Flexoelectric energy harvesters are more efficient at micro-scale than piezoelectric energy harvesters because of the significant size-dependent feature of flexoelectricity. The purpose of this study is to investigate the energy harvesting behavior of micro-beams that can be the basis for the design and measuring of functionally graded flexoelectric energy harvesters. To this end, the controlled vibration as well as the analysis of the electrical behavior and energy harvesting of micro-beam under harmonic excitation, including two flexoelectric layers and a functionally graded porous core are investigated using Timoshenko beam model. The generalized differential quadrature and Newmark methods have been utilized to resolve the microbeam equations. Finally, the effect of several parameters, such as size effect, type of porosity distribution, flexocoupling coefficient, and geometric dimensions, on forced vibration, output voltage, and power density has been investigated in detail. Due to the flexoelectricity phenomenon, which can produce high power and energy in micro-systems, as well as due to the few of research on energy harvesting devices made of the functionally graded flexoelectric materials by supplying the electric potential function and precise numerical solution, this study might be used as a basis for future research on flexoelectric energy harvesting and small-scale controlled vibrations.

中文翻译：

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尺寸依赖的机电层状梁式多孔功能梯度柔电能量收集器


由于柔性电具有显着的尺寸依赖性特征，柔性电能量收集器在微尺度上比压电能量收集器更高效。本研究的目的是研究微梁的能量收集行为，这可以作为功能分级柔性能量收集器的设计和测量的基础。为此，使用 Timoshenko 梁模型研究了受控振动以及谐波激励下微梁的电气行为和能量收集分析，包括两个挠性电层和功能梯度多孔芯。广义微分求积法和纽马克法已被用来求解微梁方程。最后，详细研究了尺寸效应、孔隙率分布类型、挠性耦合系数和几何尺寸等几个参数对受迫振动、输出电压和功率密度的影响。由于柔性电现象可以在微系统中产生高功率和能量，并且由于功能梯度柔性电材料通过提供电势函数和精确数值解而制成的能量收集装置的研究很少，因此研究可作为未来柔性电能量收集和小规模受控振动研究的基础。