Modeling and analysis of piezoelectric beam with periodically variable cross-sections for vibration energy harvesting

A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.

Simulation of perforated rectangular cantilever immunosensor for estimation of bacterial pathogens

Micro fabricated and multilayered perforated cantilever beam immunosensor was modeled using CoventorWare for the estimation of bacterial antigens of Bacillus Anthrax, Pseudomonas aeruginosa, Coryne Bacterium Diptheria and Treponema pallidum. A rectangular cantilever beam with perforations was simulated with dimensions as length-200 μm, width-10 μm and thickness-0.5 μm. Each perforation is rectangular with length-10 μm, width-5 μm and thickness-0.5 μm. The theoretical and FEM simulations were carried out with five immunoglobulin antibodies, IgA, IgD, IgE, IgG and IgM for the estimation of bacterial antigens. The effect of perforation in cantilever beam and molecular size of antibody and antigen on the performance of the sensor has been studied. The cantilever beam without perforation showed a deflection of 1.8 e + 02 μm whereas the cantilever beam with perforation showed an increase deflection of 1.9 e + 02 μm. With IgG, the difference between analytical and simulation values is positive and low especially with low molecular weight antigens Pseudomonas aeruginosa and Treponema pallidum. The low molecular weight IgG influences the antigen-antibody interaction more fvourably. The simulated perforated rectangular cantilever beam with IgG antibody is a more promising model for the fabrication of a sensor for the estimation of highly motile Pseudomonas aeruginosa and Treponema pallidum.

一种基于MEMS的新型镂空压电悬臂梁能量采集器

在经典的矩形悬臂梁结构基础上进行改进,设计了一种新型的基板与压电膜镂空的微悬臂梁能量采集器。在悬臂梁基板与压电膜上添加镂空,分析其结构尺寸(即镂空的长度、宽度、厚度以及数量)与压电振子固有频率和开路输出电压之间的关系,并通过调节其结构尺寸,使压电能量采集器具有更低的振动频率与更高的开路输出电压。实验结果表明,在镂空长度为200μm,宽度为165μm,数量为12时,该结构振子的固有频率可达到399.7Hz,开路输出电压可达0.271V。

具有边梁的悬臂矩形板的弯曲问题

本文建议一个求解具有边梁悬臂矩形板弯曲问题的解析解法。该法将有边梁和无边梁悬臂矩形板弯曲问题的解融为一体，在有边梁悬臂矩形板的解中令边梁弯曲刚度为零即得到无边梁悬臂矩形板的解。

CAD软件有限元分析精度研究

应用CAD软件CATIA对不同网格尺寸下矩形截面悬臂梁的最大应力进行有限元分析,并与理论计算值进行对比,得出网格尺寸与有限元分析精度的关系,并给出推荐的网格尺寸及误差补偿建议。

矩形截面悬臂梁斜弯曲应力分析和实验探讨

以矩形截面悬臂梁为研究对象,研究其斜弯曲时的应力分布和中性轴位置。首先分析了矩形截面悬臂梁自由端受倾斜力作用时的挠度,定义了斜弯曲的概念;然后对矩形截面悬臂梁斜弯曲进行应力分析和中性轴位置分析,得到了矩形截面悬臂梁斜弯曲时正应力的计算公式和中性轴位置方程;最后采用电测法实验,探讨不同夹角φ对矩形截面悬臂斜弯曲梁正应力大小的影响。结果表明:随着作用力F的方向与z轴平行轴夹角的不断增大,各测点应力的理论值和实验值的相对误差越来越大。矩形截面悬臂梁斜弯曲时任一横截面形心合力方向不一定垂直于中性轴,并且由于切应力很小,其对弯曲梁强度的影响往往忽略不计。