<p>This article offers a systematic investigation of energy harvesting from a two-layer piezoelectric sensor under nonlinear single-mode operation with emphasis on the identification of optimal working conditions for maximum power harvesting. Because linear models cannot address high-amplitude near-resonance behavior, a data-driven nonlinear dynamic model is presented based on the Lagrangian approach. This model incorporates a tailored electrical network enthalpy function, which is specifically appropriate to fulfill the nonlinear material characteristics of the piezoceramic. Model parameters like nonlinear damping and stiffness coefficients are obtained using perturbation approaches. The approaches are informed by empirical data from a comparable piezoelectric actuator to guarantee the accuracy and relevance of the model in depicting actual behavior. System analysis reveals the occurrence of high quadratic damping and cubic stiffness, which indicates the need for nonlinear analysis. Nonlinearity-conscious performance analysis, developed from the model, reveals that an optimal electrical resistance value of 8 leads to the optimal nonlinear energy harvesting. This optimized resistance provides a key design parameter for such systems, enabling engineers to achieve much better power output than designs based on linear approximations. The results reveal a significant enhancement of energy harvesting efficiency through the consideration of nonlinear effects as well as the optimization of the electrical load. This research enhances the understanding and practical application of piezoelectric energy harvesting through an empirically verified model that is robust and a crucial design parameter for maximum performance.</p>