  Parametric variability is inevitable in actual energy harvesters. It can
significantly affect crucial aspects of the system performance, especially in
harvesting systems that present geometric parameters, material properties, or
excitation conditions that are susceptible to small perturbations. This work
aims to develop an investigation to identify the most critical parameters in
the dynamic behavior of asymmetric bistable energy harvesters with nonlinear
piezoelectric coupling, considering the variability of their physical and
excitation properties. For this purpose, a global sensitivity analysis based on
orthogonal variance decomposition, employing Sobol indices, is performed to
quantify the effect of the harvester parameters on the variance of the
recovered power. This technique quantifies the variance concerning each
parameter individually and collectively regarding the total variation of the
model. The results indicate that the frequency and amplitude of excitation,
asymmetric terms and electrical proprieties of the piezoelectric coupling are
the most critical parameters that affect the mean power harvested. It is also
shown that the order of importance of the parameters can change according to
the stability of the harvester's dynamic response. In this way, a better
understanding of the system under analysis is obtained since the study allows
the identification of vital parameters that rule the change of dynamic behavior
and therefore constitutes a powerful tool in the robust design, optimization,
and response prediction of nonlinear harvesters.
