摘要
为探讨夹芯板结构准静态下的弯曲失效模式和疲劳性能,以304不锈钢为面板,7050铝合金基体闭孔泡沫铝为芯层,组成泡沫铝夹芯板结构.基于三点弯曲试验获得夹芯板结构损伤变形过程和静态峰值载荷.通过三点弯曲疲劳试验得到疲劳寿命和破坏形式,采用最小二乘法和极大似然法绘制夹芯板的S-N和P-S-N曲线,并进行对比分析.结果表明:夹芯板在静态加载时的弯曲失效与载荷-位移曲线相吻合;在疲劳加载时失效方式较为单一,90％的试件因芯层断裂而失效.夹芯板疲劳寿命随着面板厚度的增加而增加,当芯层密度从0.60 g/cm3增加到0.73 g/cm3时,疲劳寿命反而出现下降;当芯层密度为0.60 g/cm3,面板厚度为0.6 mm时,夹芯板结构对加载水平敏感度最低.研究结果为夹芯板结构工程应用提供了设计基础.
Abstract
In order to explore the bending failure as well as fatigue life of sandwich structures under quasi-static conditions,the damage deformation process under three-point bending conditions was investigated with 304 stainless steel as panels and 7050 aluminum alloy substrate with closed-cell foam aluminum as the core layer.The static peak loads of different specimens were determined by the three-point bending load method.The bending life and damage forms were obtained by high-frequency fatigue testing machine.The S-N and P-S-N curves of different sandwich panels were plotted for comparative study.The results show that the bending failure of the sandwich plate under static state is consistent with the load-displacement curve.The failure mode of sandwich plate under fatigue state is relatively single,and 90％ of the specimens fail is due to core fracture.The fatigue life of sandwich panel increases with the increase of panel thickness.When the core density increases from 0.60 g/cm3 to 0.73 g/cm3,the fatigue life no longer continues to increase but begins to decrease.When the core density is 0.60 g/cm3 and the panel thickness is 0.6 mm,the fitting effect is the best and the sensitivity to the loading level is the lowest.This study provides a design basis for the subsequent practical engineering application of sandwich panels.
基金项目
陕西省自然科学基础研究计划项目(2021JQ-283)
国家科技期刊平台
NSTL
万方数据