Fatigue Life Analysis And Accelerated Test Design Of An Aero Bomb Body Structure

With the continuous development of China's military strength and the increasing speed of appearance of new technology in modern warfare,the speed of development and renewal of weapons and equipment is on a relatively high level.As a kind of cost-effective air to surface weapon,the aero bomb faces the same renewal and technical upgrading.However,when the aero bomb is mounted on the carrier plane,it will continue to be subjected to random vibration load from the plane.In such a vibration environment,it may cause the fatigue problem of the aero bomb body structure.The fatigue failure of the aero bomb body structure will threaten the safety of the aircraft and pilots seriously.So the estimation of life and reliability of aero bombs is a process that must be experienced in the development of new products.Therefore,it is necessary to summarize a set of random vibration fatigue prediction methods which are suitable for aero bombs,which will provide protection for the safety of the aircraft indirectly.This paper focuses on the theoretical analysis of the fatigue life of aero bombs.The main research contents include:(1)The three-dimensional model and finite element model of the bomb body structure were established by using Solidworks and Hypermesh software,including the simplification of the model and the generation of high quality grid.Then the static analysis,modal analysis and random response analysis of the aero bomb were carried out by using Abaqus software,with a result of the force and deformation of the whole bomb(2)Based on the results of finite element analysis,the fatigue analysis of the aero bomb was carried out by using Matlab software,where three commonly random process rain-flow amplitude distribution models were used.To verify the calculation accuracy of each model,the power spectral density of stress was converted to the time domain loading process,which was used to calculate the fatigue damage by using Rain-Flow Counting Method.The result of fatigue damage in time domain solution was used for comparing with the results of fatigue damage in frequency domain.providing a reference for the life analysis of similar products in the future.(3)Based on the frequency domain fatigue life calculation model,the equivalent relationship between the excitation and the life was derived out.According to the equivalent relation,the step stress acceleration test was designed,and the derivation formula of the test data was given,which provided a scheme for the accelerated test of the aero bomb.