[1] HAJHEIDARI P,STIHARU I,BHAT R.Performance of non-uniform functionally graded piezoelectric energy harvester beams［J］.Journal of Intelligent Material Systems and Structures,2020,31(13):1604-1616.

[5] SUSHANTA K,HARSHAL N.Piezoelectric vibration energyharvester with tapered substrate thickness for uniform stress［J］.Microsystem Technologies,2020,27(1):105-113.

[7] BOIANGIU M,CEAUSU V,UNTAROIU C D.A transfer matrix method for free vibration analysis of Euler-Bernoulli beams with variable cross section［J］.Journal of Vibration and Control,2016,22(11):2591-2602.

[8] RAJU S S,UMAPATHY M,UMA G.Design and analysis of high output piezoelectric energy harvester using non uniform beam［J］.Mechanics of Advanced Materials and Structures,2020,27(3):218-227.

[9] RAJU S S,UMAPATHY M,UMA G.Cantilever piezoelectric energy harvester with multiple cavities［J］.Smart Materials and Structures,2015,24(11):1-11.

[10] ABDELKEF A,BARSALLO N.Comparative modeling of lowfrequency piezomagnetoelastic energy harvesters［J］.Journal of Intelligent Material Systems and Structures,2014,25(14):1771-1785.