The joining of steel with lighter-weight materials—from aluminum and magnesium to plastics and carbon fiber composites—is a challenging prospect in automotive bodies. Each of these materials expands at a significantly different rate when exposed to heat in the paint baking cycle, potentially breaking adhesive bonds in joints. To avoid adhesive failure, solutions have included applying additional adhesive material and mechanical fixations, leading to higher costs and weight, in approaches that are dominantly trial-and-error based.
Until now, the industry has been unable to accurately measure and model this thermal expansion in automotive bodies fashioned from dissimilar materials. Henkel Adhesive Technologies and Clemson University, however, have developed a new approach that
feeds real experimental data into simulation software, furnishing the first accurate picture of thermal expansion. This methodology will allow development of application-specific automotive adhesive solutions that will smooth the way for incorporating a variety of materials into hybrid automotive bodies.