Effect of Adhesive Thickness on Bonding Strength of the Adhesive Composite Joint

doi:10.3901/JME.2025.04.127

Abstract

Abstract: To investigate the theory contradicted practice problem for the influence of adhesive thickness on the bonding strength of the adhesive composite joint, SJK-03 adhesive is used to bond the adhesive double-lap joint tensile specimens, the inner lap is alkali-free glass fiber/polyurethane resin pultruded flat bar, the outer lap is Q235 steel plate. For the thickness of this adhesive layer is suggested between 1 mm to 3 mm by the adhesive instructions, a total of two types 60 tensile specimens are carried out with adhesive thickness (from 1 mm to 3 mm) as variable parameter. The overlap length of the first type is 90 mm, they are used to measure the loading capability for different adhesive thickness, then the test data is used to calculated the adhesive layer shearing strain energy for corresponding adhesive thickness. The result demonstrates that the adhesive layer shearing strain energy is not invariant, it decreases with adhesive thickness increases. The overlap length of the second type is 3 mm, they are used to measure the adhesive layer shearing strain energy for specific adhesive thickness, then the test data is used to calculated the loading capability. The results and their variation tendency are consistent with the loading capability of the first type test. The safety factor is quoted to calculate the loading capability after that, the results envelope the lower limit of the loading capability of the first type test. The two types tests verify each other, which can explain the contradiction problem and be used as a reference in the bonding strength calculation of the adhesive composite joint design.

Key words: adhesive joint, double-lap, bonding strength, adhesive thickness, shearing strain energy

CLC Number:

TB301

MA Yu, WANG Hongjian, MAHAI Wuheri. Effect of Adhesive Thickness on Bonding Strength of the Adhesive Composite Joint[J]. Journal of Mechanical Engineering, 2025, 61(4): 127-136.

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