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Smart structures and fiberoptic sensor research at Florida Institute of Technology-1990
Title
Smart structures and fiberoptic sensor research at Florida Institute of Technology-1990.
Creator
Grossman, B., Caimi, F. M., Alavie, T., Franke, J., Gao, X., Hou, H., Nassar, R., Costandi, W., Ren, A., Thursby, M., Harbor Branch Oceanographic Institute
Date Issued
1990
PURL
http://purl.flvc.org/FCLA/DT/3180404
Subject Headings
Fiber optics, Smart structures
Format
Document (PDF)
Adaptive control of vibration in flexible smart structures
Title
Adaptive control of vibration in flexible smart structures.
Creator
Gopinathan, Murali., Florida Atlantic University, Pajunen, Grazyna, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This dissertation is concerned with the relevant research in developing finite dimensional indirect adaptive schemes to control vibrations in flexible smart structures based on the finite element approximation of the infinite dimensional system. The advantage of this type of modeling is that the dominant modes of vibrations wherein the total energy is concentrated are accommodated thereby avoiding the so-called "spillover" phenomenon. Further, the mass, stiffness and damping coefficients...
Show moreThis dissertation is concerned with the relevant research in developing finite dimensional indirect adaptive schemes to control vibrations in flexible smart structures based on the finite element approximation of the infinite dimensional system. The advantage of this type of modeling is that the dominant modes of vibrations wherein the total energy is concentrated are accommodated thereby avoiding the so-called "spillover" phenomenon. Further, the mass, stiffness and damping coefficients associated with each element appear explicitly in the model facilitating the derivation of the ARMA parametric representation which is suitable for on-line estimation of the structural parameters. The state-space representation of the finite dimensional model is used to design an indirect linear quadratic self tuning regulator algorithm using the parameter estimation, indicated above. Further, a method to choose the control and state weighting matrices (required to design the controller) to yield a stable closed-loop system, is presented. Simulation results demonstrating the performance of the adaptive control system are presented. Another algorithm based on the model reference technique is also developed by considering the discrete time approximation of the finite dimensional model. This control algorithm in conjunction with the parameter estimation constitute an indirect model reference adaptive control system. Simulation results are presented to demonstrate the effect of the reference model parameters, which may impose certain constraints on the force requirements causing actuator saturation and thereby affecting the stability of the closed-loop system. In order to overcome the problem of using bulky and expensive sensors to measure transverse displacement and velocity, a new spatial recursive technique to estimate these variables alternatively by using a distributed set of (measured) strain data, is developed. Relevant algorithm enables the use of smart materials to sense the strain developed at various locations along the length of the structure leading to the development of flexible smart structures. Experimental results on the personal computer based control of vibrations in an aluminum beam using patches of polyvinyldene fluoride (PVDF), and lead zirconate titanate (PZT) as sensors and control actuators respectively, are furnished to demonstrate the feasibility of real-time implementation of the above mentioned control algorithms.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/12418
Subject Headings
Adaptive control systems, Smart structures, Vibration
Format
Document (PDF)
Finite element modeling of composite laminates with embedded piezoelectric structures including debonding
Title
Finite element modeling of composite laminates with embedded piezoelectric structures including debonding.
Creator
Suarez, Beatriz., Florida Atlantic University, Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Piezoelectric sensors are one of the primary devices used in smart structures because of their capability to act as both, sensors and actuators. A finite element model has been developed to predict elastic behavior and electrical response of laminate composites with embedded piezoelectric sensors. Correlations with experimental results indicate that the model is capable of forecasting the elastic and electrical response of the structure with good accuracy. The important issue of debonding of...
Show morePiezoelectric sensors are one of the primary devices used in smart structures because of their capability to act as both, sensors and actuators. A finite element model has been developed to predict elastic behavior and electrical response of laminate composites with embedded piezoelectric sensors. Correlations with experimental results indicate that the model is capable of forecasting the elastic and electrical response of the structure with good accuracy. The important issue of debonding of any of the faces of the sensors is also studied in the current work. Finite element results indicate significant changes in the elastic response caused by debonding, as well as unreliable electrical outputs.
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Date Issued
1998
PURL
http://purl.flvc.org/fcla/dt/15603
Subject Headings
Finite element method, Piezoelectric materials, Laminated materials, Smart structures
Format
Document (PDF)