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A design procedure is developed to simulate the durability behavior of an electric wiper linkage mechanism subjected to operation cycles. The first stage determines the stress and strain levels that the linkage components are subjected to during the operation cycles. This requires the reaction loads at the joints of the wiper linkage. It is achieved by performing the mechanism dynamic analysis using multi-body dynamics software (MSC.ADMAS) together with a three dimensional transient finite element analysis (MSC.NASTRAN). Once the stress and strain of the wiper linkages are obtained during the operation cycle, the low cycle fatigue analysis is applied in the time domain. This analysis is based on strain-life curve, the Palmgreen-Miner’s rule, to compute the cumulative damage, the rain flow method for cycles counting, and the mean stress effect. Using the methodology presented in this paper, good correlation with laboratory test can be achieved.

The minimum door closing speed is an important target in vehicle door design. Engineers need a proper method to evaluate the door closing speed during the design phase. Analytical approaches are presented to solve the difficult issues in analyzing the minimum door closing speed. First, the weather strip is simplified into a discrete model with several spring elements. This method does not need to use 3-D contact analysis for the weather strip and can save computing time with acceptable accuracy. Second, the minimum closing speed is solved by using the energy equation which needs one iteration only. The method has high efficiency and can be used to evaluate the door closing speed effectively during the design phase.

Stiffness is one of the key points for research and development of vehicle body in white (BIW). Fast and effective evaluation of stiffness is very important for reducing the time and cost of research and development. How to realize weight reduction with proper stiffness is also a focus point of automobile design. In general, commercial software is used to optimize the BIW design. But the optimization process is time consuming. Therefore a simple but effective tool for fast evaluation is desired. A method to evaluate stiffness with sensitivity coefficients of sheet metal thickness of body structure is proposed in this paper. The simple mathematical relation of the sensitivity coefficients, the thickness variation of sheet metals, and the stiffness of body structure is established. The stiffness can be evaluated quickly for various combination of sheet metal thickness without running large-scale simulation using commercial software.