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This paper describes an analytical methodology for predicting the fatigue life of a door system for check load durability cycles. A check stop load durability cycle occurs when a customer opens the door beyond the door detent position with a force applied on the check link or hinge check stops. This method combines Finite Element Analysis (FEA) model and fatigue code to compute the durability requirements. The FEA model consists of Door-in-White (DIW) on body with integrated hinge check link or independent check link. Nonlinear material, geometric and parts contact were considered for the door with body-in-white (BIW). Several door hinge designs, with integrated and independent check links, were investigated. Using the Von Mises stress and plastic strain from the above analysis, the fatigue life was predicted and compared with the test data. Integrating FEA and fatigue allows predicting the threshold total strain value, which is developed, for check load durability requirements.

The sensor mounted on the door impact beam plays a major role in side impact events. The accelerations of side impact sensors are processed by sensing algorithms to make a decision on the air bag deployment. The sensing signal criterion for the deployable condition is a well understood process. However, the non-deployment sensing signal for the immunity to abuse conditions is a function of sensor attachment stiffness to the base structure. The base structure can be a door inner panel or door impact beam. In one of the production program, the acceleration based sensor attached to the impact beam showed immunity issues in the abusive door slams/opening to objects. Hence, the computer Aided Engineering (CAE) analysis was used to develop the sensor attachment criterion.

This paper describes the analytical methodology for calculating the overbend needed in the door design to counteract the non-linear seal forces acting on the door header. Overbend in the door design will allow the Original Equipment Manufacturer to achieve competitive above belt flushness and gap dimensional targets at static equilibrium of the door header and weatherstrip. This method combines two analytical models of the weatherstrip and the Door-In-White (DIW) to forecast the design overbend necessary to achieve good fit and finish. These models are: 1) Seal compression-load deflection (CLD) models for each angle of attack of the weatherstrip to the door 2) A nonlinear Finite Element Analysis (FEA) model of the trimmed DIW. Bringing these two elements together to model the static equilibrium deflection, this is developed, into overbend requirements. The design synthesis process to meet the overbend design criteria is demonstrated.