# A Linear-Arc Composite Beam Piezoelectric Energy Harvester Modeling and Finite Element Analysis
###### Abstract  
To improve the output performance of the piezoelectric energy harvester, this paper proposed the design of a linear-arc composite beam piezoelectric energy harvester (PEH-C). First the nonlinear restoring force model of a composite beam was obtained by the numerical simulation method. Afterwards, the corresponding coupled governing equations were derived by using the generalized Hamilton principle, laying the foundation for subsequent in-depth research. After this, a finite element simulation was performed in the COMSOL software to simulate the output voltage, stress distribution, and resonance frequency of the PEH-C under different curvatures. In this way, the effect of curvature change on the PEH-C was analyzed. Finally, the PEH-C with a curvature of 40 m\({}^{-1}\) was prepared, and an experimental platform was built to verify the correctness of the relevant analysis. The results showed that the resonant frequency of the PEH-C can be changed by changing the curvature, and that the stress on the composite beam will increase after the arc segment is introduced. When the curvature of the PEH-C was 40 m\({}^{-1}\), the open-circuit output voltage was 44.3% higher than that of the straight beam. energy harvester; linear-arc beam; dynamic modeling; curvature; finite element method +
Footnote †: journal: micromachines  
in some extreme environments. Therefore, it is necessary to optimize the structure of the cantilever beam itself and improve the energy capture efficiency of a single cantilever beam. [PERSON] [21] designed cantilever beams with two different thickness sections for low-frequency environments. The results show that the output power was 80% higher than traditional straight beams. [PERSON] [22] designed a cantilever beam with varying section thicknesses. A finite element simulation showed that the surface strain of the cantilever beam was larger and more uniform than the traditional straight beam under force. Through experiments, it was verified that the output power of this cantilever beam was increased by 78% compared with the straight beam. [PERSON] [23] designed a piezoelectric energy harvester composed of a rectangular section and a conical section. Experiments showed that the output voltage of this energy harvester was 76.9% higher than that of the traditional straight beam. [PERSON] [24] analyzed the influence of the shape and length of the straight beam on the piezoelectric energy harvester through finite element analysis and obtained the optimal solution. [PERSON] [25] determined the relationship between the thickness of the beam and the output power of the energy harvester through theory and experiments. [PERSON] [26] divided the piezoelectric material of the straight beam piezoelectric energy harvester into n segments to widen the frequency and improve the output power. In addition to optimizing the traditional straight beam structure, [PERSON] [27] developed an L-shaped beam and experimentally proved that it has obvious advantages compared to straight beams. [PERSON] [28] proposed an arched structural beam that is different to traditional straight beams. Simulations show that the arched structure has a larger, uniform stress distribution. Compared with straight beams, arched beams have a higher voltage output and energy conversion efficiency and double-arched beams have the highest energy conversion efficiency. [PERSON] [29] proposed a linear-arch beam piezoelectric energy harvester. Experiments showed that introducing the arched part can improve the energy harvesting efficiency. The above studies show that optimizing the cantilever beam structure can improve the output efficiency of piezoelectric energy harvesters. However, no scholars have studied the effect of arc curvature on the output characteristics of cantilever piezoelectric energy harvesters. Therefore, this paper outlines the design of a linear-arc composite beam piezoelectric energy harvester (PEH-C).