Stress-driven Approach to Vibrational Analysis of FGM Annular ‎Nano-plate based on First-order Shear Deformation Plate Theory

Vibrational behavior of small-scale functionally graded annular plate based on the first-order shear deformation theory, and non-local stress-driven model is investigated. For the first time, generalized differential quadrature rule is utilized to solve the governing equation and related boundary conditions. The convergence, accuracy, and efficiency of the generalized differential quadrature rule are investigated using problem-solving for different situations. The effects of parameters such as size parameter, inhomogeneity coefficient of functionally graded materials, thickness to outer radius ratio, inner radius to outer radius ratio, and boundary conditions on the natural frequency of the structure have been investigated. Results show that, unlike the strain-driven model, the non-local stress-driven theory predicts the same behavior for all boundary conditions and increasing the size parameter has led to a stiffening behavior and an increase in the natural frequency of the structure

Three-Dimensional Thermo-Mechanical Elastic Analysis of Functionally Graded Five Layers Composite Sandwich Plate on Winkler Foundations

In this work, the first shear deformation theory (FSDT) is used for the thermo-mechanical analysis of a simply supported five-layer functionally Graded (FG) sandwich plate resting on a Winkler elastic foundation. The sandwich plate consists of five layers (two functionally graded face sheets (AL−AL2O3), with aluminum (Al) as the metal and Alumina (AL2O3) as ceramic phases. Two vinyl ester adhesive layers bond the face sheets to an Elastollan core. The governing equations are obtained using the principle of virtual displacements. A uniform distributed load q with constant magnitude is applied on the top face sheet while all layers experience a steady temperature equal to T. We adapted layerwise theory (LT) to solve each layer’s stress distribution. Navier solution is employed to produce the semi-analytical solution results, which are compared with those of three-dimensional finite element analysis obtained by ABAQUS software. A parametric study is presented to observe the effect of the material gradation, variation in plate dimensions, variation in the thermo-mechanical load, and elastic foundation on the deflections and stresses in the functionally graded sandwich plate. For a composite sandwich plate with mechanical load, in the absence of thermal load, results of the first-order shear layer theory obtained by using the Navire method are relatively good in comparison to the normal stresses obtained for investigated points, which are obtained by finite element

Free Vibrational Analysis of a Functionally Graded Five-Layer Sandwich Plate Resting on a Winkler Elastic Foundation in a Thermal Environment

The effect of adhesive layers bonding to the core of functionally graded (FG) surface layers is investigated using the free vibration of a five-layer sandwich composite plate resting on a Winkler elastic foundation in a thermal environment. It is assumed that all layers are experiencing a steady-state temperature ΔT. The layer-wise theory is used to derive the governing equations with the help of Hamilton’s principle. The Navier solution is employed to obtain the closed-form solutions. The numerical results obtained using the present theory are compared with three-dimensional finite elements implemented by ABAQUS software. The results show that the proposed theory is not only accurate but also efficient in predicting the natural frequencies of sandwich plates resting on Winkler foundations

Free Vibrational Analysis of a Functionally Graded Five-Layer Sandwich Plate Resting on a Winkler Elastic Foundation in a Thermal Environment

The effect of adhesive layers bonding to the core of functionally graded (FG) surface layers is investigated using the free vibration of a five-layer sandwich composite plate resting on a Winkler elastic foundation in a thermal environment. It is assumed that all layers are experiencing a steady-state temperature ΔT. The layer-wise theory is used to derive the governing equations with the help of Hamilton’s principle. The Navier solution is employed to obtain the closed-form solutions. The numerical results obtained using the present theory are compared with three-dimensional finite elements implemented by ABAQUS software. The results show that the proposed theory is not only accurate but also efficient in predicting the natural frequencies of sandwich plates resting on Winkler foundations

Preparation and Characterization of a Polymer Concrete and Estimation of Compressive Strength Using a Two-Phase Micromechanical Model

In comparison with conventional concrete, the polymer concrete has considerably better mechanical properties. Meanwhile, polymer concrete is more expensive than traditional cement concretes. Considering the good mechanical properties of polymer concrete, its applications can be developed by reducing manufacturing costs. In this study, in order to improve the mechanical properties and reduce the manufacturing costs of polymer concrete, a new formulation is presented. In this formulation, the more common mixture of large and small aggregates was replaced by silica sand. In addition, in order to reduce the manufacturing costs, polyester resin was used instead of epoxy resin as the base material. The compressive and three-point bending tests showed that the polyester-based concrete had a higher compressive strength (20%) in comparison with the epoxy-based concrete, while their bending strength was approximately the same. As a result, the manufacturing cost for the polymer concrete prepared using this new formulation can be reduced without decrements in mechanical properties. Moreover, a two-phase micromechanical model was applied to estimate the compressive strength of the polymer concrete. Using the two-phase micromechanical model, the mechanical properties of the polymer concrete were predicted. The results obtained from the modeling and experiments were in good agreement with each other (6.8% error). The excellent mechanical properties of polyester-based concrete developed in the present research and its low cost in comparison with the epoxy-based concrete are key factors that can help its wider applications