Southwest Research Institute 2000 Annual Report, Engineering Dynamics

SwRI engineers and scientists use experiments and large-scale numerical simulations to study the dynamic response of materials and structures that are subjected to extreme loads and harsh environments. Expertise is applied to military and civilian needs for such things as body armor, foreign object damage, and vulnerability studies. Tools and capabilities developed for defense applications are also applied to the civilian sector for safety assessments, impact studies, and high-performance computing.

Future U.S. combat vehicles are expected to be much lighter and more agile compared to today's heavily armored vehicles. To maintain the same survivability on the battlefield, the armor of these lighter-weight tanks must engage any incoming projectiles before they reach the vehicle. This is the concept behind the Active Protection system, which combines active armor elements with sensors to detect, engage, and intercept incoming threats. SwRI is in the first year of a multi-year effort, funded by the U.S. Army Tank-Automotive Research, Development, and Engineering Center, to understand the lethality of debris resulting from engagement of the vehicle with large-caliber anti-tank projectiles. Using advanced large-scale hydrocodes, analytical modeling techniques, and ballistic experimentation, Institute engineers can characterize the debris field and evaluate the threat.

The Institute has completed a three-year research effort, funded by the Defense Advanced Research Projects Agency (DARPA) and managed by the U.S. Army Soldier and Biological Chemical Command, Natick Soldier Center, to develop concepts for an ultra-lightweight body armor capable of defeating a rifle-fired, 7.62-mm, armor-piercing (APM2) bullet. Three novel concepts were developed, and their feasibility was demonstrated experimentally and computationally. For a new DARPA effort, a SwRI team will fabricate, test, and deliver ultra-lightweight body armor inserts that can defeat an APM2 bullet at muzzle velocity.

Under funding from the Air Force Research Laboratory, SwRI is using an advanced ruby laser holographic camera system developed by MetroLaser Inc. to provide three-dimensional images of debris generated behind a variety of targets. The camera system can "freeze" the motion of solid particles, liquid droplets, and powdery materials. SwRI engineers will enhance existing software to identify and measure the particles shown in the holographic images. Visualization schemes will allow the information to be displayed interactively.

The compressed gas guns at the SwRI Ballistics and Explosives Range saw continued activity this year in aircraft and industrial shield testing, as well as in Federal Aviation Administration (FAA) bird-strike testing. The Large Compressed Gas Gun Facility was upgraded with a larger 9.8-inch-diameter barrel and a mobile base. The new barrel allowed testing of a turbine engine blast shield in which pieces of engine turbines and compressors were launched at different shield types. Separate programs were carried out in support of bird-strike survivability testing for aircraft components. One program involved FAA certification of a wing section to be used on a future production aircraft. The second program involved testing a horizontal stabilizer using a new technique for manufacturing large composite parts.



Computational fluid dynamics simulations are used to design large-scale experiments. In this example, explosive detonation in a room attached to a hallway is simulated to demonstrate the ability of a new diffuser section, placed at the exit of the hallway, to dissipate the blast wave and thereby allow filters to collect dispersed particles without altering the flow field in the hallway. Isosurfaces of velocity are displayed at four instants of time in this dynamic simulation. This new diffuser was then used in physical experiments.

The Institute continues to develop methods to enhance efficiency and use of computer simulation software that will run on clusters of workstations connected by either local area networks or wide area networks. For the NASA meta-computing project, SwRI staff developed PAL (Parallel Applications Library), which provides code developers a verified set of subroutines that simplify the development of parallel algorithms.

For the National Science Foundation, SwRI engineers are performing detailed studies of the characteristics of message passing methods over wide area networks. Different message sizes are continuously transmitted between computers at SwRI and the Instituto Tecnol-gico y de Estudios Superiores de Monterrey, Mexico, with simulations lasting from one hour to 72 hours. This study will help ensure computational efficiency over many hours or days using geographically dispersed computer resources.

Copyright© 2001 by Southwest Research Institute. All rights reserved under U.S. Copyright Law and International Conventions. No part of this publication may be reproduced in any form or by any means, electronic or mechanical, including photocopying, without permission in writing from the publisher. All inquiries should be addressed to Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, phone (210) 522-2257, fax (210) 522-3547.