Nonlinear Thermoelastic Analysis of Graded CNT-Reinforced Sandwich Structure Embedded with SMA Fibre- Theoretical and Experimental Verification

Abstract

The nonlinear thermoelastic behavior of the graded nanotube reinforced sandwich panel structure bonded with and without shape memory alloy (SMA) fibre is computed numerically using a generic micromechanical model. Further, the solution accuracy has been verified with those available published data and own experimental test values. For the numerical analysis purpose, the graded nanotube sandwich structural model is derived mathematically using a higher-order polynomial kinematics and Green-Lagrange nonlinear strain including the influences of variable temperature profile (uniform and linear). Also, the material nonlinearity of SMA fibre due to the elevated thermal environment is included in the micromechanical model through the marching technique. Additionally, the model generality has been maintained by adding all of the nonlinear higher-order mid-plane strains in the formulation part. The individual properties of the reinforcement (nanotube), matrix and the functional materials (SMA) are assumed to be temperature dependent. The numerical responses are obtained through a suitable customized computer code (developed in MATLAB environment) with the help of currently derived higher-order micromechanical model. Moreover, the convergence of the finite element solution including the correctness has been confirmed via solving different kinds of numerical examples. The results are compared with available published data obtained either numerically or exact solution techniques. Also, the responses are compared with own experimental data for the few specific cases i.e. vibration and linear/nonlinear bending values of the composite/sandwich structures. In addition, the commercial finite element package (ANSYS) also utilized to model the graded nanotube structure and the sandwich panel via the batch input technique (ANSYS parametric design language code) for the evaluation of desired responses. Finally, the influences of variable design input parameters (thickness ratio, aspect ratio, type of geometry, support at the edges, curvature ratio and temperature) on the nanotube-reinforced composite/sandwich structural responses embedded with and without functional materials (SMA volume fractions, prestrain values and temperature loading) are explored by solving different kinds of numerical example including the effect of the nanotube grading configurations and temperature dependent properties.