基于修正单层梁理论的夹层梁最大弯曲正应力计算

Calculation of Maximum Bending Normal Stress for Sandwich Beam Based on Revised Single Layer Beam Theory

目的计算夹层梁横截面的最大弯曲正应力。方法将夹层梁等效成等截面均质单层梁,进而推导出了理论计算公式,并在此基础上进行了三点弯曲试验的算例研究。结果当破坏载荷与夹层梁横截面的尺寸一定时,随着芯层与总厚度比的增加,修正单层梁理论计算的最大正应力值逐渐增加,而单层梁理论计算的结果为恒定值。对于同样结构的夹层梁,随着芯层弹性模量与表层模量比的增加,修正单层梁理论计算的最大正应力与单层梁理论的差异值越来越小。结论修正单层梁理论与层合梁理论计算的结果是一致的,该方法可有效进行最大弯曲正应力的预测与计算。

Objective To set up maximum bending normal stress equation for sandwich beam. Methods New methodology was proposed based on the equivalent single layer beam theory, after that the numerical examples were demonstrated according to three point flexural test. Results When the cross section of beam and the maximum loading were fixed, the maximum bending normal stress calculated by Revised single layer beam theory （RSLBT） was increased accordingly with increasing ratio of core thickness to the whole ,whereas the calculation result was a constant using the Single layer beam theory （SLBT）. In addition, for the same sandwich construction, the difference between RSLBT and SLBT became smaller with increasing ratio of core modulus to the top. Conclusion RSLBT, which is equivalent to the Multi-layer beam theory, can provide a new method to calculate the maximum bending normal stress with suitable accuracy.