Thesis
Two dimensional mesoscale simulations of projectile instability during penetration of dry sand
Washington State University
Master of Science (MS), Washington State University
2007
Handle:
https://hdl.handle.net/2376/102742
Abstract
Projectiles penetrating geologic media can experience instabilities characterized by divergence from their initial path and projectile bending. To gain insight into the effects of geologic features on projectile instability, a set of 2D non-continuum (mesoscale) simulations which account for the granular nature of sand was completed. The physical features of dry sand were accounted for by explicitly modeling and tracking each grain of sand in the target created using the program ISP-SAND. Penetration simulations were performed using the Lagrangian multi-body finite element code ISPTROTP. Projectile instability was examined using projectile rotational momentum, unbalanced off-axis forces, and projectile deviation from path. Specific variables of interest were penetration velocity, grain size, grain distribution, target porosity, intergranular friction, material properties, and sand grain randomness. Results show that the granular system can produce unbalanced radial forces which cause a projectile to become unstable. In all cases where penetration velocity was considered, projectiles became increasingly unstable as penetration velocities increased from 0.5 km/s to 1.5 km/s. For the cases considered, the effect of different target properties on projectile instability have been quantified with reference to a set of baseline simulations. Throughout the simulations, which consider an elastic penetrator, an oscillation is seen with a uniform length scale that correlates with the lowest projectile bending mode.
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Details
- Title
- Two dimensional mesoscale simulations of projectile instability during penetration of dry sand
- Creators
- Russell Daniel Teeter
- Contributors
- Y. M. Gupta (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525183801842
- Language
- English
- Resource Type
- Thesis