Electromagnetic spinning type split-Hopkinson torsional bar

Abstract

The invention belongs to the technical field of dynamic mechanics performance experimental equipment for materials and in particular relates to an electromagnetic spinning type split-Hopkinson torsional bar. The electromagnetic spinning type split-Hopkinson torsional bar comprises an incident bar, a transmission bar and test pieces and further comprises a cylindrical fixed frame, wherein the testpieces are arranged at adjacent ends of the incident bar and the transmission bar; the fixed frame is coaxially arranged at the overhanging end of the incident bar; a plurality of rotating blades arefixed on the incident bar; the rotating blades are pushed by a pulsed electromagnetic loader arranged on the inner side of the fixed frame; and the pulsed electromagnetic loader is electrically connected with a transient power supply pack and a control component. According to the split-Hopkinson torsional bar disclosed by the invention, the pressure is applied to the rotating blades by utilizing the pulsed electromagnetic loader, so that the defects of the conventional pre-energy storage type split-Hopkinson torsional bars, explosive-driven split-Hopkinson torsional bar devices and T-shaped split-Hopkinson torsional bar devices are overcome, the experimental difficulty is greatly reduced, and the experimental efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of experimental equipment for dynamic mechanical properties of materials, and in particular relates to an electromagnetic pressure-rotating Hopkinson torsion bar. Background technique [0002] Split Hopkinson rod is an effective experimental device for studying the dynamic mechanical properties of materials under one-dimensional stress state. In contrast to Hopkinson compression and tie rods, the Hopkinson torsion bar has no radial inertia effect in the rod. Therefore, the torsion test is closest to the one-dimensional stress wave assumption, and furthermore, the torsional wave propagation in the elastic rod does not take place. In the 1970s, T.Nicholas and others invented the pre-storage-type separate Hopkinson torsion bar. The so-called pre-storage separated Hopkinson torsion bar is to divide the torsion incident bar into two parts, one end has a rotating head for adding external torque (load), and the o...

AI Technical Summary

Problems solved by technology

Compared with the pre-torque loading method, explosive impact loading can avoid the problems that the fixture pressure is not easy to control and the experiment is prone to failure, and the explosive loading is also instantaneous, which can greatly reduce the rise of the stress front, but there are also obvious shortcomings : (1) Due to the influence of unpredictable factors such as the composition and quantity of explosives are not easy to be accurately controlled and the explosives are damp, the loading torque cannot be accurately controlled, and the repeatability of the experiment is poor; (2) During the explosive loading process, the specimen is actually loaded by variable strain rate effect, that is, it is difficult to guarantee the constant strain rate loading by the common explosion loading method

Therefore, this method has not been widely used

[0006] In 2013, Jiang Xiquan and others invented the T-shaped separated Hopkinson torsion bar. This invention almost overcomes all the shortcomings of the pre-storage torsion bar. However, due to structural reasons, complex bending waves are inevitably generated in the conversion device. This bending wave, which is difficult to eliminate, is transmitted into the torsional incident rod

In addition, for a torsion bar with a large diameter (such as 1000mm), it takes a long time for the wave to propagate on the cross section of the bar. Increased experimental strain rate

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