Study On The Shock Response Of Some Slender Equipment In Ships

During the service of the ship,it may be affected by the impact of an underwater explosion,this effect will cause impact damage to the internal equipment.There is a series of slender structures of ship's equipment,such as Large Scale Piping System,Ship Propulsion Shafting,Lifting Device,and ship girder,etc,whose impact resistance is closely related to the vitality of the ship.However,in engineering calculation,different structure requires different engineering problems.Thus,this article mainly starts with the impact stress of the ship piping system and low frequency acceleration caused by the total vibration of the hull.This will be of certain significance to improve the impact resistance of these structures.The specific contents are as follows:First,the simplification of the ship piping system is studied,mainly from boundary condition,inner liquid,modeling process and loading mode.Derivation by the knowledge of structural mechanics,the whole piping system can be simulated by taking two lines of pipeline in the target tube section;By comparing the fluid solid coupling and the additional mass,exploring the participation coefficient of the fluid in the tube with the change of the pipe diameter;Developing the fast modeling software for pipeline fine model with APDL language.Second,two methods for calculating the impact of the pipeline and related factors are proposed.Through finite element calculation,the location and law of dangerous nodes are given.And through the calculation of the simplified model,it verifies the simplified method proposed in this paper is feasible.The transfer matrix is obtained based on the Timoshenko theory,and comparing the results of finite element and program calculation to verify the method's feasibility.By these methods,I study the factors of impact resistance,such as loading mode,stiffness and damping of support hanger.Third,a new prediction method of low frequency acceleration is proposed in this paper.We can get the system response function by solving the vibration differential equation of beam.Comparing the function of acceleration and strain,they differ in a proportional coefficient under each mode and prove that the coefficient is related to the structural mode and natural frequency.And a method to predict the vibration mode and the natural frequency based on the transfer function is proposed.Last,we designs a shrinkage model test to verify the method,and apply this method to deal with real ship data to calculate spectrum parameters.