Some Basic Problems on the Mechanics of Functionally Graded Materials

摘要

Grading thermomechanical properties of composites by continuously varying the volume fractions of their constituents is becoming a powerful tool in designing new materials for specific applications. The broad objective of this project has been to identify and study a series of basic mechanics problems relating to the failure of this new class of composites called functionally graded materials. The fields selected for investigation which also have important technological applications are fracture mechanics of thermal barrier coatings and thermoelectric cells, contact mechanics of graded materials, and wave propagation in inhomogeneous solids. In each case first the basic concepts are studied analytically. Then a series of benchmark problems are considered in order to demonstrate the distinguishing features of the mechanics of graded materials and to provide some results that could be used in practical applications. Because of its importance in life prediction and failure analysis of structural components, a greater part of the research effort in the project was devoted to the fracture mechanics of graded materials. In solving the benchmark problems the method used has been generally analytical, the exceptions being the layered thermal barrier coatings and the nonlinear post-buckling examination of spallation problems for which finite element methods were used.