Adhesive bonding in automotive hybrid multi-cell square tubes: Experimental and numerical investigation on quasi-static axial crashworthiness performance

Abstract

The increasing demand for lightweight vehicles to improve fuel efficiency and performance has driven the adoption of thin-walled tubes made from lightweight hybrid materials as key energy-absorbing components in automotive structures. However, joining these hybrid materials presents a challenge, as traditional methods like welding are unsuitable. This study examines the axial crushing behavior of multi-cell, thin-walled energy-absorbing tubes with square cross-sections, joined using adhesive bonding. A two-cell square aluminum tube was experimentally constructed and tested to evaluate its energy absorption characteristics and failure modes. Additionally, the tube was modeled in ABAQUS software, incorporating elastoplastic deformation of the aluminum and cohesive contact properties for the adhesive layer. After validating the model with experimental data, a parametric study was conducted to assess the impact of different plate material combinations and wall thicknesses on crashworthiness and failure modes. The findings revealed that the effectiveness of material combinations (Al/St) with varying wall thicknesses depends on the adhesive bond's ability to maintain plate integrity during axial loading. In some cases, specific Al/St combinations with particular wall thicknesses resulted in a loss of structural integrity, leading to global cohesive failure. Finally, an analytical equation was developed to predict the axial mean crush force, which demonstrated strong agreement with both experimental and numerical results.