Strain concentration caused by the closed end contributes to cartridge case failure at the bottom  

作　　者：Song Cai Jie Feng Hui Xu Kun Liu Zhong-xin Li Zhi-lin Wu 

机构地区：[1]School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing,210094,Jiangsu,China

出　　处：《Defence Technology（防务技术）》2020年第6期1151-1159,共9页Defence Technology

基　　金：The authors are grateful for the reviewers’instructive suggestions and careful proofreading.This work was supported by the Equipment Development Department of the Central Military Commission of China(grant nos.301090702);the Foundation of National Laboratory(grant nos.61426060102162606005 and JCKYS2019209C001).

摘　　要：Ruptures at the bottom of cartridges are a common cause of failure of ammunitions,which directly threatens the safety of weapons and shooters.Based on plastic tube theory,this study analyses the radial and axial deformation of a cartridge,considering the radial constraint of the closed end at the bottom of the cartridge.Owing to the influence of the closed end,the bottom of a cartridge does not establish complete contact with the chamber.Owing to strain concentration in the non-contact area,this area is more amenable to the occurrence of cartridge rupture.This theory predicts the location of the fracture more accurately than the traditional theory.The maximum axial deformation of a cartridge comprises bending and friction deformation.The maximum strain at the bottom of the cartridge increased by 135%owing to the introduction of bending strain caused by the closed end.The strain distribution of a cartridge was measured using digital image correlation technology,and the measured result was consistent with the predicted results of the bending deformation theory and rupture case.The effects of wall thickness,radial clearance,friction coefficient,and axial clearance on the axial deformation of the cylinder were studied.Increasing the wall thickness and reducing radial clearance were found to reduce bending deformation;furthermore,lubrication and reduction in axial clearance reduce frictional deformation,which in turn reduce cartridge rupture.

关 键 词：Closed end Cartridge case failures Strain concentration Bending deformation 

分 类 号：E92[军事—军事装备学]