The elastic modulus of columnar-grain fresh-water ice

Abstract

ABSTRACT. An analysis is presented of stress and strain meas urements mad e during a n investiga ti on of th e ch aracteri sti cs of cracks form ed in column a r-g ra in , type S2, fr es h-water ice 5 during uni axial , compressive loading a t th e nominal strain ra tes of 10 3, 10 4 a nd 10 S i , and temperatures of _5°, -10°, -20° a nd -30°C. Th e a na lysis hows th a t for this range of strain rate and temperature, ice behaves as a n a nelas ti c so lid. R es ults are given for th e tim e, g rain -size and temperature d epend ence of th e elas ti c modulus in th e plan e perpendicula r to th e long direc tion of th e grains. They are shown to be in reaso na ble agreement with res ults of an earlier stud y of the a nelas ti c behaviour of the sam e type of ice. I t is suggested th a t th e grain -size a nd tempera ture dependence of th e elas tic modu li of ice for this ra nge of stra in rate a nd tempera ture may be du e, in part, to th e d epend ence of the relaxa tion time on these variab les.

Statistical characteristics for the strain-dependent density and the spatial position for deformation-induced cracks in columnar-grain ice

“…He also found that for total strain of 6 x 10-4 to 9 x 10-\ applied in the constant-strain-rate tests, the proportion of grain-boundary cracks decreased from about 100% at the nominal strain rate of 10 2 s I, to about 65% at the nominal rate of 10-5 s-I. The delayed elastic component of the strain increased with decreasing strain rate and there was a significant plastic component at the nominal rate of 10 5 s I (Gold, 1994). In summary, the occurrence of the maxima ",,'ith decreasing strain rate is associated with an increasing proportion of trans crystalline cracks and an increasing delayed elastic and plastic strain.…”