Determination of residual stresses by local annealing to laser speckle pattern interferometry
Conference
·
OSTI ID:484532
- Westinghouse Savannah River Company, Aiken, SC (United States)
- Univ. of Alabama, Huntsville, AL (United States)
One of the most common methods of experimentally determining residual stresses is Blind Hole Drilling (BHD). A new method which is a thermo-optical analog to BHD is being developed. This method uses local heating to anneal a tiny spot and uses laser speckle interferometry to measure the strain that results. This strain is used to determine the state of stress prior to heating. The peak temperatures are on the order of 200 Celsius so that for most metals, there will be no changes in phase or other material properties except for a slight reduction in yield stress. Preliminary experiments with type 304 stainless steel were performed using resistance heating. The experimental results were in excellent agreement with finite element model predictions of the process. Subsequently, the resistance heating was replaced with laser heating. The heat input (22.5 Watt peak) from a small sealed radio frequency excited Carbon Dioxide laser was used. In order to both control the heating temperature and efficiently couple the infrared photons from the laser into the test specimen, a substance known as Liquid Temperature Indicating Paint was used. Without this substance the laser power would be so large as to make this approach impractical. Furthermore the measurement and control for the heat input would be very complicated. Using this laser heating approach was successful in obtaining similar results to those obtained in other work. Since this laser based technique is a thermo-optical analog to blind hole drilling a simple stress model is required to interpret the measured results. This simple stress model is presented. As in BHD, the simple model must be modified by empirical coefficients to be useful. These empirical coefficients are determined by experimentation and/or numerical analysis
- Research Organization:
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-96SR18500
- OSTI ID:
- 484532
- Report Number(s):
- SRT-MTS--97-3001; CONF-970763--1; ON: DE97060079
- Country of Publication:
- United States
- Language:
- English
Similar Records
Residual stress measurement results in refinery vessels
On the use of the hole-drilling technique for residual stress measurements in thin plates
Modeling of residual stress in thick section weldments
Conference
·
Sat Nov 30 23:00:00 EST 1996
·
OSTI ID:403189
On the use of the hole-drilling technique for residual stress measurements in thin plates
Journal Article
·
Sat Aug 01 00:00:00 EDT 1992
· Journal of Pressure Vessel Technology; (United States)
·
OSTI ID:6847524
Modeling of residual stress in thick section weldments
Thesis/Dissertation
·
Tue Dec 31 23:00:00 EST 1991
·
OSTI ID:7168071