A theoretical analysis of the lateral resonances in 1-3 piezocomposites with poling initial stress is conducted using the Bloch wave theory. Based on the linear piezoelectricity theory, theoretical formulations that i...A theoretical analysis of the lateral resonances in 1-3 piezocomposites with poling initial stress is conducted using the Bloch wave theory. Based on the linear piezoelectricity theory, theoretical formulations that include initial stress for the propagation of acoustic plane waves are made. Numerical calculations are performed to study the effects of the initial stress on the lateral mode frequencies and the stop band. It is found that lateral mode frequencies increase with the piezoelectricity of the piezocomposites, but decrease with the poling initial stress. The influence of the initial shear stress on the lateral mode frequencies is minimal, and can thus be neglected.展开更多
Incorporating the merits of both piezoelectric and nonpiezoelectric phases,piezocomposites have been thoroughly studied and extensively applied. Each of the twophases in a 2-2 piezocomposite is self-connected in two d...Incorporating the merits of both piezoelectric and nonpiezoelectric phases,piezocomposites have been thoroughly studied and extensively applied. Each of the twophases in a 2-2 piezocomposite is self-connected in two dimensions. In a展开更多
Since piezoelectric ceramic/polymer composites have been widely used as smart materials and smart structures, it is more and more important to obtain the closed-from solutions of the effective properties of piezocompo...Since piezoelectric ceramic/polymer composites have been widely used as smart materials and smart structures, it is more and more important to obtain the closed-from solutions of the effective properties of piezocomposites with piezoelectric ellipsoidal inclusions. Based on the closed-from solutions of the electroe- lastic Eshelby's tensors obtained in the part I of this paper and the generalized Bu- diansky's energy-equivalence framework, the closed-form general relations of effective electroelastic moduli of the piezocomposites with piezoelectric ellipsoidal inclusions are given. The relations can be applicable for several micromechanics models, such as the dilute solution and the Mori-Tanaka's method. The difference among the various models is shown to be the way in which the average strain and the average electric field of the inclusion phase are evaluated. Comparison between predicted and exper- imental results shows that the theoretical values in this paper agree quite well with the experimental results. These expressions can be readily utilized in analysis and design of piezocomposites.展开更多
使用0-3型PZT/P(VDF-TFE)压电复合材料研制出一种圆柱形水听器,对水听器的结构、材料以及灵敏度进行了理论分析,测量了水听器样品灵敏度随频率的变化曲线。研究结果表明,利用0-3型PZT/P(VDF-TFE)压电复合材料可制作出灵敏度高达-202.3 d...使用0-3型PZT/P(VDF-TFE)压电复合材料研制出一种圆柱形水听器,对水听器的结构、材料以及灵敏度进行了理论分析,测量了水听器样品灵敏度随频率的变化曲线。研究结果表明,利用0-3型PZT/P(VDF-TFE)压电复合材料可制作出灵敏度高达-202.3 dB ref.1V/μPa的水听器,静态电容量较大,制作工艺简单,实际测量值和理论计算值很相近。展开更多
This paper presents the design and prototype of a small quadruped robot whose walking motion is realized by two piezocomposite actuators. In the design, biomimetic ideas are employed to obtain the agility of motions a...This paper presents the design and prototype of a small quadruped robot whose walking motion is realized by two piezocomposite actuators. In the design, biomimetic ideas are employed to obtain the agility of motions and sustainability of a heavy load. The design of the robot legs is inspired by the leg configuration of insects, two joints （hip and knee） of the leg enable two basic motions, lifting and stepping. The robot frame is designed to have a slope relative to the horizontal plane, which makes the robot move forward. In addition, the bounding locomotion of quadruped animals is implemented in the robot. Experiments show that the robot can carry an additional load of about 100 g and run with a fairly high velocity. The quadruped prototype can be an important step towards the goal of building an autonomous mobile robot actuated by piezocomposite actuators.展开更多
该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电...该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电复合材料换能器厚度振动等效电路,获得其等效导纳,以此计算电导谱,同时基于有限元技术数值计算相应电导谱,二者有较好的一致性。在此基础上分别设计制作复合压电材料,多匹配层材料以及由此构成的空气耦合超声换能器。换能器的实测电导谱与数值仿真结果一致。进一步的换能器回波信号测试及其谱分析结果表明,所研制的160 k Hz中心频率空气耦合换能器样品有较好灵敏度和带宽。这些结果说明,该文研制的空气耦合超声换能器的初样是成功的。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.90205030 and 10472088)
文摘A theoretical analysis of the lateral resonances in 1-3 piezocomposites with poling initial stress is conducted using the Bloch wave theory. Based on the linear piezoelectricity theory, theoretical formulations that include initial stress for the propagation of acoustic plane waves are made. Numerical calculations are performed to study the effects of the initial stress on the lateral mode frequencies and the stop band. It is found that lateral mode frequencies increase with the piezoelectricity of the piezocomposites, but decrease with the poling initial stress. The influence of the initial shear stress on the lateral mode frequencies is minimal, and can thus be neglected.
文摘Incorporating the merits of both piezoelectric and nonpiezoelectric phases,piezocomposites have been thoroughly studied and extensively applied. Each of the twophases in a 2-2 piezocomposite is self-connected in two dimensions. In a
基金The project supported by the National Natural Science Foundation of China
文摘Since piezoelectric ceramic/polymer composites have been widely used as smart materials and smart structures, it is more and more important to obtain the closed-from solutions of the effective properties of piezocomposites with piezoelectric ellipsoidal inclusions. Based on the closed-from solutions of the electroe- lastic Eshelby's tensors obtained in the part I of this paper and the generalized Bu- diansky's energy-equivalence framework, the closed-form general relations of effective electroelastic moduli of the piezocomposites with piezoelectric ellipsoidal inclusions are given. The relations can be applicable for several micromechanics models, such as the dilute solution and the Mori-Tanaka's method. The difference among the various models is shown to be the way in which the average strain and the average electric field of the inclusion phase are evaluated. Comparison between predicted and exper- imental results shows that the theoretical values in this paper agree quite well with the experimental results. These expressions can be readily utilized in analysis and design of piezocomposites.
文摘使用0-3型PZT/P(VDF-TFE)压电复合材料研制出一种圆柱形水听器,对水听器的结构、材料以及灵敏度进行了理论分析,测量了水听器样品灵敏度随频率的变化曲线。研究结果表明,利用0-3型PZT/P(VDF-TFE)压电复合材料可制作出灵敏度高达-202.3 dB ref.1V/μPa的水听器,静态电容量较大,制作工艺简单,实际测量值和理论计算值很相近。
文摘This paper presents the design and prototype of a small quadruped robot whose walking motion is realized by two piezocomposite actuators. In the design, biomimetic ideas are employed to obtain the agility of motions and sustainability of a heavy load. The design of the robot legs is inspired by the leg configuration of insects, two joints （hip and knee） of the leg enable two basic motions, lifting and stepping. The robot frame is designed to have a slope relative to the horizontal plane, which makes the robot move forward. In addition, the bounding locomotion of quadruped animals is implemented in the robot. Experiments show that the robot can carry an additional load of about 100 g and run with a fairly high velocity. The quadruped prototype can be an important step towards the goal of building an autonomous mobile robot actuated by piezocomposite actuators.
文摘该文针对超声无损检测与成像功能空气耦合换能器开展了分析计算和研制。为解决压电材料与空气间巨大的阻抗失配问题,进行了多匹配层设计,并基于有限元技术仿真设计了1-3压电复合材料参数。借助复数压电方程,导出考虑损耗的多匹配层压电复合材料换能器厚度振动等效电路,获得其等效导纳,以此计算电导谱,同时基于有限元技术数值计算相应电导谱,二者有较好的一致性。在此基础上分别设计制作复合压电材料,多匹配层材料以及由此构成的空气耦合超声换能器。换能器的实测电导谱与数值仿真结果一致。进一步的换能器回波信号测试及其谱分析结果表明,所研制的160 k Hz中心频率空气耦合换能器样品有较好灵敏度和带宽。这些结果说明,该文研制的空气耦合超声换能器的初样是成功的。
