Applications: Residual Stress Map in Weld Plate

	HOME
	Principle
	- make cut
	- measure surface
	- calculate stress
	Validations
	Applications
	- bent beam
>	- weld plate
	- quenched steel
	- impacted plate
	- alum. forging
	- friction stir weld
	- Ti FSW
	- Railroad rails
	Publications
	More info

Residual Stress
Conferences

paper on these measurements: M. B. Prime, R. J. Sebring, J. M. Edwards, D. J. Hughes, P. J. Webster, "Laser Surface-Contouring and Spline Data-Smoothing for Residual Stress Measurement," Experimental Mechanics, 44(2), pp. 176-184, April 2004. (LA-UR-02-7241)

Results: Axial Residual Stress Map Measured Over Plate Cross-section: Great results! Agreement between contour and neutron results is better than combined uncertainty. Neutron mapping done at Chalk River Labs in Canada by Dr. Darren Hughes and Professor Peter Webster of Engineering Science Group at the University of Salford, UK Specimen prepared by TWI as part of VAMAS-TWA 20 effort to standardize neutron diffraction measurements of residual stress Some report of variability of neutron results in this specimen available in D.J. Hughes, P.J. Webster and G. Mills, Mater. Sci. Forum 404–407 (2002), pp. 561–566 . However, that is only strains, not stresses. Details of this measurement and specimen:
Weld Plate Ferritic steel: BS 4360 50D 12.5 mm thick (1/2 inch) 6 mm wide, 8 mm deep groove machined along length Filled in with 12 pass TIG weld	Weld Plate

Cut Beam using wire EDM Beam carefully clamped during cutting. See picture. Use 100 µm (0.004") diameter wire. Cut using "skim cut settings" so that minimal stresses are put in during cutting.	Sketch of EDM Cut

Measure Surface Contour with CMM Use 4 mm diameter ruby tip on CMM Measure surface (both halves) on a 0.4 mm grid: gives ~12,000 data points Peak-to-peak contour of about 75 µm (0.003")	Shape of cut surface, magnified 80x

Calculate Stress using FEM Make 3-D model of weld plate after cut Start with flat surface Using displacement boundary conditions, force cut surface to opposite of measured contour Extract stresses normal to surface.	FEM model forced to opposite shape of contour, magnified 80x

			Managed by Triad National Security, LLC Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA contact: Mike Prime at prime@lanl.gov \| Copyright & Disclaimer U.S. patent 6,470,756 \| Last Modified: October 26, 2012