梁的疲劳开裂各向同性弯曲损伤分析

An Isotropic Damage Analysis on Beams under Fatigue Pure Bending Load

在梁的纯弯曲损伤基本假设条件下,利用疲劳损伤耦合理论,导出了梁弯曲疲劳损伤的基本方程。根据疲劳实验测得的跨中挠度随荷载循环次数的变化规律,得到梁底缘应变与循环荷载重复作用次数的关系曲线。利用梁弯曲疲劳损伤的基本方程可分别得到中性轴偏移量和有效惯性矩与循环荷载重复作用次数的关系曲线,最后可预测矩形截面梁疲劳寿命。

In this paper,based on assumptions of pure bending damage of beams,basic equations of bending fatigue damage of beams are derived by applying the coupling theory of fatigue damage.According to the fatigue test,the variation regularity of mid-span deflection with the number of load cycles is measured to determine relation curves of the strain at the beam’s bottom changing with the number of repeated cyclic loading.By using the basic equations of bending fatigue damage of beams,the relation curves of the neutral axis offset and the effective moment of inertia changing with the number of repeated cyclic loading can be obtained respectively.Finally,the fatigue life of rectangular beams can be predicted.