A methodology to predict damage initiation, damage growth, and residual strength in titanium matrix composites

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:536400

Bakuckas, Jr, J G ^[1]; Johnson, W S ^[2]

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1. Galaxy Scientific Corp., Egg Harbor Township, NJ (United States)
2. Georgia Inst. of Tech., Atlanta, GA (United States). School of Material Science and Engineering

In this research, a methodology to predict damage initiation, damage growth, fatigue life, and residual strength in titanium matrix composites (TMC) is outlined. Emphasis was placed on micromechanics-based engineering approaches. Damage initiation was predicted using a local effective strain approach. A finite element analysis verified the prevailing assumptions made in the formulation of this model. Damage growth, namely, fiber-bridged matrix crack growth, was evaluated using a fiber bridging (FB) model that accounts for thermal residual stresses. This model combines continuum fracture mechanics and micromechanics analyses yielding stress-intensity factor solutions for fiber-bridged matrix cracks. In the FB model, fibers in the wake of the matrix crack are idealized as a closure pressure, and an unknown constant frictional shear stress is assumed to act along the debond length of the bridging fibers. This frictional shear stress was used as a curve-fitting parameter to the available experimental data. Figure life and post-fatigue residual strength were predicted based on the axial stress in the first intact 0{degree} fiber calculated using the FB model and a three-dimensional finite element analysis.

• Sponsoring Organization: Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 536400
• Report Number(s): CONF-940399--; ISBN 0-8031-2039-7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACK PROPAGATION
DAMAGE
FATIGUE
FINITE ELEMENT METHOD
FRACTURE MECHANICS
MATHEMATICAL MODELS
RESIDUAL STRESSES
THERMAL STRESSES
TITANIUM BASE ALLOYS