Numerical Simulation Of Dynamic Response Of Blast-Loaded RC Beams

Blast can cause serious damage to building structures as well as heavy loss of live and property. It is increasingly necessary and in fact required to carry out extensive research in this field when increased terrorism and local conflicts become worse. The terrorist explosion activities are increasingly concerns which could harm the national security and the social stability. The topic of blast effects on buildings is of widely interest to researchers and engineers all over the world. But the research in our country is still lag behind. Therefore, sponsored by the Ministry of Education under the Major Project"Integrated Disaster Resistance and Health Research for Civil Engineering Structures", aiming at the propagation rules of blast shock wave and the dynamic response of blast-loaded reinforced concrete beam, the following work has been done by numerical simulation:(1) Using ALE algorithm and the JWL state equation for the product of explosive detonation, the propagation rules of shock wave in the free air induced by explosions has been studied. A three-dimensional model is established using ANSYS, and the program LS-DYNA is used to calculate and analyze. The numerical simulation result is compared with those calculated by empirical formulas.(2) The principle of dynamic response of SDOF system under the effect of blast load is presented, and the numerical simulation of the shock wave flows around an obstacle is conducted when the explosive detonates. The initial development of three-dimensional explosive field and the around-flow behavior with an obstacle around explosive source are obtained. By using post-processing software LS-PREPOST a visual revelation to the around-flow course is obtained. The three-dimensional analysis model is established using ANSYS/LS-DYNA for the numerical analysis of the dynamic response of blast-loaded RC beam.(3) The influence of the several factors, such as longitudinal reinforcement ratio, tie spacing, span-depth ratio, strength of concrete, on the failure modes of the blast-loaded beams is investigated. It is pointed out that the flexural failure transfers to the shearing failure with increasing longitudinal reinforcement ratio tie spacing, span-depth ratio, or decreasing span-depth ratio, strength of concrete. Finally, the content of this thesis is summarized and some problems, which need further study, are proposed.