Fatigue resistance of an aluminium one-component polyurethane adhesive joint for the automotive industry: Effect of surface roughness and adhesive thickness

• Published in: International journal of adhesion and adhesives Vol. 83; pp. 143 - 152
• Main Authors: Boutar, Y., Naïmi, S., Mezlini, S., Carbas, R.J.C., da Silva, L.F.M., Ben Sik Ali, M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-06-2018; Elsevier BV
• Subjects: Adhesive bonding; Adhesive joints; Adhesive thickness; Adhesives; Aluminum base alloys; Automobile industry; Bonded joints; Cyclic loads; Damping; Dynamic tests; Fatigue life; Fatigue strength; Lap joints; Polyurethane adhesive; Polyurethane resins; Single lap joint; Stress concentration; Surface roughness; Surface roughness effects; Surface treatment; Thickness; Weight reduction; Fatigue life; Single lap joint; Surface roughness; Adhesive thickness; Polyurethane adhesive
• ISSN: 0143-7496; 1879-0127
• DOI: 10.1016/j.ijadhadh.2018.02.012

Fatigue is a crucial type of loading for many structural components that contain adhesive bonding systems such as the automotive industry. One of the main advantages of adhesives is their weight-reduction aptitudes. Furthermore, adhesively bonded joints allow a good damping to the fatigue's solicitation with fewer sources of stress concentration. In addition, a suitable surface treatment allows a great joint interface adhesion under cyclic loading. Hence, the mechanical preparation of the bonded surface influences directly the bonded joint performance. Therefore, a careful consideration should be given to the choice of the bonded adhesive thickness. The aim of this paper is to investigate the influence of surface roughness of an aluminium alloy and the adhesive thickness of a one-component polyurethane adhesive, to be used in several parts for buses structure, on the fatigue behaviour of single lap joints. To achieve this purpose, four different surface roughnesses were prepared on aluminium specimens, with an arithmetic average height from Ra ≈ 0.6 µm to Ra ≈ 1.5 µm. Bonded specimens with four adhesive thicknesses from 0.3 mm to 2 mm were manufactured and tested in dynamic tests. The results confirm that there is an optimum combination of surface roughness and adhesive thickness providing the maximum fatigue life. Moreover, good agreement was found between this investigation and a previous work using the same parameters under static loading.