残余应力对身管内膛裂纹应力强度因子的影响  

Effect of residual stress on stress intensity factors of inner barrel bore cracks

作　　者：冉相辰 李强[1] RAN Xiangchen;LI Qiang(School of Mechanical and Electrical Engineeing,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学机电工程学院,太原030051

出　　处：《兵器装备工程学报》2023年第2期1-7,共7页Journal of Ordnance Equipment Engineering

基　　金：国家自然基金项目(51175481)。

摘　　要：自紧技术通过施加自紧压力使身管内膛发生塑性变形,以产生残余应力增大身管强度,也是提高身管使用寿命的有效方法。为了研究残余应力对身管内膛裂纹的影响,建立了具有残余应力的身管扩展有限元模型,计算了不同自紧度的身管在残余应力场作用下,内膛表面裂纹的强度因子,分析了自紧残余应力和裂纹深度对裂纹应力强度因子大小的影响。同时,在连续射击后发生残余应力释放的条件下,计算了自紧身管的残余应力的变化规律和表面热应力对裂纹应力强度因子的影响。结果表明:自紧残余应力能有效抑制身管裂纹的扩展,提高疲劳寿命,其抑制效果与残余应力的大小成正相关,自紧身管在射击后,热载荷作用下,表层的残余应力由压应力变成拉应力,其他区域切向残余应力数值也相应减小,残余拉应力使身管表层更容易开裂。Autofrettage creates plastic deformation of the inner bore of a barrel by applying self-tightening pressure so as to produce residual stress and increase the strength of the barrel. It is also an effective method to improve the service life of the barrel. In order to study the influence of residual stress on inner barrel bore cracks, this paper establishes a finite element model of barrel expansion with residual stress. The intensity factors of inner bore surface cracks under the action of residual stress field of the barrel with different autofrettage are calculated, and the effects of self-tightening residual stress and crack depth on the magnitude of crack stress intensity factors are analyzed. At the same time, under the condition of residual stress release after continuous shooting, the variation law of residual stress of autofrettage barrels and the effect of surface thermal stress on crack stress intensity factors are calculated. The results show that the autofrettaged residual stress can effectively inhibit the crack propagation of the barrel and improve the fatigue life, and its inhibition effect is positively related to the magnitude of the residual stress. After the barrel is shot, under the action of thermal load, the residual stress on the surface layer changes from compressive stress to tensile stress, and the values of tangential residual stress in other areas also decrease accordingly. The residual tensile stress makes the surface layer of the barrel easier to crack.

关 键 词：自紧身管 残余应力 扩展有限元 裂纹 应力强度因子 

分 类 号：TJ303[兵器科学与技术—火炮、自动武器与弹药工程]