Study of axial stress formula of embedded bolted joints under eccentric load

Abstract

Our objective is to analyze both tensional and bending stress of bolted joints under eccentric load. Especially, our analysis is under four combined conditions as described below, (1) embedded bolted joints, (2) thinner clamped plate, (3) large eccentric load, (4) permitting partial separation. Those combined conditions include some difference between ours and previous researches. The partial separation easily occurs at structural interfaces under those combined conditions, and both stresses sharply increase due to the propagation of the separation. That is the reason why it is very important to consider the effect of partial separation. There are many analytical methods based on numerical calculations or FEM analysis, however, there is no numerical calculation method, which is justly applicable under those combined conditions. We apply Faulhaber method proposed in VDI2230 and develop our original method considering the bolt axial loads, which are composed of both bolt's deflection and deflection angle as beam. Numerical calculations on the above-mentioned and experiments and elastic FEM analysis based on three dimensional contact theory were conducted. The results about our method's correlation against experiments and FEM analysis are shown in this report.

Keywords

• bolted joints
• embedded bolts
• eccentric load
• thin plates
• separation