High-fidelity simulation tools are used as an acceptable surrogate for real-world tests. These tools accelerate development and reduce cost, while informing weapons development and systems survivability for defense and homeland security applications. As weapons grew in complexity, analytical methods became insufficient and high-fidelity computational methods became necessary.

A DYSMAS computer simulation graphs the extent of a blast crater from a replicated IED.
In the late 1980s, undersea weapons researchers recognized the potential of modeling and simulation to aid in weapon design. The goal was to computationally assess new concepts in order to greatly reduce the amount of physical testing needed to field a weapon, thereby saving time, money, and personnel.

Emerging computing power made this possible, but weapons effects software was needed. The U.S. Navy evaluated available commercial and government software capabilities. The Dynamic System Mechanics Advanced Simulation (DYSMAS) software, developed in Germany, took an innovative approach to predicting underwater explosion effects and the response of naval targets. In 1993, Germany provided the software to the United States for evaluation.

Initial evaluation led to three international project agreements focused on jointly enhancing and validating the software. All of the original software modules have been upgraded or replaced, resulting in a fast, modern software package that harnesses the power of the Department of Defense’s largest supercomputers. The U.S.-German collaboration has focused on validating the software against real-world tests. Consequently, DYSMAS is now the most extensively validated full-physics software for predicting underwater explosions and their effects on marine structures.

The capabilities of DYSMAS for predicting weapons effects are not limited to naval applications. DYSMAS enjoys a wide user base spanning multiple government agencies, and it is solving real-world problems affecting sea war, land war, and homeland security.

The punishing effects of improvised explosive devices (IEDs) used against U.S. forces in Iraq and Afghanistan are well documented. Mitigating the IED threat was critical, but the IED signature in Afghanistan differed from that encountered in Iraq. Those in Afghanistan typically use fertilizer-based “homemade” explosives (HMEs). Researchers at Indian Head performed tests to quantify HME explosion output, and provided the data required to develop a computational model of the HME. Once developed, the HME model was validated by both Indian Head and Army researchers for use in DYSMAS and other software packages.

Despite an in-depth understanding of IEDs, efforts to detect IEDs before detonation, and the development of under-body kits and blast-mitigating seats, IED blasts continue to be a major source of casualties today. Better solutions are needed, and modeling and simulation continues to play an important role in the development and assessment process.

DYSMAS is being enhanced to do a better job of modeling soils and the loading that a buried blast transmits to a vehicle and its occupants — a difficult and complex problem given the wide range of soils and emplacement conditions that must be considered. DYSMAS also has been used to assess minerollers for Marine Corps vehicles and, recently, to study blast-induced traumatic brain injury. The goal is to understand the biomechanical response of the brain, enabling the development of protective technologies.

Dams are designated as critical infrastructure in the United States. They are important national assets that provide water, power, and floodcontrol to many Americans, but dams also hold back tremendous amounts of potential energy that, if released, can have devastating consequences. DYSMAS is used to study cratering of earthen dams and blast effects against arch dams and spillway gates.

DYSMAS has been used to assess other critical infrastructure, including that found in and around harbors and other waterways. Many pipelines, carrying energy supplies such as oil and gas, transit harbors and waterways on the sea floor. A major problem for explosive ordnance disposal (EOD) operations lies in assessing the risk to such assets when threats are found. DYSMAS has supported the EOD mission by analyzing the hazards to pipelines and enabling the development of safe standoff guidance for EOD operations. In related studies, DYSMAS has been used to assess the vulnerability of bridges and dry docks to explosions.

This work was done by John Hendershot and Robert Kaczmarek of the Naval Surface Warfare Center. NRL-0063

Aerospace & Defense Technology Magazine

This article first appeared in the February, 2015 issue of Aerospace & Defense Technology Magazine.

Read more articles from this issue here.

Read more articles from the archives here.