Residual Surface Strain Distributions Near Holes which are Coldworked to Various Degrees
Abstract
Residual surface strain distributions were measured in the vicinity of holes in 1/4 in. aluminum alloy plate which had been coldworked to various degrees of by a commercial process. Seven levels of coldworking between 3.8 mils and 7.8 mils radial interference were studied. Attention focused mainly on radial strains, but hoop strains were measured for two coldwork levels. A sophisticated moire technique was developed for this investigation, and refined computer routines were utilized for reduction of data and plotting of results. The moire method involved high-resolution photography of a specimen grating before and after coldworking and subsequent generation of fringe patterns in a coherent optical processor. This report contains considerable tutorial detail about these techniques. The results are quite straight forward, and they are shown to agree reasonably well with the limited available data. The plastic deformation process appears to be quite complex, and minor changes of cold- working parameters can cause large changes in the strain--a factor which must be considered by designer and manufacturer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1978
- Accession Number
- ADA068396
Entities
People
- Gary Cloud
Organizations
- Air Force Research Laboratory