ABERDEEN PROVING GROUND, Md. - Energetic material research is on a short list of scientific investigations that could radically change the way America fights and wins wars.
When - not if - American military scientists pack sufficient energy to defeat a target in a number of threat scenarios into a singular, affordable weapon system soldiers can carry easily, military defense capabilities could shift from an arsenal of weapon systems down to just one unit where soldiers control the desirable amount of firepower needed for a mission.
The Army Research Laboratory is about 10 years away from fully enabling a novel approach to modeling high-energy explosives.
Research scientists at its Aberdeen Proving Ground location have been immersed in researching multi-scale modeling of the properties and behavior of energetic materials.
A team of researchers there use computational chemistry and physics to efficiently and inexpensively screen candidates with a goal to eliminate poor performers before resources are expended.
In exploring dynamic response of the material they also use various computational methodologies that identify the fundamental mechanisms that control the conversion of the energetic material to its final products.
ARL’s ultimate goal in this research area is to exploit this information and efficiently design an energetic material that can behave in a specified fashion at exactly the right time that’s of most benefit to the soldier.
"We’d like to give the warfighter more capability. That not only means defeating harder targets, but also dialing down overwhelming power that prevents some missions from being possible when finesse is needed. Right now, the warfighter has to carry many types of munitions when they are on a mission; by controlling firepower, we can reduce the logistics burden on the mission and also in getting resources to the fight. It’s a win-win all the way from production to the battle and all the way to demil," said Dr. Patrick Baker, director of ARL's Weapons and Materials Research Directorate at Aberdeen Proving Ground, Md.
Energetic materials research is in high demand because of the unique properties: shock waves producing pressure up to 500,000 times that of Earth's atmosphere; detonation waves traveling at 10 kilometers per second; temperatures soaring to 5,500 kelvin; and power approaching 20 billion watts per square centimeter.
These materials can be found in demolition charges, missile deployment applications, starter cartridges, gas generators, and even airbags. Studying it covers a spectrum of basic molecular chemistry, detonation physics, combustion processes, pyrotechnic mapping, material science, lethality effects, process chemistry and engineering, and manufacturing technology.
Explained another way, when an energetic material in a warhead detonates, or is burned to propel a rocket or bullet, a lot of energy is given off quickly and under extreme conditions. Thus, it’s difficult to know exactly what occurred because of the violence of the event.
ARL’s researchers are looking to identify why an energetic material in a munition works the way it works; why it is explosive. To do that, they’re modeling at scales well below the realm of the observable and focusing on the atomic scale to directly witness the controlling chemistry at initiation and subsequent energy release.
"ARL is committed to establishing a science-based multi-scale modeling capability that will capture the atomic-level details of the chemistry and physics of initiation and reaction propagation of an EM, and that will accurately represent the subsequent evolution and transfer of the released energy up through the higher scales, producing an accurate depiction of the macroscale response," said Dr. Betsy Rice, a theoretical chemist and an ARL Fellow.
"Establishing such a multi-scale predictive capability requires more than simply collecting software or applying current modeling schemes at the various scales ranging from the atomistic up through the macroscopic. Instead, ARL has made the required investments in the development of models and simulations within the relevant spatial/temporal scales, and the development of methods and algorithms that will bridge the scales such that information generated at one scale can be used at another scale without the loss of fidelity," she said.
ARL has supported the appropriate experimental and theoretical verification and validation that "must be done for the emerging methods, models and simulations. ARL is committed to, as much as possible, ensure that all models have a quantum mechanical basis, which is a fairly unique and rigorous requirement not often embraced within the materials modeling community," said Rice.
She said developing new energetic material is a complicated process because of the difficult chemistry.
"The hazard of working with these materials, and the stringent safety and performance requirements imposed by the end user, the traditional procedure for formulating new energetic materials, being guided largely by intuition, experience, and testing, relies heavily on trial and error," Rice said.
"Sometimes the synthesis is extremely difficult and is not a one-pot process, but rather involves several intermediate steps, all of which are extremely complicated and sometimes dangerous.
"An example of this is octanitrocubane, once hypothesized to be a 'super-explosive.' Twenty years of research was involved in developing milligram quantities of this material, only to find out that it was not a good performer. This was an extreme example of a difficult synthesis. Once a candidate energetic material is made, it is then put into a formulation that has other non-energetic ingredients, such as binders and plasticizers – the fills in weapons are typically not pure explosive ingredients. Therefore, once a pure material is made, its compatibility with other ingredients in a formulation must be determined (and failure can often occur at this point). The formulations are subsequently subjected to a sequence of tests resulting in the discarding of many from further consideration due to unacceptable levels of performance or other problems that arise in the validation procedure," Rice said.
An illustration of the time needed to develop a new propellant can be seen in the case of M43, a high-performance tank-gun propellant. M43 was under development for almost 20 years before being type classified shortly before Operation Desert Storm.
ARL’s EM Research History
In 2008, The Army Research Laboratory, along with its partner the Army Armament Research, Development and Engineering Center, was chosen to lead a High Performance Computing Modernization Program effort to develop a science-based capability to simulate munition response to insults. The $3 million per year, six-year project has focused on developing and implementing software to enable this capability, but capability gaps in theories and methods required additional research in ARL to develop novel new methods and models, and advanced experimentation to validate and examine those models.
ARL created unique tools to predict indicators of performance enhancement and vulnerability to impact.
The bulk of its basic research in this area is conducted at the ARL Defense Supercomputing Resource Center, where researchers design simulations of the structure of homogeneous and metalized propellants, energetic crystals and simulated microstructures to predict realistic 3-D burning properties.
Future Implications of the Technology
In the near future, soldiers would have a single explosive doing the job several small arms and platform launched rockets are currently fulfilling. One round could replace many rounds.
| Date Taken: | 10.24.2013 |
| Date Posted: | 10.24.2013 16:24 |
| Story ID: | 115683 |
| Location: | ABERDEEN PROVING GROUND, MARYLAND, US |
| Web Views: | 59 |
| Downloads: | 0 |
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