胶接、胶焊与点焊接头剪切拉伸疲劳行为

通过剪切拉伸疲劳试验测定车用结构胶接接头、胶焊接头和点焊接头在不同应力水平下的疲劳寿命.基于载荷-寿命曲线在单对数坐标下为指数曲线段这一假设,利用疲劳试验数据拟合出载荷-寿命曲线,以此表征三种接头的疲劳性能.同时,对胶接接头、胶焊接头和点焊接头的疲劳行为进行对比分析.研究表明:三种连接方式的疲劳试验数据具有较好的规律性;拟合结果证实了三种接头载荷-寿命曲线在单对数坐标下为指数曲线段这一假设的正确性;胶接接头的疲劳强度最高,而点焊接头最低;胶焊接头的疲劳断裂行为比胶接接头更为安全;通过胶焊工艺可以有效提高车身接头的疲劳寿命等.研究结论为车用结构胶胶接技术的应用提供了参考依据.

Shear Tension Fatigue Behavior of Bonded Joint,Weldbonded Joint and Spot-welded Joint

A test was made on the fatigue life of structural bonded joints,weldbonded joints and spot-welded joints under different levels of stresses.Based on the hypothesis that load-life curve in single logarithm coordinate should be exponential curve,load-life curves of three kinds of joints were fitted by using of fatigue test data.Thus,fatigue performance of three kinds of joints was able to be described by these curves.And,a comparative analysis was made of the fatigure behavior of bonded joints,weldbonded joints.The study show that distribution of these fatigure test data follows a certain law.The fitted result proves that the hypothesis that load-life curve in single logarithm should be exponential curve is right.Fatigue strength of bonded joints is the highest of the three kinds of joints.On the contrary,fatigue strength of spot-welded is the lowest.Fatigue rupture behavior of weldbonded joint is more dangerous than that of bonded joint.Fatigue life of body joints can be improved by bonded process.These conclusions provide references for application of structural adhesive to vehicles.