Accession Number : AD0787430

Title :   Shakedown of Unidirectional Composites.

Descriptive Note : Interim technical rept. no. 5,

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

Personal Author(s) : Tarn,J. Q. ; Dvorak,G. J. ; Rao,M. S. M.

Report Date : APR 1974

Pagination or Media Count : 46

Abstract : Substantial shakedown effects in unidirectional metal matrix composites have been found to exist for loading states which are axisymmetric with respect to the fiber axis, and which include also a uniform thermal change. The shakedown limits for a variable cyclic loading program, can be found by a standard procedure involving the selection of parametric families of selfstress states. An alternative, direct approach to the determination of the shakedown limits is related to the recently developed kinematic hardening rules for symmetrically loaded fibrous composites. Specifically, shakedown will occur if the loading domain can be contained within a translated initial yield surface in the axisymmetric stress plane. Results are presented for B-Al, Be-Al, B-Ti and B-Mg composites.

Descriptors :   *Laminates, *Fiber reinforced composites, *Plastic properties, Loads(Forces), Thermal cycling tests, Axisymmetric, Hardening, Elastic properties, Stresses, Numerical analysis, Yield strength, Reinforcement(Structures), Boron, Fibers, Aluminum, Magnesium, Fatigue(Mechanics), Titanium, Beryllium

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE