Retired professor of Solid MechanicsResearch in Structural mechanics, finite element method, several topics as nonlinear analysis, vibrations and buckling, considering different types of materials.
This work involves the design optimization of metal–ceramic through the thickness of functionally... more This work involves the design optimization of metal–ceramic through the thickness of functionally graded material (FGM) plates subjected to thermomechanical loadings. Constrained optimization was performed for minimum mass and minimum material cost of the FGM plates. The design process of FGM plate structures requires a good choice of metal and ceramic materials and the adequate definition of the components volume fractions through the thickness direction in order to accomplish a certain structural behavior, while optimizing the material costs and/or the plate mass. Here, the optimization problems are solved with the simulated annealing (SA) algorithm, not requiring the calculation of the derivatives of the objective or constraint functions. Constrained single objective optimization cases are studied, and validated with alternative solutions, considering the p-index and the FGM plate thickness as design variables. New optimization cases, involving additionally the metal and ceramic ...
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
This paper deals with the geometrically non-linear analysis of thin plate/shell laminated structu... more This paper deals with the geometrically non-linear analysis of thin plate/shell laminated structures with embedded integrated piezoelectric actuators or sensors layers and/or patches. The model is based on the Kirchhoff classical laminated theory and can be applied to plate and shell adaptive structures with arbitrary shape, general mechanical and electrical loadings. The finite element model is a nonconforming single layer triangular plate/shell element with 18 degrees of freedom for the generalized displacements and one electrical potential degree of freedom for each piezoelectric layer or patch. An updated Lagrangian formulation associated to Newton-Raphson technique is used to solve incrementally and iteratively the equilibrium equations.The model is applied in the solution of four illustrative cases, and the results are compared and discussed with alternative solutions when available.
Resumo. Neste trabalho apresenta-se um modelo de elementos finitos baseado na teoria de deformaca... more Resumo. Neste trabalho apresenta-se um modelo de elementos finitos baseado na teoria de deformacao de corte de 3a ordem, o qual e aplicado ao controlo activo de vibracoes, incluindo o fenomeno de ressonância, em estruturas laminadas. Sensores e actuadores piezoelectricos na forma de lâminas estao colados nas superficies superior e inferior do laminado, permitindo assim um sistema de controlo, ligando os efeitos piezoelectricos directo e converso, atraves dum algoritmo baseado na realimentacao com velocidade negativa. As estruturas sao forcadas a vibrar num determinado modo, e a sua amplitude no tempo e calculada usando o metodo de Newmark. Apresenta-se uma aplicacao ilustrativa.
Abstract. Composite structures incorporating piezoelectric sensors and actuators are increasingly... more Abstract. Composite structures incorporating piezoelectric sensors and actuators are increasingly becoming important due to the offer of potential benefits in a wide range of engineering applications such as vibration and noise suppression, shape control and precision positioning. This paper presents a finite element formulation based on the classical laminated plate theory for laminated structures with integrated piezoelectric layers or patches, acting as actuators. The finite element model is a single layer triangular nonconforming plate/shell element with 18 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezoelectric element layer or patch, which are surface bonded on the laminate. An optimization of the patches position is performed to maximize the piezoelectric actuators efficiency as well as, the electric potential distribution is search to reach the specified structure transverse displacement distribution (shape ...
Abstract. This paper presents a finite element formulation based on the classical laminated plate... more Abstract. This paper presents a finite element formulation based on the classical laminated plate theory for laminated structures with integrated piezoelectric layers or patches, acting as actuators. The finite element model is a single layer triangular nonconforming plate/shell element with 18 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezoelectric element layer or patch. An optimization of the electric potential distribution is performed, in order to reach the specified structure transverse displacement distribution, minimizing an error function (shape control). A gradient based algorithm is used for this purpose. Results are presented and discussed.
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
This paper deals with buckling and free vibrations of multilaminated structures of arbitrary geom... more This paper deals with buckling and free vibrations of multilaminated structures of arbitrary geometry and lay-up using a single layer higher order shear deformation theory discrete model. This model is based on an eight-node C0 serendipity finite element with 10 degrees of freedom per node to contemplate general applications. The present model is tested on the evaluation of buckling loads
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
... Shape control and dynamic control of structures are some of the current applications of the r... more ... Shape control and dynamic control of structures are some of the current applications of the referred “intelligent structures” described by Crawley and de Luis [2]. Recent surveys can be found in Senthil et al. [3], Benjeddou [4], and Correia et al. [5]. ... Samanta et al. ...
This work involves the design optimization of metal–ceramic through the thickness of functionally... more This work involves the design optimization of metal–ceramic through the thickness of functionally graded material (FGM) plates subjected to thermomechanical loadings. Constrained optimization was performed for minimum mass and minimum material cost of the FGM plates. The design process of FGM plate structures requires a good choice of metal and ceramic materials and the adequate definition of the components volume fractions through the thickness direction in order to accomplish a certain structural behavior, while optimizing the material costs and/or the plate mass. Here, the optimization problems are solved with the simulated annealing (SA) algorithm, not requiring the calculation of the derivatives of the objective or constraint functions. Constrained single objective optimization cases are studied, and validated with alternative solutions, considering the p-index and the FGM plate thickness as design variables. New optimization cases, involving additionally the metal and ceramic ...
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
This paper deals with the geometrically non-linear analysis of thin plate/shell laminated structu... more This paper deals with the geometrically non-linear analysis of thin plate/shell laminated structures with embedded integrated piezoelectric actuators or sensors layers and/or patches. The model is based on the Kirchhoff classical laminated theory and can be applied to plate and shell adaptive structures with arbitrary shape, general mechanical and electrical loadings. The finite element model is a nonconforming single layer triangular plate/shell element with 18 degrees of freedom for the generalized displacements and one electrical potential degree of freedom for each piezoelectric layer or patch. An updated Lagrangian formulation associated to Newton-Raphson technique is used to solve incrementally and iteratively the equilibrium equations.The model is applied in the solution of four illustrative cases, and the results are compared and discussed with alternative solutions when available.
Resumo. Neste trabalho apresenta-se um modelo de elementos finitos baseado na teoria de deformaca... more Resumo. Neste trabalho apresenta-se um modelo de elementos finitos baseado na teoria de deformacao de corte de 3a ordem, o qual e aplicado ao controlo activo de vibracoes, incluindo o fenomeno de ressonância, em estruturas laminadas. Sensores e actuadores piezoelectricos na forma de lâminas estao colados nas superficies superior e inferior do laminado, permitindo assim um sistema de controlo, ligando os efeitos piezoelectricos directo e converso, atraves dum algoritmo baseado na realimentacao com velocidade negativa. As estruturas sao forcadas a vibrar num determinado modo, e a sua amplitude no tempo e calculada usando o metodo de Newmark. Apresenta-se uma aplicacao ilustrativa.
Abstract. Composite structures incorporating piezoelectric sensors and actuators are increasingly... more Abstract. Composite structures incorporating piezoelectric sensors and actuators are increasingly becoming important due to the offer of potential benefits in a wide range of engineering applications such as vibration and noise suppression, shape control and precision positioning. This paper presents a finite element formulation based on the classical laminated plate theory for laminated structures with integrated piezoelectric layers or patches, acting as actuators. The finite element model is a single layer triangular nonconforming plate/shell element with 18 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezoelectric element layer or patch, which are surface bonded on the laminate. An optimization of the patches position is performed to maximize the piezoelectric actuators efficiency as well as, the electric potential distribution is search to reach the specified structure transverse displacement distribution (shape ...
Abstract. This paper presents a finite element formulation based on the classical laminated plate... more Abstract. This paper presents a finite element formulation based on the classical laminated plate theory for laminated structures with integrated piezoelectric layers or patches, acting as actuators. The finite element model is a single layer triangular nonconforming plate/shell element with 18 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezoelectric element layer or patch. An optimization of the electric potential distribution is performed, in order to reach the specified structure transverse displacement distribution, minimizing an error function (shape control). A gradient based algorithm is used for this purpose. Results are presented and discussed.
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
This paper deals with buckling and free vibrations of multilaminated structures of arbitrary geom... more This paper deals with buckling and free vibrations of multilaminated structures of arbitrary geometry and lay-up using a single layer higher order shear deformation theory discrete model. This model is based on an eight-node C0 serendipity finite element with 10 degrees of freedom per node to contemplate general applications. The present model is tested on the evaluation of buckling loads
A high order shear deformation theory is used to develop a discrete model for the sensitivity ana... more A high order shear deformation theory is used to develop a discrete model for the sensitivity analysis and optimization of laminated plate and shell structures in non-linear response. The geometrically non-linear analysis is based on an updated Lagrangian formulation associated with the Newton–Raphson iterative technique, which incorporates an automatic arc-length procedure. Fiber orientation angles and vectorial distances from middle surface
... Shape control and dynamic control of structures are some of the current applications of the r... more ... Shape control and dynamic control of structures are some of the current applications of the referred “intelligent structures” described by Crawley and de Luis [2]. Recent surveys can be found in Senthil et al. [3], Benjeddou [4], and Correia et al. [5]. ... Samanta et al. ...
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Papers by Jose Moita