Abstract: Composite layer board model is adopted to analyse functionally gradient materials cantilever board. FGM is hetergeneous anisotropy. It is assumed that all the material properties only depend on the thickness direction. Structure optimization distortion stress is obtained through introducing the nature boundary and layer dual symmetry conditions. Thermalload distributing and transverse shear dual symmetry affects struc-ture optimization characteristic. Structure optimization gradient coefficient lead to the maximal thermal intensiey.

Key words: Complex structure, Dual symmetry, Gradient, Optimization, Stress analysis