Dynamic Compressive Response and Material Characteristics of a Foam EPDM Seal and Its Effect On Vehicle Door Closure

Automotive door weatherstrip seals, made of foam EPDM, are usually designed to meet specific compression performance with respect to door closure. The seal deformation response is generally characterized by the static compression load deflection, the force required to compress under low speed 100mm of seal, given by the OEM’s specification as the measure of the seal performance. However, vehicle door closure is a dynamic event and the weatherstrip seals exhibit non linear and viscoelastic material properties that vary with strain rate and amplitude of deformation. The material properties of the seal must be investigated carefully under the correct strain rate and amplitude in order to predict the seal dynamic response and its effect on the door closing characteristic.

In this study, we developed a new dynamic compression methodology to measure the dynamic characteristics of the material of the weatherstrip seal to predict the door closure performance. For this purpose, dynamic compression experiments were performed on the material of the seal using a pendulum system equipped with force and displacement sensors. The results of the experiments were used in a finite element model, developed in MARC, to predict the dynamic compression of the seal. The model predictions were validated using tests carried out on the pendulum. The pendulum results were then compared to a full door results measured on a vehicle. It was observed that the seal has a significant dynamic compression response and the developed methodology showed a better potential for characterizing the door closing event.