SYMPOSIA PAPER Published: 01 January 1979

Crack Propagation Measurements on Glass: A Comparison Between Double Torsion and Double Cantilever Beam Specimens


A simple and rapid method of measuring crack propagation in glass was sought. Double torsion (DT) and double cantilever beam (DCB) specimens that allow KIc values as well as (K, V) diagram determinations were tested successively, using relatively large testpieces (250 by 100 by 6 mm).

In the case of DT specimens, it is shown that relaxation experiments do not require the prior determination of specimen compliance. Excellent reproducibility thus is obtained. The technique is easy to master, but the crack front profile is not taken readily into account.

Relaxation of DCB specimens reveals the important role played by the specimen compliance compared to the testing machine compliance. Experiments are not conducted as easily as in the previous case.

In both cases, it is shown that the minimum speed that can be achieved practically during a relaxation experiment on glass is of the order of 10 −7 ms−1.

Results were obtained on float glass in ambient air. They are in satisfactory agreement and compare favorably with published data.

Author Information

Champomier, FP
Service Central de Recherche, Saint-Gobain Industries, Aubervilliers, France
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Developed by Committee: E08
Pages: 60–72
DOI: 10.1520/STP36625S
ISBN-EB: 978-0-8031-4747-8
ISBN-13: 978-0-8031-0365-8