Response of functionally graded composites to thermal gradients

A new micromechanical theory is presented for the response of functionally graded metal-matrix composites subjected to thermal gradients. In contrast to existing micromechanical theories that utilize standard homogenization schemes in the course of calculating microscopic and macroscopic field quantities, in the present approach the actual microstructural details are explicitly coupled with the macrostructure of the composite. The theory is particularly well-suited for predicting the response of thin-walled metal-matrix composites with a finite number of large-diameter fibers in the thickness direction subjected to thermal gradients. Standard homogenization techniques which decouple micromechanical and macromechanical analyses may not produce reliable results for such configurations. Examples presented illustrate the usefulness of the outlined approach in generating favorable stress distributions in the presence of thermal gradients by appropriately grading the internal microstructural details of the composite.