Careful examination of previous efforts to clamp or otherwise attach tissues to fixtures for mechanical measurements should be done.
Model development should proceed with consideration for the likely integration of WMRD models with those developed by other organizations. Such integration requires a careful documentation of model assumptions, prudent choices of grid geometries, and the provision for data interchange with other models.
The Weapons and Materials Research Directorate conducts activities across a very wide breadth and depth. The fact that even in time of war when heavy demands have been placed on WMRD, the directorate has to respond in the short term to serious problems faced by the warfighter (e.g., up-armoring Humvees) and still has been able to maintain an excellent series of R&D programs to ensure that the warfighter of the future will receive the same benefits. WMRD’s slogan, Technology Driven, Warfighter Focused, suggests a top-down organizing principle buttressed by science and technologies derived from internal efforts as well as from various Materials Centers of Excellence at several universities. The interaction of WMRD staff with the MCoEs has benefited the organization by creating a link between the basic research results coming out of academia and the somewhat more applied needs and programs of ARL. MCoEs have also been the source of a number of summer postdoctoral researchers, some of whom have stayed on as staff members. Many of the presenters in the 2008 review were postdoctoral researchers and young staff members who showed the enthusiasm of youth in their presentations. WMRD is encouraged to continue and even to expand these connections to universities.
The experimental work and the computational materials, modeling, and simulation work being carried out are, in almost all of the activities, of high quality. For example, the work employing DFT to develop various nonlinear optical materials including chromophores for use as eye and sensor protection films is an excellent example of good research that profits from the close interaction between synthetic and computational chemists.
The laudable success of the Affordable Precision Munitions program was due in no small part to its emphasis on multidisciplinary design (MDD). This approach combines capabilities from a number of disciplines that in this case included virtual wind tunnel techniques allowing a wide range of designs to be explored, a novel guidance approach, and special propellants. In this case, MDD has resulted in a highly successful program, and WMRD has employed this technique as a means of accelerating development and reducing risk; it should be considered as a model in the future for use in designing other lethality and survivability systems.
The use of virtual wind tunnels and virtual fly-outs allows a much larger range of designs to be explored at much lower cost in much less time. Significant, and surprising, results have been achieved in terms of nose and body interactions, jet interactions, and diverter interactions that have permitted development to avoid costly pursuit of what would be unusable designs. Documentation of model assumptions and ongoing validation of models and virtual wind tunnel and virtual fly-out codes are essential to maintaining confidence in the program results.
Continual refinement of models and their use by various personnel require that all model assumptions be carefully documented. Systematic and selected validation experiments must be conducted in wind tunnels and on instrumented ranges to ensure that models and the performance testing codes are sufficiently trustworthy to support decisions on final designs.