Publications

Finite Element Analysis capability for application to welding has been developed and enhanced during a two year Cooperative Research and Development Agreement(CRADA) between Pratt & Whitney, United Technologies Research Center, and Sandia National Laboratories. Because of the nature of electron beam welding at Pratt & Whitney -- set-up is time consuming, the parts to be welded are complicated, and experimentation is costly -- finite element analysis has found many potential applications. The results of most interest in these analyses are the residual stress and final distortion of the component. The work has made use of the Sandia finite element codes JACQ3D, for thermal analysis, and JAS3D, for mechanical analysis. Both codes use an efficient, non-linear conjugate gradient solution technique, which enables large problems to be solved on engineering workstations. This presentation describes several technical challenges that were overcome in the application of the Sandia codes to this class of problems. Stress and distortion results predicted for an electron beam weld of a PW4000 gas turbine engine drum rotor will also be discussed.

When the Morton Salt Mine in Weeks Island, Louisiana was converted into a strategic Petroleum Reserve oil reservoir, massive concrete bulkheads were installed to seal the access shafts against oil or water leakage. Recent inspection of these bulkheads has raised questions about their ability to perform satisfactorily in the event of a catastrophic water leak into the mine. Calculations are reported here which examine the response of the five bulkheads to a worst-case scenario of flooding by brine from the surface into the oil reservoir below the bulkheads. These calculations show that, under conservative analysis assumptions, factors of safety under such a load for the bulkheads sealing the service shaft and the two raisebores are close to 1. The Markel incline and production shaft bulkheads exhibit safety factors in excess of 2 and 3, respectively. 10 refs., 24 figs., 3 tabs.