Numerical Modelling of Humidity Behaviour in the Electronics Housing

Exposure of electronics into harsh climate conditions leads to about 40 % typical humidity related failure modes on PCBA of the total electronics failures. These humidity related failures are mainly electrochemical migration, corrosion, leakage currents and conductive anodic filament formation. Numerical modelling and prediction of humidity and temperature is very useful in the electronics design as it may help in postponing electronics humidity related failures and prolonging the electronics lifetime. Thus, the work concerns the moisture transport into electronics housing when the housing is exposed to a step change in ambient temperature and relative humidity. Such exposure of electronics housing can be considered as thermal and humidity shock. The RC model is developed and used to predict the temperature and humidity behaviour based on the heat and mass transfer mechanisms. Moreover, the heating effect was also considered in the study. The response of humidity and temperature were simulated and analysed inside the air-filled volume and the wall material of the housing.