Mechanical Performance Evaluation of Multi-Point Clinch–Adhesive Joints of Aluminum Alloy A5052-H34 and High-Strength Steel JSC780

The clinch–adhesive process, which combines mechanical clinching and adhesive bonding, is one of the most applied processes for joining aluminum alloy and steel in the manufacturing of vehicle bodies. In this hybrid process, the clinching joints and adhesive bonds are coupled and influenced by each other, posing challenges to the process design and joining strength evaluation. To understand the influence of the clinching process on the performance of the adhesive layer, this study analyzes the mechanical behavior of clinch–adhesive joints between high-strength steel JSC780 and aluminum alloy A5052-H34 with different stack-up orientations and varying numbers of clinching points. The results reveal that, under the steel-on-top condition, the clinching process causes a discontinuous distribution of the adhesive layer, which significantly decreased the bonding strength. In contrast, under the aluminum-on-top condition, the clinching process has a lesser impact on the distribution of the adhesive layer, resulting in much higher strength than the steel-on-top condition. Simulation models are constructed to quantify the effect of clinching points on the performance of the adhesive layer. The results highlight the need to consider diverse cohesive zone model parameters for the different stack orientations and clinching points in the design of clinch–adhesive aluminum alloy/steel structures.