Effect of Lap Length and Stiffness of Peel-Stop Fasteners in Single Lap Joints

Atsushi Takano,Ryuta Kitamura,Chao Li

doi:10.3390/app11031086

Abstract

Strength tests on single lap joints with one adhesive (AV138/HV998) and one adhesive layer thickness (0.5 mm), three peel stoppers (brass bolt, nylon bolt and steel pin), and four lap lengths (12.5 mm, 25 mm, 40 mm and 100 mm) were conducted to investigate the effects of varying the lap length and stiffness of the peel-stop fasteners. Joint failure stress decreased, but failure force increased with lap length. Furthermore, joint failure stress was higher with the peel stopper. The effect of the brass-bolt peel stoppers was significant, whereas the effects of the nylon bolts and steel pins were smaller than that of the brass bolts. This indicates that the axial clamp strength and stiffness of the peel stopper are important factors in the shear strength of the lap. In addition, the effect of the stopper was negligible for the 12.5 mm lap. The reason is that the shear strength in the case of the 12.5 mm lap was large and thus the effect of the peel stopper was comparatively small. Moreover, the strength of the 100 mm lap reached the adherent material’s strength.

Highlights

Adhesivejoints jointswith withmechanical mechanicalfasteners fastenersare areoften oftenused usedin inaircraft aircraftand andspace spacevehicle vehicleAdhesive structures for their high stiffness and reliability.Mechanical fasteners are used on adhesive structures for their high stiffness and reliability
The results show that the lap shear strength with peel stoppers was higher than the sum of strength without peel stoppers or the strength of peel stoppers, with the exception of the 12.5mm lap length
Lap lengths of 25 and 40 mm with brass bolts experienced adhesive failure, as shown in Figures 9, 11 and 13. These results show that failure load increases with increasing lap length for brass bolts, despite lap shear stress decreases with increasing lap length

Summary

Introduction

Adhesivejoints jointswith withmechanical mechanicalfasteners fastenersare areoften oftenused usedin inaircraft aircraftand andspace spacevehicle vehicleAdhesive structures for their high stiffness and reliability.Mechanical fasteners are used on adhesive structures for their high stiffness and reliability. Adhesivejoints jointswith withmechanical mechanicalfasteners fastenersare areoften oftenused usedin inaircraft aircraftand andspace spacevehicle vehicle. Adhesive structures for their high stiffness and reliability. Mechanical fasteners are used on adhesive structures for their high stiffness and reliability. Mechanical fasteners are used on adhejoints to prevent bending failures duedue to offset loads andand peelpeel failures on the adhesives. Sive joints to prevent bending failures to offset loads failures on the adheFigure shows the peel failure mode. Publisher’s with regard to jurisdictional claims in tral with regard to jurisdictional published maps and institutional claims in published maps and insti-affiliations.affiliations. Publisher’s with regard to jurisdictional claims in tral with regard to jurisdictional published maps and institutional claims in published maps and insti-affiliations.affiliations. tutional

Results

Discussion

Conclusion