On Dynamic Non-Linear Finite Element Analysis of Bullet and Barrel Interface Kevin Russell, Ph.D. Small Caliber Weapon Systems Team

Agenda:  Objective  Description of System  Model and Modeling Process  Example Problem  Current and Future Work

Objective: Build realistic virtual bullet/barrel models to:  accurately calculate the dynamic performance of bullet and barrel  calculate the effects of model variations on interior and exterior ballistics

Bullet and Barrel Description: Source: Military Small Arms, Allsop, Popelinsky, 1997

ANSYS/LS-DYNA Model M249 Model Includes:  Elastic Barrel Properties  Elastic and Plastic Bullet Properties  Pressure-Time Curves in System  Friction, Clearances and Interferences

Modeling Process  Build Solid Models  Mesh Solid Models  Material Properties/Loads  Simulate the Model Firing a Single Shot

Example Problem Given the following:  Pro/E Models of Bullet and Barrel Components  Material Props and P-T Curve Data build virtual models that match M856 dynamic characteristics

ANSYS/LS-DYNA Model

ANSYS/LS-DYNA Model

M249 Model Single Shot Animations

M249 Single Shot Animations

M249 Single Shot Animations

M249 Single Shot Animations

M249 Single Shot Animations

Interior Ballistics Results Comparison

M249 Model Results Comparison (M856) max diff: 4.45% (muzzle)

M249 Model Results Comparison (M856) max diff: 4.05% (muzzle)

M249 Model Results Comparison (M856) max diff: 5.45% (muzzle)

Bullet Parameter Variation (M856)

Exterior Ballistics Results Comparison

M249 Model Results Comparison (M856) range diff: 1.71% max height diff: 4% launch angle 1

M249 Model Results Comparison (M856) max drift diff: 5.89% launch angle 1

M249 Model Results Comparison (M856) max vel. diff: 1.11% launch angle 1

M249 Model Results Comparison (M856) max spin diff: 6.91% launch angle 1

Current and Future Efforts  Thermal Effects  Worn Barrels  Dispersion

Conclusions Build realistic virtual bullet/barrel models to:  accurately calculate the dynamic performance of bullet and barrel  calculate the effects of model variations on interior and exterior ballistics