孔径尺寸对干涉配合铆接件超高周疲劳性能的影响

合理的干涉配合铆接工艺可以有效提高构件疲劳性能,本文通过试验研究与数值模拟相结合分析孔径尺寸对干涉配合铆接件超高周疲劳性能的影响。利用20kHz超声疲劳试验系统测试了三种不同孔径尺寸下干涉配合铆接件的超高周疲劳性能;基于ABAQUS模拟分析了铆接工艺过程以及孔径尺寸对干涉量和孔边残余应力的影响,通过分析高频低幅加载下孔边应力分布,结合超高周疲劳试验及断口形貌观察,分析了孔径尺寸对铆接件超高周疲劳性能的影响。结果表明:不同孔径尺寸铆接件的裂纹萌生扩展方式类似,疲劳裂纹萌生均发生在孔边距表面1.5mm最大残余拉应力处;适当减小孔径尺寸所形成的合理干涉量可以提高铆接件疲劳寿命,φ4.10mm的孔径可以形成0.66%的孔边平均干涉量,铆接件疲劳寿命最高达到3.63×108周。

On the Effect of Aperture Size on Very High Cycle Fatigue Performance of Interference Fit Riveted Part

Reasonable interference fit riveting technology can effectively improve construction member's fatigue behavior.In this paper,the effect of aperture size on very high cycle fatigue performance of interference-fit riveted part was investigated by the combination of experimental study with numerical simulation.By using 20kHz ultrasonic fatigue experimental system,the very high cycle fatigue performance of interference fit riveted part with three different aperture sizes was tested.In addition,based on ABAQUS,the riveting process and the effect of aperture size on interference quantity and residual stress in hole side area were numerically simulated.Through the analysis of stress distribution around the riveted hole under high frequency and low amplitude loading condition,combining with very high cycle fatigue experiment and fracture surface observation,the effect of aperture size on very high cycle fatigue performance of riveted part was analyzed.Results show that the crack initiation and growth patterns of riveted part with different aperture sizes are similar;all fatigue cracks initiate at the position below the surface 1.5 mm in hole side area,where the maximum residual stress appears.Suitable reduction of reasonable interference quantity caused by the formation of aperture size can improve the fatigue life of riveted part.The hole with (ψ)4.10mm aperture size can produce 0.66％ average interference quantity in hole side area.The maximum fatigue life of riveted part can reach 3.63× 108 cycle times.