Synchronous measurement method of split Hopkinson pressure bar experiment based on digital images

A technology of Hopkinson compression bar and digital image, which is applied in the direction of measuring device, analyzing materials, and testing material strength by using one-time impact force, which can solve the problems of waveform synchronization, stress-strain data error, and inability to truly realize the test piece. Problems such as strain synchronization measurement

Inactive Publication Date: 2014-12-24
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since the times for recording incident waves, reflected waves and transmitted waves are often different, the time starting points of these three waveforms are artificially selected in data processing. If the selected time starting points are inconsistent, it will lead to errors in stress-strain data, especially When testing some materials (such as soft materials, etc.) that require a long time to achieve uniform stress, it becomes more difficult to select the time starting point of the transmitted wave and the reflected

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  • Synchronous measurement method of split Hopkinson pressure bar experiment based on digital images
  • Synchronous measurement method of split Hopkinson pressure bar experiment based on digital images

Examples

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Embodiment

[0024] In this embodiment, the length of the incident rod 1 is 320cm, the length of the transmission rod 2 is 200cm, the cross-section of the incident rod and the transmission rod is circular, and its diameter is 74mm, all of which are steel rods. The high-speed camera adopts the Phantomv1610 system and is tested Part 3 is a cylindrical steel fiber reinforced concrete with a diameter of 70.2 mm and a height of 31.6 mm, which has withstood multiple impacts. figure 1 The 4 in represents the shooting area of ​​the high-speed camera.

[0025] A digital image-based method for simultaneous measurement of split Hopkinson compression bar experiments, including

[0026] Such as figure 1 As shown, before the experiment, a marking area is made on the outer surface of the incident rod 1 in contact with the test piece 3, and on the outer surface of the transmission rod 2 in contact with the test piece 3. The marking area is composed of speckles, and the speckle The particle size is deter...

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Abstract

The invention discloses a synchronous measurement method of a split Hopkinson pressure bar experiment based on digital images. The method comprises the steps as follows: before the experiment, mark areas are made on the outer surface of one end where an incident bar and a tested piece are contacted as well as the outer surface of one end where a transmission bar and the tested piece are contacted; in the experiment process, moving images of the tested piece and the mark areas in the impact experiment process are obtained by a high-speed camera; through trace analysis of deformation of the mark area, strain of the tested piece as well as the incident bar and the transmission bar at the two ends of the tested piece is further obtained; and according to the principle of the Hopkinson pressure bar experiment, , stress of the two ends of the tested piece is calculated based on strain of the two bars; and further, through the novel experimental technology based on the digital images, the strain of a test piece and the stress of two ends of the test piece can be obtained synchronously.

Description

technical field [0001] The invention relates to a separate Hopkinson compression bar experiment, in particular to a digital image-based synchronous measurement method for the separate Hopkinson compression bar experiment. Background technique [0002] The split Hopkinson compression bar technique is an experimental method for testing the dynamic mechanical properties of materials. It has been widely used in the testing of mechanical properties of engineering materials under high strain rates. In the traditional separated Hopkinson compression rod experiment technique, strain gauges are first attached to the incident rod and the transmission rod, and then the stress-strain data of the specimen are converted according to the signals collected by the strain gauges during the experiment. Since the times for recording incident waves, reflected waves and transmitted waves are often different, the time starting points of these three waveforms are artificially selected in data proce...

Claims

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Application Information

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IPC IPC(8): G01N3/30G01N3/06
Inventor 汤立群谢倍欣张晓阳刘逸平蒋震宇刘泽佳张泳柔程经纬
Owner SOUTH CHINA UNIV OF TECH
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