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High strain rate studies in rock
Author(s) -
Grady Dennis
Publication year - 1977
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl004i007p00263
Subject(s) - strain rate , shock (circulatory) , shock wave , compression (physics) , amplitude , materials science , projectile , mechanics , deformation (meteorology) , geology , stress (linguistics) , dolomite , strain (injury) , mineralogy , composite material , optics , physics , metallurgy , medicine , linguistics , philosophy
Dynamic compression studies using high velocity impact are usually considered to involve a catastrophic process of indeterminate loading rate by which a material is brought to a shock compressed state. Although this is frequently the case, methods are also available to control the rate of strain during the shock compression process. One of the most accurate of these methods makes use of the anomalous nonlinear elastic property of glass to transform an initial shock or step wave input into a ramp wave of known amplitude and duration. Fused silica is the most carefully calibrated material for this purpose and, when placed between the test specimen and the impact projectile, can provide loading strain rates in the range of 10 4 /s to 10 6 /s for final stress states of approximately 3.9 GPa or less. Ramp wave compression experiments have been conducted on dolomite at strain rates of 3 × 10 4 /s. Both initial yielding and subsequent deformation at this strain rate agrees well with previous shock wave studies (⋵ ∼ 10 6 /s) and differs substantially from quasi‐static measurements (⋵ ∼ 10 −4 /s). The ramp wave studies have also uncovered a pressure‐induced phase transition in dolomite initiating at 4.0 GPa.