@misc{schwalbe_fracture_mechanics_2005, 
author={Schwalbe, K.-H., Newman, J.C., Shannon, J.L.},
title={Fracture mechanics testing on specimens with low constraint - standardisation activities within ISO and ASTM},
year={2005},
howpublished = {journal article},
doi = {https://doi.org/10.1016/j.engfracmech.2004.04.006},
abstract = {Two procedures are being developed; one based on the 5 crack tip opening displacement, the other on the constant value of the crack tip opening angle, c.  The measurement of 5 is   well established and relatively simple, whereas c is more difficult to determine experimentally.  Evaluations of c from  finite-element analyses are currently the most accurate approach, since measurements can only be made on the exterior surfaces. Questions naturally arise regarding the correspondence of surface indication with full-thickness response in the laboratory experience. Both measures of crack extension resistance are suitable for structural assessment.  The 5 concept is applied by means of crack driving force formulae from existing assessment procedures. The CTOA concept is potentially more accurate; but its structural application requires numerical methods, which have been successful in predicting the failure of large-scale cracked structural components.},
note = {Online available at: \url{https://doi.org/10.1016/j.engfracmech.2004.04.006} (DOI). Schwalbe, K.; Newman, J.; Shannon, J.: Fracture mechanics testing on specimens with low constraint - standardisation activities within ISO and ASTM. Engineering Fracture Mechanics. 2005. vol. 72, no. 4, 557-576. DOI: 10.1016/j.engfracmech.2004.04.006}}