In FY 2016 SERDP initiated three SERDP Exploratory Development (SEED) projects in the Munitions Response program area related to penetration modeling of munitions in various soils. In many cases the remedy chosen in munitions response will involve subsurface removal of munitions. Modern geophysical surveying techniques can be used to characterize these sites. However, the most commonly-used electromagnetic induction sensors have a limited depth of detection that is well understood. Less well understood is the likely depth at which munitions will be found. Site managers and regulators require evidence that any munitions present are within the detection depth of the geophysical sensor in order to have confidence that the munitions of concern are detected and removed. Alternatively, this information can inform risk management decisions if the munitions are likely to reside at depths beyond the sensor’s detection capability.
Meshfree Modeling of Munitions Penetration in Soils (MR-2628) is being led by Profs. Sheng-Wei Chi and Craig Foster of the University of Illinois at Chicago. This project has developed a meshfree framework based on the Reproducing Kernel Particle Method for handling extremely large deformation caused by munitions impact. To accurately represent the behavior of the soil, a novel viscoplasticity model was developed. Initial results have focused on simulations with varying impact angles.
Munition Penetration Depth Prediction (MR-2629), a project led by Dr. Jay Clausen of the U.S. Army Engineer Research and Development Center (ERDC), is also largely analytical/computational in nature but utilizes results of unique grain-scale experimental results that have been generated by the ERDC in recent years. The initial model efforts were focused on the grain properties of the well-studied Eglin Air Force Base (AFB) sand, which has been used in both contact experiments and projectile penetration testing.
The third project in this group, Physics-Based Prediction of Unexploded Ordnance Penetration into Granular Materials (MR-2630), is being led by Dr. Jae Chung of the University of Florida. This project is based on the use of combined use of the finite element method (for discretization of UXO) and extended discrete element method (for discretization of idealized granular soil masses). Prototype scaled munitions were subjected to centrifuge testing with a number of substrates to provide data to validate the models.
All three of these projects presented their first-year’s results at the Spring MR In-progress Review. They are currently preparing follow-on proposals to continue their work. I’ll update the results as these project proceed.