Power generation performance of dielectric elastomer generator with laterally-constrained configuration

A new loading method with laterally-constrained configuration was proposed to study the energy conversion behavior of dielectric elastomer generator (DEG) based on experimental tests and theoretical calculation. The influence of lateral pre-stretch ratio and the loading rate on the energy transformation of DEG (VHB 4905) was investigated under both the quadrangular and triangular harvesting schemes, and the latter shows higher energy density and conversion efficiency than the former. The energy density increases with the lateral pre-stretch ratio at the range of 2 to 4, with the maximum value of 76 mJ g−1 for the quadrangular cycle and 186 mJ g−1 for the triangular cycle at the loading rate of 90 mm s−1 (strain rate of 2 s−1), respectively. The advantage of larger lateral pre-stretch ratio is mainly attributed to the increased capacitance density of the elastomer membrane at the maximum stretch, which enlarges the operational area confined by multiple failure limits on the voltage-charge work-conjugate plane. As the loading rate decreases, the energy density within each cycle decreases monotonically due to the increased charges leakage. Since the mechanical energy loss within a single cycle decreases at the lower loading rate, the conversion efficiency for the triangular cycle shows slight increase at the lower loading rate, with the maximum value of 15.4% for stretching rate of 50 mm s−1 (strain rate of 1.11 s−1).