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Prediction of the behaviour of copper alloy components under complex loadings by electro-thermomechanical coupled simulations

: Weber, M.; Helm, D.

Postprint urn:nbn:de:0011-n-5311872 (866 KByte PDF)
MD5 Fingerprint: fce2b21fc10a4ea96376a58f70c589a1
Erstellt am: 18.05.2019

Materials science and technology (2018), Online First, 9 S.
ISSN: 0267-0836
ISSN: 1743-2847
Bundesministerium fur Wirtschaft und Energie BMWi (Deutschland)
IGF; 17278N
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWM ()
stress relaxation; elasto-viscoplastic material model; finite element simulation; parameter identification

Electronic devices must be served with electric power for different reasons. A robust and reliable electric connectivity is often realised by electric connectors. For its leading properties, precipitation hardened copper alloys are widely used for designing connectors with high level mechanical or conductance properties. However, copper alloys show a characteristic stress relaxation under mechanical or thermal loads. Finite element analysis is a standard method to design and optimise components with respect to reliability and performance. Hence, a material model considering the characteristic of the mechanical properties and allowing for the simulation of time and temperature dependent elasto-viscoplastic material behavior was developed at the Fraunhofer IWM. The parameters of the model were determined using tensile and relaxation test data of a C19010 alloy. The material model is applied to electro-thermomechanical coupled finite element simulations of connectors with different load histories. The goal of the simulations is the analysis of the impact of stress relaxation on the mechanical properties of systems over time. From the numerical results with the new model it is shown, how stress relaxation influences the connector clamping forces or contact pressure, respectively, in dependence with time or temperature. The simulation results documents that stress relaxation has to be taken into account in finite element simulations during the designing process of electrical devices.