Cleavage and creep fracture of rock salt

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(96)00004-3· OSTI ID:389807

Chan, K S ^[1]; Munson, D E ^[2]; Bodner, S R ^[1]; Fossum, A F ^[3]

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1. Southwest Research Inst., San Antonio, TX (United States)
2. Sandia National Labs., Albuquerque, NM (United States)
3. RE/SPEC Inc., Rapid City, SD (United States)

The dominant failure mechanism in rock salt at ambient temperature is either cleavage or creep fracture. Since the transition of creep fracture to cleavage in a compressive stress field is not well understood, failure of rock salt by cleavage and creep fracture is analyzed in this paper to elucidate the effect of stress state on the competition between these two fracture mechanisms. For cleavage fracture, a shear crack is assumed to cause the formation and growth of a symmetric pair of wing cracks in a predominantly compressive stress field. The conditions for wing-crack instability are derived and presented as the cleavage fracture boundary in the fracture mechanism map. Using an existing creep fracture model, stress conditions for the onset of creep fracture and isochronous failure curves of specified times-to-rupture are calculated and incorporated into the fracture mechanism map. The regimes of dominance by cleavage and creep fracture are established and compared with experimental data. The result indicates that unstable propagation of cleavage cracks occurs only in the presence of tensile stress. The onset of creep fracture is promoted by a tensile stress, but can be totally suppressed by a high confining pressure. Transition of creep fracture to cleavage occurs when critical conditions of stress difference and tensile stress for crack instability are exceeded.

• OSTI ID: 389807
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 9 Vol. 44; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
CRACK PROPAGATION
CRACKS
DEFORMATION
DISLOCATIONS
FRACTURE MECHANICS
FRACTURE PROPERTIES
MATHEMATICAL MODELS
NUCLEATION
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
RUPTURES
SALT DEPOSITS
STRESSES