关于夹芯梁四点弯曲试验的计算分析

Calculation and Analysis for Bending Test of Sandwich Beam with Four Points

在材料力学推导出的矩形截面梁剪应力公式基础上,利用夹芯梁轴向位移,弯曲挠度与剪切应变的几何关系,推导出了夹芯梁截面弯曲应力及弯曲挠度表达式,弹性理论及有关试验结果都证明了该方法的计算精确度较高。理论计算分析表明:外载荷作用下夹芯梁四点弯曲时,在外载荷作用处夹芯梁面板与芯材结合部位应采用强度理论进行校核;均布载荷作用下剪切变形对梁的弯曲正应力及挠度都有影响;集中力作用下剪切变形仅对梁弯曲挠度有影响,而对梁的弯曲正应力没有影响。该结论对材料力学关于夹芯梁四点弯曲试验内容的教学有一定启发和指导作用。

Based on the shear stress formula of rectangular beam derived from mechanics of materials,and the geometric relations among bending deflection and shear strain and the axial displacement of sandwich beam,the expressions of bending stress and bending deflection of sandwich beam section are deduced.The elastic theory and the experimental results show that the calculation accuracy of the method is high.The theoretical calculation results show that when the sandwich beam is bending at four points under external load,the joint of the sandwich beam panel and core material should be checked by using strength theory,the shear deformation under uniformly distributed load has influence on the bending normal stress and deflection,and the shear deformation under concentrated load has influence only on the bending deflection but not on the bending normal stress.The conclusion has some enlightening and guiding effect on the teaching of four-point bending experiment of sandwich beam in the course of material mechanics.