This paper proposes a multidirectional piezoelectric vibration energy harvester based on an improved U-shaped structure with cross-connected beams. Benefitting from the bi-directional capacity of U-shaped beam and additional bending mode induced by cross-connected configuration. the proposed structure can well capture the vibrations in 3D space at the frequencies lower than 15 Hz. The... https://cosmeticssquadets.shop/product-category/collagen-supplements/