木质夹层梁横向承载挠度的预测与验证

Modeling and Verification of Sandwich Beam with Wooden Skin and Honey-Comb Core Subjected to Transverse Loading

修正基于Reissner假设的传统一阶剪切理论,将加载点处的压痕变形融入到模型中,推导出夹层梁横向承载跨中挠度的计算公式,并通过试验进行验证。结果表明:通过解析横截面切应力分布规律,推导出表板承受的剪力近似等效于同厚度芯层承受剪力的一半。修正一阶剪切理论计算夹层梁跨中挠度的精度整体好于传统一阶剪切理论。在同样的受力条件下,"∥"方向试件跨中挠度均大于"⊥"方向试件,主要表现在"∥"方向试件的剪切变形大于"⊥"方向试件。随着芯层厚度的增加,夹层梁弯曲挠度、剪切挠度逐渐减小,但剪切挠度占总挠度比重越来越大。修正一阶剪切理论计算的剪切挠度与横截面芯层切应力均小于传统一阶剪切理论,而随着芯层厚度的增加,2种理论的计算结果趋于一致。

The equation to calculate transverse displacement in mid span of sandwich beam was derived by revision of Reissner theory and considering indentation deformation of central loading. It was shown that the resistance to the shear force of skin was equivalent to the half thickness of honey-comb core. By comparison with test results, Revised first-order theory. （RFOT）had higher accuracy than classical first-order theory （CFOT）in general to calculate the transverse displacement of sandwich beam. Furthermore, the transverse displacement of ＂ ∥＂ direction specimens were bigger than ＂ ⊥ ＂direction ones because of shear deformation. It was also indicated the transverse displacement including bending and shear deformation were all decreased gradually with increasing core thickness, but the proportion of shear displacement to the total became larger step by step. In addition, shear displacement and cross-sectional stress calculated by RFOT was less than CFOT, but the two theories tended to be identical with increasing core thickness.