Due to the very high speed of the hypersonic missile body, it must withstand very high temperatures and aerodynamic loads. In this situation, the use of materials such as ceramics seems suitable due to their high thermal resistance, but ceramics have little structural strength. The solution is combining a ceramic phase and a metal phase with high mechanical resistance. This material is called functionally graded material.
In this research, the effect of imperfect of Functionally Graded Material on the buckling behavior of the FGM plate is studied using a hyperbolic shear deformation function. The properties of the Functionally Graded materials change with the power distribution function of the property changes along the thickness. The structure of these materials during the production process cannot be completely in accordance with the intended pattern, which leads to the production of imperfect Functionally Graded material. Therefore, in this research, a linear perfect model and two imperfect models are considered. The governing differential equations are derived using Hamilton's principle. The obtained equations were solved using Navier's method for simple boundary conditions. The effects of important geometrical and mechanical parameters, including thickness-to-length ratio, length-to-width ratio, and power function of changes in the properties of the imperfect Functionally Graded plate, have been investigated.