The Structural intensity (STI ) is a powerful tool for identifying energy sources and sinks and analysing the transmission paths of vibrational energy within structures. Vibroacoustic metamaterials (VAMMs), which utilize local resonance effects to create stop bands, inhibit free wave propagation within specific frequency ranges. This study introduces an approach that uses active structural intensity to quantitatively assess the stop band behavior in complex, curved, finite VAMM plate-like structures. The proposed power-based method offers a robust framework for evaluating stop band characteristics by analyzing active power flow and quantifying the energy loss due to the VAMM’s resonators. Furthermore, damping plays a crucial role in the application of the power-based method, and it is necessary to distinguish between the influences of the structural damping and metamaterials. The effectiveness of this approach is confirmed by comparing the predicted stop band with the frequency response function (FRF) of the structure, demonstrating its accuracy in capturing the stop band behavior. In this work, the effect of uncertainty of the resonator parameters on the stop band width is explored to assess the sensitivity of the power-based method in predicting the stop band behavior under varying parameters.