Victor M. Franco Correia

Modelling and design of adaptive composite structures

Recent developments in adaptive composite structures with distributed piezoelectric actuators and sensors have attracted significant attention in the research community due to their potential commercial benefits in a wide range of applications such as vibration suppression, shape control, noise attenuation and precision positioning. The complexity in the design and fabrication of the adaptive laminated composites has resulted in a need to develop reliable and refined models to study their material properties and mechanical behaviour. Here, higher order finite element formulations and an analytical closed form solution have been developed to study the mechanics of adaptive composite structures with embedded and/or bonded piezoelectric actuators and sensors. Optimization of adaptive composite structures is also an important design aspect in order to maximize actuator performance. Two optimization schemes are considered in this study where the design variables are the layer thickness, actuator size and location. To demonstrate the validity, usefulness and eAciency of the proposed models several illustrative examples are presented and discussed. ” 2000 Elsevier Science S.A. All rights reserved.

Optimal design of piezolaminated structures

This paper presents refined finite element models based on higher-order displacement fields to study the mechanical and electrical behavior of laminated composite plate structures with embedded and/or surface bonded piezoelectric actuators and sensors. Sensitivity analysis and optimization techniques are also applied in order to maximize the piezoelectric actuator efficiency, improve the structural performance and/or minimize the weight of the structure. The application of structural optimization to the static shape control of adaptive structures is also addressed. To show the performance of the proposed models, several illustrative and simple examples are presented.

Refined models for the optimal design of adaptive structures using simulated annealing

This paper deals with refined finite element models based on higher-order displacement fields applied to the mechanical and electrical behavior of laminated composite plate structures with embedded and/or surface bonded piezoelectric actuators and sensors. Simulated annealing, a stochastic global optimization technique is implemented to find the optimal location of piezoelectric actuators in order to maximize its efficiency. The same technique is also used to solve optimization problems of piezolaminated plate structures where the discrete design variables are the ply orientation angles of orthotropic layers. The implemented scheme helps to recover from the premature convergence to a local optimum, without the need of reinitiating the optimal design process, as it is the case of the gradient-based methods with continuous design variables. To show the performance of the proposed optimization methods, two illustrative and simple examples are presented and discussed.

Optimization of multilaminated structures using higher-order deformation models

Abstract A refined shear deformation theory assuming a non-linear variation for the displacement field is used to develop discrete models for the sensitivity analysis and optimization of thick and thin multilayered angle ply composite plate structures. The structural and sensitivity analysis formulation is developed for a family of C 0 Lagrangian elements, with eleven, nine and seven degrees of freedom per node using a single layer formulation. The design sensitivities of structural response for static, free vibrations and buckling situations for objective and/or constraint functions with respect to ply angles and ply thicknesses are developed. These different objectives and/or constraints can be generalized displacements at specified nodes, Hoffmans stress failure criterion, elastic strain energy, natural frequencies of chosen vibration modes, buckling load parameter or the volume of structural material. The design sensitivities are evaluated either analytically or semi-analytically. The accuracy and relative performance of the proposed discrete models are compared and discussed among the developed elements and with alternative models. A few illustrative test designs are discussed to show the applicability of the proposed models.

Optimal Design of Composite Structures with Integrated Piezoelectric Laminae

A family of nine-node Lagrangian finite element models based on higher order displacement fields is applied to the optimal design of laminated composite plates with embedded and/or surface bonded piezoelectric layers and/or patches. The described formulation introduces, for the electric behavior, one electric potential degree of freedom for each piezoelectric layer in each element. In the optimal design, the design variables are the ply orientation angles in the orthotropic layers, the ply thickness of both the substrate and piezoelectric layers and the electrical potentials applied to the piezoelectric actuators. The design objectives are the minimization of structural weight and/or the minimization of specified displacements subjected to behavioral constraints.

Optimal Design of Thin Laminated Composite Structures

A numerical model for the optimal design of thin plate-shell laminated type structures, made of composite materials, is presented . The model is based on a plate-shell finite element with 18 degrees of freedom, using the discrete Kirchhoff theory. Sensitivity analysis with respect to fiber orientation and ply thickness is obtained through analytical formulation which is directly included in the finite element code. The model is applied to the optimal design of test cases.

Numerical model for the optimal design of composite laminated structures with piezoelectric laminate

In this work, refined finite element models based on higher order displacement fields have been developed to study the mechanical and electrical behavior of laminated composite plate structures with embedded and/or surface bonded piezoelectric actuators and sensors. Sensitivity analysis and optimization techniques are also applied in order to maximize the piezoelectric actuator efficiency, improve the structural performance and/or minimize the weight of the structure. To show the performance of the proposed models several illustrative and simple examples are presented.