The Bauschinger Effect on Stress Intensity Factors for a Radially Cracked Gun Tube.
Abstract
The theoretical predicted fatigue life of a high strength steel tube which has undergone an autofrettage procedure is significantly higher than the experimental prediction. To account for the discrepancy, attention is now turned to developing better elastic-plastic models for a high strength steel. An improved material model shows that reverse yielding may occur in the inner portion of the tube. This reverse yielding reduces the residual compressive hoop stress considerably which has an adverse effect on bore crack propagation. This study considers the stress intensity factors due to a radial crack taking the Bauschinger effect into consideration. The elastic-plastic interfaces during loading and unloading in the autofrettage process divide the tube into three-ring regions. The residual stress distribution in each region is quite different. When a crack grows from one region into another, the previous method using functional stress intensity fails. A new method is used to obtain stress intensity factors for a radial crack growing out of the reverse yielding zone. This approach is based on crack face weight functions obtained by Sha using stiffness derivative finite element techniques coupled with singular crack-tip elements. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1986
- Accession Number
- ADA174432
Entities
People
- P. C. Chen
- S. L. Pu
Organizations
- United States Army Armament Research, Development and Engineering Center