CN103398667B - A fast measuring device and method for plane deformation based on optical principle - Google Patents

Abstract

The invention provides the quick measurement mechanism of a kind of plane deformation based on optical principle, comprise NI-G plate and digital camera that four are cross-shaped arrangement, four NI-G plates comprise the first NI-G plate and the second NI-G plate of two panels horizontally set, and the 3rd NI-G plate that longitudinally arranges of two panels and the 4th NI-G plate, every sheet NI-G plate all offers a bolt slot, be provided with a bolt in bolt slot, bolt can slide along bolt slot; First NI-G plate is fixedly installed the first lateral marker thing and the second lateral marker thing, the second NI-G plate is fixedly installed the 3rd lateral marker thing; 3rd NI-G plate is fixedly installed first longitudinal mark and second longitudinal mark, the 4th NI-G plate is fixedly installed the 3rd longitudinal mark.The present invention repeatedly can measure the distortion of planar structure at diverse location, has simple to operate, with low cost, high temperature resistant and precision high; The present invention also provides the quick measuring method of a kind of plane deformation based on optical principle simultaneously.

Description

A fast measuring device and method for plane deformation based on optical principle

technical field

The invention belongs to the field of optical measurement, and in particular relates to a fast measurement device and method for plane deformation based on optical principles.

Background technique

Deformation is a ubiquitous phenomenon in nature. It refers to the change of shape, size and position of a deformed object in the time and space domains under various loads. In the field of engineering, when the amount of deformation does not exceed a certain range, it will not cause harm; if it exceeds the allowable value that the deformed body can bear, it may cause serious disasters. Therefore, it is very important to carry out regular deformation measurement on the structure.

At present, strain gauges are the most common deformation measuring instruments, but strain gauges generally have the following three disadvantages: 1. Temperature changes cause changes in the resistance of the strain gauge’s sensitive grid, and the linear expansion coefficients of the test piece material and the sensitive grid material are different. Additional strain will be generated, causing a large measurement error; 2. The range of the strain gauge is limited, and it has a large nonlinearity under large strain; 3. The output signal of the strain gauge is weak, and the anti-interference ability poor.

Contents of the invention

Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a fast measuring device for plane deformation based on optical principles, which can measure the deformation of plane structures multiple times at different positions, and has the advantages of simple operation, low cost, high temperature resistance and high precision. Features; the present invention also provides a fast measurement method for plane deformation based on optical principles.

The present invention is achieved through the following technical solutions:

A fast measurement device for plane deformation based on optical principles, characterized in that it includes four nickel-cadmium plates arranged in a cross shape and a digital camera, and the four nickel-cadmium plates include two first nickel-cadmium plates arranged horizontally and The second nickel-cadmium plate, and two longitudinally arranged third nickel-cadmium plates and fourth nickel-cadmium plates, each nickel-cadmium plate is provided with a bolt groove, and a bolt is installed in the bolt groove, and the bolt can be moved along the The bolt groove slides; the bottom end of the bolt is fixed on the object to be measured;

The first horizontal marker and the second horizontal marker are fixedly arranged on the first nickel-cadmium plate, and the third horizontal marker is fixedly arranged on the second nickel-cadmium plate; the first horizontal marker, the second horizontal marker and the The center point of the third horizontal marker is located on the same horizontal straight line; the second horizontal marker is located between the first horizontal marker and the third horizontal marker;

The first longitudinal marker and the second longitudinal marker are fixedly arranged on the third nickel-cadmium plate, and the third longitudinal marker is fixedly arranged on the fourth nickel-cadmium plate; the first longitudinal marker, the second longitudinal marker and the The center point of the third longitudinal marker is located on the same longitudinal straight line; the second longitudinal marker is located between the first longitudinal marker and the third longitudinal marker; the transverse straight line and the longitudinal straight line are perpendicular to each other.

The further setting of the present invention is that the first horizontal marker, the second horizontal marker, the third horizontal marker, the first vertical marker, the second vertical marker and the third vertical marker are all silicon nitride, The silicon nitride is welded on the nickel-cadmium board.

The present invention also provides a fast measurement method for plane deformation based on the optical principle, which includes the following steps:

(1) the plane deformation quick measurement device based on optical principle described in claim 1 is installed on the object to be measured, and a distance is left between the first nickel-cadmium plate and the second nickel-cadmium plate arranged laterally in two pieces, There is a gap between the two longitudinally arranged third nickel-cadmium plates and the fourth nickel-cadmium plates;

(2) After the installation is completed, use a digital camera to take the first photo of the four nickel-cadmium plates, and the resulting image is used as a reference image; note that the distance between the first horizontal marker and the center point of the second horizontal marker is n _x pixels, the distance between the first horizontal marker and the center point of the third horizontal marker is m _x pixels; the distance between the first vertical marker and the center point of the second longitudinal marker is n _y pixels, the first The distance between the longitudinal marker and the center point of the third longitudinal marker is m _y pixels;

When first observed,

The actual distance between the center point of the first horizontal marker and the third horizontal marker is

The actual distance between the center point of the first longitudinal marker and the third longitudinal marker is

Wherein, N _x is the actual distance between the center point of the first horizontal marker and the second horizontal marker, and N _y is the actual distance between the center point of the first longitudinal marker and the second longitudinal marker;

(3) Periodically or irregularly observe the four nickel-cadmium plates during the deformation period of the object to be measured; when performing the i-th observation, i is a positive integer greater than 1;

Note that the distance between the first horizontal marker and the center point of the second horizontal marker is n' _x pixels, and the distance between the first horizontal marker and the center point of the third horizontal marker is m' _x pixels; The distance between a longitudinal marker and the center point of the second longitudinal marker is n' _y pixels, and the distance between the first longitudinal marker and the center point of the third longitudinal marker is m' _y pixels;

At the i-th observation,

The actual distance between the center point of the first horizontal marker and the third horizontal marker is

The actual distance between the center point of the first longitudinal marker and the third longitudinal marker is

(4) Obtain the deformation of the object to be measured at the time of the i-th observation:

The amount of deformation in the x direction is: ${\mathrm{\Δx}}_i=l_x^{\′}-l_x=N_x(\frac{m_x^{\′}}{{\mathrm{no}}_x^{\′}}-\frac{m_x}{{\mathrm{no}}_x})$

The amount of deformation in the y direction is: ${\mathrm{\Δy}}_i=l_{\mathrm{the\; y}}^{\′}-l_{\mathrm{the\; y}}=N_{\mathrm{the\; y}}(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}_{\mathrm{the\; y}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{{\mathrm{no}}_{\mathrm{the\; y}}})$

The total deformation of the object to be measured is: ${\mathrm{\Δ\; L}}_i=\sqrt{N_x^2{(\frac{m_x^{\′}}{{\mathrm{no}}_x^{\′}}-\frac{m_x}{m_x})}^2+N_{\mathrm{the\; y}}^2{(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}_{\mathrm{the\; y}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{m_{\mathrm{the\; y}}})}^2}.$

The fast measurement device and method for plane deformation based on the optical principle of the present invention can measure the deformation of the plane structure multiple times at different positions, and has the characteristics of simple operation, low cost, high temperature resistance and high precision; The measuring device performs multiple measurements on the object to be measured, and can obtain the deformation law of the object to be measured as the time changes. Compare the deformation value with the allowable deformation value that the object can bear, so as to effectively evaluate the safety performance of the structure.

Description of drawings

Fig. 1 is a structural diagram of a quick measurement device for plane deformation based on optical principles according to the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the present invention provides a quick measurement device for plane deformation based on the optical principle, including four nickel-cadmium plates arranged in a cross shape and a digital camera. Because the nickel-cadmium material has stable chemical properties, there is no obvious Expansion with heat and contraction with cold, when measuring, the nickel-cadmium plate itself does not deform.

The four nickel-cadmium plates include two horizontally arranged first nickel-cadmium plates 1 and the second nickel-cadmium plate 2, and two longitudinally arranged third nickel-cadmium plates 3 and the fourth nickel-cadmium plate 4, each nickel-cadmium plate A bolt groove 11 is provided on the cadmium plate, and a bolt 12 is installed in the bolt groove 11, and the bolt 12 can slide along the bolt groove 11 and be fixed at any position. The bottom ends of the bolts 12 are fixed on the object to be measured; the four nickel-cadmium plates form an angle of 90° with each other.

The first horizontal marker 5 and the second horizontal marker 6 are fixedly arranged on the first nickel-cadmium plate 1, and the third horizontal marker 7 is fixedly arranged on the second nickel-cadmium plate 2; the first horizontal marker 5, The center points of the second horizontal marker 6 and the third horizontal marker 7 are located on the same horizontal straight line; the second horizontal marker 6 is located between the first horizontal marker 5 and the third horizontal marker 7;

The first longitudinal marker 8 and the second longitudinal marker 9 are fixedly arranged on the third nickel-cadmium plate 3, and the third longitudinal marker 10 is fixedly arranged on the fourth nickel-cadmium plate 4; the first longitudinal marker 8, The center points of the second longitudinal marker 9 and the third longitudinal marker 10 are located on the same longitudinal straight line; the second longitudinal marker 9 is located between the first longitudinal marker 8 and the third longitudinal marker 10; the horizontal straight line and The longitudinal straight lines are perpendicular to each other.

The first horizontal marker 5, the second horizontal marker 6, the third horizontal marker 7, the first vertical marker 8, the second vertical marker 9 and the third vertical marker 10 are silicon nitride, so The above-mentioned silicon nitride is welded on the nickel-cadmium plate, and the silicon nitride can provide good optical measurement effect under light.

In this embodiment, the distance between the center points of the two markers 5 and 6 on the first nickel-cadmium plate 1 is set to 3 mm, and the distance between the center points of the two marks 8 and 9 on the third nickel-cadmium plate 3 is also set to 3 mm.

The present invention also provides a fast measurement method for plane deformation based on the optical principle, which includes the following steps:

(1) Install the above-mentioned fast measuring device for plane deformation based on the optical principle on the object to be measured, reserve a certain distance between the two nickel-cadmium plates in the horizontal direction, and reserve a certain distance between the two nickel-cadmium plates in the vertical direction, The distance is selected according to the estimation of the deformation of the object to be measured; the purpose of reserving a certain distance between the two nickel-cadmium plates is to prevent the deformation of the object to be measured from being negative, if the reserved distance is small, As the object to be measured shrinks and deforms, the two nickel-cadmium plates will come into contact, making deformation measurement impossible.

(2) After the installation is completed, use a digital camera to take the first photo of the four nickel-cadmium plates, and the resulting image is used as a reference image; note that the distance between the first horizontal marker and the center point of the second horizontal marker is n _x pixels, the distance between the first horizontal marker and the center point of the third horizontal marker is m _x pixels; the distance between the first vertical marker and the center point of the second longitudinal marker is n _y pixels, the first The distance between the longitudinal marker and the center point of the third longitudinal marker is m _y pixels;

First observation:

The actual distance between the center point of the first horizontal marker and the third horizontal marker:

The actual distance between the center point of the first longitudinal marker and the third longitudinal marker: Wherein, N _x is the actual distance between the center point of the first horizontal marker and the second horizontal marker, and N _y is the actual distance between the center point of the first longitudinal marker and the second longitudinal marker;

(3) During the deformation period of the object to be measured, observe the four nickel-cadmium plates regularly or irregularly; when the i-th observation is made (i is a positive integer greater than 1), record the first horizontal marker and the second horizontal marker The distance between the center points of the markers is n' _x pixels, the distance between the center points of the first horizontal marker and the third horizontal marker is m' _x pixels; the first vertical marker and the second vertical marker The distance between the center points is n' _y pixels, and the distance between the center points of the first longitudinal marker and the third longitudinal marker is m' _y pixels;

The i-th observation:

The actual distance between the center point of the first horizontal marker and the third horizontal marker:

The actual distance between the center point of the first longitudinal marker and the third longitudinal marker:

(4) Obtain the deformation of the object to be measured at the time of the i-th observation:

The amount of deformation in the x direction is: ${\mathrm{\Δx}}_i=l_x^{\′}-l_x=N_x(\frac{m_x^{\′}}{{\mathrm{no}}_x^{\′}}-\frac{m_x}{{\mathrm{no}}_x})$

The amount of deformation in the y direction is: ${\mathrm{\Δy}}_i=l_{\mathrm{the\; y}}^{\′}-l_{\mathrm{the\; y}}=N_{\mathrm{the\; y}}(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}_{\mathrm{the\; y}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{{\mathrm{no}}_{\mathrm{the\; y}}})$

The total deformation of the object to be measured is: ${\mathrm{\Δ\; L}}_i=\sqrt{N_x^2{(\frac{m_x^{\′}}{{\mathrm{no}}_x^{\′}}-\frac{m_x}{{\mathrm{no}}_x})}^2+N_{\mathrm{the\; y}}^2{(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}_{\mathrm{the\; y}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{{\mathrm{no}}_{\mathrm{the\; y}}})}^2}$

In this embodiment, N _x = N _y = 3 mm, n _x = n _y = n, n' _x = n' _y = n' then

The amount of deformation in the x direction is: ${\mathrm{\Δx}}_i=l_x^{\′}-l_x=3(\frac{m_x^{\′}}{{\mathrm{no}}^{\′}}-\frac{m_x}{\mathrm{no}})$

The amount of deformation in the y direction is: ${\mathrm{\Δy}}_i=l_{\mathrm{the\; y}}^{\′}-1_{\mathrm{the\; y}}=3(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{\mathrm{no}})$

The total deformation of the object to be measured is: ${\mathrm{\Δ\; L}}_i=3\sqrt{{(\frac{m_x^{\′}}{{\mathrm{no}}^{\′}}-\frac{m_x}{\mathrm{no}})}^2+{(\frac{m_{\mathrm{the\; y}}^{\′}}{{\mathrm{no}}^{\′}}-\frac{m_{\mathrm{the\; y}}}{\mathrm{no}})}^2}$

It will be obvious to those skilled in the art that the present invention may be modified in various ways and such modifications are not to be regarded as departing from the scope of the present invention. All such modifications obvious to those skilled in the art are intended to be included within the scope of this claim.

Claims (3)

1. the quick measurement mechanism of the plane deformation based on optical principle, it is characterized in that, comprise NI-G plate and digital camera that four are cross-shaped arrangement, described four NI-G plates comprise the first NI-G plate and the second NI-G plate of two panels horizontally set, and the 3rd NI-G plate that longitudinally arranges of two panels and the 4th NI-G plate, every sheet NI-G plate all offers a bolt slot, and be provided with a bolt in described bolt slot, described bolt can slide along bolt slot; The bottom of described bolt is fixed on object under test;

Described first NI-G plate is fixedly installed the first lateral marker thing and the second lateral marker thing, the second NI-G plate is fixedly installed the 3rd lateral marker thing; The central point of the first lateral marker thing, the second lateral marker thing and the 3rd lateral marker thing is positioned on same horizontal straight line; Second lateral marker thing is between the first lateral marker thing and the 3rd lateral marker thing;

Described 3rd NI-G plate is fixedly installed first longitudinal mark and second longitudinal mark, the 4th NI-G plate is fixedly installed the 3rd longitudinal mark; The central point of first longitudinal mark, second longitudinal mark and the 3rd longitudinal mark is positioned on same longitudinal straight line; Second longitudinal mark is between first longitudinal mark and the 3rd longitudinal mark; Described horizontal straight line is mutually vertical with longitudinal straight line.

2. according to the plane deformation quick measurement mechanism of claim 1 based on optical principle, it is characterized in that, described first lateral marker thing, the second lateral marker thing, the 3rd lateral marker thing, first longitudinal mark, second longitudinal mark and the 3rd longitudinal mark are silicon nitride, and described silicon nitride is welded on NI-G plate.

3., based on the quick measuring method of plane deformation of optical principle, it is characterized in that, comprise the following steps:

(1) will be arranged on object under test in the quick measurement mechanism of the plane deformation based on optical principle according to claim 1, between the first NI-G plate and the second NI-G plate of two panels horizontally set, leave spacing, between the 3rd NI-G plate that two panels is longitudinally arranged and the 4th NI-G plate, leave spacing;

(2) after installation, carry out first time shooting with digital camera to four NI-G plates, gained image is as reference image; Remember that the distance between the first lateral marker thing and the second lateral marker thing central point is n _xindividual pixel, the distance between the first lateral marker thing and the 3rd lateral marker thing central point is m _xindividual pixel; Distance between first longitudinal mark and second longitudinal mark central point is n _yindividual pixel, the distance between first longitudinal mark and the 3rd longitudinal mark central point is m _yindividual pixel;

When observing for the first time,

Actual range between first lateral marker thing and the 3rd lateral marker thing central point is

Actual range between first longitudinal mark and the 3rd longitudinal mark central point is

Wherein, N _xbe the actual range between the first lateral marker thing and the second lateral marker thing central point, N _yit is the actual range between first longitudinal mark and second longitudinal mark central point;

(3) between object under test deformation phases, carry out regularly or irregularly observing to four NI-G plates; When carrying out i-th observation, _ifor being greater than the positive integer of 1;

Remember that the distance between the first lateral marker thing and the second lateral marker thing central point is n ' _xindividual pixel, the distance between the first lateral marker thing and the 3rd lateral marker thing central point is m ' _xindividual pixel; Distance between first longitudinal mark and second longitudinal mark central point is n ' _yindividual pixel, the distance between first longitudinal mark and the 3rd longitudinal mark central point is m ' _yindividual pixel;

During i-th observation,

Actual range between first lateral marker thing and the 3rd lateral marker thing central point is

Actual range between first longitudinal mark and the 3rd longitudinal mark central point is

(4) obtain when i-th observation, the deflection of object under test is:

Deflection on x direction is: ${\mathrm{\Δx}}_i=l_x^{\′}-l_x=N_x(\frac{m_x^{\′}}{n_x^{\′}}-\frac{m_x}{n_x})$

Deflection on y direction is: ${\mathrm{\Δy}}_i=l_y^{\′}-l_y=N_y(\frac{m_y^{\′}}{n_y^{\′}}-\frac{m_y}{n_y})$

Object under test total deformation is: ${\mathrm{\ΔL}}_i=\sqrt{N_x^2{(\frac{m_x^{\′}}{n_x^{\′}}-\frac{m_x}{n_x})}^2+N_y^2{(\frac{m_y^{\′}}{n_y^{\′}}-\frac{m_y}{n_y})}^2}.$