Title: An Inverse Problem in Nondestructive Evaluation of Spotwelds

Speaker: Thomas Hoft, Interview Candidate, University of Minnesota
 
Date/Time: Tuesday, April 26, 2005, 9:00-10:15 am (PT)

Location: Building 980, Room 95 (Sandia NM), Building 915, Room S101 (Sandia CA)

Brief Abstract: A thermal imaging method for nondestructive evaluation of spotwelds has been proposed. In this method, a transducer is employed to generate heat near the weld while the surface temperature is measured. The inverse problem is to access the quality of the weld from the temperature.

In this presentation we develop a simple model for the thermal diffusion problem. The inverse problem we seek to solve, amounts to finding a heat source in a 2-D domain, given temperature as a function of space and time. We solve this classically ill-posed problem by devising a time-stepping algorithm which solves a regularized problem at each time step. We illustrate the main ideas with numerical examples.