Accession Number : AD0775534

Title :   Fatigue and Shakedown in Metal Matrix Composites.

Descriptive Note : Interim technical rept. no. 1,

Corporate Author : DUKE UNIV DURHAM N C DEPT OF CIVIL ENGINEERING

Personal Author(s) : Dvorak,George J. ; Tarn,J. Q.

Report Date : NOV 1973

Pagination or Media Count : 49

Abstract : Simple mechanical models of unidirectional metal matrix composites are used to analyze elastoplastic deformation and shakedown in the matrix under cyclic composite loads. Both axial and off-axis loadings of a lamina are considered. It is shown that the fatigue limits of as-fabricated B-Al, Be-Al, W-Cu, and other composites generally coincide with the composite shakedown limits, because the matrix yield stresses and fatigue limits are equal. In heat-treated composites, the matrix yield stress is usually much higher than the fatigue limit, and matrix fatigue failure can take place in the shakedown state. The residual microstresses caused by heat treatment are estimated, and their influence on fatigue is discussed. A method for improvement of the fatigue resistance of heat-treated composites is proposed. (Modified author abstract)

Descriptors :   *Composite materials, *Fatigue(Mechanics), Metals, Matrix materials, Fiber reinforcement, Fibers, Beryllium, Aluminum, Boron, Copper, Tungsten

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE