Analysis of the Wrinkle of an Automobile Weather-Strip Seal in Bending

Weather-strip seals in automotive door systems play a major role in determining the door closing effort, isolating the passenger compartment from water and reducing the wind noise inside the vehicle. The phenomenon of a wrinkle often occurs in weather-strips when they are assembled on the door surfaces which have bent or twisted profiles. Wrinkles in automobile weather-strip seals will affect the closing effort and noise isolation characteristics of the automotive door system. The wrinkle of anethylene-propylene-diene (EPDM) automobile weather-strip seals when bent and the critical conditions for a wrinkle to develop were characterized in this study. The hyperelastic material behavior of the EPDM sponge and EPDM dense rubber in the seal were modeled using the Foam model and Mooney–Rivlin model, respectively. Then a finite element analysis (FEA) model of the automobile weather-strip seal in assembly was developed and analyzed using then on linear FEA software Marc. The deformation of the seal and the thickness decrease in the critical region where it was prone to wrinkle were obtained by this FEA method. Finally the critical criterion of wrinkling was determined by analysis of the reaction forces in the critical region. The proposed analysis method can shorten the product design cycle and decrease the design and trial-product cost considerably.