Multi-scale analysis of the adhesive bonding behavior of laser surface-treated carbon fiber reinforced polymer composite structures

Abstract

Laser surface treatment has considerable potential to provide high-quality adhesive-joining of carbon-fiber-reinforced polymer (CFRP) composites by removing contaminants and the top polymer layer and increasing the surface roughness without damaging the fibers. Yet, predicting the failure strength and mechanism of the laser surface-treated adhesively bonded joints under static and cyclic loads is important to designing reliable structures. In this study, a multi-scale Finite Element Analysis (FEA) of the adhesively bonded CFRP composite structures was developed to accurately predict the failure load and damage growth. Numerical simulations of the single lap joint (SLJ) specimen was executed, employing the cohesive zone modeling (CZM) technique between adjacent surfaces to simulate the bonding behavior of the secondary bonded CFRP parts. Using the homogenization procedure, the micro-scale simulation of the contact region of the laser-treated adherent surface and adhesive was performed to extract traction separation law (TSL) parameters. The mechanical interlocking contribution of the laser surface treatment was imported to the macro-scale FEA, analyzing the representative volume element (RVE) of the bonding interface region. We presented that the multi-scale analysis estimated the experimentally measured mechanical behaviour, strength values, and failure modes successfully with a negligible error (7 %).