OBJECTIVES

Use 3D finite element analysis to study ballistic effects on S-2Glass/SC15 composite laminates
Use LS-Dyna to simulate results of ballistic testing and study effects of damage mechanisms of perforation and penetration in composites
Analyze the four main penetration phases for each ballistic simulation for above and below the ballistic limit
Estimate the ballistic limit or V50 for 88 layer S-2Glass/SC15 composite block

TERMINOLOGY

P-PHASE: Projectile penetrates through the composite until the back layer velocity is non zero
T-PHASE: Projectile begins to perforate through composite until it stops penetrating through composite
F-PHASE: Projectile continues to perforate through until relative velocity between projectile and laminates is zero
R-PHASE: After maximum dynamic deflection, laminates begin to retract back

LS-PrePost Model / Impact Parameters

88 Layer S2-Glass/SC-15 [02/902]2S Composite
Right circular cylinder (RCC) projectile represents 50 cal. bullet
Boundary Conditions: edges of composite block were unable to move in X,Y, or Z direction in order to have same conditions as Quasi-Static Punch Shear Test

Impact Velocity vs Residual Velocity

Eight simulations were ran with different initial velocities
Graph was made to show relationship between impact and residual velocities

Impact Velocity vs Displacement

Graph was made to show velocity and displacement relationship
Trend shows simulation result
Retracting towards zero displacement means the projectile did not penetrate
Coiling and spiraling means the projectile arrested
Retaining a constant velocity means the projectile penetrated

Deformation Imagining for Below and Above V50

Nodal Displacement and Velocity Graphs

Velocity and displacement data was taken from nodes from bottom center of the projectile and bottom layer
Graphs illustrate common behavior of simulations that do or do not penetrate the composite block

3D Deformation Graphs

Matlab took X and Z coordinate data from the simulations to show deformation as a function of time

CONCLUSIONS

VR/VI curve was interpolated to estimate V50 to be 1390 m/s
Perforation of bottom layer occurs when the projectile speed is greater than 1200 m/s
As simulations approached V50, projectiles would arrest and need more time to stabilize

ACKNOWLEDGEMENTS

This work is supported by the University of Delaware Center for Composite Materials and Dr. Bazle Haque