MS&E Colloquium - Dr. Michael B. Prime, Los Alamos National Laboratory
Date: March 12, 2010 from 2:00 pm to 3:00 pm EST
Location: 214 S. W. Mudd
Contact: For further information regarding this event, please contact Chad Gurley by sending email to cg2029@columbia.edu .
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Residual Stress Mapping with the Contour Method:

Experimental Mechanics Novelty and Lessons

 

Michael B. Prime

Los Alamos National Laboratory

 

For presentation at Columbia University, March 12, 2010

 From LA-UR's 00-205, 00-1900, 02-1071, and 03-585


The recently developed contour method can measure complex stress maps in situations where existing measurement methods cannot be applied. This talk first describes the principle of the contour method, which involves simple stress and strain concepts but with a departure from common practice. The experimental trials and tribulations in first putting this method into practice are then illustrated. Lessons are learned about interpreting real world data.


Next, this talk gives several examples of applications. The method is validated by comparing with neutron diffraction measurements in a TIG-welded steel plate and a friction stir weld between dissimilar aluminum alloys. Several applications are shown that demonstrate the unique power of the contour method: large aluminum forgings, a penetrated plate of HSLA-100 steel, and railroad rails.

Finally, this talk explains why the contour method is significant departure from conventional experimental mechanics. Other relaxation methods, for example hole drilling, can only measure a 1-D profile of residual stresses, and yet they require a complex inverse calculation to determine the stresses from the strain data. The contour method measures a 2-D map over a full cross-section, but only a simple, more direct calculation is needed to reduce the data. The reason for these advantages is explored.