Experimental Study on the Cohesive Model of Steel-Carbon Fiber Reinforced Plastic Interface by Laser Treatment

Abstract

The interfacial bonding performance between steel and CFRP significantly influences the mechanical properties of steel-CFRP hybrid structures. Surface treatment is commonly employed to enhance the bonding interface of steel-CFRP. Laser surface treatment is particularly advantageous due to its high efficiency, automatic production capabilities, and widespread use in enhancing interfacial bonding performance. However, little attention has been given to the impact of laser surface treatment on the property parameters that describe the cohesive mode's mechanical behavior at the steel-CFRP interface. This study examined the cohesive zone modes of both original and laser-treated steel-CFRP joints through a double lap shear test following ASTM D3528-96 (2016) standards. Non-contact strain measurement was conducted using 3D digital image correlation techniques. The analysis indicates that the bilinear cohesive model effectively describes the mechanical behavior of the steel-CFRP interface. Laser surface treatment resulted in a respective increase of 83.8% in maximum shear strength, 111.6% in the relative slip corresponding to maximum shear strength and 116.8% in maximum relative slip. Consequently, this study showcases the efficacy of laser surface treatment in improving the mechanical performance at the steel-CFRP interface while quantitatively assessing these improvements through performance parameters within the cohesive zone model.