Weldbonding of Structural Adhesives for Body Stiffening

Five structural adhesives were evaluated for vehicle stiffening. Commonly known as weld bonding, these epoxy adhesives were used in conjunction with spot welds to study the stiffening effect. The adhesives chosen required no surface cleaning prior to bonding and were formulated to allow spot welding through the adhesive layer. Experimental testing included structural components, coupon samples, and a vehicle build. The components were evaluated by static bending, torsional stiffness and fatigue testing. Coupon samples were evaluated by measuring lap shear and fatigue strength in various environments. The effects of adhesive type, bondline thickness, steel gauge and type, and environmental exposure on the adhesive's strength were studied. A vehicle build was conducted to determine the stiffening effect of an adhesively bonded structure. Lastly, a finite element model of the component was done. As a result of the study, the use of adhesive increased component and vehicle stiffness, demonstrated the possible reduction in the use of spot welds, and indicated a reduction in the noise levels of a body structure.