高锁螺栓干涉配合安装工艺参数对凸瘤的影响分析

 干涉配合螺栓连接是提高飞机结构疲劳寿命的一种有效方法,干涉安装中产生的凸瘤对结构强度极为不利。分析了凸瘤产生的原因,对M8钛合金高锁螺栓进行了静态压入试验,同时建立了有限元模型进行数值模拟,通过对比压入力和凸瘤大小,验证了有限元模型。对影响凸瘤产生的工艺参数进行了分析。有限元模拟结果表明:最佳干涉量为1.5%,顶铁中孔直径略小于螺栓2倍时产生的凸瘤较小,钉孔间摩擦因数须小于0.15,孔出口0.2×120°倒角可减小凸瘤和降低此处的应力集中效应。

Analysis of Process Parameters Influencing Protuberance During Interference Fit Installation of Hi-lock Bolts

Interference fit is an effective process method for improving the fatigue life of bolted joints, but the protuberance produced in installation is harmful to the strength of joints. The causes of protuberance arising are analysised, and then reports a squeezing installation test of titanium alloy M8 hi-lock bolts. A finite element model (FEM) is developed and the process of installation is simulated. The experimental squeezing force and protuberance sizes are compared with the results from finite element analysis (FEA) to validate the FEM. Several process parameters are analyzed. The FEA results indicate that the best interference fit size is 1.5%,when the diameter of the bucking bar central hole is slightly smaller than twice the bolt diameter, the protuberance is relatively small. The friction coefficient should be less than 0.15, and 0.2×120°chamfer around the hole exit side can reduce protuberance and stress concentration.