RESPONSE OF FUNCTIONALLY GRADED COMPOSITES TO THERMAL-GRADIENTS

A new micromechanical theory is presented for the response of function ally graded metal-matrix composites subjected to thermal gradients. In contrast to existing micromechanical theories that utilize standard h omogenization schemes in the course of calculating microscopic and mac roscopic field quantities, in the present approach the actual microstr uctural details are explicitly coupled with the macrostructure of the composite. The theory is particularly well-suited for predicting the r esponse 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 micromec hanical 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 inte rnal microstructural details of the composite.