对采用真空导入工艺的泡桐木夹层梁进行4点弯曲疲劳试验,研究发现泡桐木夹层梁的破坏形式主要有界面的脱黏、芯材的剪切破坏、面板分层等.试验过程中采集试件的S-N曲线,采用3种寿命预测公式对其进行线性拟合,得到该泡桐木夹层梁的寿命预测公式.基于S-N曲线在实际工程中的应用,引入失效率的概念,采用双参数的Weibull函数分布,对不同应力等级下的失效率进行研究,从而得到泡桐木夹层梁P-S-N曲线。
Paulownia core sandwich composite beams manufactured by vacuum infusion molding process were tested by four-point flexural test for bending fatigue property research. It was found from the experiments that interface debonding, warp, shear and bending failure of core materials, and surface stratification were the main fatigue failure modes of the beams. The curves of fatigue stress versus cycles were collected and linearly fitted to obtain the fatigue life prediction formula of the beams. Based on S-N curves in practical engineering, the failure rate under different level of stress was studied by double parameter Weibull function method to obtain P-S-N curves.