Research On Dynamic Response Of Pile Groups Under Ship Impacting

The principal objects of the ship bridge collision are the ship, the bridge and soil. When the ship collided with the bridge, pile groups have complex dynamic response. This paper considers the change of the characteristics of objects associated with the collision, study the effect of dynamic response of the pile groups by model test and numerical simulation.In the model test, models of ship, pile groups and pile cap are made by referring to the reality of a 1:50 ratio. The pile groups are seted in the soil tank. When the ship hits pile cap, acquire the dynamic response datas, such as the displacement, the acceleration.The finite element model of the ship, pile groups and soil are created by ANSYS to simulate the process of collision, the model of the ship is made by layered shell element, and the model of pile groups and soil are made by solid element.The dynamic response of pile groups are studied by the factors such as the ship tonnage, the speed of the ship, the pile spacing, the length of pile above the ground, the diameter of pile, the vertical load on the cap, the number of pile groups, the angle of the impact, the location of the impact, the dynamic elastic modulus of soil. At last, the results of the model test and the finite element simulation are compared.The results show that the ship tonnage and the speed of the ship have a significant effect on the maximum ship collision force, the maximum acceleration of the pile cap, the maximum displacement of the pile cap; the pile spacing has a little effect on the dynamic response of pile groups; the length of pile above the ground, the diameter of pile, the vertical load on the cap, the type of pile groups have a significant effect on the maximum acceleration of the pile cap and the maximum displacement of the pile cap,but they have a little effect on the maximum ship collision force; the angle of the impact has a certain effect on the duration of ship collision, the maximum displacement of the pile cap, the maximum deflection angle of the pile cap; the location of the impact has a little effect on the ship collision force, the acceleration and displacement of the pile cap, however,it has a significant effect on the maximum deflection angle of the pile cap; the dynamic elastic modulus of soil has a significant effect on the maximum acceleration of the pile cap and the maximum displacement of the pile cap, but it has a little effect on the maximum ship collision force.