Multiband elastic wave energy localization for highly amplified piezoelectric energy harvesting using trampoline metamaterials

•A trampoline metamaterial is designed for realizing multiband energy localization and harvesting.•Bragg-scattering and local resonance is exploited to control the bandgap at high and low frequencies.•Flexural wave energy is localized through defect modes by breaking the periodicity.•High-performance piezoelectric energy harvesting is achieved at multi-frequency range.