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The sliding electrical contact performance of the electromagnetic railgun is the main factor affecting the launch accuracy, launch efficiency, and working life of the electromagnetic railgun. The objective evaluation of the sliding electrical contact performance of the electromagnetic railgun is crucial for the research of the electromagnetic railgun theory and engineering design. Because the sliding electrical contact process of the electromagnetic rail gun is complex, the mechanism and performance requirements of the launcher in different phases are different, so it is difficult to evaluate according to the unified standard. In this paper, the whole launch process is divided into three phases: dry friction, liquefaction layer, and high-speed instability. The sliding electrical contact mechanism of these three phases is analyzed separately, and the evaluation model is established, respectively. Then, the theoretical analysis, expert evaluation, and experimental data statistics are used to comprehensively determine the weight system of the three phases. Finally, the comprehensive evaluation model of the three phases is established. The validity of the above-mentioned model is verified by the actual launch test. The evaluation method of this model has practical significance for the scientific research, engineering design, and model development of the electromagnetic rail gun. [ABSTRACT FROM AUTHOR]

Sliding contact of electromagnetic railgun affects launch accuracy, launch efficiency, and rail life. The research on sliding contact of electromagnetic railgun is very important to the theory and engineering design. However, the whole process of electromagnetic launch is high speed and big current and high heat. The state of sliding contact is complicated. The whole process is also transient process. The stage division of sliding contact is vague, and there is no definite definition about stage division. In this paper, the theoretical analysis of sliding electric contact process is introduced, and the design test is carried out to verify it. The whole launch process of electromagnetic railgun is divided into three stages: dry friction contact, liquefied layer contact, and high-speed unstable contact. The line density 15 kA/mm is defined as the critical point between dry friction stage and liquefaction stage. The armature speed 1300 m/s is defined as critical point between the liquefied contact layer and the high-speed unstable contact stage, which provides reference for the study of sliding contact in the future. [ABSTRACT FROM AUTHOR]

Currently, the bore shape in an electromagnetic launcher is usually a rectangle, round, or an inverted arc. A comparison of the current density distribution, induction gradient, moment of inertia, contact pressure, contact state, structure manufacture, and launching precision between the rectangle and inverted arc bore shapes was carried out. We got some results about the effect of bore shape on the electromagnetic launcher. The results show that the inverted arc shape performed better than the rectangle in these areas: current density distribution, induction gradient, moment of inertia, contact state, and the accuracy of armature running. [ABSTRACT FROM PUBLISHER]

To analyze the stored-to-kinetic energy conversion efficiency, a transient electric-circuit model for a railgun system is built using the electrical circuit analysis software SIMPLORER in this paper, and the electric parameters of the model are defined with measurement values of the actual system. Many results of simulations and experiments are also presented, and the results show that the equivalent series resistance of the coaxial cables and the rail resistance are major factors on the energy conversion efficiency. In the end, some methods are proposed to improve energy conversion efficiency of the pulsed-power supply system. [ABSTRACT FROM AUTHOR]