Analysis Of Service Life Of Firearms Based On Multi - Failure Mode

In this paper, we do research of the tube and locking lug of one certain machine gun. We study the reliability of the tube life based on the fatigue and ablation failure, and calculate the impact-fatigue life of the locking lug based on the impact-fatigue failure and the Laingen equation. In the end, considering the mutual effect from the several failure, we analyze the machine gun reliability based on the Copula theory. The main contents are as follows.(1)The evolvement law between fatigue damage and shoots was built based on the damage data that calculated by the local stress-strain method and Monte Carlo method. We got the average fatigue life of 4929 and 5435 respectively and the reliable life of 2950 and 3160 based on the random factor and the pseudo life method. Some experiment data showed that when gun fired more than 4000 rounds, different degree of crack appeared between the chromium layer and metal substrate interface. The test data validated the feasibility of two methods.(2)The tube erosion was calculated by ANSYS stochastic finite element method based on the theoretical degradation model. The reliability life of ablation was researched based on the performance degradation data analysis and the pseudo-failure lifetime method by the evolvement law between ablation data and shoots.(3)The load of the locking lug was analyzed and its reliability was analyzed and the impact-fatigue life was calculated by the Laingen equation.(4)The several combined distributing functions were built based on the Copula theory. The best distributing function was determined by the goodness of fit test based on the minimum distance method. The tube reliability was analyzed based on the best distributing function. The life reliability was analyzed considering the several failure.(5)The key elements life of machine gun analysis software based on multi-failure was developed.