2017-2018 Assessment of the Army Research Laboratory (2019) / Chapter Skim
Currently Skimming:
3 Sciences for Lethality and Protection
3 Sciences for Lethality and Protection
Pages 56-84
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 56... ...
ARL's research in the area of sciences for lethality and protection during the 2017-2018 reviews included basic research that improves our fundamental understanding of the scientific phenomena and technological advances in battlefield injury mechanisms in human response to threats, human protective equipment, directed energy programs, programs that address weapon-target interactions and armor and adaptive protection developments, disruptive energetics and propulsion technologies, effects on targets including ballistics and blast, and flight guidance, navigation, and control each focused on innovations designed to benefit the warfighter. ARL's breadth of Sciences for Lethality and Protection Campaign work is performed within the Weapons and Materials Research Directorate (WMRD)
|
From page 57... ...
Accomplishments and Advancements ARL is defining battlefield injury mechanisms in materials science and engineering terms, differentiating itself from the medical community, and thus providing unique input to injury modeling/simulation and armor requirements for injury prevention and assessment. Contributions from researchers and management have significantly increased the focus and coordination of this highly multidisciplinary team.
|
From page 58... ...
A baseline model has been created that can be used to evaluate human data. Clearly, this fits into ARL core mission priorities to provide the resources and staff to improve protective equipment standards for soldiers and discover baseline data of actual forces that cause injury to the brain.
|
From page 59... ...
Potential outcomes include a definition of cellular damage thresholds relevant to Army-specific hazards. A clearly defined threshold for TBI that could be used to guide the design and development of test protocols for personal protection equipment would be a transformative accomplishment for future prevention of behind-helmet blunt trauma injuries.
|
From page 60... ...
The investigation of lower leg blast injuries was undertaken through the design and development of methods to measure the impulse on lower leg simulants to provide baseline data that could be used in the design of boot protection. Clearly, this fits into ARL core mission priorities to provide the resources and staff to improve protective equipment standards for soldiers.
|
From page 61... ...
Finally, ARL's battlefield injury mechanisms programs have reached the level of maturity where timelines, well-defined goals, and a well-defined overall program roadmap are critical to guide future work. Modeling Modeling the porcine response to mechanical loading is very challenging, and its satisfactory solution requires expertise in the areas of constitutive modeling, estimating values of material parameters from test data (assuming that it is available under test conditions likely to prevail in the impact event)
|
From page 62... ...
ARL is at the cusp of establishing a transformative research program coupling engineers, microbiologists, and physicists advancing experimental methods and computational models for the future prevention of behind-helmet blunt trauma injuries. ARL's program would benefit from a larger strategic effort with transparent and clearly articulated goals that closely couple the Army medical researchers, the ARL research team, and other external researchers (e.g.,
|
From page 63... ...
Some brief mentions were provided of external collaborations, but presented information remained largely focused on the local ARL researchers, resulting in an assessment that potential programmatic reward will be limited in scope. Characterizing the constitutive behavior of the skull subjected to ballistic loading conditions is a crucial step in the development of predictive models for blunt trauma.
|
From page 64... ...
technique to improve laser propagation through atmospheric mediums using high-peak-power, ultrashort laser pulses to "burn" their way through the air and obscurants to create quasi-steady-state waveguides called filaments. Further, ARL presented two additional projects that encountered materials properties challenges that the PIs were aware of, and they are encouraged to be persistent in pursuing solutions.
|
From page 65... ...
While most of these improvements directly apply to the laser-DE program, the overall quality of work is good and on an upward trend, with examples of exceptional work. The overall scientific quality of the research is comparable to that at leading national and international institutions, with several projects demonstrating impressive quality and uniqueness with realistic potential for high payoffs, such as diode clad pumped broadband Raman fiber lasers working to achieve potential power scaling in the ballpark of 80-100 kW from a single fiber aperture, and nonlinear optical materials and coatings that are frequency agile in the visible spectrum to passively protect army optical sensors from DE laser threats such as that from straight damage, jamming, dazzling, and so on.
|
From page 66... ...
ARL researchers have taken high-performance computing (HPC) to a whole new level -- an impressive display of using computational sensitivity analysis of a very, very large problem with multiple length scales.
|
From page 67... ...
This, then, is a significant challenge faced by ARL researchers. A balanced technical effort of HPC combined with well-planned experiments with appropriate diagnostics could provide insights and guidance for progress while a longer-term research effort addresses the fundamental unknowns.
|
From page 68... ...
Already lessons have been learned about shielding and X-ray film requirements for quantitative assessments. Penetration Mechanics and Adaptive Protection Adaptive protection is a subcategory of the Sciences for Lethality and Protection Campaign, with the objective of developing mass-efficient, novel threat defeat mechanisms.
|
From page 69... ...
ARL management is encouraged to investigate what can be done to allocate dedicated ranges to some of its important efforts in the penetration, armor, and adaptive protection program areas. There is a start of work in the UQ area of research, but there is a long way to go.
|
From page 70... ...
Penetration Mechanics and Adaptive Protection Adaptive protection is a subcategory of the Sciences for Lethality and Protection Campaign, with the objective of developing mass-efficient, novel threat defeat mechanisms. The challenge is real-time threat sensing and identification (while minimizing false positives)
|
From page 71... ...
DISRUPTIVE ENERGETICS AND PROPULSION TECHNOLOGIES The focus of research in the disruptive energetics and propulsion technologies area is the exploration and development of new and novel energetic materials that can potentially revolutionize munitions and propulsion systems by enhancing energy release and lethality greater than that provided by traditional energetic materials. The review of the disruptive energetic material and propulsion technology covered the areas of new material synthesis, small-scale energetic material characterization using laser flyers and rapid heating diagnostics, experimental studies of structural bond energy release nanomaterials, quantum to force field molecular modeling, multiscale coarse-grain modeling of energetic composites, and multiphase rocket and gun propellant modeling.
|
From page 72... ...
Currently, little is known about the energy flow processes occurring at the molecular level that lead to the dynamic response of energetic materials. A more fundamental understanding of reactive behavior requires measuring electronic excitations occurring at femtosecond time scales and the coupling
|
From page 73... ...
Feasibility of the SBER mechanism has yet to be proved as a viable energetic material concept. A series of flyer impact experiments using targets of nanodiamonds and composites was conducted by the ARL staff using the dynamic compression sector at the Advanced Photon Source (APS)
|
From page 74... ...
Although the challenge of producing sufficient quantities of new energetic materials appears to be on a well-defined path, it is the rate of synthesis that remains an open question. For example, BODN can be synthesized at ARL in kilogram quantities within 3 weeks from the first step of the synthesis.
|
From page 75... ...
Nonetheless, comparative response using the ultrafast heating and diagnostics may be a viable means to assess the reactive behavior of new energetic molecules. In future studies of structural bond energy release, experiments using the ARL ultrafast laser shock facility may achieve conditions needed to generate the high-temperature plasma conditions that are currently viewed as necessary requirements to trigger SBER.
|
From page 76... ...
The connection of the modeling to the experimental efforts is essential for providing relevant data for validation. In the modeling and simulation of multiphase reactive flow for rockets and gun propellants, an improvement in chemistry prediction may require incorporating condensed phase reactions and phase changes of the initial solid with the added influences of microstructure of individual grains to position this work to known mission challenges of nonoptimal performance in accident scenarios associated with abnormal mechanical and thermal stimuli.
|
From page 77... ...
Improved modern imaging diagnostics could create a new way of imaging the responses at suitable temporal scales and could expand the field of view for optical observations. Computational modeling of energetic materials has traditionally been a leading effort at ARL.
|
From page 78... ...
The connection of the modeling to the experimental efforts is essential in providing relevant data for validation. A continued theme in modeling is the need to implement a V&V strategy and quantify the uncertainties to ensure that the relevant physics is being addressed for energetic materials.
|
From page 79... ...
The unique diagnostic capabilities being applied at ARL position this group to lead the scientific community in the development of advanced computational and validation methodologies in the design of more efficient and effective materials and structures. The multiscale efforts of the fracture modeling and the energetic materials modeling present a potential for synergies with and broad impact on the external community.
|
From page 80... ...
The presentations focused on solutions directed toward increased maneuverability, but little work was presented on extended range. The flight guidance, navigation, and control presentations were exemplary of a high-quality program that could benefit from attention in the following areas: end-to-end modeling of operational cases to better characterize parametric goals, additional model validation (e.g., using simulation or experiment)
|
From page 81... ...
OVERALL QUALITY OF THE WORK In the battlefield injury mechanisms area, the integration of experiment and modeling is well done, although the level of modeling sophistication does not seem to match that of other ARL research groups. The group is at an early stage of defining key mechanical impact limits of injury, and this has been correctly identified as a critical end point for the group.
|
From page 82... ...
The sensitivity analyses have resulted in identification of unknowns and issues, quantification of design variations, and establishing where basic information is required for higher fidelity simulations. The disruptive energetics and propulsion technologies effort at ARL is staffed by exceptional researchers who are working to provide advancements in energetic material science.
|
From page 83... ...
CONCLUSIONS AND RECOMMENDATIONS ARL's research on sciences for lethality and protection ranges from basic research that improves its basic understanding of scientific phenomena to the generation of technology that supports battlefield injury mechanisms, human response to threats, and human protective equipment; directed energy programs; and penetration, armor, and adaptive protection developments. The ARL basic research management team needs to acknowledge that true knowledge research has to be allowed to fail often.
|
From page 84... ...
To accelerate integration and given the complex ity of its objectives, ARL scientists and engineers should leverage software and methodologies developed at other Department of Energy and Department of Defense laboratories. In the disruptive energetics and propulsion technologies area, acquisition of state-of-the-art instrumentation is the biggest challenge in advancing diagnostics to characterize energetic materials.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.