Simulation analysis method of adhesive bonding strength for steel-carbon fiber composites and its application in automotive B-pillars

This paper investigates the adhesive bonding strength of steel-carbon fiber reinforced composites and their simulation analysis method, validating the approach on an automotive hybrid B-pillar to provide a basis for reliable joining of dissimilar materials. By combining adhesive bonding mechanics theory, the material property parameters of DC04 steel and carbon fiber reinforced polymer (CFRP) substrates are determined, offering parameters for finite element modeling of dissimilar material adhesive bonding. Lap shear and butt tensile tests are designed for the adhesive-bonded joints of DC04 steel and CFRP, enabling determination of main mechanical properties of Araldite 2015 structural adhesive and its adhesive performance. A finite element model of the DC04 steel-CFRP adhesive-bonded joint is built to simulate maximum load and failure displacement of the joint, analyze adhesive bonding strength, and compare results with test data. Scanning electron microscopy (SEM) is employed to analyze failure modes of the adhesive joints. A simulation analysis method for adhesive bonding of DC04 steel-CFRP dissimilar materials is established. Adhesive bonding simulations are performed on the automotive steel-CFRP hybrid B-pillar. Based on performance requirements of the B-pillar, simulations are conducted for axial tension, axial compression, lateral bending, and rearward bending, calculating deformation and stress parameters of the adhesive bonding elements under each condition. The carbon fiber composite B-pillar reinforcement plate is manufactured and bonded to the steel outer panel using Araldite 2015 adhesive. A three-point bending test was conducted on the hybrid material B-pillar assembly. Simulation values for displacement and stress are compared with test results, with maximum errors of 2.94% and 3%, respectively. The results validate accuracy and correctness of the adhesive bonding simulation for the dissimilar material B-pillar assembly and demonstrate feasibility and reliability of the proposed adhesive bonding simulation method and strength analysis for the steel and CFRP dissimilar material combination.