Development Of New Handheld Electromagnetic Riveter

Electromagnetic riveting(EMR) is a new kind of technology that is developed from traditional riveting technologies on the basis of electromagnetic forming. The electromagnetic riveter is the applicable equipment in the electromagnetic riveting process. At present, electromagnetic riveters abroad have already been widely applied in the aerospace field; but electromagnetic riveters at home have been in the stage of exploration in project application. Moreover, the design theory of electromagnetic riveter is still imperfect. and there are other problems such as insufficient riveting force, big recoil and heavy electromagnetic riveter unconveniently used.The characteristic and principles of the EMR and the development of EMR at home and abroad was introduced in the first part of the paper Meanwhile, the present problems existed in the process of electromagnetic riveter design was analyzed.The discharge circuit was equivalent to double-loop model to solve the discharge current based on EMR principle. On the basis of mutual inductance solution of two ring coils, the value of electromagnetic force acting on the drive plate can be obtained. The way of stress-wave communicating in the thin column was analyzed and the difference of two boundary conditions during wave reflection and superposition was obtained. The status of the electromagnetic riveter vibration isolation system was described and simplified vibration isolation model of electromagnetic riveter was analyzed according to the theory of vibration isolation impact.The loose coupling method was adopted to analyze the process of electromagnetic riveter discharge. The electromagnetic field coupling was established by using ANSYS module. Taking the model as boundary condition, the analysis mode of rivet deformation was established based on the high strain rate constitutive relation by using ANSYS/LS-DYNA module. The simulation results showed that the furniture materials with different magnetic conductivity have great influence on the interior electromagnetism field distribution, of the riveter. When furniture material is insulated material, the equivalent electromagnetic force is the biggest, and furniture is not influenced by electromagnetic force. Driving plate is mainly driven by the axial magnetic field, and the tendency is that the equivalent electromagnetic force increases with the increasing thickness of driving plate. The rivet deformation of EMR composed of the whole free upsetting and the local free upsetting under the action of magnetic pressure. Coil number of windings, amplifier quality, inclining angle and other structural parameters have certain influence to the rivet distortion.The three dimensional solid modeling of electromagnetic riveter was created and assembled. The new handheld electromagnetic riveter was designed and manufactrued according to the theoretical analysis and numerical simulation result. After the assembly, the overall weight of riveter assembled is 4.3 kg, and it is convenient to operate; it can be used to formΦ4 mm aluminum alloy rivet. The electromagnetic riveter's recoil was tested using the piezoelectric quartz strength sensor. In the situation of biggest electric discharge energy, the maximum average impulse is 2.23 N·s, which is much lower than the national military standards of 9.8 N·s and has no harm to operators'health and safety.