The Fatigue Properties of Spot Welded, Adhesive Bonded and Weldbonded Joints in High Strength Steels

The fatigue properties of bonded box hat structures are influenced by adhesive type, sheet thickness, overlap length and flange width.

High strength/modulus adhesives confer high rigidity to the structure and therefore enhance the fatigue properties.

Similarly, increasing overlap length/flange width also results in improvements. These findings can be attributed to redistribution of the stresses in the joint.

The fatigue properties of weldbonded structures are similar to adhesive bonded structures. Whilst higher fatigue strengths were noted with bonded compared to spot welded structures at sheet thicknesses ∼0.7mm, this advantage is lost at thicknesses >1.2mm. Failure mode was influenced by weld pitch, adhesive type and overlap length.