Electromechanical response of 1-3 piezoelectric composites with hollow fibers

Abstract

A finite element model is developed to characterize the complete electromechanical response of piezoelectric composite materials with hollow fibers and to obtain a quantitative assessment of the relative effects of the introduction of porosity and a piezoelectric second phase in a piezoelectric matrix material. Fifteen characteristic composites are identified for each of the two model ceramic-based and polymer-based matrix systems ͑i.e., barium titanate and polyvinylidine difluoride͒ by systematically varying the volume fractions of porosity and the second phase ͑i.e., lead zirconate titanate͒. It is demonstrated that the fundamental properties and the piezoelectric figures of merit of the piezoelectric composites generally exhibit greater sensitivity to the presence of porosity in the electroelastically stiffer ceramic-based systems while the piezoelectrically active second phase has a dominant influence in the electroelastically compliant polymer-based systems.Piezoelectric materials with their unique electromechanical coupling characteristics have been recognized for their potential utility in many electromechanical device applications. 1 Toward optimizing their electrical and mechanical characteristics, several approaches toward modifying the structure of monolithic piezoelectric materials have been identified. By following an additive approach, wherein solid piezoelectrically active fibers are introduced within a compliant polymeric matrix, piezoelectric ͑solid fiber͒ composites with enhanced mechanical flexibility can be obtained. 2-9 By adopting a subtractive approach, wherein porosity is introduced within a solid piezoelectric material, porous piezoelectric materials with enhanced piezoelectric characteristics ͑i.e., improved piezoelectric coupling and reduced acoustic impedance͒ can be designed. [10][11][12][13][14][15][16][17][18][19] While the additive and subtractive approaches allow for the modification of a piezoelectric material in one dimension each, a few preliminary studies have examined the combined effects of additive and subtractive approaches wherein a second piezoelectric phase and porosity are introduced simultaneously within a matrix material to create composites with hollow fibers. 20 However, a comprehensive study that captures the complete electromechanical response of piezoelectric composites with hollow fibers is not yet available. Hence, the objectives of the present study are ͑i͒ to systematically characterize the elastic, dielectric, and piezoelectric properties of piezoelectric systems with hollow fibers and ͑ii͒ to assess the relative impact of porosity and the second piezoelectric phase on the effective performance characteristics of piezoelectric composites.In general, the complete electromechanical response of a piezoelectric material is captured by the coupled constitutive relationships which, in the linear elastic domain, are represented in a matrix format as 21 ͑1͒where ͓C E ͔ 6ϫ6 is the elasticity matrix, ͓e͔ 3ϫ6 the piezoelectric matrix, and ͓K ͔ 3ϫ3 the dielectric matri...

Electromechanical Response of Piezoelectric Honeycomb Foam Structures

“…Kar‐Gupta and Venkatesh also developed numerical models to examine the electroelastic properties of 3–1‐type open foam structures with circular and elliptical porosity and demonstrated that the orientation of the porosity with respect to the poling direction had a significant influence on the effective piezoelectric properties . Marcheselli and Venkatesh presented models to characterize the piezoelectric properties of 3–1‐type open foam structures with hollow fibers and demonstrated that the effective properties of such foam materials can be suitably tailored by modifying the matrix and the fiber material . Challagulla and Venkatesh developed three‐dimensional finite element models to completely characterize the elastic, dielectric, and piezoelectric properties of 3–3‐type open piezoelectric foam structures with asymmetric interconnects, symmetric interconnects, and without any interconnects and benchmarked them with respect to 3–1‐type long porous piezoelectric foams .…”

Piezoelectric Properties of 1-3 Piezoelectric Tubular Composites

“…In 2004, Brei and Cannon analyzed the static axial character of sheet shaped 1-3 piezoelectric composites with long tubes [5]. In 2008, Marcheselli and Venkatesha used finite element method to study the mechanical and electrical properties of piezoelectric composites with hollow fibers, which were polarized axially [6]. This paper researches on the piezoelectric properties of 1-3 piezoelectric tubular composites.…”

Performance of 1–3 piezoelectric composites with porous piezoelectric matrix

“…Analytical models [2][3][4][5][6][7][8][9][10] and finite element models [11][12][13][14] have been presented to study 1-3 piezocomposites with a non-porous matrix. Simple models for composites used in ultrasonic transducer application have been presented by Smith and co-workers [2][3][4] and Chan and Unsworth.…”