Expanding Excalibur's Accessibility for Ground Shock & Seismology
Harvey, Allen (Applied Research Associates, Inc.)
Computational Structure Mechanics
Applied Research Associates, Inc. (ARA), in support of the Defense Threat Reduction Agency (DTRA), develops and maintains the structural mechanics software, Excalibur, used to simulate ground shock due to conventional and nuclear weapon detonations above or embedded into the ground and water. Historically, the execution of Excalibur required many error-prone steps with little feedback to the user, and ARA has made significant advances in its accessibility and useability. The execution of Excalibur simulations has been streamlined to use one text input file and a few Python scripts to control the setup, run, or post-processing phases. It has been installed on several of the DSRCs at various classification levels, where the scripts provided with Excalibur will automatically load the appropriate modules and handle job submission duties for the user. Recently, Excalibur has added support for cell-erosion and transmitting boundary conditions, and Cubit journals have been developed to allow for the rapid creation of meshes appropriate for a wide variety of tunnel emplacements and running simulations into far-field seismic regimes. In addition to useability enhancements, ARA has also developed enhanced, universal rock models based on the geomechanical properties of tuff, granite, basalt, ultramafic, sandstone, schist, gneiss, and limestone for use with effective stress models. Work is currently underway to develop new models for marble and shale. Geomechanical properties for each rock type are based on a wide ranging data set spanning weak to intact rock and low to high intact porosity values. These models and others (such as soils, clay, water, etc.) can be defined within and imported from DTRA's WinGS software. Excalibur is now distributed with a script for use with ParaView to automatically calculate DTRA defined damage metrics to predict severe damage in tunnels from 3D ground shock simulations. Interested users of Excalibur can obtain beginner and intermediate level classroom training from DTRA that spans how to setup a simulation, create meshes, create terrain model, define rock models, run simulations, and visualize and analyze results.