CN203672722U - Bending rigidity testing device used in high-low temperature environments - Google Patents

Abstract

Bending stiffness test device in high and low temperature environment, including high resolution camera, high rigidity rod, lifting device, etc., laser measurement group, high and low temperature box, etc., in the high and low temperature box, the tested piece is fixed by the mounting seat of the tested piece, and the high resolution The high-rate camera is fixed on the observation window on the top of the high-low temperature box, the high-rigidity rod passes through the high-low temperature box vertically and acts on the measured piece, the upper end of the high-rigidity rod is fixed to the lifting device through the force sensor, and the laser measurement group is fixed at the high-low temperature box. Outside the box and opposite to the observation window on the side of the high and low temperature box. The utility model uses a high-rigidity rod to load the force without changing the direction of the force, uses a high-resolution camera to obtain the value of the force arm, and uses a laser measurement group to obtain the deformation of the rotation angle, thereby accurately obtaining the bending moment-angle of the bending stiffness of the test piece Deformation curve, easy to use, strong reliability, good real-time performance, high measurement accuracy.

Description

Bending stiffness test device under high and low temperature environment

technical field

The utility model relates to the field of bending stiffness testing of components under high and low temperature environmental conditions. the

Background technique

Stiffness tests on structural parts are usually carried out at room temperature unless there are special requirements. Existing stiffness tests have many methods and structures according to different test requirements and application fields, but for components in high and low temperature environments Stiffness test, due to the deformation of test fixtures and loading mechanisms in high and low temperature environments, which will affect the loading of force, the measurement of moments and angles, and because of the overheating and cooling of the environment, most precision instruments or equipment for testing will It cannot be used normally and affects the testing work. the

At present, the bending stiffness test under high and low temperature is carried out in a high and low temperature box, the mechanism components are placed in the high and low temperature box, and the tested part is a cantilever beam. Patent application number CN200810124707.8 "Laser amplification measurement method for bending and twisting structural deformation" mentioned a component that fixes a laser emitter on the corner of the component to be measured, and uses the principle of optical levers to amplify the micro deformation Stiffness test method, which can realize non-contact measurement. However, for the stiffness test at high and low temperatures, the laser emitter cannot be located on the component, and the deformation of the machine base must also be considered during the test. The patent application number is 201110370253.4 for "three-dimensional deformation measurement device of the measured part in the high and low temperature box" and the patent application number is 201110370271.2 for the "high precision measurement system for three-dimensional small deformation of the mechanical device in the high and low temperature box" to provide a high and low temperature box A method for measuring the three-dimensional deformation of a component, but this method can only follow the three-dimensional displacement of a certain point, and the stiffness test needs to obtain accurate loading force and the size of the moment arm. the

Contents of the invention

In order to overcome the influence of temperature and improve the reliability and measurement accuracy requirements of bending stiffness testing, the utility model provides a stiffness testing method for structural parts under high and low temperature environmental conditions. the

The technical scheme that the utility model solves its technical problem adopts is:

Bending stiffness test device in high and low temperature environment, including high resolution camera, support rod, lifting device, laser measurement group, high and low temperature box. the

The test piece is fixed in the high and low temperature box by the test piece mounting seat. the

The top and side of the high and low temperature box are provided with observation windows, and the high resolution camera is fixed on the top of the high and low temperature box. the

The lower end of the support rod is a smooth spherical surface, and the support rod vertically passes through the high and low temperature chamber to act on the measured piece. catch. the

A calibration point is set at the root of the connection between the tested part and the mounting base, and the vertical distance from the calibration point to the support rod is the moment arm of the bending stiffness test at normal temperature. The high-resolution camera can take position images of calibration points at any temperature. the

The laser measurement group includes a pyramid reflector, a laser head and a calculation module. The laser head is fixed outside the high and low temperature box and is opposite to the observation window on the side of the high and low temperature box. The mounting bases are respectively fixed on the end of the measured piece and the mounting base of the tested piece, there are two pyramidal mirrors on the mounting base of the pyramidal mirror, and each laser head corresponds to a pyramidal mirror. the

The testing method of the present utility model is:

1. At room temperature, fix the standard steel ruler on the horizontal plane where the calibration point is located. The standard steel ruler is parallel to the focal plane of the high-resolution camera. Use the high-resolution camera to record the pixel position of the calibration point. The scale size obtains the proportional relationship between the image pixel and the actual size, and records the vertical distance L ₁ from the calibration point to the center of the support rod.

2. Seal the high and low temperature box to make it reach the temperature required for the test. After the temperature is stable, control the lifting device to move up and down, load the tested piece through the support rod, and directly measure the loaded force value F through the sensor. the

3. Use a high-resolution camera to take an image, compare it with the initial image taken in a normal temperature environment, and obtain the offset distance ΔL of the calibration point along the direction of the force arm. The value of the force arm in the current high and low temperature environment is L=L ₁ +ΔL.

4. The high-resolution camera can also take a full set of images between the calibration point and the loading point of the support rod, and directly obtain the force arm through the ratio between the captured images at room temperature and high and low temperature and the image pixels and the actual size The size of the value L. the

5. Measure the corner deformation of the tested part through laser measurement group: after the bending moment is applied, the measured part is deformed, and the reflected optical path of the laser beam changes. If the optical path difference is recorded as s, then the corner deformation θ=arcsin(s/2d). Reflectors are installed on both the DUT and the mounting base of the DUT, and the measured value of the angular deformation on the DUT is θ1 through the calculation module, the measured value of the angular deformation on the DUT mounting base is θ ₂ , and the actual rotation angle of the DUT is The deformation is θ'=θ1-θ ₂ .

6. Draw a bending moment-angle deformation curve that can reflect the bending stiffness of the tested piece through the measured force F, moment arm L, and rotational angle deformation θ'. the

Design ideas and advantages of the present utility model are as follows:

In high and low temperature environments, most of the precision instruments or equipment used for testing will not work normally, and the base of the tested piece and the tested piece will be deformed due to thermal expansion and contraction, which adds great difficulty to the bending stiffness test. The utility model uses the support rod to load the force without changing the direction of the force, uses the high-resolution camera to obtain the force arm value, and uses the laser measurement group to obtain the corner deformation, so as to accurately obtain the bending moment-angle deformation of the bending stiffness of the test piece curve. the

The support rod is very little affected by the high and low temperature environment, so the use of the support rod for loading can not consider the deformation effect of the loading member in the high and low temperature environment; the lower end of the support rod is a smooth spherical surface, which is in sliding contact with the surface of the tested part, which can ensure the force. The direction is always vertical, and a force sensor is installed between the support rod and the lifting platform, which can easily measure the force value acting on the tested piece. the

Under extremely high or extremely low temperature, the measured piece and its mounting seat will produce a certain deformation, and it is difficult to accurately measure the force arm value; the utility model adopts the method of image processing to measure the force of the support rod under normal temperature Arm size, and record a calibration point, the vertical distance between the calibration point and the support rod is the force arm value, use a high-resolution camera to take the position image of the calibration point, and then take another photo when testing in a high and low temperature environment One position image, according to the relationship between the image pixels and the actual size, analyze the two images to obtain the offset distance ΔL of the calibration point along the direction of the original force arm, and calculate the value of the force arm in the current high and low temperature environment. Image processing technology is very mature, the higher the resolution, the higher the accuracy. The high-resolution camera is fixedly installed on the observation window on the top of the high and low temperature box, which can clearly capture the images of the calibration points in the high and low temperature box, and is easy to install, and is not affected by the temperature in the high and low temperature box during the test. the

The corresponding angular deformation of the tested part can be measured non-contact by the laser measuring group. Among them, the laser measurement group applies the radar principle, Doppler frequency difference effect and optical heterodyne principle, and uses the frequency shift generated by the reflection of the laser beam when the mirror moves to measure the displacement. A set of laser heads and pyramid reflectors are also arranged on the mounting seat of the tested part to measure the angular deformation. Finally, the deformation angle at both ends of the component is obtained through calculation, and the difference is the actual deflection angle of the component, with high measurement accuracy. the

The beneficial effects of the utility model are mainly manifested in that: it can accurately apply the bending moment and measure the deflection angle deformation amount of the measured piece, and it is convenient to use, has strong reliability, has high measurement accuracy, good real-time performance, and can output reflection components. The bending moment-rotation angle curve of the bending stiffness characteristic and so on. the

Description of drawings

Figure 1 is a schematic diagram of the bending stiffness test device under high and low temperature environment

Figure 2 is a schematic diagram of calculation of rotation angle measurement

Detailed ways

With reference to the accompanying drawings, a bending stiffness testing device in a high and low temperature environment includes a high-resolution camera 10, a support rod 7, a laser measurement group, a force sensor 8, a lifting device 9, and the like. the

The DUT 2 and its mounting base 5 are placed in the high and low temperature chamber 1, one end of the support rod 7 is fixedly connected to the lifting device 9, and the other end of the support rod 7 is a smooth spherical surface and vertical Acting on the measured piece 2, a force sensor 8 is installed between the support rod 7 and the lifting device 9. the

The high-resolution camera 10 is fixed on the observation window 11 at the top of the high and low temperature box 1, and a calibration point 12 is set at the root of the connection between the tested part 2 and the mounting base 5, and the distance between the calibration point 12 and the support rod 7 is The vertical distance is the moment arm value of the bending stiffness test at room temperature. The high-resolution camera 10 can capture the position image of the calibration point 12 at any temperature. the

The laser measurement group includes a pyramid reflector 4, a laser head 6 and a computing module; the end of the measured object 2 and the mounting seat of the measured object are each equipped with a pyramid reflector mount 3, and the pyramid reflector is installed Seat 3 vertical support rods 7, two pyramid reflectors 4 are installed on the described one pyramid reflector mount 3, the distance between the two pyramid reflectors 4 is a certain value d, the laser 6 heads Installed outside the high and low temperature box 1 and opposite to the observation window on the high and low temperature side, the laser head 6 emits laser light and is reflected by the corner mirror 4 to obtain the Doppler frequency shift of the laser frequency, and each of the laser heads 6 corresponds to A corner reflector4. the

The corner mirror 4 on the DUT mounting base 3 and the corresponding laser head 6 are not affected by the support rod. the

A retroreflector mount has two retroreflectors at a known distance d. As shown in Figure 3, in the initial state (the two reflectors are perpendicular to the light, that is, the AB vertical light), the laser heads H1 and H2 emit laser light to the two reflectors at A and B respectively and receive them. At this time, the difference in optical path is zero; after the bending moment is applied, the two mirrors of the measured piece deform and move to C and D respectively. Therefore, the distances of AC and BD in the light direction can be obtained from the two laser heads respectively. The optical path difference between the two is s, then delt1=s/2, so the corner deformation θ ₁ =arcsin(delt1/d)=arcsin(s /2d). In the same way, the angular deformation of the other end of the tested object can be obtained θ ₂ =arcsin(delt2/d), so the actual angular deformation of the tested object can be obtained as θ'=θ1-θ ₂ .

Claims (1)

1. Bending stiffness test device under high and low temperature environment, characterized in that: it includes a high-resolution camera, a support rod, a lifting device, a laser measurement group, and a high and low temperature box; Test piece; The top and side of the high and low temperature box are provided with observation windows, and the high resolution camera is fixed on the observation window on the top of the high and low temperature box; The lower end of the support rod is a smooth spherical surface, and the support rod vertically passes through the high and low temperature chamber to act on the measured piece. catch; The laser measurement group includes a pyramid reflector, a laser head and a computing module; the laser head is fixed outside the high and low temperature box and is opposite to the observation window on the side of the high and low temperature box, and the pyramid reflector passes through the corner cone reflector The mounting bases are respectively fixed on the end of the measured piece and the mounting base of the tested piece, there are two pyramidal mirrors on the mounting base of the pyramidal mirror, and each laser head corresponds to a pyramidal mirror. the

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