Research On Force-magnetic Effect Of Ferromagnetic Material Under Impact Load

With the increasing demand to combat deep underground targets,the weapons of hard targets at home and abroad is developing extremely rapidly.How to provide accurate explosion onset signal and improve the damage efficiency of weapons and equipment has become the essential element.Accordingly,the process information identification technology is an important means to solve this problem.The higher the penetration speed and the greater the aspect ratio,the worse the structural response signal and penetration signal adhesion of the tile,resulting in the failure to obtain an accurate number of penetration layers.For the layer number identification problem of invading multi-layer hard targets,according to the phenomenon that the leakage magnetic field would be caused under the action of the impact resistance of the penetration process,the force-magnetic relationship of ferromagnetic materials under impact load is studied.The main work is as follows:Firstly,the positive correlation of the force-magnetic relationship under shock load is clarified by theoretical analysis,and used the finite element analysis software LS-DYNA and COMSOL to establish the model of tile penetration concrete target plate,made the layer simulation calculation,combined with the force magnetic coupling analysis obtaining the strength of the magnetic field generated by the shell when penetrating the layer and the change curve of the force-magnetic relationship.Secondly,the shock simulation test platform is set up.The force situation during penetrating the target plate is simulated by applying a dynamic load through the Hopkinson rod and the drop hammer.Analysis of test data showed that the relationship between force and magnetic of ferromagnetic materials under impact load is positively correlated;Though the comparison of the results of simulation and simulation test,the change trend of magnetic signal is basically keep the same,the change of stress can affect the change of the magnetic signal,which could also change with the stress.Finally,the real cannonball penetration test is carried on.And we also study the forcemagnetic relationship and the changing law of magnetic signal in the practical application environment.According to the test results,we can conclude that,Ferromagnetic materials can produce a force-magnetic effect under impact load,to change the magnetic signal on the surface of the ferromagnetic specimen,it is consistent of the change interval of the magnetic signal and the acceleration signal,and with the increase of the impact load,the change amount of the magnetic signal will also increase;it shows that the magnetic signal is worth studying as a penetration layer signal.