The factors contributing to delamination of PV module is temperature, humidity and irradiance. By increasing the temperature and humidity conditions EVA delamination can be created with ingress of water. Partial shading condition can change the amount of irradiance falling on different cells and will cause local heating due to variation of diode current and form hotspots which will also delaminate the EVA encapsulation.

Other than shading, suggested by Kalidas, he has hinted in his answer, that a local temperature gradient can cause delamination. You can you use a spatially periodic heating source and change the cells location from time to time.

Yes as Mr. Gilad was saying about shading I just wanted to add one more point. Partial shading also affects the MPPT module associated with the panel or array. Due to partial shading there can be multiple peaks in the IV curve so the common MPPT algorithms like P&O may get stuck at the local maxima and the global maxima will be left out due to this multiple peaks in the curve. This will make the panels to generate power at a reduced rate than the possible Maximum power. I think GMPPT algorithms can solve this problem.