Effect of anisotropy on steady creep in a whisker reinforced functionally graded composite disk

International Conference on Smart Materials & Structures

June 15 -17, 2015 Las Vegas, USA

V K Gupta1 and Tejeet Singh2

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

In many whisker reinforced composites, anisotropy may result due to material flow during processing operations such as forging, extrusion etc. The consequence of anisotropy, introduced during processing, has been investigated on the steady state creep deformations in a constant thickness rotating disk made of functionally graded 6061Al-SiCw (subscript â??wâ?? stands for whisker). The disk material is assumed to yield according to Hillâ??s anisotropic criterion. The distribution of SiCw reinforcement in the disk is assumed to decrease linearly from the inner to outer radius. The stresses and strain rates in the disk are estimated by solving the force equilibrium equation of the rotating disk along with the constitutive equations describing multi-axial creep. The results obtained for anisotropic functionally graded (FG) disk are compared with those estimated for isotropic FG disk with the same average whisker content. The anisotropic constants, appearing in Hillâ??s yield criterion are obtained from the available experimental results. The results show that the presence of anisotropy reduces the tangential stress in the middle of the disk, but near the inner and outer radii the tangential stress is higher than the isotropic disk. The steady state creep rates in the anisotropic disk are significantly lower than the isotropic disk, with the maximum difference observed at the inner radius. In the presence of anisotropy, the distribution of strain rates becomes relatively uniform over the entire disk, which may reduce the chances of distortion in the disk.