A comprehensive review on mechanical amplifier structures in piezoelectric energy harvesters

AbstractThis paper presents a comprehensive review of structural optimization for the piezoelectric energy harvesters by summarizing the characteristics, working principles, advantages, disadvantages, performance, evaluation factors, and potential applications of each amplifier structure. This includes the cantilever, flexure structure, combined structure, multistage structure, and derivative designs such as compound and hinge designs. Examples and optimization method of structural design which utilizes the compressive mode, 33-mode configuration, and stacking design of piezoelectric material is provided. The power output, amplification ratio, and the applied mechanism theory of each structure are then compared and discussed to ease the benchmarking process for future research.HIGHLIGHTSMechanical amplifier frames relevant to piezoelectric transducer are reviewed.Summarized previous work on design characteristics, applications, pros, and cons.Figure of merit with power density and amplification factor is presented.Design trends and guidance are provided for future research.Keywords: CantileverCymbalFlexcompressiveflextensionalmultistageRhombus Disclosure statementThe authors report there are no competing interests to declare.Additional informationFundingThe authors wish to acknowledge the financial support from Universiti Malaya International Collaboration Grant (ST046-2022) under SATU Joint Research Scheme Program; and Universiti Malaya Research University Grant (RU Faculty) under grant number GPF081A-2018.