Abstract: A new method for the numerical analysis of structures is proposed, based on momentum conservation laws to calculate the dynamic responses of the sutructre with different input simplified force-time curves using finite element model, and it stops until the numerical result is consistent with the actual value. Based on the background of the "Zhong Quan" Sinopec accident, a three dimensional model of high-pile cleat is eatablished with explicit dynamic analytical software LS-DYNA, and the failure process of the cleat under ship's impact load is analyzed by the proposed method. The results show that the residual displacements of the cleat are consistent with the actual values when the impact time is 13.75 s, and the shear failure mode of the abutment is consistent with the situation. Also, they show that the concrete of the filling piles is damaged in various degrees at the fixed end, the steel sleeves enter the yield stage, and the cleat is evaluated as medium damage.