A Study of Vibration-induced Fretting Corrosion in Electrical Connectors Based on Experimental Test and FEA Simulation
Type of DegreeMaster's Thesis
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In the field of electrical contacts, vibration induced fretting corrosion is generally recognized as one of the major failure mechanisms. Many factors affect fretting corrosion, including the normal force and the surface friction coefficient. Previous literature has identified the basic mechanisms of fretting degradations. Nevertheless, due to the complex structure and the uncertainty of random noise excitations, vibration induced fretting corrosion of connector systems still needs more research and understanding. The random vibration and first mode natural frequency vibration along the axial direction were applied to investigate the fretting threshold for a sample connector. Variations in finish type, friction forces, normal forces and issues with wire length were studied. In addition, it is difficult to experimentally observe the motion inside a connector pair. Computer-based FEA is utilized to assist in analyzing the motion of contact parts inside the connector. In the present study, the dynamic response and fretting characteristics of a series of connectors were investigated. Four different types of connectors, identified as 2C, 3A, 3B and 3C, with different finishes and spring forces, were considered. Each type was evaluated for wire lengths of 2cm, 4cm, 6cm and 8cm. For the experimental testing, each sample configuration considered five samples for the transfer function and fretting input threshold tests. ABAQUS and ANSYS three dimensional FEA models were developed to gain further insight into the experimental results. The dynamic model was examined for both overall dynamic response and for the specific transfer function of a given configuration. The results of the FEA simulation are compared to the experimental test results. The basic results are summarized below: The friction forces and spring forces for type 2C, 3A, 3B and 3C are obtained experimentally. From these results, the corresponding coefficients of friction are calculated. 3D ABAQUS Explicit FEA models are developed. Using the spring forces and coefficients of friction acquired in the experimental tests, the simulation friction forces are calculated and compared to the experimental friction force results. The transfer functions of all four types of connector with different wire lengths are determined experimentally and compared to results from the FEA simulations with good correlation. Using the transfer function results as a guide, fretting thresholds at the natural frequency for each sample are determined experimentally and compared to the results predicted by the corresponding simulation model, with good correlation.