Development of Supporting System of Design of the Functionally Graded Materialsand its Constitutional Equations

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This research project consists of two parts : [1] Study of constitutional equations of the functionally graded materials (FGMs) under thermal load, [2] Developments of programming system to release the thermal stresses in FGMs with and without a crack by Finite Element Methods (FEM).PART [1] : Study of constitutional equations of the functionally graded materials (FGMs) under thermal load. The functionally graded materials (FGMs) are consisted by compositional components of the ceramics and metals. Then, FGMs can be considered as one of the composite materials which its compositional components dependent on the position. The constitutional equations are proposed for the functionally graded materials taking into consideration of thermal load. The equations are developed by an incremental theory which describes the thermal elasto-plastic behavior and damage behavior of particulate-reinforced composites, based on Eshelby's solution of an ellipsoidal inclusion and Mori-Tanaka's conception … More of average stress-strain for the finite concentration of particles under thermal load.PART [2] : Developments of programming system to release the thermal stresses in FGMs with and without a crack by Finite Element Methods (FEM).(1) We could develop programming system to discuss the thermal stresses in the FGMs by used of the proposed constitutional equations.(2) The stress-strain curves are calculated for the matrix and the particle by used of the proposed constitutional equations. Even if the average stress is zero, large compressible stress occurs in the matrix, but large tensile stress occurs in the particle. The stress-strain curves largely depend on the manufacturing process of the FGMs.(3) From the results of calculation for the time variation of the stress intensity factor of the functionally graded plate with an edge crack under heating-cooling cycle heat supply, we obtained the following results. The region of the large stress intensity factor is restricted within a very thin layr, and length of crack growth is restricted within one time tenth of the thickness of the plate. The optimal composition of the component of FGMs is linear distribution from the ceramics to the metal. Less