A Wide Range K Expression for the C-Shaped Specimen
Abstract
A new expression has been developed to calculate K for the C-shaped specimen over a wider range of specimen parameters, namely a/W, X/W, and r sub 1/r sub 2 than had previously been available. The rationale used to derive the expression was to utilize known stress intensity factor solutions for short and deep cracks to develop a nondimensional form of K which approaches finite values as a/W goes to both zero and one. Numerical K solution results from prior work were then nondimensionalized to this form with the finite limiting values, and the dependent of K on a/W was determined by multi-variable, linear regression. The final expression agrees with the numerical K solutions within plus or minus 1.0% for .45 less than or equal to a/W less than or equal to .55 for all r sub 1/r sub 2 and X/W of either 0 or .5; within plus or minus 1.5% for .2 less than or equal to a/W less than or equal to 1 for all r sub 1/r sub 2 and X/W equal to 0 or .5; and within about plus or minus 3% for .2 less than or equal to a/W less than or equal to 1 for all r sub 1/r sub 2 and 0 less than or equal to X/W less than or equal to 1. The accuracy of this expression will allow expanded use of the C-shaped specimen for R-curve determination and fatigue crack growth rate testing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1980
- Accession Number
- ADA085719
Entities
People
- J. A. Kapp
- J. C. Newman Jr.
- John H. Underwood
Organizations
- United States Army Armament Research, Development and Engineering Center