Mechanical Properties of Glasses

Thermomechanical deformations in photovoltaic laminates

“…In fact, although setting E Ã 2 = 0 was a reasonable approximation in the present application, this assumption should be checked with care if other materials are used. Second, improving the predictions of equation (14) has permitted the authors to understand that the elastic modulus of backsheet is a key parameter for the use of the present monodimensional beam model.…”

“…More specifically, considering the Young's moduli, glass and silicon are much stiffer than backsheet and EVA. In fact E G = 73 GPa [14], E Si = 130 GPa [15], and E bs = 2:8 GPa. The value for the backsheet is determined from tensile tests using ASTM D638 TYPE I specimens and a strain velocity of 0.175/min.…”

“…5). Let the general formula (14) now be considered, which allows different scenarios to be investigated towards the understanding of the role played by the different constituents on the deformability of PV modules, since all the materials are taken into account. The model predictions have been carried out for temperatures down to À35 8C, consistently with the elastic modulus data of EVA plotted in Fig.…”

“…The norm of the relative error between the analytical predictions and the experimental results is equal to 2.06. Here, it has to be remarked that equation (14) corresponds to the physical situation consisting in a perfect bonding between the interfaces of the stacks in beams 1 and 2, and between the two beams themselves. It also assumes that the cross-sections Shear effects globally included in Eq.…”

“…Comparing these predictions with those , note that they are both very close to experiments, apart from T\ À 20 8C where the solid line deviates from the experimental trend. The reason behind the search for an optimal solution using equation (14) is not to find the best agreement as possible with experiments, but rather to understand the reasons for the discrepancy between the predictions provided by equation (14) (considering all the materials, square dots line in the figure) and the experimental trend. From the present analysis it is possible to conclude that the stiffness of the backsheet plays an important role in the monodimensional model.…”