Optimization of laser parameters for structural bonding of CFRP components with paste adhesive

Abstract

Carbon fiber reinforced polymer composites (CFRPs) are finding increasing usage in many industrial sectors, including aerospace industry. Adhesive bonding is often the most attractive joining technique for these materials in terms of structural efficiency, simplicity and cost of manufacture. The surfaces play an important role in the bonding process and are, perhaps, the most important process governing the quality of an adhesive bond joint. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply are not ideal in terms of adhesively bonded CFRP structures because of variations in their application. On the other hand, energetic methods, i.e. laser, offer some advantages in the ability to automate and produce reproducible surfaces and seem to be promising for providing a bond-promoting patterned surface.This study focuses on the optimization of Nd-YAG laser parameters in order to improve the paste adhesive bond quality of CFRP adherends. The influence of various laser parameters has been studied in terms of roughness, wettability, single lap shear strength and failure mode. The main criterion for the optimization was to abrade only resin layer without damaging the fibers to get a rough surface. Microscopic investigation of the sections has been performed to characterize laser pulses in this respect.Carbon fiber reinforced polymer composites (CFRPs) are finding increasing usage in many industrial sectors, including aerospace industry. Adhesive bonding is often the most attractive joining technique for these materials in terms of structural efficiency, simplicity and cost of manufacture. The surfaces play an important role in the bonding process and are, perhaps, the most important process governing the quality of an adhesive bond joint. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply are not ideal in terms of adhesively bonded CFRP structures because of variations in their application. On the other hand, energetic methods, i.e. laser, offer some advantages in the ability to automate and produce reproducible surfaces and seem to be promising for providing a bond-promoting patterned surface.This study focuses on the optimization of Nd-YAG laser parameters in order to improve the paste adhesive bond quality of CFRP adherends. The influence of various laser...