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We determine the critical temperatures of a composite elastic plate in a constant temperature field two opposite sides of which are under conditions of sliding contact and the other two sides are free. For the special case of a homogeneous plate, we investigate the dependence of critical forces applied to the sliding sides on the width of the free sides and Poisson's ratio and deduce approximate formulas for the computation of the critical temperature for wide and narrow plates. The critical temperature of a composite plate composed of copper and aluminum plates is calculated. [ABSTRACT FROM AUTHOR]

This article presents a technique for the generation and detection of Lamb waves guided along large plate-like structures made from various types of materials (metal, polymer, fibre-reinforced composite, etc.). A multi-element matrix ultrasonic probe is driven using the well-known phased array principle, for launching and detecting pure Lamb modes in/from specific directions along the plate, which are arbitrary for isotropic materials and limited to specific directions for anisotropic materials, e.g. principal directions or directions for which both phase and group velocities are collinear. The probe is gel-coupled to the tested specimen and allows quick inspection of large area from its fixed position, even of zones with limited access. The technique, which takes into account the frequency dispersive effects, is different than SHM-like (Structural Health Monitoring) inspection, since all transmitting or receiving elements are grouped together in a localized area defined by the active surface of the probe, and not permanently attached to the tested structure. The use of a multi-element probe, for long range Lamb waves-based inspection, is also distinctive from that usually performed, which consists of very local inspection of a material by steering the ultrasonic beam below and nearby the probe. A prototype is presented, as well as measurements of its performances in terms of modal selectivity and directivity. Finally the detection and localisation of a through-thickness hole in a large aluminium plate, of a delamination-like defect in a carbon epoxy composite plate and of an impact damage on a stiffened composite curved plate are shown. [ABSTRACT FROM AUTHOR]

An element-free Galerkin method is presented to analyze isotropic and laminated composite plates. This method employs the moving least square technique to approximate functions. In the analysis procedure, a collocation method is used to enforce boundary conditions. A consistent multi-objective optimization procedure is also applied. The function introduced here consists of minimizing the weight and cost, as well as of maximizing the load. A genetic algorithm is used for the optimization process. [ABSTRACT FROM AUTHOR]

Based on the shear spring model, the propagation of Love wave in two-layered piezoelectric/elastic composite plates under the influence of interfacial defect is investigated. The piezoelectric layer is electrically shorted at both top and bottom surfaces. The wave form solutions of the piezoelectric and elastic layers are obtained, and the dispersion equation is derived by subjecting the boundary conditions and the continuity conditions to the obtained wave form solutions. Numerical results are performed for PZT4/aluminum composite plate. The phase velocities and the mode shapes of mechanical displacement and electric potential are illustrated graphically. The results show that both the interfacial defect and the thickness ratio between the piezoelectric and elastic layers have significant effect on the propagation characteristics of Love wave. One important feature is observed that the interfacial defect always decreases the phase velocities. [ABSTRACT FROM AUTHOR]

The effect of initial stress concentrations around two neighboring cylindrical horizontal holes in an orthotropic rectangular simply supported plate is investigated. The plate is loaded by uniformly distributed normal tensile or compressive forces on its two opposite end faces parallel to the longitudinal axes of the holes and by uniformly distributed normal forces on its upper face. The corresponding problem is formulated within the framework of the 3D linearized theory of elasticity and is solved numerically by using the 3D finite-element method. The influence of material and geometrical parameters, interaction between the holes, and initial stresses on the concentration of stresses around the holes is shown and discussed. [ABSTRACT FROM AUTHOR]

An analytic-numerical approach to the construction of solutions of two-dimensional (in spatial coordinates) quasistatic problems of thermoelasticity for piecewise-homogeneous bodies is proposed. Using this approach, we represent the solution of the thermoelasticity problem for a composite unbounded plate heated by the environment and a uniformly distributed heat source in the form of series in multiple error integrals. On the basis of these results, the corresponding heat and thermoelastic states of this composite plate are computed. [ABSTRACT FROM AUTHOR]

An efficient numerical algorithm for analyzing dynamic response of orthotropic viscoelastic composite laminates has been developed in the time domain. The integral form of the constitutive laws is exploited. Generalized Wiechert model is adopted to simulate the viscoelasticity of the structure Mindlin-Reissner plate theory is utilized in finite element formulation employing the consistent mass matrix. The proposed algorithm is incorporated in the framework of the finite element based on the displacement model. Newmark Constant average acceleration method is used for integration equation of motion. The developed recurrence formula permits the new time solutions to be evaluated using only previous time values. The developed solution technique is applied to orthotropic plate under two types of force, which are the step-pulse and sin-pulse force. [ABSTRACT FROM AUTHOR]

Present research work is based on the unique properties of isogeometric analysis (IGA) like smarter, faster and cheaper analysis for the thermo-elastic bending of laminated and sandwich composite plates. IGA, based on isoparametric concept, is a breakthrough in the area of structural analysis, which employs non-uniform rational B-spline (NURBS) as a basis function to represent less erroneous geometry. Unlike finite-element method (FEM), increasing the polynomial order in IGA gives higher continuous basis functions naturally and easily with reduced computational cost. A procedure has been developed for thermo-elastic bending analysis of laminated composite plates and sandwich structures using IGA approach. The developed NURBS-based code is validated and computational efficacy of thermo-elastic analysis is investigated. A detailed parametric study has been carried out for the quadratic, cubic and quartic NURBS elements with respect to the variation of temperature. Different types of temperature profiles have been considered. Change of deflections, stresses and moment resultants are analysed with an aim to understand the thermo-elastic behaviour of laminated and sandwich composite plates. Several thermo-elastic numerical examples have been analysed extensively. Obtained numerical results are compared with available literature to show the advantage of current formulation. [ABSTRACT FROM AUTHOR]