基于梯度遗传算法的压电换能器稳健优化设计

悬臂梁式压电振动换能器是一种新型的供电装置,其设计受到加工过程等不确定因素影响。从遗传算法和田口稳健设计的理论方法出发,结合悬臂梁式压电振动换能器的理论模型,设计了以输出平均功率为优化目标的稳健优化设计方案。利用目标函数的梯度信息加速遗传算法的收敛,以遗传算法产生的每一代种群的最优个体作为内表中的一组数据,利用外正交表计算优化目标的信噪比,对优化目标信噪比进行对比分析,得到一组最优设计参数。将该组数据对应的换能器与其它优化方法得到参数对应的换能器性能进行对比,表明该组参数下,换能器有较好的工作特性。     

Correlation of direct piezoelectric effect on EAPap under ambient factors

Direct piezoelectricity of electro-active papers(EAPap)is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, such as temperature, humidity, and strain rate, are applied and analyzed. Strong piezoelectricity of EAPap is found on the basis of the test results and in comparison with polyvinylidene fluoride(PVDF)and lead zirconate titanate(PZT)-5H. The maximum piezoelectric constant is achieved to be 504 pC/N. The reason of strong piezoelectricity of EAPap is discussed in this paper. The potential of EAPap as a biomimetic actuator and sensor is also investigated.     

采煤机无线监测装置压电换能元件参数匹配分析

考虑到压电自供电装置中压电振子的几何参数直接影响其共振频率,从而影响压电自供电装置的发电量,因此需要根据环境激励频率设定最佳的压电振子的几何参数,对基于压电自供电的采煤机状态无线监测装置进行研究,通过理论分析、仿真以及实验方法对对不同悬臂梁结构在不同外界激励作用下的发电量进行研究.研究结果表明:悬臂梁自由端的质量块质量以及悬臂梁长度越大,悬臂梁压电结构的固有频率越低;随着悬臂梁厚度的增加,悬臂梁压电结构的固有频率逐渐增大.以此为依据对采煤机不同监测位置的装置选取最佳匹配的压电结构几何参数,并通过采煤机工作状态监测实验验证了本文研究的压电自供电无线监测装置的可行性.     

特制压电式传感器在纬纱检测中的应用

介绍一种新型压电式传感器的原理、特性。并阐述了该传感器在纺织机械纬纱检测系统中的应用     

P(VDF-TrFE) copolymer acoustic emission sensors

Acoustic emission (AE) sensors have been fabricated using polarized polyvinylidene fluoride/trifluoroethylene (P(VDF-TrFE)) piezoelectric copolymer films. The acoustic and electromechanical properties of the copolymers have been determined using the ultrasonic immersion technique and the resonance technique, respectively. The P(VDF-TrFE) AE sensors have been calibrated according to the ASTM standard and evaluated for potential application in the detection of AE in glass fiber reinforced polypropylene (GFPP). A ceramic AE sensor also has been fabricated using lead zirconate titanate (PZT) 7A piezoelectric ceramic and its sensitivity and performance are reported as well. The copolymer sensors do not show resonance peaks of the ceramic sensor and have adequate sensitivity. They can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.     

压电双晶片传感器灵敏度特性分析

本文用模态分析法详细分析了压电双晶片力、振动、粗糙度传感器的位移特性及灵敏度特性,并给出了灵敏度与压电材料参数及晶片几何尺寸的关系。     

PZT压电陶瓷机电耦合系数之间的关系

基于压电方程组导出了厚度伸缩振动机电耦合系数K_1与其它振动模式机电耦合系数的关系式。在满足d_(31)/d_(32)(?)S_(13)~F/S_(32)~E的条件下得到了K_t与K_(?)、K_(?)之间的简单关系式。利用此式计算了PZT压电陶瓷的K_(?)与组成的关系。理论计算结果与实验结果基本相符。     

Optimal design of butterfly-shaped linear ultrasonic motor using finite element method and response surface methodology

A new method for optimizing a butterfly-shaped linear ultrasonic motor was proposed to maximize its mechanical output. The finite element analysis technology and response surface methodology were combined together to realize the optimal design of the butterfly-shaped linear ultrasonic motor. First, the operation principle of the motor was introduced. Second, the finite element parameterized model of the stator of the motor was built using ANSYS parametric design language and some structure parameters of the stator were selected as design variables. Third, the sample points were selected in design variable space using latin hypercube Design. Through modal analysis and harmonic response analysis of the stator based on these sample points, the target responses were obtained. These sample points and response values were combined together to build a response surface model. Finally, the simplex method was used to find the optimal solution. The experimental results showed that many aspects of the design requirements of the butterfly-shaped linear ultrasonic motor have been fulfilled. The prototype motor fabricated based on the optimal design result exhibited considerably high dynamic performance, such as no-load speed of 873 mm/s, maximal thrust of 27.5 N, maximal efficiency of 43%, and thrust-weight ratio of 45.8.     

极小的压电陶瓷变压器

本文介绍了一种新型的电子陶瓷材料——压电陶瓷材料．以及它在变压器领域中的应用。详细介绍了压电陶瓷变压器的结构、工作原理及广泛的应用。