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The elastic analysis of anisotropic rotating sandwich ring with a functionally graded transition region was carried out. Like the shell sandwich structure in nature, the ring is composed of 3 well-bonded regions, of which the inner and outer regions are made of homogeneous anisotropic materials, and the intermediate transition region is made of a material with arbitrary-gradient properties along the radial direction. Based on the boundary conditions and the continuity conditions at the interface, the 2nd Fredholm integral equation for the radial stress was obtained with the integral equation method, then the stress and displacement fields of the sandwich ring structure were obtained through numerical solution. The distributions of the stress and displacement fields in the sandwich ring structure were given. Different gradient changes encountered in engineering practice can be solved only through substitution of the corresponding function model. The effectiveness and accuracy of the integral equation method were verified through comparison of the numerical solutions with the exact ones for a special power function gradient variation form. The more general Voigt function model was adopted for the intermediate transition region, and the influences of the anisotropy degree, the gradient parameter, and the thickness on the stress and displacement fields were analyzed. The proposed Fredholm integral equation method provides a powerful tool for the optimal design of anisotropic functionally graded materials and sandwich ring structures. The numerical results make a theoretical guidance for the safety design of anisotropic functionally graded sandwich ring structures. [ABSTRACT FROM AUTHOR]

The elastic problem of anisotropic functionally graded rotating disks with non-uniform thicknesses was studied. The material properties and thicknesses of the disk change with an arbitrary gradient along the radial direction, and the disk displacement is constrained at the central axis of rotation and the edge is free. According to the equilibrium differential equations for the anisotropic rotating disk, the Fredholm integral equation of radial stresses was obtained, and then numerically solved to calculate the displacement and stress fields. For any specific situation of gradient change, it is only needed to substitute the corresponding gradient parameters into the equation for solution. In the numerical examples, firstly, the parameters such as the thickness and the elastic modulus were assumed to be of special power functions. The numerical solutions obtained from the Fredholm integral equation were compared with the corresponding exact solutions and the FEM solutions by the ANSYS software for the common Voigt model, to validate the method. Then, the effects of the thickness change, the gradient parameters and different degrees of anisotropy on the stress and displacement fields, were numerically analyzed with the common Voigt model. The proposed elastic analysis method for disk structures with arbitrary gradient changes along the radial direction, is promising in the application of structural optimization. The analysis results can guide the engineers to design safer and more economical functionally graded structures. [ABSTRACT FROM AUTHOR]