Adhesively Bonded Steel Structures

Abstract

The amount of weld bonding on thin sheet steel structures has increased dramatically since year 2000. Weld bonding is used for improvement of stiffness, durability,strength, crash performance and weight reduction of car body structures. This thesis work focus on the effect of adhesive in crash performance for High Strength Steel (HSS) and Ultra High Strength Steel (UHSS). The influence of epoxy-based and rubber-based adhesives was investigated in hat-lid beams. The beams were tested in different sheet thicknesses (1,5 mm or 1,0 mm), spot weld spacing (80 mm or 40 mm), steel grades (Usibor or DP600) and joining methods (spot welding or weld bonding). In the case of weld bonded beams, the joints were bonded with either epoxy- based or rubber-based adhesive. The beams without adhesive were used as reference. The beams were tested in 4-point bending in computer simulations and in experimental tests. The weld bonded beams were compared with the resistance spot welded beams, in order to distinguish which combination was able to reduce the deformation. The possibility to increase spot weld spacing of weld bonded beams for different thicknesses was also studied. The simulations results were validated by experimental tests of 4-point bending. Rubber-based and epoxy-based adhesives had positive influence in deformation reduction and flange separation in DP600. The contribution of adhesive was small in Usibor.