This paper investigates the effect of electrical contact on the thermal contact stress of a microrelay switch. A three-dimensional elastic-plastic finite element model with contact elements is used to simulate the contact behavior between the microcantilever beam and the electrode. A model with thermal-electrical coupling and thermal-stress coupling is used in the finite element analysis. The effects of contact gap, plating film thickness and number of switching cycles on the contact residual stress, contact force, plastic deformation, and temperature rise of the microrelay switch are explored. The numerical results indicate that the residual stress increases with increasing contact gap or decreasing plating film thickness. The results also show that the residual stress increases as the number of switching cycles increases. A large residual stress inside the microcantilever beam can decrease the lifecycle of the microrelay.
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