چكيده به لاتين
Sandwich structures are widely used in various fields, such as aerospace, due to its stiffness to weight ratio and high capacity for bending loads. In bolted joints of steel structures, the primary shear force is usually distributed uniformly over several bolts. In this type of structure, the possibility of cutting the bolt is more than other types of damages. However, in anisotropic composite materials, the distribution of force is non-uniform and the probability of failure of the composite is greater than the bolt.
In this research, the force distribution of bolt in a kind of single-lap bolted joints in a sandwich structure with foam core and glass-epoxy face sheets is analyzed analytically and numerically. The bolted joints are subject to especially conditions, including shear properties in the sandwich core, pre-load on the bolt and friction. The joint under investigation is single-lap joints with three bolts that have the same distances relative to each other and under a single axial tention load. After presenting the analytical solution method and extracting the results using MATLAB softwares, the results of the analytical and numerical solutions are compared and important points in the joints are investigated. Two important parameters in joints are, core thickness and yang modulus for the upper and lower layers of the sandwich panel. In this study, these two parameters are partly considered in simulations, and it has been shown that bolted joints in sandwich panels will cause the distribution of uneven forces in the upper and lower layers. This leads to significant differences between the analytical and the numerical results. Finally, considering that the purpose of analyzing the joints in the composites is to prevent collapse in the composite, it is concluded that the calculation of the force on the bolts is not a suitable measure to prevent failure in the sandwich panels, and in such structures the failure criterion in the sandwich panel should be Check directly.
