Research And Analysis On Accelerated Life Test Of Gun

Gun barrel life test is an important content of the gun type finalization test. In order to solve the problem of long life test time, large amount of ammunition consumption and high cost, the existing method of life test should be improved. Based on the fatigue life and erosive wear life of the of gun barrel, combination with the test method adopted at present, comprehensive utilization of accelerated life test method, utilizing the dynamics and numerical simulation software, the fatigue life and the erosive wear life of the barrel were investigated by means of the accelerated life test design, and the simulation results were analyzed.The basic theory of accelerated life test were studied, including the loading method, the basic assumptions, study on acceleration model and its scope of application, and parameters estimation method of acceleration model.The fatigue failure mechanism of the barrel was analyzed. The mathematical model between the maximum tangential stress of the inner wall of the barrel and fatigue life of gun barrel was established by use of the theory of Paris crack growth rate. By means of the dynamics simulation software ABAQUS, the finite element model of the dangerous section was constructed. The influence of different accelerated stress on maximum tangential stress in case of bore pressure as the accelerated stress. Based on mathematical model of fatigue life of the barrel and Monte-Carlo simulation, the design method of gun barrel fatigue life accelerated test was proposed with consideration of the random distribution of the material parameters, and the distribution of fatigue life was obtained. The inverse power law-acceleration model was established. The parameters estimation was studied by using the least square method for the acceleration model. The data predicted by acceleration model was compared with that from the test of normal stress level, and the results verified the correction of the acceleration model and the feasibility of the test scheme.Based on systematic analysis of the erosive wear of gun barrel, the relationship between ablation and peak temperature in the inner wall of gun barrel was built up, and then the relationship between ablation wear life under a running fire and peak temperature was found out. With ambient temperature as the accelerated stress, the accelerated test design of the erosion wear life of the barrel was carried out by using ANSYS PDS reliability analysis module. The barrel material parameters were parameterized and treated as the random input variables, and the peak temperature of the inner wall of barrel was outputted as random variables by using stochastic finite element method. By combination of erosion wear life prediction model and Monte-Carlo simulation method, the reliability of gun barrel ablation wear life at different stress levels were analyzed. Arrhenius accelerating model of the accelerated test was established, and the error of the prediction result of the acceleration model was analyzed.The design method of the gun barrel accelerated life test of the fatigue and erosion can provide some reference for the study of accelerated life test.