COBEM99

S24 Mecânica dos Sólidos

Title:

MICROMECHANICS OF PARTICULATE METAL MATRIX COMPOSITES: MODELING EFFECTIVE MODULI

Summary :

ABSTRACT. METAL MATRIX COMPOSITES ARE ATTRACTIVE FOR HIGH TEMPERATURE ENGINEERING APPLICATIONS DUE TO THEIR HIGH STRENGTH EVEN UNDER EXTREME SITUATIONS. A KEY POINT ON COMPOSITE APPLICATIONS IS THE MATERIAL EFFECTIVE PROPERTIES. IN THIS PAPER, THE THERMAL-ELASTIC MODULI FOR METAL MATRIX COMPOSITES ARE CALCULATED BASED ON MICROMECHANICAL MODELS. THIS WORK IS FOCUSED ON PARTICULATE METAL MATRIX COMPOSITES, WHOSE FIBERS ARE ASSUMED TO BE AS SPHERICAL INCLUSIONS ON A MATRIX, AND ON WEAK INTERFACE FIBER/MATRIX CONDITION. THIS SPHERICAL INCLUSION IS SURROUNDED BY AN INTERFACE IN A CONCENTRIC SPHERICAL SHELL SHAPE. DUE TO THIS GEOMETRIC CONSIDERATION THE CONCENTRIC SPHERES MODEL IS APPLIED IN SUCH A WAY THAT THE WEAK INTERFACE FIBER/MATRIX CONDITION, WHICH IS REPRESENTED BY A DISPLACEMENT AND TRACTION DISCONTINUITY ACROSS THE INTERFACE, IS SATISFIED. THE MATERIAL PROPERTY BOUNDS FOR SUCH TYPE OF PROBLEM ARE CALCULATED, AND NEW EXPRESSIONS FOR THE THERMAL CONDUCTIVITY ARE PROPOSED BASED ON THE ANALOGY BETWEEN SHEAR LOADING AND CONDUCTIVITY. MOREOVER, ON THE PROPOSED MODEL, THE INTERFACE MATERIAL PROPERTIES ARE DESCRIBED BY THE MODIFIED RULE OF MIXTURES. NUMERICAL SIMULATIONS FOR TWO SETS OF METAL MATRIX COMPOSITES, TI/SIC AND AL/SIC, ARE SHOWN AND COMPARED AGAINST EXPERIMENTAL AND NUMERICAL SIMULATION RESULTS AVAILABLE IN THE LITERATURE WITH GOOD AGREEMENT. KEYWORDS: METAL MATRIX COMPOSITES, MICROMECHANICS, BOUNDS FOR EFFECTIVE MODULI, THERMAL CONDUCTIVITY.

Author :

Avila, Antonio Ferreira
Deniculi, Fulvio Dias

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