驳船-圆柱碰撞的修正半波正弦荷载模型

Modified Half-wave Sine Load Model for Barge-cylinder Collision

为建立考虑冲击效应的船撞实用荷载模型,建立6艘不同吨位驳船的有限元精细化模型,采用驳船撞击刚性圆柱模型,通过数值仿真得到252条不同速度和不同径宽比下的撞击力时程原始样本。通过对样本的观察与分析,提出采用修正半波正弦函数作为撞击力过程的近似荷载模型,并通过数理统计的方法确定具体模型参数,由此根据驳船吨位、撞击速度、撞击径宽比等因素直接确定撞击荷载曲线。基于简化模型推导过程,指出修正半波正弦荷载模型的3个误差来源,并以2座不同结构形式的桥梁为例进行动力反应计算分析。以驳船接触碰撞的动力响应为基准,分析简化荷载模型计算结果的准确性,并进一步讨论3个误差来源对荷载模型误差的贡献大小与误差机理。研究结果表明:模型参数取值的精度良好;2个算例的动力响应对比分析得出,提出的修正半波正弦荷载模型对于柔性及刚性的桥梁结构均有良好的整体计算精度,具有广泛的实际工程应用价值。

In this study,six barge finite element models were developed and rigid cylinders were used to simulate the impact process to establish a simplified method considering the impact effect.Then,252 samples of history curves of the impact force under different velocities and radiuswidth ratios were obtained by numerical simulations.A modified half-wave sine function was used to simplify the history curves of the impact force.The specific parameters of the model were determined by mathematical statistics. Therefore,the impact load curve can be directly determined based on barge tonnage,impact speed,impact ratio,and other factors.The error analysis indicates good accuracy of the model parameters.Three types of errors of the modified half wave sine load model were identified,and dynamic response analysis was carried out using two bridge models of different structural features.The accuracy of the calculation results of the simplified load model was analyzed and compared with the dynamic response of barge contact collision,which is regarded as the exact solution.The error contributions of the simplified load model were discussed.A comparison of the calculation results of two bridges indicates that the modified half-wave sine load model has good accuracy for the dynamic analysis of both flexible and rigid structures.In conclusion,this modified half-wave sine load model has some significance forpractical engineering applications.