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Journal ArticleDOI

Electro-thermo-elastic formulation for the analysis of smart structures

01 Apr 2006-Smart Materials and Structures (IOP Publishing)-Vol. 15, Iss: 2, pp 401-416
TL;DR: In this article, coupled electro-thermo-elastic equations applicable for the analysis of smart structures with piezoelectric patches/layers have been derived from the fundamental principles of mass, linear momentum, angular momentum, energy and charge conservation.
Abstract: Coupled electro-thermo-elastic equations applicable for the analysis of smart structures with piezoelectric patches/layers have been derived from the fundamental principles of mass, linear momentum, angular momentum, energy and charge conservation. The relevant constitutive equations have been obtained by using the second law of thermodynamics. The interaction of the electric field and polarization introduces distributed non-linear body force in the piezo material, and in addition renders the stress tensor non-symmetric due to distributed couple. Using the linear equations, and applying a layer-by-layer finite element model, the induced electric potential and mechanical deformations in the piezo and non-piezo core material have been obtained for various cases of actuation and sensing of a smart beam under external mechanical, electrical and thermal loadings. The mathematical formulation and the solution technique have been validated by comparing the results of the present study with those available in the literature. It is also shown that piezo patches can be effectively used for shape control.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the influence of full coupling between thermal, elastic, magnetic, and electric fields on the natural frequency of functionally graded magneto-electro-thermo-elastic plates has been investigated.
Abstract: In this article, the influence of full coupling between thermal, elastic, magnetic, and electric fields on the natural frequency of functionally graded magneto-electro-thermo-elastic plates has bee...

51 citations


Cites methods from "Electro-thermo-elastic formulation ..."

  • ...Ahmad et al. (2006) derived a coupled electrothermo-elastic equations from the fundamental principles of mass, linear momentum, angular momentum, energy, and charge conservation. Pérez-Fernández et al. (2009) presented different types of constitutive relations of thermo-magneto-electro-elasticity using solid thermodynamics. Soh and Liu (2005) discussed the mathematical properties of the thermodynamic potentials and the relations between the material constants....

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  • ...Ahmad et al. (2006) derived a coupled electrothermo-elastic equations from the fundamental principles of mass, linear momentum, angular momentum, energy, and charge conservation. Pérez-Fernández et al. (2009) presented different types of constitutive relations of thermo-magneto-electro-elasticity using solid thermodynamics....

    [...]

  • ...Ahmad et al. (2006) derived a coupled electrothermo-elastic equations from the fundamental principles of mass, linear momentum, angular momentum, energy, and charge conservation....

    [...]

Journal ArticleDOI
TL;DR: In this paper, an improved eight noded layered shell finite element formulation for piezothermoelastic analysis of smart fiber reinforced polymer (FRP) composite shell structures with bonded piezoelectric sensors and actuators is presented.

39 citations

Journal ArticleDOI
TL;DR: This work develops a systematic theory for coupled electrical, thermal and mechanical responses of soft electrets and predicts the electrocaloric effect for the first time in such materials and shows that a proper design and a reasonable choice of materials can lead to a temperature reduction.
Abstract: A temperature variation can electrically polarize a pyroelectric material. In its converse manifestation, the electrocaloric effect entails a change in temperature due to the application of an electric field. These phenomena have wide applications ranging from infrared detection sensors and solid-state refrigeration to energy harvesting. However, the pyroelectric-electrocaloric effect is typically observed in certain classes of hard, brittle crystalline materials that must satisfy a stringent set of lattice symmetry conditions. Some limited experiments have however demonstrated that embedding immobile charges and dipoles in soft foams (thus creating an electret state) may lead to a pyroelectric-like response as well as large deformations desired from soft matter. In this work, we develop a systematic theory for coupled electrical, thermal and mechanical responses of soft electrets. Using simple illustrative examples, we derive closed-form explicit expressions for the pyroelectric and electrocaloric coefficients of electrets. While pyroelectricity in electrets has been noted before, our derived expressions provide a clear quantitative basis to interpret (and eventually design) this effect as well as insights into how the geometrically nonlinear deformation and Maxwell stress give rise to its emergence. We present conditions to obtain a larger pyroelectric and electrocaloric response. In particular, the electrocaloric effect is predicted for the first time in such materials and we show that a proper design and a reasonable choice of materials can lead to a temperature reduction of as much as 1.5 K under the application of electrical fields of 10 MV cm-1.

27 citations

Journal ArticleDOI
TL;DR: In this paper, the second-order nonlinear constitutive equations are used in the variational principle approach to develop a nonlinear finite element (FE) model for piezoelectric laminated composite plates and shells.
Abstract: In this article, we focus on static finite element (FE) simulation of piezoelectric laminated composite plates and shells, considering the nonlinear constitutive behavior of piezoelectric materials under large applied electric fields. Under the assumptions of small strains and large electric fields, the second-order nonlinear constitutive equations are used in the variational principle approach, to develop a nonlinear FE model. Numerical simulations are performed to study the effect of material nonlinearity for piezoelectric bimorph and laminated composite plates as well as cylindrical shells. In comparison to the experimental investigations existing in the literature, the results predicted by the present model agree very well. The importance of the present nonlinear model is highlighted especially in large applied electric fields, and it is shown that the difference between the results simulated by linear and nonlinear constitutive FE models cannot be omitted.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a thermodynamically consistent derivation of field equations for electro-thermo-mechanical systems is presented, in order to justify their feasibility and verify their strength of modeling a physical system.

20 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a scaling analysis is performed to demonstrate that the effectiveness of actuators is independent of the size of the structure and evaluate various piezoelectric materials based on their effectiveness in transmitting strain to the substructure.
Abstract: This work presents the analytic and experimental development of piezoelectric actuators as elements of intelligent structures, i.e., structures with highly distributed actuators, sensors, and processing networks. Static and dynamic analytic models are derived for segmented piezoelectric actuators that are either bonded to an elastic substructure or embedded in a laminated composite. These models lead to the ability to predict, a priori, the response of the structural member to a command voltage applied to the piezoelectric and give guidance as to the optimal location for actuator placement. A scaling analysis is performed to demonstrate that the effectiveness of piezoelectric actuators is independent of the size of the structure and to evaluate various piezoelectric materials based on their effectiveness in transmitting strain to the substructure. Three test specimens of cantilevered beams were constructed: an aluminum beam with surface-bonded actuators, a glass/epoxy beam with embedded actuators, and a graphite/epoxy beam with embedded actuators. The actuators were used to excite steady-state resonant vibrations in the cantilevered beams. The response of the specimens compared well with those predicted by the analytic models. Static tensile tests performed on glass/epoxy laminates indicated that the embedded actuator reduced the ultimate strength of the laminate by 20%, while not significantly affecting the global elastic modulus of the specimen.

2,719 citations

Journal ArticleDOI
TL;DR: In this paper, the formulation of the basic field equations, boundary conditions and constitutive equations of simple micro-elastic solids is discussed. And explicit expressions of constitutive expressions of several simple micro elastic solids are given and applied to some special problems.

1,309 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an overview and assessment of the technology leading to the development of intelligent structures, which are those which incorporate actuators and sensors that are highly integrated into the structure and have structural functionality, as well as highly integrated control logic, signal conditioning and power amplification electronics.
Abstract: HIS article presents an overview and assessment of the technology leading to the development of intelligent structures. Intelligent structures are those which incorporate actuators and sensors that are highly integrated into the structure and have structural functionality, as well as highly integrated control logic, signal conditioning, and power amplification electronics. Such actuating, sensing, and signal processing elements are incorporated into a structure for the purpose of influencing its states or characteristics, be they mechanical, thermal, optical, chemical, electrical, or magnetic. For example, a mechanically intelligent structure is capable of altering both its mechanical states (its position or velocity) or its mechanical characteristics (its stiffness or damping). An optically intelligent structure could, for example, change color to match its background.17 Definition of Intelligent Structures Intelligent structures are a subset of a much larger field of research, as shown in Fig. I.123 Those structures which have actuators distributed throughout are defined as adaptive or, alternatively, actuated. Classical examples of such mechanically adaptive structures are conventional aircraft wings with articulated leading- and trailing-edge control surfaces and robotic systems with articulated manipulators and end effectors. More advanced examples currently in research include highly articulated adaptive space cranes. Structures which have sensors distributed throughout are a subset referred to as sensory. These structures have sensors which might detect displacements, strains or other mechanical states or properties, electromagnetic states or properties, temperature or heat flow, or the presence or accumulation of damage. Applications of this technology might include damage detection in long life structures, or embedded or conformal RF antennas within a structure. The overlap structures which contain both actuators and sensors (implicitly linked by closed-loop control) are referred to as controlled structures. Any structure whose properties or states can be influenced by the presence of a closed-loop control system is included in this category. A subset of controlled structures are active structures, distinguished from controlled structures by highly distributed actuators which have structural functionality and are part of the load bearing system.

470 citations

Journal ArticleDOI
TL;DR: In this article, the authors derived the differential equations and boundary conditions describing the behavior of an electrically polarizable, finitely deformable, heat conducting continuum in interaction with the electric field.

353 citations