Theoretical And Method Research For Ship-bridge Collision Calculation Based On DFEM

With the rapid development of economy,highway and railway construction projects have been vigorously developed,and the number of bridge construction projects in inland river and sea areas has also increased.But the accidents of ship-bridge collision are also increasing,it causes huge economic losses.ship-bridge collision is a complex dynamic mechanical process and the dynamic finite element model of ship-bridge collision is established by dynamic finite element software ANSYS LS-DYNA to analyze the influence of superstructure simulation method on the dynamic response.The functional relationship between the peak values of impact forces and impact speed,ship mass and impact height is fitted through a large number of finite element simulation results and ORIGIN.The relationship between dynamic response and static response is analyzed by using MIDAS CIVIL to established the continuous rigid frame bridge,establishing functional expression of the bearing capacity of the pier,pier section characteristics and material characteristics.The main contents of this paper are as follows.(1)It summarizes the research status of ship-bridge collision at home and abroad,and reviews the finite element simulation of ship-bridge collision,the calculation of impact force and the analysis of pier bearing capacity.(2)It introduces and summarizes several kinds of collision theories,and analyzes those collision theories' s application scope,advantages and disadvantages.The simplified formulas of ship collision force are sorted out,and the applicable conditions of empirical formulas are summarized.Lastly it analyzes the finite element simulation theory of ship collision.(3)It establishes the finite element model of ship collision by LS-DYNA,studying the influence of superstructure's simulation method on the dynamic response of ship collision.The time-history curve of collision force,energy conversion and pier stress are analyzed and the finite element model of bridge bearing capacity is established to analyze the bearing capacity value of pier.(4)Based on the Code for Design on Railway Bridge and Culver and the results of LS-DYNA finite element simulation,ORIGIN software is used to analyze the relationship between ship collision force and impact speed,ship mass and impact height,and the functional relationship between impact force and impact speed,ship mass and impact height is established through data analysis and fitting.(5)The continuous rigid frame bridge'FEM is established by MIDAS CIVIL to analyze the relationship between dynamic response and static response.The dynamic response results are magnified relative to the static response results.The bearing capacity of piers is analyzed under the finite element model of the whole bridge.Lastly,the function relation between the bearing capacity of pier and pier sectional characteristic,material characteristic and reinforcement ratio is established.