Method for testing dynamic indentation of material

Abstract

The invention discloses a method for testing dynamic indentation of a material. The method is characterized by comprising the following steps of: fixedly arranging a tested piece on the end face of one end, which faces a transmission bar, of an incident bar, and fixedly arranging a tested piece on the end face of one end, which faces the incident bar, of the transmission bar; sticking a first strain gauge to the incident bar; sticking a second strain gauge to the transmission bar; electrically connecting the first strain gauge and the second strain gauge with an ultra-dynamic strain indicator respectively; striking the incident bar by using a striking bar to ensure that the two test pieces and a stress ball extrude one other to form indentations; and processing the indentations to obtain a time travel curve of press-in force and press-in displacement of the tested pieces. The method has the advantages that the dynamic mechanical performances of the material are measured by using an experimental method, the phenomenon of impedance mismatch of the connecting part of a pressure head and a pressure bar in the prior art is avoided, and the problem that part of the connecting part of the incident bar and the pressure bar generates plastic deformation during dynamic loading in the prior art is solved, so that the measurement accuracy of the method is high, and the maximum indenting velocity can be higher than 30 m / s.

Description

technical field [0001] The invention relates to an experimental testing method of material properties, in particular to a material dynamic indentation experimental method. Background technique [0002] The mechanical behavior of engineering materials is obviously affected by its stress state, and under dynamic loading conditions, the mechanical behavior of materials is more related to the loading speed (specifically measured as strain rate). The material hardness test is a simple and effective test method for the mechanical properties of materials widely used in the engineering field, while the instrumented indentation and nano-indentation test technology is a further development of the traditional hardness measurement, which can measure the deformation and hardness of the indentation process. force, but the existing technology is limited to the static performance test of the material. Although there are also experimental techniques using dynamic indentation such as the com...

AI Technical Summary

Problems solved by technology

The material hardness test is a simple and effective test method for the mechanical properties of materials widely used in the engineering field, while the instrumented indentation and nano-indentation test technology is a further development of the traditional hardness measurement, which can measure the deformation and hardness of the indentation process. force, but existing technology is limited to static performance testing of materials

Although there are also experimental techniques using dynamic indentation such as the common Leeb and Shore hardness testers, they only have formal "dynamic" and cannot really measure the dynamic mechanical properties of materials.

[0003] At present, Hopkinson pressure rods are also used to carry out dynamic indentation experiments on materials, but the existing methods have the mismatch of wave impedance between the indenter and the pressure rod, and local plasticity will occur at the connection between the indenter and the pressure rod. Due to problems such as deformation, the measurement error of the indentation time history in the experiment is relatively large; and due to the support method of the dynamic force sensor, the measurement of the indentation force inevitably contains additional oscillations, which affects the measurement accuracy and limits its use. Use at higher loading speeds

Images