加筋板广布疲劳损伤的剩余强度分析

RESIDUAL STRENGTH ANALYSIS FOR WIDESPREAD FATIGUE DAMAGE IN STIFFENED PANEL

给出加筋板广布疲劳损伤的两种损伤类型和两个剩余强度判据 ,剩余强度判据是净截面塑性区屈服判据和裂尖韧带屈服判据。给出蒙皮带有多裂纹和蒙皮带有多裂纹且桁条也带有裂纹时应力强度因子的近似工程估算方法。文中也给出加筋板含多裂纹时剩余强度净截面塑性区屈服判据和裂尖韧带屈服判据的表达式及塑性区尺寸估算方法。对三种损伤的加筋板进行剩余强度试验 ,指出多裂纹尤其是桁条也带裂纹时剩余强度降低较多。用上述两种判据进行加筋板广布疲劳损伤剩余强度预测 。

Two distinct types of damage and two residual strength criteria for widespread fatigue damage in stiffened panel are given. The residual strength criteria are the net section yield criterion and crack tip ligament yield criterion. The approximate engineering approaches for stress intensity factor(SIF) of skin with multiple site cracks and skin and stringer with cracks are given. The expression of net section yield criterion and crack tip ligament yield criterion and estimation of plastic zone size for multiple site cracks in stiffened panel are also given. The residual strengths of three types of damage in stiffened panel are tested. It is point out that the decrease of residual strength for multiple site cracks, particularly, for stringer with crack, are rather larger. Residual strength for widespread fatigue damage in stiffened panel is predicted by the two criteria, and the prediction and the testing results are in good agreement.