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为了得到结构在动荷载下的真实响应,需要以合理的动力本构模型为依据,进行非线性有限元分析。首先介绍了用于船舶撞击桥梁的几种使用较多的混凝土动力本构模型:钢筋混凝土损伤模型、弹塑性帽盖模型、TCK模型、RHT模型、HJC模型;然后采用LS-DYNA软件进行了2组仿真分析:刚性小球与混凝土靶墙碰撞试验和重锤与钢筋混凝土梁碰撞试验;针对上述各种混凝土动力本构模型分别进行试验仿真,并将计算得出的动态撞击力-时间曲线和位移-时间曲线与试验数据进行了对比分析,发现钢筋混凝土损伤模型对结构裂缝发展和混凝土损伤变化的仿真更接近试验结果,更准确地考虑了构件配筋率对撞击力的影响。在此基础上,对钢筋混凝土损伤本构关系进行了参数敏感性分析,并提出了考虑多种影响因素的撞击力公式。研究结果表明:最大撞击力随着配筋率和钢筋屈服强度的增加而增大,在船-桥碰撞分析中应考虑其影响。
In order to obtain the true response of the structure under dynamic load, nonlinear finite element analysis needs to be based on a rational dynamic constitutive model. Firstly, several kinds of concrete dynamic constitutive models which are used more frequently are introduced, such as reinforced concrete damage model, elasto-plastic cap model, TCK model, RHT model and HJC model. Then LS-DYNA software is used to carry out 2 Group simulation analysis: collision test between rigid ball and concrete target wall and collision test between heavy hammer and reinforced concrete beam. According to the dynamic simulation model of concrete, the dynamic impact force-time curve and The displacement-time curves and experimental data are compared and analyzed. It is found that the simulation of reinforced concrete damage model to the development of structural cracks and concrete damage is closer to the experimental results, and more accurately considers the influence of component reinforcement ratio on impact force. On this basis, the parameter sensitivity analysis of the damage constitutive relationship of reinforced concrete is carried out, and the impact force formula considering various influencing factors is proposed. The results show that the maximum impact force increases with the increase of the reinforcement ratio and the yield strength of the steel bar, and its impact should be considered in the ship-bridge collision analysis.