Development And Research Of Openable Coil For Tube Parts Based On Magnetic Pulse Crimping

Vehicle light-weighting serves national carbon peaking and carbon neutrality goals.The application of lightweight materials has become one of the important ways to realize the lightweight of automobiles.The application of multi-material directly brings about the joining problem of dissimilar materials.As a high-speed joining technology,magnetic pulse joining technology can realize reliable joining between dissimilar materials.Most of the existing magnetic pulse crimping devices for pipe fittings are closed-loop structures.When used to connect workpieces with structures such as closed frames,long straight parts,and enlarged end parts of pipe fittings,due to the particularity of the structure,it is difficult to remove the workpiece after the joining is completed.To solve this problem,it is necessary to develop a detachable device to use the magnetic pulse joining technology for the joining of such structures.In this paper,the development and research of the separate magnetic pulse joining coil are carried out from the aspects of structural design,numerical simulation,experimental verification,etc.The specific research contents are as follows:(1)The equivalent circuit model of the magnetic pulse joining system was built based on ANSYS EM Suite.An openable coil configuration was proposed,and its electromagnetic parameters such as current density and magnetic field strength were analyzed,and its structure was optimized to obtain a reasonable openable coil structure.Based on the constructed magnetic pulse joining equivalent circuit,the output current curves of different configuration coils were obtained,which provided input conditions for the electromagneticstructure coupling field numerical simulation model.(2)The LS-DYNA numerical simulation software was used,the numerical simulation model of the electromagnetic field-structural field of the configuration Ⅱ coil was built.The stress-strain and displacement distribution of the coil under the design energy were analyzed,and the structure and material strength were verified to meet the requirements;the electromagnetic field and structural field of the deformed part were analyzed under the energy of 25 k J.The result shows that the electromagnetic force distribution of the axial element of the deformed part in the working area of the coil has a certain inhomogeneous phenomenon.There was magnetic flux leakage at the joints in the circumferential direction;the deformation speed and displacement of the deformed parts can meet the needs of magnetic pulse welding.(3)According to the numerical simulation results,an openable magnetic pulse joining coil experimental platform was built.Using a Photonic Doppler Velocimeter,the deformation velocity of AA5052 aluminum alloy pipe fitting was measured.Current curves through the coil at different energies were measured using Rogowski coils to accumulate raw data for coil design.The accuracy of the electromagnetic field-structural field coupling model was verified through the measurement of the actual data and the comparison with the simulated data.(4)Through the craft experiment test,it was proved that the openable coil can realize the welding and crimping process.According to the data of the outer contour size and tensile strength of the joint,a contour-strength prediction model was established by using the method of machine learning;the joining of complex structural parts was realized by using the coil,thus proving the function of the split coil design.