Dynamic Analysis To Ship Impact Of Piling Wharf Based On Lagrangian

Based on the frame-pier wharf of Guoyuan Phase II in Chongqing port,it has been established a collision model between ship and frame-pier wharf by means of Lagrange and the giant general-purpose finite element software LS-DYNA.It has been studied the impact force-time curves and analysed the dynamic response of structure under different influence factors such as velocity,tonnage,collision angle and impact location and the rubber fender.Some conclusions as follows:(1)The analysis results of dynamic response indicate that the Collidion Force-Time Curves is similar to inverted triangle sinusoidal and in future studies,it was could use half-sine impact load to simulate striking force.The impact force reaches a maximum at 0.6 seconds,then decreases to 0 at a slower rate.(2)The influence of velocity,collision angle and tonnage to the dynamic response of structure: The peak of impact force is increased with these three factors.In the vertical direction,different heights of the X-direction(normal of the impact)displacement value basically as arithmetic sequence,the maximum displacement is in the highest point.The displacement of Z-direction(tangent of the impact)doesn't increase as the velocity and collision angle increase,the displacement fluctuate within a certain range.(3)The influence of impact location and impact water level to the dynamic response of structure: when ship hit the middle bent,the impact force is larger,with short duration;when ship hit the outside bent,the impact force is smaller,lasted longer.The total displacements of striked bent,the nearby bent and the quay is larger than other places.When ship impacts the lower two water level,the impact force peak is larger than the above there water level.When the ship impact the frame-pier wharf at the lowest water level,the maximum stress is obviously larger than others,the Maximum Principal Stress-Time Curves of the points above the impact location have the variation of Cascade Distribution.(4)The mechanical characteristics of the frame-pier wharf indicate that rubber fenders greatly reduce the impact force peak,it delayed the whole process of impact.But when with no rubber fenders,finite element results of impact force is too large,the maximum value is 7 times as much as the former,collision duration is one-ninth of the former.The style of Collision Energy-Time Curves of pier's composite concrete and pier's steel are nearly the same,the former is 10 times as much as the latter.After comparative analysis to the peak of force of each cross-section,we can find that the peak of force of each cross-section is not a single descending along the transfer direction,but decrease and then increase.