CN-121994358-A - Infrared temperature measuring device for Hopkinson bar

Abstract

The invention relates to the field of dynamic testing of materials, and particularly discloses an infrared temperature measuring device for a Hopkinson bar. The device comprises an incident rod, a transmission rod, a sample, a dust cover, an infrared filter, two off-axis parabolic mirrors, an optical chopper, a beam splitting cube, a laser, an HgCdTe infrared sensor, a signal amplifier and an oscilloscope. The device is provided with a dust cover and vacuumizes to isolate environmental interference, a focusing light path is formed by adopting an off-axis parabolic reflector to collect infrared radiation of a sample, a beam splitting cube is used for coupling visible light of a laser and infrared light of the sample to realize coaxial accurate positioning of a temperature measuring point, an optical chopper is combined for sensor calibration, finally, the infrared signal is converted into an electric signal through an HgCdTe infrared sensor, and the electric signal is amplified and then the temperature change is recorded in real time by an oscilloscope. The device realizes real-time non-contact accurate measurement of the temperature of the sample in the dynamic loading process.

Inventors

• QIN LIANG
• LU XIAOXIA
• ZHANG BEICHEN
• KANG KAI
• YAN XIAOFANG
• Mei Zongshu
• CHEN PENG
• Yu Liufang
• ZHAO SHOUTIAN

Assignees

• 中国人民解放军军事科学院防化研究院

Dates

Publication Date

20260508

Application Date

20260123

Claims (10)

1. 1. The infrared temperature measuring device for the Hopkinson bar is characterized by comprising an oscilloscope (1), a signal amplifier (2), an HgCdTe infrared sensor (3), a beam splitting cube (4), a laser (5), an optical chopper (6), a second off-axis parabolic reflector (7), a first off-axis parabolic reflector (8), a dust cover (9), an infrared filter (10), an air suction hole (11), an incident bar (12), a transmission bar (14) and a sample (13); the oscilloscope (1) is connected with the signal amplifier (2) and is used for recording and displaying a temperature change curve; The signal amplifier (2) is connected with the HgCdTe infrared sensor (3) and is used for amplifying the electric signal; The HgCdTe infrared sensor (3) is arranged on a platform capable of being adjusted in multiple degrees of freedom and is used for receiving infrared radiation and converting the infrared radiation into an electric signal; the optical chopper (6) is arranged between the light splitting cube (4) and the HgCdTe infrared sensor (3) and is used for periodically shielding the infrared radiation beam to calibrate the HgCdTe infrared sensor (3); The beam splitting cube (4) is arranged between the second off-axis parabolic reflector (7) and the HgCdTe infrared sensor (3) and is positioned right in front of the optical path of the laser (5) and used for coupling and separating the visible laser beam emitted by the laser (5) and the infrared radiation beam generated by the sample (13) in the optical path; the first off-axis parabolic reflector (8) and the second off-axis parabolic reflector (7) are sequentially arranged in the light path, the first off-axis parabolic reflector (8) is used for reflecting the infrared radiation of the sample (13) into collimated light, and the second off-axis parabolic reflector (7) is used for focusing the collimated light; The dust cover (9) surrounds the sample (13) and is provided with a window and an air extraction hole (11), the window is made of a material with high infrared light transmittance, and the air extraction hole (11) is used for connecting air extraction equipment to extract vacuum; the infrared filter (10) is arranged at a window of the dust cover (9); the incidence rod (12) and the transmission rod (14) are respectively positioned at two sides of the sample (13) and are used for applying dynamic load to the sample (13).
2. 2. The infrared temperature measuring device for the Hopkinson bar according to claim 1, wherein the dust cover (9) comprises an upper cover and a cover body which are connected through a hinge, and a rubber sealing strip is arranged at the joint.
3. 3. Infrared temperature measurement device for hopkinson bar according to claim 1, characterized in that the effective aperture of the first off-axis parabolic mirror (8) and the second off-axis parabolic mirror (7) are identical, the focal length being different.
4. 4. Infrared temperature measurement device for hopkinson bar according to claim 1, characterized in that the light-splitting cube (4) allows the passage and reflection of the visible laser beam of the laser (5) to the surface of the sample (13) while allowing the unobstructed penetration of the infrared radiation beam generated by the sample (13) to the HgCdTe infrared sensor (3).
5. 5. The infrared temperature measuring device for the Hopkinson bar according to claim 1, wherein the HgCdTe infrared sensor (3) realizes multi-degree-of-freedom adjustment through a triaxial displacement turntable (15).
6. 6. The infrared temperature measuring device for the hopkinson bar according to claim 1, wherein the optical chopper (6) is used for periodically shielding an infrared radiation beam in a calibration process, so that the HgCdTe infrared sensor (3) receives the periodically-changed infrared signal, and a response curve is generated for calibration.
7. 7. The infrared temperature measuring device for hopkinson bar according to claim 1, wherein the signal amplifier (2) is used for linearly amplifying weak electric signals output by the HgCdTe infrared sensor (3) and suppressing background noise.
8. 8. The infrared temperature measuring device for hopkinson bar according to claim 1, wherein the oscilloscope (1) receives the amplified electric signal in real time and converts it into a temperature-time variation curve.
9. 9. The infrared temperature measuring device for the hopkinson bar according to claim 1, wherein the laser (5) is horizontally and vertically arranged on a connecting line of the second off-axis parabolic reflector (7) and the HgCdTe infrared sensor (3) and is opposite to the beam splitting cube (4).
10. 10. The infrared temperature measurement device for hopkinson bar of claim 1, wherein the window is made of a material having high transmittance to near infrared light.

Description

Infrared temperature measuring device for Hopkinson bar Technical Field The invention relates to the field of dynamic testing of materials, in particular to an infrared temperature measuring device for a Hopkinson bar, which is mainly applied to a split Hopkinson bar (SHPB) dynamic loading experimental system and is used for accurately measuring the temperature change of a sample in a dynamic loading process in real time. Background In the research of dynamic mechanical properties of materials, a Split Hopkinson Pressure Bar (SHPB) experimental technology is a widely applied dynamic and material mechanical parameter measurement means. The technology can simulate the stress state of the material under high strain rate and study the dynamic mechanical response of the material. In the dynamic loading process, the temperature of the sample can be obviously changed due to factors such as plastic deformation, energy dissipation and the like, and the temperature change can adversely affect the mechanical properties of the material, so that the temperature change of the sample in the dynamic loading process is measured in real time, and the method has a great significance for deeply understanding the dynamic mechanical behavior of the material. The existing temperature measurement method for the SHPB experiment system has a plurality of defects. In the traditional thermocouple temperature measurement method, the contact between a thermocouple and a sample can interfere the dynamic response of the sample, the response speed is relatively slow, and the instantaneous change of the temperature of the sample under high strain rate is difficult to capture in real time. Although the non-contact optical temperature measurement method can avoid structural damage and environmental influence caused by direct contact, the existing optical temperature measurement device is often influenced by factors such as shielding, vibration and dust generated in the experimental device (such as an incident rod and a transmission rod) in the SHPB experimental environment, so that the temperature measurement precision is low, the stability is poor, and the requirements of high-precision experimental research are difficult to meet. Therefore, research and development of an infrared temperature measuring device which can adapt to an SHPB dynamic loading experimental environment, has high temperature measuring precision, high response speed and strong anti-interference capability, and is a technical problem to be solved in the field. Disclosure of Invention First, the technical problem to be solved The invention aims to solve the technical problems of easiness in interference caused by factors such as shielding, dust and the like, low temperature measurement precision and low response speed of a temperature measuring device in the existing SHPB dynamic loading experiment system, and provides an infrared temperature measuring device for a Hopkinson bar, so that the real-time accurate measurement of the temperature of a sample in a dynamic loading process is realized. (II) technical scheme In order to achieve the above purpose, the invention provides an infrared temperature measuring device for a Hopkinson bar, which has the core thought that a dust cover is arranged around a Hopkinson bar sample, an off-axis parabolic mirror focusing light path, a light splitting cube and a laser are combined to achieve accurate positioning of a temperature measuring point, and the HgCdTe infrared sensor and a chopper are utilized for calibration, so that non-contact, anti-interference, rapid and accurate measurement of the temperature of the sample in a dynamic loading process is achieved. The infrared temperature measuring device for the Hopkinson bar, as shown in fig. 1, comprises an incident bar 12, a transmission bar 14, a sample 13, a dust cover 9, an infrared filter 10, an air extraction hole 11, a first off-axis parabolic reflector 8, a second off-axis parabolic reflector 7, an optical chopper 6, a beam splitting cube 4, a laser 5, an HgCdTe infrared sensor 3, a signal amplifier 2, an oscilloscope 1 and the like. The incident beam 12 and the transmission beam 14 are located on both sides of the sample 13, respectively, for applying a dynamic load to the sample 13. The dust cap 9 can be opened and closed conveniently. The device is used for preventing dust, fragments and the like generated in the experimental process from affecting the normal work and temperature measurement precision of each part, and can conveniently vacuumize to prevent the temperature of the surrounding air of the sample caused by heating of the sample. The dust cover 9 is provided with a window which is made of a material with high infrared light transmittance, so that effective transmission of near infrared light can be ensured, and impurities such as dust can be blocked. The dust cover 9 is also provided with an air suction hole 11 for connecting air suction equipment to perform va