扭力梁疲劳分析方法研究

Research on Fatigue Analysis of Twist Beam

扭力梁的第一阶固有自由模态频率通常在路面载荷激励频段内。为研究基于准静态法和模态叠加法疲劳分析的准确性,以实测应变为基准,通过时域和频域对比发现准静态法分析值与实测值更加吻合;通过伪损伤值对比,准静态法和模态叠加法分别为实测的148. 44%和764. 48%,验证了准静态法精度较高,模态叠加法分析值偏大。对主梁疲劳进行对比,两种方法的疲劳损伤分布基本一致,损伤区域主要位于主梁中部,模态叠加法损伤值高于准静态法损伤值,进一步验证扭力梁疲劳分析时模态叠加法偏于保守。

The first natural free mode frequency of twist beam is usually within the load excitation frequency band.In order to study the accuracy of fatigue analysis based on quasi-static method and modal superposition method,based on the measured strain,it is found that the analytical values of the quasi-static method is more consistent with the measured values by comparing the time domain and frequency domain.By comparison of the pseudo damage values,the quasi-static method and the modal superposition method are 148.44% and 764.48% of the measured values respectively,which proves that the precision of the quasi-static method is high and the modal superposition method has a large analysis value.Finally,by comparing the fatigue damage of the main beam,the damage distribution of the two methods is basically the same.The damage area is mainly located in the middle of the main beam,and the damage value of the mode superposition method is higher than that of the quasi-static method.It is verified that the modal superposition method is conservative for twist beam fatigue analysis.