Introduction

At Femto Engineering we enable innovation; With the TU Delft nearby, we’re in the perfect spot to collaborate in pioneering research projects. Over the last five years Femto has gained experience in Smooth Particle Hydrodynamics (SPH). SPH is a numerical method which uses particles instead of elements to model the behavior of materials. While FEM uses a fixed element structure, SPH particles are floating entities.

Approach

As an experiment Femto created a simulation of a fully coupled solution of FEM and SPH to create an aquaplaning simulation. For this model a pool of rain was simulated through SPH. The properties of water were assigned to each of the particles, creating a material that spurts and flows like water.

During the simulation one wheel of a truck is driving through a digital yet realistic pool. To ensure that the amount of air in the inflatable inner tire remains the same, the volume and pressure of this part are continuously calculated and adjusted.The combination of moving finite elements and smooth particles in this simulation is challenging. Elements have to recognize particles and vice versa in order for them not to move through each other. The smaller the distance between a particle and an element, the larger the force pushing them apart.

In the video below the wheel first rolls through the pool as it is supposed to, but then loses contact with the subsoil and starts spinning backwards. What happened? The space underneath the wheel got overcrowded after the rolling movement dragged particles under. These particles generate a significant uplifting force causing the wheel to lose contact with the road.

Conclusion

Simulations using SPH have great potential in the automotive industry. The physical testing of tyres with varying load cases, subsoils and profiles can be shortened by using computer simulations first, resulting in reduced costs and a shorter time-to-market. Interested in what Femto Engineering could do for you? Get in touch!

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