Thermal conduction analysis of layered functionally graded materials

A thermal conduction analysis is performed on layered functionally graded materials (FGMs) subjected to thermal shock by sudden cooling of the material in order to investigate the results obtained from three different mixing laws: linear, quadratic, and half-order. The functionally graded material considered in this research is a composite of nickel and carbon nanotubes at different compositions varying from two to five layers. Each FGM component is 10 mm high and 190 mm wide. The two-layer functionally graded material is composed of two layers, one that is 100% Ni and one that is 100% carbon nanotube. The middle layers for the three to five layers are composed of graded (i.e., gradually changing) percentages of nickel and carbon nanotube. The thermal analysis was performed using a finite-element code. The thermal properties of nickel and carbon nanotube are obtained from literature. The thermal conductivity, specific heat and density for the composites were calculated depending on the percentages of materials in each layer, and assuming different rules of mixture. The thermal conduction analysis is parameterized by different cooling times, different mixing rules and with different heat transfer coefficients.