Experimental Investigation On EMR By Using Composite-Aluminium Alloy Plate

Electromagnetic riveting is developed as a new kind of technology that is based on electromagnetic forming and traditional riveting technologies. In this paper, the interrelated theory of discharge circuit and one dimension elastic stress wave are analyzed. Subsequently, the rivet samples which are applied to the electromagnetic riveting experiment are also compressed in high dynamic load and relative static load. A series of rivets were riveted in constraint die with aim to obtaining reliable experimental parameter which can guide the riveting experiment of composite and aluminium alloys sheet. Finally, the complex material and aluminium alloys sheet are jointed by using electromagnetic riveting technology and gain the test sample which accord with the technological requirements.The discharging circuit of electromagnetic riveting is analyzed by using single-circuit and two-circuit model. The elastic-plasticity waves which transmit through the punch die and rivet is simplified to the one dimension elastic stress wave, and then, the reflection characteristic and superposition characteristic of this simplified wave in transmitter substance are researched. Consequently, the following conclusion is achieved: the waveform of reflected wave is identical as the input wave; otherwise, their transmission directions are opposite. The displacement and speed of particle are null at fixed boundary, accordingly, the mean stress of reflected wave is twice as large as input wave. At the same time, the propagation characteristic of stress wave in different materials and variable cross-section are analyzed.By designing the constraint die, the technology simulating experiment is implemented in which the rivet sample is restricted with the die and acquires the electrical parameters character as follows: the deformation degree increases gradually as the raise of the discharge energy. The deformation degree is also increasing along with the growing quantity of capacitance when the discharge energy is stated. Test and verify the structural parameter character that included angle between the amplifier and horizontal direction effect the deformation of rivet. Wider angle can increase the deformation of rivet sample. Testify that forward direction riveting need lower discharging energy to get the same deformed rivet piece than reverse direction riveting in existing condition of experiment. The generation and development of fracture shear zone are observed by using metallographic microscope.Try the electromagnetic riveting experiment to join the composite and constraint die (aluminium alloys sheet.) with rivets. The connecting pieces according to the technological requirements are obtained by adopting the data of technology simulating experiment. Approve that the riveting interference increases when the discharging energy is enlarged or the aperture is narrowed. The rivet shaft expansion of electromagnetic riveting is more unformed than pneumatic riveting by macroscopic measure and microscopic metallographic examination.