The Effect of Low Temperatures on the Breaking Strength of Sheet Glass
JSGT 1948 V32 T005-T019
The strength of sheet glass was determined at 17·5° and at -40° by two methods, namely, by the modulus of rupture on loading and by impact. Careful attention was paid to the selection and preparation of each of the several hundred specimens tested. Reduction in temperature from 17·5° to -40° was accompanied by an increase in the modulus of rupture of strips 6 cm long, 0·8 cm wide and 0·29-0·30 cm thick from 10·1 to 12·6 kg.Jmm2 in the case of specimens with mechanically-polished edges; and from 21·4 to 25·4 kg.Jmm2 for specimens with fire-finished edges, with the intermediate value of 22·9 kg.Jmm2 at -20°. Using 4 inch square test pieces, the height of fall of a pendulum of effective weight 500 g required to cause fracture rose from 17·1 cm at 17·5° to 20·6 cm at -40° for specimens re-annealed after being cut, and from 18·7 cm at 16° to 21·9 cm at -40° for unannealed specimens. The results were in general agreement with those of A. Smekal, F. W. Preston & G. O. Jones and W. E. S. Turner.
A. J. Holland
