双孔耳片衬套冷挤压强化的残余应力和疲劳寿命  

Residual stress and fatigue life for cold expansion strengthening of bushing in double-hole lug

作　　者：唐伟 林忠亮 吴保全 刘烨欣 张涛 王宝辉 白清顺[3] TANG Wei;LIN Zhong-liang;WU Bao-quan;LIU Ye-xin;ZHANG Tao;WANG Bao-hui;BAI Qing-shun(Aerospace Precision Products Co.,Ltd.,Tianjin 300300,China;Tianjin Key Laboratory of Fastening Technology,Tianjin 300300,China;School of Mechatronics Engineering,Harbin Institute of Technology,Harbin 150001,China;The Second Military Representative Office of Air Force Armament Department in Tianjin,Tianjin 300300,China)

机构地区：[1]航天精工股份有限公司,天津300300 [2]天津市紧固连接技术企业重点实验室,天津300300 [3]哈尔滨工业大学机电工程学院,黑龙江哈尔滨150001 [4]空军装备部驻天津地区第二军事代表室,天津300300

出　　处：《塑性工程学报》2023年第2期55-63,共9页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(52075129);天津市紧固连接技术企业重点实验室开放课题(TKLF2021-02-B-06)。

摘　　要：为提高双孔耳片连接孔的疲劳强度和服役寿命,采用衬套冷挤压强化技术建立了双孔耳片挤压工艺的数值仿真模型,得到了应力的数值大小和分布区域变化规律。结合有限元分析和疲劳试验方法,获得了冷挤压后耳片-衬套试件的疲劳寿命,并对断口的宏观和微观形貌进行了分析。结果表明,挤压量的增大提高了切向残余压应力,同时扩大了压应力沿衬套厚度方向和耳片径向的分布区域。芯棒的挤压过程加剧了沿厚度方向应力分布的不均匀性,较大的压应力区域出现在距挤入面2~8 mm范围处。综合考虑挤压量对残余压应力平均值和分布区域的影响,确定最佳挤压量为4%,挤压量的适当增加可以有效提高构件的疲劳寿命。挤压量为1.5%时,疲劳试验所得疲劳寿命为316957次循环,疲劳寿命仿真值为338844次循环,二者相对误差较小。耳片-衬套构件的断裂位置均发生在孔的最小截面处,裂纹断裂方向与主应力方向基本垂直,出现了许多大小不一的裂纹条带。To improve the fatigue strength and service life of the connecting hole of double-hole lug,the numerical simulation model of the double-hole lug extrusion process was established using the bushing cold extrusion strengthening technology.The variation law of values and distribution area of stress was obtained.Combined with finite element analysis and fatigue test methods,the fatigue life of the lug-bushing specimen after cold extrusion was obtained,and the macroscopic and microscopic morphologies of the fractures were analyzed.The results show that the increase of extrusion amount increases the tangential residual compressive stress.At the same time,the distribution areas of compressive stress along the thickness direction of bushing and the radial direction of lug are enlarged.The extrusion process of mandrel exacerbates the inhomogeneity of the stress distribution along the thickness direction.Larger compressive stress area appears at the position 2-8 mm away from the extrusion surface.Comprehensively considering the influence of extrusion amount on the average value and distribution area of residual compressive stress,the optimal extrusion amount is determined to be 4%,and appropriate increase of the extrusion amount can effectively improve the fatigue life of the components.When the extrusion amount is 1.5%,the fatigue life obtained from the fatigue test is 316957 cycles and the simulation value of fatigue life is 338844 cycles,presenting a small relative error.The fracture positions of the lug-bushing components all occurr at the minimum cross-section of the hole,the fracture direction of the crack is basically perpendicular to the principal stress direction,and many crack strips with different sizes occur.

关 键 词：冷挤压 强化技术 残余应力 压合衬套 双孔耳片 

分 类 号：TG376.3[金属学及工艺—金属压力加工] TH114[机械工程—机械设计及理论]