Experimental and Numerical Analysis of Clinch (Hemflange) Joints Used in the Automotive Industry

The clinch or hemflange joint is commonly used in the automotive industry to join together the inner and the outer skin in a car door. In order to determine the effect of using a structural adhesive instead of spotwelding, a detailed series of tests and finite element analyses were conducted. The adhesive was a toughened epoxy and the adherend was a mild steel typical of that used in the manufacture of car bodyshells. Impact tests on the door frame showed that the inner door panel can be pulled out of the clinch. To avoid expensive mock-ups of doors and cars, a test specimen was developed that could be tested in the laboratory since no known testing had yet been carried out on this type of joint. Experimental results on adhesively-bonded clinch joints were compared with spotwelded joints and adhesively-bonded double lap joints. From the experimental and theoretical evidences, it can be concluded that this joint fails because of large plastic deformation in the adherend. (C) Koninklijke Brill NV, Leiden, 2009