J and CTOD Estimation Equations for Shallow Cracks in Single Edge Notch Bend Specimens,
Abstract
Results from two dimensional plane strain finite-element analyses are used to develop J and CTOD estimation strategies appropriate for application to both shallow and deep crack SE(B) specimens. Crack depth to specimen width (a/W) ratios between 0.05 and 0.70 are modelled using Ramberg-Osgood strain hardening exponents (n) between 4 and 50. The estimation formulas divide J and CTOD into small scale yielding (SSY) and large scale yielding (LSY) components. For each case, the SSY components is determined by the linear elastic stress intensity factor, K sub I. The formulas differ in evaluation of the LSY component. The techniques considered include: estimating J or CTOD from plastic work based on load line displacement (A sub pl/ILLD), from plastic work based on crack mouth opening displacement (A sub pl/CMODpl), and from the plastic component of crack mouth opening displacement (CMOd pl). A sub plCMOD provides the most accurate J estimation possible. CTOD estimates based on scalar proportionality of CTOD sub 1sy and CMOD pl are highly inaccurate, especially for materials with considerable strain hardening, where errors up to 38% occur.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA261679
Entities
People
- Mark T. Kirk
- Robert H.
Organizations
- University of Illinois Urbana–Champaign