柴油机曲轴断裂预报技术研究

运用理论计算和试验模态分析方法,对光轴和曲轴是否有裂纹的情况进行了分析,结果表明:当光轴或曲轴发生裂纹时,各阶固有频率均有明显变化;当裂纹位置一定时,裂纹越深,固有频率变化越大,其变化的绝对值可以在现场检测中识别。如作出各阶固有频率变化量随裂纹位置和深度分布的曲面,用试验中测出的固有频率变化量去截取各曲面,可得到多阶等高线曲线,将各等高线两两重叠,就可识别裂纹在轴上的位置和深度,并具有较高精度。

Study on Forecast Technique of Crankshaft-Breaking Of Diesel Engine

It was analyzed whether there was crackle on the shaft or crankshaft by theoretical calcula- tion and test mode analysis method.Analysis result shows each natural frequency of the shaft or crankshafts would change obviously when the fatigue crackle is occured on the shaft or crankshaft.When the location of crackle is fixture,the deeper crackle depth is;the bigger the change of each natural frequency is.The abso- lute value of frequency change is sufficient to be distinguished by detecting.If making a curved surface that is the change value of each natural frequency is related to the change of depth and location of crackle,and by cuting out the every curved surface using the change value of each natural frequency measured in experiment, a multistage contour curve can be obtained.Depth and location of crackle on the shaft or crankshaft can be distinguished with higher precision by overlapping the multistage contour curve.