FEM simulation of bullet sensor
|Title||FEM simulation of bullet sensor|
|Summary||Simulate a magnetic reluctance sensor that detects speeding bullet|
|Keywords||electro magnetism, physics|
https://patents.google.com/patent/US9709593B1/en"https://magnetospeed.com https://patents.google.com/patent/US9709593B1/en" cannot be used as a page name in this wiki.
|Supervisor||Stefan Axelsson, Struan Gray, Pererik Andreasson|
A new entry on the market of ballistic chronographs (i.e. devices that measure the muzzle velocity of bullets) is Magnetospeed. While other, previous, sensors typically measure light occlusion, this chronograph works on the principle of magnetic reluctance (the same type of sensor that measures the rotational speed of the wheels in your car for the ABS system). Here a bullet, of a conducting but non-magnetic material, is shot into a static magnetic field. This field induces a current in the bullet, that in turn induces a magnetic field that is picked up by a coil.
Muzzle velocity is important from a number of aspects, i.e. developing loads that shoot accurately, but also make sure that hunting ammunition fulfill legal energy requirements for particular types of hunting etc.
I have already built such a sensor bar, and they are commercially available, but the geometry, field strengths etc. are not sufficiently well understood from an engineering perspective. An analytical solution is probably complex, but a FEM (Finite Element Modeling) solution is probably within reach. We have the COMSOL software at the school, but there are also free and open multi-physics simulation software available such as ELMER (from CSC in Finland).
So this thesis would develop such a model based on real bullets, speeds etc. and calibrate/compare it with real field measurements (using a .223 and .308 caliber hunting rifle with moderator). Sponsorship and guidance from the hunting/gun shop just across the parking lot from the school has been secured in the form of an experienced former police officer with access to rifles and the local range. (Thus also ensuring the legality and safety of the project).