In-field eigen oscillation-measurement for detection of UV-induced EVA-degradation

Photovoltaic-modules are exposed to static mechanical loads, such as snow and wind loads during conventional use. Wind also triggers oscillations. It is obvious that the dynamic loads are more likely to cause well known fatigue of materials even with little amplitudes, especially of brittle behaving PV-cells and ductile copper connecting wires. The dynamic behavior of PV-modules depending on the UV-induced aging of the ethylene vinyl acetate encapsulation is analyzed in outdoor strain-measurements. A detailed numeric model of a PV-module was created and mechanical loads for measurements in inaccessible regions in the laminate were calculated. The dependence from aging condition of encapsulation polymer shown in outdoor-results could be reproduced in the model.