Functionally Graded Material Panels Research Articles

Numerical study of noise transmission through functionally graded panels.

Functionally graded panels are panels made of either functionally graded materials (FGMs) or functionally graded structures. FGM panels are traditionally used as thermal insulation barriers and they find applications in space and launch vehicles. Functionally graded structures include foams with continuous variations in pore size from one side to the other side. Such foams are incorporated as the core layer in sandwich panels. The latter is often used as partition walls in the building and transportation industries. In this study, we are concerned with the noise transmission characteristics of functionally graded panels. We developed an analytical model to derive the transfer matrix for the functionally graded medium. Using this model, we were able to make numerical predictions for sound transmission through functionally graded panels. The gradation parameter provides an additional degree of freedom in controlling the noise transmission characteristics. This is helpful in maximizing the noise reduction in panel design. Furthermore, our transfer matrix model applies to conventional discretely layered panels as well. In fact, the latter is just a special case in our modeling formulation. Numerical examples and results are presented and discussed.

Volume fraction optimization of functionally graded composite panels for stress reduction and critical temperature

The volume fraction optimization of functionally graded (FG) composite panels is studied by considering stress reduction and thermo-mechanical buckling. The structure is made up of ceramic layer, functionally graded materials (FGMs) and metal layer. Material properties are assumed as temperature dependent, and continuously varying in the thickness direction according to a simple power-law distribution in terms of the ceramic and metal volume fractions in FGMs. The 3-D finite element model is adopted for modeling of material properties and temperature fields in the structure. For the various FGM thickness ratios and volume fraction distributions, mechanical stress analysis and thermo-mechanical buckling analysis are performed. Based on the results, the optimal designs of FGMs panels are investigated for stress reduction and improving thermo-mechanical buckling behavior.

Thermal post-buckling and limit-cycle oscillation of functionally graded panel with structural damping in supersonic airflow

Abstract This paper investigates the supersonic aero-thermo post-buckling behaviors and limit-cycle oscillations of Functionally Graded Material (FGM) panels. In order to model the panel, the first-order shear deformation theory (FSDT) of plate is applied, and structural damping effect is considered in the supersonic airflow. Material properties are assumed to be temperature dependent, and to vary in the thickness direction of the panel according to a simple power law distribution. Also, the von-Karman strain–displacement relations are adopted to consider the geometric nonlinearity due to large deformation of the structure. Rayleigh damping coefficient is used to consider the structural damping, and the first-order piston theory is applied to model the supersonic aerodynamic loads. Newmark’s time integration method is adopted, and Guyan reduction technique is employed to get the computational efficiency. Numerical results are compared with the previous works, and the effects of structural damping on the limit-cycle oscillation of FGM panels under supersonic airflow are studied in detail.

Optimization of volume fractions for functionally graded panels considering stress and critical temperature

Volume fraction optimization of Functionally Graded Materials (FGMs) is investigated considering stress and critical temperature. Material properties are assumed to be temperature dependent, and are assumed to be varied continuously in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituent materials. The effective material properties are obtained by applying linear rule of mixtures. The 3-D finite element model is adopted using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. For the various FGMs volume fraction distributions, mechanical stress analysis and thermo-mechanical buckling analysis are performed to get the critical conditions. Finally, the optimal designs of FGMs panels are investigated for stress reduction and improving thermo-mechanical buckling behavior.