Hygro-thermo-mechanical modeling of LED Luminaires

The purpose of this work is to conduct the multi-physics simulation analysis of LED luminaire under certain temperature and humidity environment, and to find out the vulnerable spot of the LED luminaire. The coupled modeling of LED luminaire under the temperature and humidity conditions is simulated by ANSYS. Five types of modeling, i.e. thermal and thermo-mechanical modeling, moisture diffusion and hygro-mechanical modeling, and thermo-mechanical-moisture modeling. The Coupled stress of the LED luminaire at 85 °C and 85% relative humidity is performed by multi-physics approach which using finite element method combined with additional user subroutines. Then, the effect of thermal expansion, hygroscopic swelling and delamination in the luminaire is predicted. Finally, the failure modes of LED luminaire, which is concluded from the LED luminaire SSAT experiment, is compared and discussed with the crucial locations of LED luminaire in FEM simulation. It is shown that the simulation results agree with vulnerable spot well from the test, which indicates that the multi-physics approach can be used for simulating the condition of LED luminaire in real and predicting the failure modes.