Application of a Drucker-Prager Approach for Reliability Modelling of Inorganic Encapsulation Materials Used for Power Electronic Applications

New inorganic encapsulation materials (e.g. based on cement formulations) can increase the efficiency, performance and reliability of power electronic applications, active and passive electric components or electrical machines. The main advantages are increased thermal conductivity, enhanced temperature stability and linear thermo-mechanical behavior without any glass transition or creeping effects within the required temperature range. To enable enhanced reliability modeling and to exploit the potential of inorganic cement-based materials by FEA, adapted material approaches are needed. Therefore, material characterization and parameter identification of a modified Drucker-Prager damage model was performed for different cement-based encapsulation materials. This work includes the needed determination of the temperature dependent fracture strength for the Drucker-Prager approach, but also the measurement of elastic, plastic and softening parameters. In combination with thermal material properties, resulting datasets are leading to an extended constitutive material law, taking elastic and plastic deformation and the structural damage of the new encapsulation material into account.