Shear stress distribution in the adhesive layer of composite hybrid bonded-bolted single-lap joint structure

ZHANG Sheng; ZHU Fuxian; HU Kejun; ZHANG Kunlong; ZHANG Zhen

doi:10.16579/j.issn.1001.9669.2026.07.013

Abstract：[Objective]Adhesive layer failure frequently occurs in composite bonded-bolted hybrid single-lap joint structures.An analytical model for shear stress in the adhesive layer was established to provide reference for strength design and failure prevention of joint structures.[Methods]Firstly,an analytical formula for shear stress in the adhesive layer of hybrid bonded-bolted joints was derived based on the shear stress calculation formula of adhesive structures and the double spring model,and bolt reaction forces were calculated to propose a calculation method for adhesive layer shear stress.Secondly,carbon/glass hybrid composite specimens were fabricated according to ASTM D5961 standard,and tensile tests were carried out to obtain load-displacement curves.Then,a finite element model was established by Abaqus software,and progressive damage model and cohesive zone model were introduced to simulate the structural failure process.Finally,theoretical calculation,test and simulation results were compared to verify the model accuracy and analyze the shear stress distribution law of the adhesive layer.[Results]The results show that the loading process of composite bonded-bolted hybrid single-lap joint structures can be divided into three stages:adhesive layer bearing stage,adhesive layer failure stage and pure bolt bearing stage.The shear stress distribution of the adhesive layer presents a U-shape with high values at both ends and low value in the middle.The adhesive layer failure expands gradually from both ends to the middle.The error of maximum failure load between finite element simulation and test is less than 3.3％,and the calculation results of the analytical model are in good agreement with the simulation results.