Introduction

As with nearly all engineering designs, bullets are tested to determine their effectiveness and penetration, while armour is tested for its effectiveness in stopping said penetration.

During their design phases they undergo many changes, which makes the testing and analyses costly. The results of impact simulations using computers are getting better, so it is becoming more and more interesting for the industry’s to use computer analyses to predict the behaviour of materials.

One of these methods is SPH (Smooth particle hydrodynamics). This method uses a particle based meshless material description, allowing for high deformation and fragmentation.

Problem Definition

To develop better armour, ballistic lab testing has to be performed to understand the results of impact. To enhance this process there have been studies made using different types of software to simulate the impact of bullets on steel, Kevlar® and ceramic. Femto engineering has initiated a study using the SPH method to create impact calculations and researching the pro and cons of this method.

Approach

First research had to be done on finding the proper references to outline the study. Input was based on numerical simulations and experiments performed by Dale S. Preece and Vanessa S. Berg.  During these experiments a 338 Winchester Magnum A-frame hunting bullet was used. The first tests were done with the bullet fired at bare steel from a Ruger M70 bolt action rifle. During the second series of tests a Kevlar® plate was placed between the steel and the rifle. The bullet velocity was chronographed during each shot.

Femto performed numerical simulations using the SPH (Smooth Particle Hydrodynamics) method, an element method that uses particles to simulate materials. In comparison to earlier studies done with Altair software, good correlation between numerical results and experiment could be made.

Conclusion

The use of SPH is a good step forward in assisting the process of predicting material behaviour. Further research and validation has to be performed to create more exact simulations.