Fast and Reliable Solution of GDoF-Problems on NAVO/BABBAGE and AFRL/HAWK Systems

Fast and reliable structures and materials analysis of full fuselage, wing, and/or empennage sections is now for first time possible with access to highly optimized software, called STRIPE, and the Naval Oceanographic Office (NAVO) BABBAGE and air force research laboratory (AFRL) HAWK systems. Analyses of this type have opened up the possibility for considering the statistical uncertainties in material data, geometry, crack locations, etc. Very detailed analysis can be performed on huge models which are geometrically exact down to rivet details where growth of numerous cracks at numerous locations is studied. Access to this type of analysis results can drastically reduce inspection requirements, prevent premature retirement of old aircraft and increase aircraft safety; all resulting in a potential to save billions of dollars if implemented across the United States Air Force (USAF) fleet. By applying a novel mathematical multi-scale scheme, these problems can be split into solving many thousand smaller problems and one very large problem. The efficient implementation of these two different activities is crucial for computing in a shared environment. This technique results in solution of 109 sets of equations for the large problem with greater than 104 right hand sides and thousands of smaller problems having about 106 degrees-of-freedom (DoF) each. Iterative solvers are not competitive so direct solvers must be used. The major difficulty in achieving scalability is then related to the extensive input/output (I/O) traffic characteristic of commercially available (MSC/NASTRAN and ABAQUS for example) software. The paper describes various techniques adopted to achieve high system scalability when solving the worldpsilas largest strength of materials problem related to aircraft maintenance and design. Support from major software vendors (SGI, IBM), MSRCpsilas support specialists as well as I/O specialists at the University of Tennessee (as a part of the PET-program) have strongly contributed to the successful results demonstrated. The technological capability developed is demonstrated by analyzing an idealized C-130 center wing box.