TY - GEN

T1 - Energy approach to the high-temperature creep of fiber-reinforced metal-matrix composites

AU - Pan, H. H.

AU - Weng, G. J.

PY - 1992

Y1 - 1992

N2 - Based on a new definition of effective stress introduced by Qiu and Weng (1992) for a heterogeneously deformed matrix, and the use of elastic-creep secant moduli to characterize the weaking constraint power of the ductile matrix, a theory is proposed to estimate the development of tensile creep strains of a fiber-reinforced metal-matrix composite, and to examine the evolution of maximum interfacial tensile stress under transverse loading. The effective stress is defined in terms of the distortional energy of the matrix of a linearly elastic comparison composite, and, since the contribution of the locally perturbed deviatoric stress is accounted for, the theory can be applied to a concentration level which is higher than the traditional mean-field approach. Consideration of the weakening constraint power in the creep matrix also permits the theory to be applied to a somewhat greater range of creep strain as compared to the method of elastic constraint, which is suited only when the creep strain is about of the same order, or even less, of the elastic strain. The calculated axial creep, transverse tensile creep, and bi-axial tensile creep for the Borsic/aluminum composites indicate that the overall creep response of the system is indeed softer than those calculated by the elastic-constraint approach. The interfacial tensile stress under a transverse tension, and under a combination of transverse tension and lateral compression, is shown to grow continuously, leading to potential interfacial debonding under long-term creeping condition.

AB - Based on a new definition of effective stress introduced by Qiu and Weng (1992) for a heterogeneously deformed matrix, and the use of elastic-creep secant moduli to characterize the weaking constraint power of the ductile matrix, a theory is proposed to estimate the development of tensile creep strains of a fiber-reinforced metal-matrix composite, and to examine the evolution of maximum interfacial tensile stress under transverse loading. The effective stress is defined in terms of the distortional energy of the matrix of a linearly elastic comparison composite, and, since the contribution of the locally perturbed deviatoric stress is accounted for, the theory can be applied to a concentration level which is higher than the traditional mean-field approach. Consideration of the weakening constraint power in the creep matrix also permits the theory to be applied to a somewhat greater range of creep strain as compared to the method of elastic constraint, which is suited only when the creep strain is about of the same order, or even less, of the elastic strain. The calculated axial creep, transverse tensile creep, and bi-axial tensile creep for the Borsic/aluminum composites indicate that the overall creep response of the system is indeed softer than those calculated by the elastic-constraint approach. The interfacial tensile stress under a transverse tension, and under a combination of transverse tension and lateral compression, is shown to grow continuously, leading to potential interfacial debonding under long-term creeping condition.

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M3 - Conference contribution

AN - SCOPUS:0026964183

SN - 0791811085

T3 - American Society of Mechanical Engineers, Applied Mechanics Division, AMD

SP - 195

EP - 212

BT - Damage Mechanics in Composites

PB - Publ by ASME

T2 - Winter Annual Meeting of the American Society of Mechanical Engineers

Y2 - 8 November 1992 through 13 November 1992

ER -