Dynamic calibration system for split-type Hopkin bar torsion bar
By using electromagnetic loading devices and cantilever mechanisms in separate Hopkin torsion rods to generate torsion torque, combined with strain gauge and amplifier, the problem of torsion rod signal measurement and calibration is solved, accurate dynamic calibration of the measurement system is achieved, and experiments are improved The accuracy and simplification of the experimental process.
Patent Information
- Application Number
- CN202420785089.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-16
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2034-04-16
AI Technical Summary
In the prior art, signal measurement calibration of the separate Hopkin torsion rod is difficult to apply a known strain signal to the torsional injector rod, resulting in the accuracy and sensitivity of the measurement system being limited and dynamic calibration cannot be performed effectively.
The electromagnetic loading device and cantilever mechanism are used to generate torsional torque on the incident rod, combined with standard mass and strain gauge, and signals are collected through ultra-dynamic strain amplifiers and transient oscilloscopes to achieve quasi-static calibration of the measurement system.
The signal voltage amplitude corresponding to the strain was obtained through the quasi-static method, which significantly improved the accuracy of the experiment and simplified the experimental difficulty, and realized the dynamic calibration of the separated Hopkin torsion rod.
Smart Images
Figure CN222280387U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of material dynamic mechanical performance experimental equipment, in particular to a dynamic calibration system of a separated Hopkin bar torsion bar. Background Art
[0002] The split Hopkinson bar is an effective experimental device for studying the dynamic mechanical properties of materials under one-dimensional stress state. Compared with the Hopkinson compression bar and tension bar, the Hopkinson torsion bar does not have radial inertia effect in the bar. Therefore, the torsion test is closest to the one-dimensional stress wave hypothesis. Moreover, the propagation of torsion waves in the elastic bar will not be diffused. However, the calibration in the signal measurement process is significantly different from the split Hopkinson compression bar technology.
[0003] The calibration work of the split Hopkinson pressure bar signal measurement process is relatively clear and simple. The impact bar hits the incident bar to generate an incident wave in the incident bar. According to the one-dimensional stress wave theory, if the impact bar and the incident bar are made of the same material, the same shape and the same cross-section, the wave value of the strain wave in the bar is in a certain proportional relationship with the impact velocity of the impact bar. Therefore, as long as the velocity of the impact bar is accurately measured, it is equivalent to applying a certain strain to the incident bar. The strain in the incident bar can be measured by measurement systems such as strain gauges (meters), ultra-dynamic strain amplifiers, and transient oscilloscopes. The output of the oscilloscope is the voltage corresponding to the strain. Given the impact bar velocity, the strain value is given, and the ratio of the given strain value to the measured voltage value is the calibration coefficient of the measurement system. For the signal measurement calibration of the split Hopkinson torsion bar, it is difficult to apply a known strain signal to the torsion incident bar. According to incomplete research, there is no good calibration method so far. The static calibration method of the resistance strain gauge measurement system has to be used. However, the defect of the static calibration method is that the quality of the strain gauge itself, the accuracy of the sensitivity coefficient, the level of the patch process, etc. are not included in the calibration factors. Utility Model Content
[0004] The utility model aims to overcome the defects of the prior art and provide a dynamic calibration system for a split Hopkin bar torsion bar.
[0005] In order to achieve the above-mentioned utility model purpose, the utility model adopts the following technical solutions:
[0006] The utility model provides a dynamic calibration system of a split Hopkin bar torsion bar, comprising an electromagnetic loading device, the electromagnetic loading device is connected to an incident rod, a transmission rod, and a test piece placed at the adjacent ends of the incident rod and the transmission rod, the transmission rod and the incident rod are both supported by a support;
[0007] The incident rod is provided with a cantilever mechanism, one end of which is temporarily fixed to the end of the incident rod near the specimen, and the other end is hung with a standard mass block, the gravity of the standard mass block forms a torque on the axis of the incident rod.
[0008] Further technology of the utility model:
[0009] Preferably, the electromagnetic loading device is powered by a power supply through a high-voltage and high-current transmission line.
[0010] Preferably, the electromagnetic loading device, the incident rod, the test piece, and the transmission rod are arranged in a straight line.
[0011] Preferably, the standard mass blocks are weights of different mass levels.
[0012] Preferably, strain gauges are pasted on the incident rod and the transmission rod, and bridged according to the requirements of measuring shear deformation, and connected to an ultra-dynamic strain amplifier and a transient oscilloscope.
[0013] Compared with the prior art, the utility model has the following technical effects:
[0014] In the utility model, the mass block and the cantilever mechanism are used to generate a torsional moment on the axis of the incident rod, which is equivalent to providing a standard shear strain to the incident rod; the signal voltage amplitude corresponding to the strain is obtained by the quasi-static acquisition method, and the measurement system can be accurately calibrated, which greatly reduces the difficulty of the experiment and greatly improves the accuracy of the experiment.
[0015] Other features and advantages of the present invention will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0017] Figure 1 A front view of the structure of a dynamic calibration system for a split Hopkin bar torsion bar provided by the present invention;
[0018] Figure 2 A right view of the structure of a dynamic calibration system for a split Hopkin bar torsion bar provided by the present invention;
[0019] Explanation of numbers in the figure: 1-power supply, 2-high voltage and high current transmission line, 3-electromagnetic loading device, 4-incident rod, 5-strain gauge, 6-ultra-dynamic strain amplifier and transient oscilloscope, 7-support, 8-standard mass block, 9-cantilever mechanism, 10-test piece, 11-transmission rod. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be further described in detail below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model but not all. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0021] like Figure 1-2 , this embodiment provides a dynamic calibration system for a split Hopkin bar torsion bar, comprising an electromagnetic loading device 3, the electromagnetic loading device 3 is connected to an incident rod 4, and also comprises a transmission rod 11, and a test piece 10 placed at the adjacent ends of the incident rod 4 and the transmission rod 11, the transmission rod 11 and the incident rod 4 are both supported by a support 7;
[0022] The incident rod 4 is provided with a cantilever mechanism 9 , one end of which is temporarily fixed to the end of the incident rod 4 near the specimen 10 , and the other end is hung with a standard mass block 8 , the gravity of the standard mass block 8 forms a torque on the axis of the incident rod 4 .
[0023] The electromagnetic loading device 3 is powered by a power source 1 through a high-voltage and high-current transmission line 2 .
[0024] The electromagnetic loading device 3, the incident rod 4, the test piece 10, and the transmission rod 11 are arranged in a line.
[0025] The standard mass blocks 8 are weights of different mass levels.
[0026] The measurement system is assumed to have sufficient response frequency, that is, it is assumed that they have the same response capability to quasi-static signals and dynamic signals. According to relevant rules, resistance (semiconductor) strain gauges 5 are pasted on the incident rod 4 and the transmission rod 11, and bridges are assembled according to the requirements of measuring shear deformation, and connected to the ultra-dynamic strain amplifier and transient oscilloscope 6. The distance between the axis of the incident rod 4 and the mass block suspension wire is accurately measured, and the oscilloscope acquisition time is adjusted to the second level.
[0027] An ultra-dynamic strain amplifier and a transient digital oscilloscope are used as the main components of the measurement system, and the acquisition time of the oscilloscope is adjusted to reach the second level.
[0028] Suspending mass blocks of different sizes, voltage signals of different amplitudes are obtained. The torque is calculated based on the mass block gravity and distance, and the shear strain on the incident rod 4 surface is calculated based on the torque and the cross-sectional shape and size of the incident rod 4. The shear strain is divided by the corresponding voltage amplitude, which can be used to calibrate the torsion bar measurement system.
[0029] The above contents are merely examples and explanations of the structure of the utility model. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the utility model or exceed the scope defined in the claims, they should all fall within the protection scope of the utility model.
Claims
1. A dynamic calibration system for a split Hopkin bar torsion bar, comprising an electromagnetic loading device connected to an incident rod, a transmission rod, and a test piece placed at adjacent ends of the incident rod and the transmission rod, wherein the transmission rod and the incident rod are both supported by a support, characterized in that: The incident rod is provided with a cantilever mechanism, one end of which is temporarily fixed to the end of the incident rod near the specimen, and the other end is hung with a standard mass block, the gravity of the standard mass block forms a torque on the axis of the incident rod.
2. A dynamic calibration system for a split Hopkin bar torsion bar according to claim 1, characterized in that: The electromagnetic loading device is powered by a power supply through a high-voltage and high-current transmission line.
3. A dynamic calibration system for a split Hopkin bar torsion bar according to claim 1, characterized in that: The electromagnetic loading device, the incident rod, the test piece and the transmission rod are arranged in a straight line.
4. A dynamic calibration system for a split Hopkin bar torsion bar according to claim 1, characterized in that: The standard mass blocks are weights of different mass levels.
5. A dynamic calibration system for a split Hopkin bar torsion bar according to claim 1, characterized in that: Strain gauges are pasted on the incident rod and the transmission rod, and bridged according to the requirements of measuring shear deformation, and connected to the ultra-dynamic strain amplifier and transient oscilloscope.