of reliability of the ship structure under fatigue and corrosion, but also avoid the complicated numerical integration. It could be seen that this method was easy to achieve. Furthermore, the time-variant reliability was compared with the annual instantaneous reliability through an example, which indicated that this method was more precise, and could provide some references to the decision-making of the reliability, maintenance and safeguard.