Projectile penetration into ballistic gelatin.

Area of Science:

• Biomechanics
• Materials Science
• Forensic Science

Background:

• Ballistic gelatin serves as a surrogate for soft biological tissues under impact.
• Understanding projectile penetration dynamics is crucial for forensic and safety applications.

Purpose of the Study:

• To investigate the penetration mechanics of spherical projectiles in ballistic gelatin.
• To develop and validate predictive models for gelatin's response to impact.

Main Methods:

• Testing penetration depth of steel spheres (7-11mm) in various gelatin formulations at velocities below 120m/s.
• Analyzing the relationship between penetration depth, projectile velocity, diameter, and gelatin properties.
• Comparing experimental data with existing predictive models and proposing a modified Froude number relationship.

Main Results:

• Penetration depth showed a linear relationship with impact velocity above a critical threshold.
• Normalized penetration depth (by projectile diameter) condensed data for different sphere sizes onto a single curve.
• A refined predictive model incorporating projectile diameter, threshold velocity, and estimated shear modulus was developed.
• Normalized penetration data best fit a modified elastic Froude number with a slope of 1/2.

Conclusions:

• The study provides a robust model for predicting ballistic gelatin penetration.
• The findings offer improved understanding of soft tissue response to projectile impact.
• The modified elastic Froude number offers a more accurate predictive tool within the tested parameters.