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Free keywords:
Contacts (fluid mechanics); Electric contacts; Tin oxides, Experimental procedure; Higher energy density; Silver tin oxides; Switching contact; Temperature dependent; Temporal and spatial; Thermally induced; Thermo-mechanical stress, Silver
Abstract:
Composite materials based on silver tin oxide (Ag/SnO2) are widely used as switching contacts in electromechanical contactors and relays. The ongoing miniaturization coming along with increased energy densities is a common trend for these applications. The higher energy density causes an increase in thermally induced mechanical stresses in the contact material due to switching arcs. In this study finite element (FEM) simulations were performed to estimate the induced mechanical stresses for a contactor under heavy duty switching. First of all the paper describes the experimental procedure to determine the boundary conditions for simulation. Furthermore, the approach for temperature dependent modelling of elastic and plastic properties of the contact material Ag/SnO2 is presented in detail. Temporal and spatial stress distributions resulting from these simulations as well as their practical relevance are discussed. Via parameter variation it was possible to utilize the simulation models for optimizing the stress release behavior of Ag/SnO2 based contact systems.
