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

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

3. 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

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

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

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

7. 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

8. ANSYS/LS-DYNA Model

9. ANSYS/LS-DYNA Model

10. M249 Model Single Shot Animations

11. M249 Single Shot Animations

12. M249 Single Shot Animations

13. M249 Single Shot Animations

14. M249 Single Shot Animations

15. Interior Ballistics Results Comparison

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

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

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

19. Bullet Parameter Variation (M856)

20. Exterior Ballistics Results Comparison

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

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

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

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

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

26. 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