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An electronic connector provides a separable interface between two subsystems of an electronic system. The contact spring is probably the most critical component in an electronic connector. Mechanically, the contact spring provides the contact normal force, which establishes the contact interface as the connector is mated. However, connector manufacturers have a basic struggle between the need for high normal contact forces and low insertion forces. Designing connectors with large numbers of pins that are used with today’s integrated circuits and printed circuit boards often results in an associated rise in connector insertion force. It is possible to lower the insertion force of a connector by redesigning the geometry of the contact spring, but this also means a decrease in contact normal force. In this paper, structural shape optimization techniques are used to find the optimal shape of the contact springs of an electronic connector. The process of the insertion of a PCB into the contact springs of a connector is modeled by finite element analysis. The maximum insertion force and the contact normal force are calculated. The effects of several design parameters are discussed. The geometry of the contact springs is then parameterized and optimized. The required insertion force is minimized while the normal contact force and the resulting stress are maintained within specified values. In our example, the insertion force of the final contact spring design is reduced to 68.3% of that of the original design, while the contact force and the maximum stress are maintained within specified values.

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Disc wheels intended for normal use on passenger cars have to pass three tests before going into production: the dynamic cornering fatigue test, the dynamic radial fatigue test, and the impact test. This paper describes a probability model for prediction of fatigue failures of aluminum disc wheels, which intends to better link the prediction using simulation results with historical test data. Finite element models of 54 aluminum wheels, which are already physically tested, are constructed to simulate the dynamic cornering fatigue test. Their mean stresses and stress amplitudes during the fatigue loading cycle are calculated and plotted on a two-dimensional plane. Matching with historical test data, the failure probability contour can be drawn. For a new wheel, the failure probability of dynamic cornering fatigue test can be read directly from this probability contour. The test result of the new wheel can be added into the set of historical test data and the failure probability contour is updated. Same procedure is directly applied to the fatigue prediction of dynamical radial fatigue test. At this point we only have 20 historical test data to construct the failure contour. The prediction will become more and more reliable as the number of historical test data increases.

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