Three-Dimensional Numerical Analyses of Earth Penetration Dynamics
Abstract
A new three-dimensional numerical code, TRIFLE, is described which provides, for the first time, a rigorous yet efficient analytical tool to investigate the penetration dynamics of semi-rigid projectiles under asymmetric (non-normal) impact conditions. This is a key development since most real impacts and penetrations involve at least some degree of both yaw and obliquity, and since small degrees of asymmetry can have significant effects on the design environment of earth penetrating systems. In the TRIFLE code formulation, the full three-dimensional equations of motion are solved using a moving polar cylindrical coordinate reference frame aligned with the projectile, a Fourier representation of circumferential variation to couple together several r-z finite-difference planes in the target media, an arbitrary Lagrangian/Eulerian transformation to allow these planes to remain planes, and a momentum exchange procedure to determine forces on the penetrator. The circumferential Fourier representation in TRIFLE provides highest resolution near the penetrator, and hence, TRIFLE is more efficient and practical than a three-dimensional cartesian finite-difference formulation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 1979
- Accession Number
- ADA109678
Entities
People
- F. W. Ross-perry
- R. B. Nelson
- Y. M. Ito