基于加速度信号的悬置螺栓疲劳寿命研究

RESEARCH ON THE FATIGUE LIFE OF THE BOLTS AT ENGINE MOUNTS BASED ON ACCELERATION SIGNAL

零件在实验工况下所受应力数据对预测其疲劳寿命至关重要。针对发动机悬置螺栓等无法通过应变片传感器直接得到载荷数据的部位,提出一种基于加速度信号的悬置螺栓疲劳寿命估计方法。通过宏观断口及力学模型分析,明确了在不同工况下造成悬置螺栓疲劳失效的主要矢量载荷与加速度载荷的转换关系。结合悬置螺栓S-N曲线,计算出不同工况下由加速度引起的弯矩和拉压波动载荷的时间历程,并进行了发动机悬置螺栓的疲劳损伤计算,从而形成了一种复杂载荷下的发动机悬置螺栓疲劳寿命分析方法。最后基于悬置螺栓在两种道路的应力载荷谱所分别对应的疲劳寿命,建立起了针对悬置螺栓的道路间的当量关系。

Loading spectrum statistic acquired from proving ground has great effect on the component fatigue life prediction.a fatigue damage and life prediction method based on the acceleration signal was put forward,this method is applied to engine mount bolt whose loading spectrum can＇t be directly acquired in working condition. First,by macrofracture observation and mechanical model analysis,the relationship between the main stress load and acceleration load of different condition was defined.Then according to the S-N curve of engine mount bolt,and applying the acceleration signal in different working condition,bending moment and tensile stress in time series was calculated. The engine mount bolt fatigue damage was figured out based on those time series. Finally,by compearing with the fatigue life of two measured roads,the equivalent relationship between the two roads is established.