Constitutive equations for 0-3 polarized PLZT actuators

Abstract

a b s t r a c tThis article presents constitutive equations of transparent lead lanthanum zirconate titanate (PLZT) materials poling along thickness direction or with 0-3 polarization. Discussed first are the Beer's law of light transmission in transparent solid and the photovoltaic current density in PLZT materials. Formulas for field strength and electrical potential between two electrodes of a PLZT wafer are then derived from the basic photovoltaic equations. By superposing the photovoltaic and the converse piezoelectric effects, we formulate a novel expression for photo-induced strain that is nonlinearly dependent of incident light intensity and varies with light penetration depth in through-thickness direction. On the basis of the derived photo-induced strain, linear and nonlinear constitutive equations of 0-3 polarized PLZT actuators are formulated. The present model is validated by using the available experimental data in the literature. By using the present model with an exponential variation of strain through the thickness, closed-form solutions for the equivalent loads acting on a PLZT unimorph, bimorph and intelligent beam are obtained and then compared with numerical results available in the literature.

Multi-physics field models of photostrictive unimorphs and heterogeneous bimorphs subjected to light illumination and mechanical loading

“…When light illuminates on the transparent electrode of a 0-3 polarized PLZT strip, the light intensity, induced electrical field and the photo-strain decrease 0020-7683/$ -see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijsolstr.2010.03.031 with light penetration depth (Luo and Tong, 2009b). The photostrain variation across the thickness enables bending directly.…”

“…The charge carrier current satisfies continuity equation and the electrical conductivity is equal to the sum of dark and photo conductivities (Fridkin, 1979;Poosanaas-Burke et al, 1998). As the photocurrent density is equal to conductivity multiplied by field strength (Saslow, 2002), the photo-induced electrical field strength E 3 at light penetration depth z d (measured from the light irradiating surface) of a 0-3 polarized PLZT wafer is given by (Luo and Tong, 2009b):…”

“…(1) and (2) potential difference of the bottom and top electrodes can be derived by the integration of the gradient equation in 0 6 z d 6 t (Luo and Tong, 2009b):…”

Mathematical model and characteristic analysis of hybrid photovoltaic/piezoelectric actuation mechanism

“…When ultraviolet light with a wavelength near 365 nm illuminates polarized PbLaZrTi (PLZT) materials, an electrical field can be generated along the spontaneous polarization direction due to the photovoltaic effect [1][2][3]. Based on the photovoltaic effect and the converse piezoelectric effect, PLZT may also exhibit a photostrictive effect [4][5][6]. Because of its advantages of non-contact optical control and lower susceptibility to electric/magnetic disturbances, PLZT wafers were used as distributed actuators in the study of photonic vibration control of flexible shells [7][8][9][10][11][12].…”

Research on the response improvement of optical actuation based on lead lanthanum zirconate titanate ceramics

“…Varieties of optical micro-devices using PLZT ceramics were proposed, for example, photo-driven micro-walking machines, 1,2 ''sunflower'' device, 3 photo-driven relay, 4 electrostaticoptical motor, 5 photo-driven gripper, 6,7 and photophone device. 8 Meanwhile, a large number of PLZT actuators were proposed, such as rainbow 1 School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, China 2 School of Intelligent Science and Control Engineering, Jinling Institute of Technology, Nanjing, China configuration actuator, 9 bimorph configuration actuator, 7 0-3 polarization PLZT actuator, 10 twodimensional (2D) distributed opto-electro-mechanical actuator, 11 multi-degree-of-freedom (DOF) photostrictive actuator, 12 and Skew-Quad actuator. 13 Furthermore, active vibration or shape control for flexible structures laminated with PLZT actuators was carried out, 14,15 for example, beams, 16,17 plates, 11,18,19 cylindrical shells, [20][21][22] and spherical and parabolic shells.…”