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• Multiobjective optimization approach to minimize weight and maximize modal damping. • Direct MultiSearch (DMS) solver for multiobjective optimization problems. • Applications for L-shaped and T-shaped plates. • The obtained results can be very useful in the design of this kind of structures. This paper presents a multiobjective optimization approach to minimize weight and maximize modal damping in laminated composite panels with Constrained Layer Damping (CLD) treatments. The design variables are the number and position of the CLD patch treatments on the surface of the laminated plate. The Direct MultiSearch (DMS) solver for multiobjective optimization problems is used in this work. DMS is a solver which does not use any derivatives of the objective functions. A previously developed finite element model for sandwich plates with viscoelastic core and anisotropic laminated face layers is adapted to model the plate with the CLD treatments. Applications for L-shaped and T-shaped plates are presented and both trade-off Pareto optimal fronts and the respective treatment configurations are obtained and the results are analyzed and discussed. [ABSTRACT FROM AUTHOR]

Abstract This work presents a new layerwise mixed model for the static analysis of multilayered plates with embedded functionally graded material (FGM) layers subjected to transverse mechanical loads. This model is capable to fully describe a two-constituent metal-ceramic FGM layer continuous variation of material properties in the thickness direction, using any given homogenization method to estimate its effective properties. The present model is based on a mixed least-squares formulation with a layerwise variable description for displacements, transverse stresses and in-plane strains, chosen as independent variables. This mixed formulation ensures that the interlaminar C 0 continuity requirements at the layers interfaces, where the material properties actually change, are fully fulfilled a priori for all independent variables. The order of the in-plane two-dimensional finite element approximations and the order of the z -expansion through each layer thickness, as well as the number of layers, whether FGM layers or not, are considered free parameters. The full description of the FGM effective properties is achieved by applying to the z -continuous elastic coefficients a z -expansion through the layer thickness of a given order, set as an added free parameter, in a similar approach to finite element approximations. The numerical results consider both single-layer and multilayered functionally graded plates with different side-to-thickness ratios, using either Mori-Tanaka or the rule of mixtures estimates for the FGM effective properties with different material gradation profiles. The present model results are assessed by comparison with three-dimensional (3D) exact solutions and closed form solutions, which demonstrate its capability to predict a highly accurate quasi-3D description of the displacements and stresses distributions altogether. [ABSTRACT FROM AUTHOR]

In this work a finite element model is presented for buckling and nonlinear analysis of multilayer sandwich plates and shells, with a soft core sandwiched between stiff elastic layers. The finite element is obtained by assembling all element-layers through the thickness using specific assumptions on the displacement continuity at the interfaces between layers, but allowing for different behaviors of the layers. The stiff elastic layers are modelled using the classic plate theory and the core is modelled using Reddy׳s third order shear deformation theory. The present finite element model is a non-conforming triangular plate/shell element with 24 degrees of freedom for the generalized displacements. This model is applied in the solution of illustrative examples and the results are presented and discussed. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we present a layerwise finite element model for the analysis of sandwich laminated plates with a viscoelastic core and laminated anisotropic face layers. The stiffness and mass matrices of the element are obtained by Carrera’s Unified Formulation (CUF). The dynamic problem is solved in the frequency domain with viscoelastic frequency-dependent material properties for the core. The dynamic behaviour of the model is compared with solutions found in the literature, including experimental data. [Copyright &y& Elsevier]

Abstract: In this work a finite element model is developed for vibration analysis of active–passive damped multilayer sandwich plates, with a viscoelastic core sandwiched between elastic layers, including piezoelectric layers. The elastic layers are modelled using the classic plate theory and the core is modelled using the Reissener–Mindlin theory. The finite element is obtained by assembly of N “elements” through the thickness, using specific assumptions on the displacement continuity at the interfaces between layers. The lack of finite element plate-shell models to analyse structures with passive and active damping, is the principal motivation for the present development, where the solution of some illustrative examples and the results are presented and discussed. [Copyright &y& Elsevier]

Driscoll and Heryudono [1] developed an adaptive method for radial basis functions method. This article addresses the adaptive analysis of composite plates in bending with radial basis multiquadric functions using Driscoll and Heryudono's technique. In this article, various laminates, thickness to side length ratios, and boundary conditions are considered. The method allows for a more natural and automatic selection of the problem grid, where the user must only define the error tolerance. The results obtained show an interesting and promising approach to the static analysis of composite laminates. [ABSTRACT FROM AUTHOR]

Abstract: Three methods for the damage localization of impact damage in laminated composite plates, based on their vibrational characteristics, are presented in this paper. These methods use double pulse TV holography with acoustic excitation for mode shapes acquisition and the differences in translations, rotations and curvatures. The rotations and curvatures are obtained by numerical differentiation of mode shapes translations using a differentiation/smoothing technique. The methods are applied to a carbon fiber reinforced epoxy rectangular plate, free in space, subjected to two cases of impact damage. It is shown that the method based on curvatures allows the localization of both cases of damage, which can be undetected by visual, X-ray or C-scan inspections. The best localizations are achieved by selecting and applying the method to the most changed mode. [Copyright &y& Elsevier]

Abstract: In this paper two non-destructive methods for elastic and piezoelectric parameter estimation in active plate structures with surface bonded piezoelectric patches are presented. These methods rely on experimental undamped natural frequencies of free vibration. The first solves the inverse problem through gradient based optimization techniques, while the second is based on a metamodel of the inverse problem, using artificial neural networks. A numerical higher order finite element laminated plate model is used in both methods and results are compared and discussed through a simulated and an experimental test case. [Copyright &y& Elsevier]

Abstract: Mathematical programming provides general tools for engineering design optimization. We present numerical models for simultaneous analysis and design optimization (SAND) and multidisciplinary design optimization (MDO) represented by mathematical programs. These models are solved with numerical techniques based on the feasible arc interior point algorithm (FAIPA) for nonlinear constrained optimization. Even if MDO is a very large optimization problem, our approach reduces considerably the computer effort. Several tools for very large problems are also presented. The present approach is very strong and efficient for real industrial applications and can easily interact with existing simulation engineering codes. [Copyright &y& Elsevier]