TY - JOUR
T1 - Stress non-uniformity in a hollow cylinder torsional sand specimen
AU - Naughton, Patrick J.
AU - O'Kelly, Brendan C.
PY - 2007/6
Y1 - 2007/6
N2 - The hollow cylinder torsional apparatus (HCTA) facilitates more generalized stress path testing although it has been criticized on account of the level of stress non-uniformity that may develop because of the curvature of the test specimen wall. The stress non-uniformity which may develop in dense sand specimens (inner radius, 35.5 mm; outer radius, 50.0 mm; height, 200 mm) over small to medium strain levels in the HCTA was studied using an isotropic linear elastic stress analysis. The stress non-uniformity, quantified in terms of the stress non-uniformity coefficient βR, increased in proportion to the stress ratio R, and was generally acceptable throughout the stress space for R < 1.5. Regions where unacceptable stress non-uniformity may develop were identified in the vicinity of (b,ασ), equal to (1,0°) and (0,90°) and for all values of the parameter b in the vicinity of ασ = 45°. It was found that placing restrictions on the difference in the confining pressures which may be applied across the specimen wall thickness reduced the stress non-uniformity but also limited the regions in stress space that could be probed.
AB - The hollow cylinder torsional apparatus (HCTA) facilitates more generalized stress path testing although it has been criticized on account of the level of stress non-uniformity that may develop because of the curvature of the test specimen wall. The stress non-uniformity which may develop in dense sand specimens (inner radius, 35.5 mm; outer radius, 50.0 mm; height, 200 mm) over small to medium strain levels in the HCTA was studied using an isotropic linear elastic stress analysis. The stress non-uniformity, quantified in terms of the stress non-uniformity coefficient βR, increased in proportion to the stress ratio R, and was generally acceptable throughout the stress space for R < 1.5. Regions where unacceptable stress non-uniformity may develop were identified in the vicinity of (b,ασ), equal to (1,0°) and (0,90°) and for all values of the parameter b in the vicinity of ασ = 45°. It was found that placing restrictions on the difference in the confining pressures which may be applied across the specimen wall thickness reduced the stress non-uniformity but also limited the regions in stress space that could be probed.
KW - Hollow cylinder torsional apparatus
KW - Sand
KW - Stress non-uniformity
KW - Stress path
UR - http://www.scopus.com/inward/record.url?scp=34250667889&partnerID=8YFLogxK
U2 - 10.1080/17486020701377124
DO - 10.1080/17486020701377124
M3 - Article
AN - SCOPUS:34250667889
SN - 1748-6025
VL - 2
SP - 117
EP - 122
JO - Geomechanics and Geoengineering
JF - Geomechanics and Geoengineering
IS - 2
ER -