Size-dependent transient thermal stress analysis of a rotating thin and moderately thick porous FGM microblade under cooling thermal shock

The present work focuses on the development of a simple finite element formulation for the size-dependent transient thermal stress analysis of a rotating moderately thick and thin porous FGM microblade subjected to cooling thermal shock. The upper and lower layers of the FGM microblade are made of SUS304 stainless steel and AISI 1020 carbon steel, respectively. A cooling thermal shock is applied on the upper metallic surface of the FGM microblade, however, the lower ceramic surface of the same is held constant at room temperature. First-order shear deformation theory (FSDT) in conjunction with von Karman-type nonlinearity is used in the development of the finite element formulation. The governing differential equation for the present analysis is obtained using the total Lagrangian formulation in conjunction with the modified coupled stress theory (MCST). Modified Newton–Raphson in conjunction with the Newmark average acceleration method is used to obtain the transient displacements of the porous FGM pretwisted rotating microblade. Further, the transient thermal stresses are obtained from the stress-strain relationship. The results obtained from the present finite element formulation are first compared with the available benchmark for a wide range of parameters. New results are presented to investigate the effect of rotational velocity, intensity of the thermal shock, material scale ratio, porosity, volume fraction index and FGM configuration on the transient thermal stress analysis of a rotating moderately thick and thin SUS304/AISI 1020 porous FGM rotating microblade under cooling thermal shock.