CN103940517A - Method for obtaining three-dimensional temperature field in metal structure - Google Patents

Abstract

The invention discloses a method for obtaining a three-dimensional temperature field inside a metal structure. First, a calibration method is used to determine the distance between the geometric nodes of the front and rear surfaces of the three-dimensional finite element model of the metal structure and the nodes of the two-dimensional image of the thermal imager of the metal structure. Using the mapping relationship, the temperature distribution diagram on the surface of the metal structure can be obtained; then, using the geometric information of the 3D finite element model of the metal structure, the user-specified cross-section inside the metal structure is used to locate, and then the linear calculation method is used Calculate the temperature value of each node on the user-specified section inside the metal structure, and then obtain the temperature distribution on all user-specified sections; finally, combine these temperature distribution maps to obtain the three-dimensional temperature field inside the metal structure.

Description

A method for obtaining three-dimensional temperature field inside metal structure

technical field

The invention relates to infrared temperature testing technology, in particular to a method for obtaining three-dimensional temperature distribution inside a metal structure.

Background technique

Infrared temperature measurement technology is widely used in machinery, aerospace, building materials, metallurgy, chemical industry, petroleum and other industries. Temperature measurement is one of the important contents of modern industrial control system, and its performance directly affects the quality of the controlled object. Controlling the heating temperature through accurate temperature measurement, so that it can reach the set value quickly and accurately, has very important practical significance for improving product quality and increasing production efficiency.

In the process of temperature control, temperature is also one of the main controlled parameters. The temperature distribution inside a typical component directly reflects the stability of the equipment, which can help the staff to observe intuitively and control the temperature according to the actual situation. The temperature distribution is related to the geometric dimensions, materials and other factors of typical components, so it can also reflect whether the design and manufacture of typical components are reasonable or not. From the temperature control process, the automatic control technology based on the temperature distribution analysis technology of typical components will provide an effective guarantee for the safety, high efficiency and low pollution of equipment operation.

However, due to the limitation of measurement means, the existing measuring instruments can only measure the temperature distribution on the surface of the component, and the temperature distribution inside the component cannot be directly known by the existing measurement means. In order to be able to obtain the temperature distribution inside the component, the current feasible solutions are the technology of reconstructing the three-dimensional temperature field by using the two-dimensional temperature field. For example, many researchers have realized the reconstruction of the three-dimensional temperature field by using the inverse solution method of image processing structure radiation transfer, and it has been applied in the three-dimensional temperature field visualization of coal-fired boilers in power stations. In 2007, the DRESOR method based on Monte Carlo technology was used to calculate the radiation transfer process in the furnace. According to the established linear relationship between the flame temperature image and the three-dimensional temperature field in the furnace, the improved Tikhonov regularization method was used to reconstruct the flame temperature image. Three-dimensional temperature field in the furnace. In recent years, some three-dimensional temperature field reconstruction techniques have been proposed using acoustic methods. These methods can be roughly divided into two categories: one is the 3D temperature field reconstruction method based on 2D typical plane reconstruction and 3D interpolation. The other is the direct three-dimensional temperature field reconstruction method. The first type of method, first take several typical layers in the three-dimensional measured space, and then arrange the acoustic wave transceivers as uniformly as possible around these typical layers to form multiple uniformly distributed acoustic flight paths through the plane, and calculate or measure The time-of-flight of the acoustic wave on these typical layers, use the two-dimensional temperature field reconstruction algorithm to reconstruct the temperature field of these typical layers, and then use the three-dimensional interpolation method to obtain the temperature field at the corresponding position on the remaining layers, so as to obtain the entire three-dimensional temperature Field reconstruction results. The direct three-dimensional temperature field reconstruction method first arranges acoustic transceivers around the measured space to form multiple uniformly distributed acoustic flight paths passing through the same layer and different layers of the measured area, and calculates the acoustic flight time. The direct 3D temperature field reconstruction algorithm reconstructs the 3D temperature field.

At present, these methods are only feasible schemes for the reconstruction of the three-dimensional temperature field of the penetrable gas or flame, and no relevant literature has been found for the reconstruction method of the three-dimensional temperature field of the solid structure with impenetrable materials.

Contents of the invention

The purpose of the present invention is to provide a method for reconstructing the internal three-dimensional temperature field from the two-dimensional temperature field on the outer surface of the metal structure.

To achieve the above object, the present invention is achieved by taking the following technical solutions:

A method for obtaining a three-dimensional temperature field distribution inside a metal structure, characterized in that it comprises the following steps:

The first step, first, establish a three-dimensional finite element model of the metal structure, and determine two outer surfaces parallel to the XY axis of the geometric coordinate system of the model, namely the front surface and the rear surface, where the Z-axis direction is from the rear surface to the front surface Then adjust the shooting position of the thermal imager to ensure that the XY axis of the pixel point coordinate system of the thermal imager two-dimensional map of the metal structure front and rear surface temperature distribution is in the same direction as the XY axis of the geometric coordinate system of the three-dimensional finite element model; Take pictures of the front and rear surface temperature distribution maps of the metal structure respectively, forming two two-dimensional maps of the surface temperature distribution of the metal structure;

The second step is to use the three-dimensional finite element model of the metal structure and two two-dimensional maps of the surface temperature distribution of the metal structure to establish a mapping relationship between the two. The specific steps are as follows:

(1) Establish the mapping relationship between the geometric coordinates of the three-dimensional finite element model of the metal structure and the pixel coordinates of the thermal imager two-dimensional image of the temperature distribution on the front surface of the metal structure, as shown in formula (1), since the two-dimensional map does not have Z Axis coordinates, so it is not considered when establishing the mapping relationship, and the formula (2) is the same;

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, X _1q and Y _1q are the horizontal and vertical coordinates of a pixel on the two-dimensional image of the thermal imager, unit: pixel; X _2q and Y _2q are the horizontal and vertical coordinates of the corresponding nodes on the front surface of the three-dimensional finite element model of the metal structure , the unit is the structural standard unit; X ₀ , Y ₀ are the horizontal and vertical coordinates of the origin of the three-dimensional finite element model of the metal structure in the two-dimensional image of the thermal imager, unit: pixel; L ₁ is the three-dimensional finite element model of the metal structure in The length in the two-dimensional image of the thermal imager, unit: pixel; _L2 is the structural length of the three-dimensional finite element model of the metal structure, and the unit is the physical unit used by the structure;

(2) Establish the relationship between the geometric coordinates of the three-dimensional finite element model of the metal structure and the pixels of the two-dimensional image of the temperature field distribution on the surface of the metal structure, as shown in formula (2):

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, X _1h and Y _1h are the horizontal and vertical coordinates of a node on the two-dimensional image of the thermal imager, unit: pixel; X _2h and Y _2h are the horizontal and vertical coordinates of the corresponding node on the rear surface of the three-dimensional finite element model of the metal structure , the unit is the structural standard unit;

(3) Use equations (1) and (2) to correspond the structural points on the front or rear surface of the metal structure with the pixels of the two-dimensional image of the thermal imager’s temperature distribution on the front and rear surfaces of the metal structure, and then, from the thermal image The temperature value of the node on the front surface or back surface of the metal structure obtained by the instrument is assigned to the corresponding structure point on the back surface or back surface of the metal structure; finally, the temperature distribution diagram of the surface of the metal structure is obtained;

The third step is to establish a three-dimensional temperature field inside the metal structure based on the temperature distribution map on the surface of the metal structure. The specific steps are as follows:

1) Use the geometric coordinate system of the three-dimensional finite element model of the metal structure to locate the internal section of the metal structure, and determine the user-specified section inside the metal structure; the specific positioning method is: first, obtain the depth of the user-specified section, and the three-dimensional The maximum coordinate value of the third direction of the node on the finite element model, and then subtract the actual depth input by the user from the maximum coordinate value of the third direction, and then the third direction coordinate of the user-specified section can be obtained, that is, it is located on the user-specified section ;

2) Calculate the temperature value of each node on the user-specified cross-section. The specific method is: for any point on the user-specified cross-section, according to its horizontal and vertical coordinates, find the horizontal and vertical coordinates in the front and rear surface structure data of the three-dimensional finite element model of the metal structure. The corresponding nodes whose coordinates are the same as the horizontal and vertical coordinates of this point; then, obtain their third direction coordinates from the metal structure data; and then use the second step method to obtain their temperature values according to the coordinates of these two corresponding nodes , use formula (3) to calculate the temperature value of the node:

T _i ＝T _iq +(T _iq -T _ih )|ZZ _iq |/|Z _iq -Z _ih | (3)

Among them, T _i is the temperature at any point on the user-specified section, T _iq and T _ih are the temperature of the corresponding node on the front surface and the corresponding node on the rear surface of the three-dimensional finite element model of the metal structure, respectively, and Z is the user-specified section The third direction coordinates, Z _iq and Z _ih are the third direction coordinates of the corresponding nodes on the front and rear surfaces of the three-dimensional finite element model of the metal structure; finally, according to the same method, calculate the temperature values of all nodes on the user-specified section ;

3) Using formula 1), find the corresponding pixel points in the two-dimensional image from all nodes on the user-specified section, and assign the temperature value obtained in step 2) to the corresponding pixel points; use the nearest neighbor point interpolation method to obtain the user Specify the temperature values of other pixels on the section, and draw a two-dimensional temperature distribution map of the user-specified section;

4) Combine the two-dimensional temperature distribution diagrams of all user-specified sections inside the metal structure to obtain the three-dimensional temperature field inside the metal structure.

Compared with the prior art, the beneficial effect of the present invention is to use the measurable two-dimensional temperature field distribution data on the front and rear surfaces of the metal structure, and then calculate and obtain any temperature on any section specified by the user inside the structure according to the three-dimensional structure information of the metal structure. The temperature data of the joints and the temperature distribution map on any cross-section specified by the user.

Detailed ways

A method to obtain the three-dimensional temperature field distribution inside the metal structure:

The first step, first, establish a three-dimensional finite element model of the metal structure, and determine the two outer surfaces parallel to the XY axes of its geometric coordinate system as the front surface and the rear surface, where the Z-axis direction is from the rear surface to the front surface. Then adjust the shooting position of the thermal imager to ensure that the XY axes of the thermal imager two-dimensional image pixel coordinate system of the metal structure front and rear surface temperature distribution are in the same direction as the XY axes of the geometric coordinate system of the three-dimensional finite element model of the metal structure. Finally, the two surface temperature distribution maps of the front and back of the metal structure are taken respectively to form two two-dimensional maps of the surface temperature distribution of the metal structure.

In the second step, using the three-dimensional finite element model of the metal structure and two two-dimensional maps of the temperature distribution on the surface of the metal structure, the mapping relationship between the two is established. Specific steps are as follows:

First, the mapping relationship between the geometric coordinates of the three-dimensional finite element model of the metal structure and the pixel coordinates of the thermal imager two-dimensional image of the temperature distribution on the front surface of the metal structure is established, as shown in formula (1). Since the two-dimensional map has no Z-axis coordinates, it will not be considered when establishing the mapping relationship. Formula (2) is the same.

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, X _1q and Y _1q are the horizontal and vertical coordinates of a pixel on the two-dimensional image of the thermal imager (unit: pixel), X _2q and Y _2q are the horizontal and vertical coordinates of the corresponding nodes on the front surface of the three-dimensional finite element model of the metal structure Coordinates (the unit is the structural standard unit), X ₀ and Y ₀ are the horizontal and vertical coordinates (unit: pixel) of the origin of the three-dimensional finite element model of the metal structure in the two-dimensional image of the thermal imager (unit: pixel), and L ₁ is the three-dimensional finite element model of the metal structure The length of the element model in the two-dimensional image of the thermal imager (unit: pixel), _L2 is the structural length of the three-dimensional finite element model of the metal structure (the unit is the physical unit used by the structure).

Then, the relationship between the geometric coordinates of the three-dimensional finite element model of the metal structure and the pixels of the two-dimensional image of the temperature field distribution on the back surface of the metal structure is established, as shown in formula (2).

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, X _1h and Y _1h are the horizontal and vertical coordinates of a node on the two-dimensional image of the thermal imager (unit: pixel), X _2h and Y _2h are the horizontal and vertical coordinates of the corresponding node on the rear surface of the three-dimensional finite element model of the metal structure Coordinates (the unit is the structural standard unit), X ₀ and Y ₀ are the horizontal and vertical coordinates (unit: pixel) of the origin of the three-dimensional finite element model of the metal structure in the two-dimensional photo of the thermal imager (unit: pixel), and L ₁ is the three-dimensional finite element model of the metal structure. The length of the element model in the two-dimensional image of the thermal imager (unit: pixel), _L2 is the structural length of the three-dimensional finite element model of the metal structure (the unit is the structural standard unit).

Using the formulas (1) and (2), the structure points on the front surface or the back surface of the metal structure are corresponding to the pixel points of the two-dimensional thermal imager image of the temperature distribution on the front and back surfaces of the metal structure. Furthermore, the temperature values of the pixel points on the front or back surface of the metal structure obtained from the thermal imager can be assigned to the corresponding structure points on the back or back surface of the metal structure. Finally, to obtain the temperature distribution diagram on the surface of the metal structure, in order to facilitate the establishment of the above-mentioned method of mapping the relationship between the structure points on the front or rear surface of the metal structure and the pixels of the two-dimensional image of the thermal imager's temperature distribution on the front and rear surfaces of the metal structure called calibration.

The third step is to establish a three-dimensional temperature field inside the metal structure based on the temperature distribution on the surface of the metal structure. The specific steps are as follows:

1) Use the geometric information of the three-dimensional finite element model of the metal structure to locate the internal section of the structure. The specific positioning method is as follows: First, obtain the depth of the section specified by the user and the maximum coordinate value of the node in the third direction on the three-dimensional finite element model of the metal structure, and then subtract the actual depth input by the user from the maximum coordinate value in the third direction. The coordinates of the third direction of the user-specified section can be obtained, that is, it is located on the user-specified section. Based on this method, user-specified sections inside metallic structures can be determined.

2) After determining the user-specified cross-section inside the metal structure, calculate the temperature value of each node on the user-specified cross-section, and then obtain the temperature distribution on the user-specified cross-section. The specific method is: for any point on the section specified by the user, according to its horizontal and vertical coordinates, find the corresponding node whose horizontal and vertical coordinates are the same as the horizontal and vertical coordinates of this point in the front and rear surface structure data of the three-dimensional finite element model of the metal structure. Then, their third-direction coordinates are obtained from the metal structure data. Then use the method of the second step to obtain their temperature values according to the coordinates of these two corresponding nodes, and use the formula (3) to calculate the temperature value of the node.

T _i ＝T _iq +(T _iq -T _ih )|ZZ _iq |/|Z _iq -Z _ih | (3)

Among them, T _i is the temperature at any point on the user-specified section, T _iq and T _ih are the temperature of the corresponding node on the front surface and the corresponding node on the rear surface of the three-dimensional finite element model of the metal structure, respectively, and Z is the user-specified section The third direction coordinates, Z _iq , Z _ih are the third direction coordinates of corresponding nodes on the front and rear surfaces of the three-dimensional finite element model of the metal structure, respectively. Finally, according to the same method, the temperature values of all nodes on the user-specified section are calculated.

3) By using the formula (1), all the nodes on the section specified by the user can be used to find the corresponding pixel points in the two-dimensional image, and assign temperature values to the corresponding pixel points. Using the nearest neighbor point interpolation method, the temperature values of other pixel points on the user-specified section can be obtained. And it can draw the two-dimensional temperature distribution diagram of the user-specified section.

Using the above method, the temperature distribution of all user-specified sections inside the metal structure can be obtained, that is, the three-dimensional temperature field distribution of the metal structure, and the two-dimensional temperature distribution map of any user-specified section can also be given. The three-dimensional temperature field inside the metal structure is obtained by combining the two-dimensional temperature distribution maps of all user-specified sections inside the metal structure.

The above-mentioned method of the present invention is illustrated below with a typical metal structure-rolling bearing.

The first step is to calibrate the camera or plane based on the geometric information of the three-dimensional finite element model of the rolling bearing, that is, to find the mapping relationship between the nodes on the front surface of the rolling bearing and the nodes in the plane photo of the thermal imager. Taking a node on the front surface of the rolling bearing as an example, the abscissa of the node is X ₂ =-4.09493 mm, the ordinate is Y ₂ =-4.429293 mm, and the abscissa of the origin of the three-dimensional finite element model in the plane photo of the thermal imager X ₀ =158 pixels, the ordinate is Y ₀ =111 pixels, the length L 1 of the three-dimensional finite element model in the plane photo of the thermal imager is L ₁ =212 pixels, and the structural length L ₂ of the three-dimensional finite element model is 90 mm. The abscissa X ₁ =148 pixels and the ordinate Y ₁ =100 pixels of the corresponding node on the plane photo of the thermal imager can be calculated by using the two formulas in the formula (1).

Then, using the abscissa and ordinate (148, 100) of the corresponding node on the plane photo of the thermal imager, the temperature value 12oC of the node (148, 100) on the two-dimensional temperature distribution on the upper surface of the typical structural bearing is assigned to the front of the rolling bearing. On the structure point (-4.09493, -4.429293) of the surface. Using the same method, the temperature values of all other points on the front or rear surface of the rolling bearing can be obtained. Finally, the three-dimensional temperature distribution map of the rolling bearing surface is obtained.

In the second step, based on the results of the first step, the three-dimensional temperature field data inside the rolling bearing is calculated. The specific steps are as follows: the first small step, based on the geometric information of the three-dimensional finite element model of the rolling bearing, locate the internal section of the rolling bearing. The coordinates of all surface nodes of the rolling bearing obtain the maximum third-direction coordinate value of 39.77539 mm, subtract the depth of the user-specified section from the maximum ordinate, and then obtain the third-direction coordinate Z of the user-specified section = 34.77539 mm, that is, the positioning User specified section.

The second small step, when the user-specified cross-section is determined, calculate the two-dimensional temperature data of all nodes on the user-specified cross-section. First, for any point on the section, such as the node (-.313396, -3.16591), according to its coordinates, find the horizontal and vertical coordinates in the front and rear surface structure data of the three-dimensional finite element model of the rolling bearing (-.313396, -3.16591) of the corresponding nodes, their third direction coordinates Z _io =30.8138 and Z _ib =-38.7618 are obtained from the three-dimensional structure data of the rolling bearing. Then, using the method of the first step according to the coordinates of the two corresponding nodes, their temperature values are respectively T _io =49.6°C and T _ib =44.7°C. Using formula (3), calculate the temperature value of the node (-.313396, -3.16591) to be 53.56159°C. Finally, according to the same method, the temperature values of all nodes on the user-specified section are calculated.

The third small step is to use the formula (1) to find the corresponding pixel points from all nodes on the user-specified section, and assign temperature values to the corresponding pixel points. For example, from the node (-.313396, -3.16591), the abscissa X1=157 pixels and the ordinate Y1=103 pixels of the corresponding pixel in the two-dimensional picture can be calculated by using the two formulas in formula (1). Finally, using the nearest neighbor point interpolation method, the temperature values of other pixel points on the user-specified section can be obtained. And it can draw the two-dimensional temperature distribution diagram of the user-specified section.

Using the above method, the temperature distribution of all user-specified sections inside the structure is obtained, that is, the three-dimensional temperature field distribution of the rolling bearing. For reasons of space, Table 1 gives the temperature values of the area from the 100th pixel to the 200th pixel on the ordinate and from the 105th pixel to the 114th pixel on the abscissa on the user-specified section with a depth of 5 mm. Furthermore, it can also give a two-dimensional temperature distribution map of any user-specified section.

Table 1 (unit: pixel)

Horizontal and vertical coordinates 105 106 107 108 109 110 111 112 113 114 100 63.155 66.53999 69.395 72.165 74.05 75.92001 77.20499 78.00501 78.79 79.275 101 76.915 78.785 79.955 81.225 82.01001 82.795 83.38001 83.86501 84.07999 84.565 102 80.635 80.635 79.955 81.225 82.01001 82.795 83.38001 83.86501 84.07999 84.565 103 81.4 80.3 79.3 78.20001 77.6 77.185 76.885 76.685 76.685 76.9 104 68.085 65.91499 64.43 63.045 62.245 61.645 61.16 61.06 61.06 61.275 105 56.345 54.075 52.605 51.22 50.52 49.835 49.35 49.25 49.25 49.365 106 45.78 44.295 43.21 42.125 41.625 41.04 40.74 40.64 40.64 40.84 107 36.77 35.68501 34.9 34.115 33.715 33.415 33.03 32.93 32.93 33.03 108 31.145 30.345 29.66 29.06 28.76 28.375 28.09 27.99 27.99 27.99 109 25.79 25.09 24.32 23.92 23.535 23.335 23.05 22.95 22.95 22.95 110 22.45 21.95 21.465 20.98 20.78 20.495 20.395 20.295 20.295 20.295 111 19.31 18.91 18.525 18.325 18.125 17.84 17.74 17.825 17.825 17.74 112 17.34 17.04 16.755 16.555 16.455 16.17 16.255 16.07 16.07 16.07 113 15.685 15.485 15.47 15.37 15.27 15.17 14.985 14.985 14.985 14.985 114 14.6 14.4 14.485 14.57 14.385 14.285 14.1 14.1 14.1 14.1 115 14 13.9 13.9 13.985 13.8 13.7 13.7 13.785 13.785 13.6 116 13.5 13.13 13.13 13.215 13.215 13.3 13.3 13.385 13.2 13.2 117 13.115 12.93 12.93 13.015 13.1 13.1 13.185 13 13 12.915 118 12.915 12.73 12.73 12.815 12.815 12.985 12.985 12.715 12.715 12.715 119 12.63 12.63 12.53 12.53 12.615 12.615 12.615 12.615 12.615 12.615 120 12.43 12.43 12.43 12.43 12.43 12.43 12.43 12.43 12.43 12.43 121 12.33 12.33 12.33 12.33 12.33 12.245 12.245 12.33 12.33 12.33 122 12.415 12.415 12.415 12.23 12.23 12.415 12.415 12.415 12.415 12.415 123 12.415 12.415 12.23 12.23 12.23 12.23 12.23 12.415 12.23 12.23 124 12.23 12.23 12.23 12.23 12.23 12.23 12.23 12.23 12.23 12.13 125 12.13 12.045 12.045 12.045 12.045 12.045 12.13 12.13 12.13 12.13 126 12.13 12.045 12.045 12.045 12.045 12.13 12.13 12.13 12.13 11.945 127 12.045 12.045 12.045 12.045 12.045 12.13 12.13 12.13 12.13 11.945 128 12.045 12.045 12.045 12.045 12.13 12.13 11.945 12.13 12.13 12.03 129 12.13 12.13 12.13 12.13 12.13 12.13 12.13 11.945 12.03 12.03 130 12.13 12.13 11.945 11.945 11.945 12.13 12.03 12.03 12.03 11.845 131 11.945 12.03 12.03 12.03 12.03 12.03 12.03 12.03 11.845 11.845 132 11.845 11.845 12.03 12.03 12.115 11.845 11.845 11.845 11.845 11.845 133 11.845 11.845 11.845 11.845 11.93 11.845 11.845 11.845 11.93 11.93 134 11.845 11.845 11.845 11.845 11.93 11.845 12.03 12.115 11.93 11.93 135 12.03 12.03 11.845 11.845 11.93 11.93 12.115 12.115 12.115 11.93 136 12.03 12.03 11.845 11.93 11.93 11.93 11.93 12.115 12.115 11.93

137 12.03 11.845 11.845 11.745 11.745 11.93 11.93 11.93 11.93 11.845 138 11.845 11.845 11.845 11.745 11.745 11.745 11.745 11.93 11.845 11.845 139 11.845 11.845 11.93 11.745 11.745 11.745 11.745 11.745 11.745 11.66 140 11.845 11.93 11.93 11.93 11.93 11.93 11.745 11.745 11.745 11.745 141 11.93 11.93 11.93 11.93 11.93 11.93 11.93 11.745 11.745 11.745 142 11.93 11.93 11.93 11.93 11.845 11.845 11.845 11.745 11.745 11.745 143 11.93 11.845 11.845 11.845 11.845 11.845 11.845 11.745 11.745 11.745 144 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.745 11.745 11.745 145 11.93 11.745 11.745 11.745 11.745 11.66 11.66 11.745 11.745 11.745 146 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 147 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 148 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 149 11.93 11.93 11.93 11.93 11.93 11.745 11.745 11.745 11.745 11.745 150 11.93 11.93 11.93 11.845 11.745 11.745 11.745 11.745 11.745 11.745 151 11.745 11.93 11.93 11.66 11.745 11.745 11.745 11.745 11.745 11.745 152 11.66 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.93 153 11.66 11.66 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.93 154 11.66 11.66 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 155 11.845 11.845 11.745 11.93 11.745 11.745 11.745 11.745 11.745 11.745 156 11.745 11.93 11.93 11.93 11.93 11.745 11.745 11.745 11.745 11.745 157 11.745 11.93 11.93 11.93 11.93 11.745 11.745 11.745 11.745 11.745 158 11.745 11.93 11.93 11.93 11.745 11.66 11.66 11.66 11.745 11.745 159 11.93 11.93 11.93 12.015 11.83 11.745 11.66 11.66 11.745 11.745 160 11.845 11.845 11.93 11.83 11.83 11.745 11.745 11.66 11.745 11.745 161 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 162 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 163 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.83 11.83 11.745 164 11.745 11.745 11.745 11.745 11.745 11.66 11.93 11.93 12.015 11.93 165 11.93 11.745 11.745 11.745 11.745 11.845 11.845 11.93 11.93 11.93 166 11.845 11.93 11.745 11.745 11.745 11.745 11.845 11.845 11.845 11.93 167 11.845 11.93 11.745 11.745 11.745 11.66 11.845 11.845 11.845 11.845 168 11.845 11.93 11.745 11.745 11.66 11.66 11.66 11.845 11.845 11.845 169 11.93 11.93 11.745 11.66 11.66 11.66 11.66 11.845 11.845 11.845 170 11.93 11.745 11.745 11.745 11.66 11.66 11.66 11.845 11.845 11.845 171 11.745 11.745 11.745 11.745 11.745 11.66 11.66 11.845 11.845 11.845 172 11.745 11.745 11.745 11.745 11.745 11.66 11.845 11.845 11.93 11.745 173 11.745 11.745 11.745 11.745 11.745 11.845 11.845 11.93 11.745 11.745 174 11.745 11.745 11.745 11.745 11.745 11.845 11.845 11.745 11.745 11.745 175 11.745 11.745 11.745 11.745 11.745 11.66 11.66 11.745 11.745 11.745 176 11.745 11.745 11.745 11.745 11.745 11.66 11.66 11.745 11.745 11.745 177 11.745 11.745 11.745 11.745 11.745 11.66 11.66 11.745 11.745 11.745 178 11.66 11.745 11.745 11.745 11.745 11.845 11.845 11.745 11.745 11.745 179 11.845 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 180 11.93 11.93 11.745 11.745 11.745 11.745 11.745 11.745 11.745 11.745 181 11.93 11.93 11.745 11.745 11.745 11.745 11.745 11.745 11.93 11.93 182 11.93 11.93 11.745 11.745 11.745 11.745 11.745 11.93 11.93 11.845 183 11.93 11.93 11.93 11.745 11.745 11.745 11.93 11.845 11.845 11.845 184 11.93 11.93 11.93 11.93 11.93 11.93 11.93 11.845 11.845 11.845 185 11.745 11.93 11.93 11.93 11.93 11.93 11.93 11.845 11.845 11.845

186 11.845 11.93 11.93 11.93 11.93 11.93 11.93 11.845 11.845 11.845 187 11.845 11.93 11.93 11.93 11.93 11.93 11.93 11.845 11.845 11.845 188 11.845 11.845 11.93 11.93 11.93 11.93 11.93 11.845 11.845 11.845 189 11.845 11.845 11.845 11.845 11.93 11.93 11.66 11.66 11.66 11.66 190 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.66 11.66 191 11.845 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.66 192 11.845 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.66 193 11.845 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.745 194 11.845 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.745 195 11.845 11.845 11.845 11.845 11.845 11.845 11.845 11.66 11.66 11.845 196 11.76 11.76 11.76 11.845 11.845 11.845 11.845 11.845 11.845 11.845 197 11.86 11.86 11.945 11.945 12.03 11.93 11.93 11.845 11.845 12.03 198 12.045 12.045 12.045 11.945 12.03 12.03 12.03 12.03 12.03 12.03 199 12.045 12.045 12.045 12.045 11.945 12.03 12.03 12.03 12.03 12.03 200 12.045 12.045 12.045 12.045 12.13 12.13 12.13 12.13 12.215 12.215

Claims (1)

1. obtain the method that metal construction interior three-dimensional temperature field distributes, it is characterized in that, comprise the steps:

The first step, first, sets up the three-dimensional finite element model of metal construction, and determines two outside surfaces that parallel with this model geometric coordinate system XY axle: front surface and rear surface, and wherein Z-direction is pointed to front surface by rear surface; Then adjust the camera site of thermal imaging system, make the XY axle of pixel coordinate system of the forward and backward surface temperature distribution X-Y scheme of metal construction and the XY axle of three-dimensional finite element model geometric coordinate system in the same way; Finally shoot respectively this former and later two surface temperature distribution figure, form the X-Y scheme of two these metal structure surface Temperature Distribution;

Second step, utilizes the X-Y scheme of three-dimensional finite element model and two metal structure surface Temperature Distribution of metal construction, sets up the mapping relations between the two, and concrete steps are as follows:

(1) set up the mapping relations between the geometric coordinate of metal construction three-dimensional finite element model and the thermal imaging system two dimensional image vegetarian refreshments coordinate of metal construction front surface Temperature Distribution, shown in (1), because X-Y scheme does not have Z axis coordinate, so do not consider in the time setting up mapping relations, formula (2) in like manner;

$\left\{\begin{array}{c}{X}_{1q}=X_{2q}*L_1/L_2+X_0\\ Y_{1q}=Y_{2q}*L_1/L_2+Y_0\end{array}\right.---\left(1\right)$

Wherein, X _1q, Y _1qthe transverse and longitudinal coordinate of a pixel on thermal imaging system X-Y scheme, unit: pixel; X _2q, Y _2qbe the transverse and longitudinal coordinate of the corresponding node of front surface in the three-dimensional finite element model of metal construction, unit is construction standard unit; X ₀, Y ₀the initial point of three-dimensional finite element model of the metal construction transverse and longitudinal coordinate in thermal imaging system X-Y scheme, unit: pixel; L ₁for the three-dimensional finite element model of the metal construction length in thermal imaging system X-Y scheme, unit: pixel; L ₂for the structure length of the three-dimensional finite element model of metal construction, unit is the physical unit that structure is used;

(2) set up the relation between the geometric coordinate of metal construction three-dimensional finite element model and the X-Y scheme pixel of temperature field, metal construction rear surface distribution, shown in (2):

$\left\{\begin{array}{c}{X}_{1h}=X_{2h}*L_1/L_2+X_0\\ Y_{1h}=Y_{2h}*L_1/L_2+Y_0\end{array}\right.---\left(2\right)$

Wherein, X _1h, Y _1hthe transverse and longitudinal coordinate of a node on thermal imaging system X-Y scheme, unit: pixel; X _2h, Y _2hbe the transverse and longitudinal coordinate of the corresponding node in rear surface in the three-dimensional finite element model of metal construction, unit is construction standard unit;

(3) utilize formula (1) and formula (2) that the pixel of the thermal imaging system X-Y scheme of the system point of metal construction front surface or rear surface and metal construction front and rear surfaces Temperature Distribution is mapped, and then, the temperature value of node the metal construction front surface obtaining from thermal imaging system or rear surface is given on the counter structure point of metal construction front surface or rear surface; Finally, obtain the temperature profile of metal structure surface;

The 3rd step, the temperature profile based on metal structure surface is set up metal construction interior three-dimensional temperature field, and concrete steps are as follows:

1) utilize the geometric coordinate of metal construction three-dimensional finite element model to be, metal construction inner section is positioned, determine user's specified cross-section of metal construction inside; Concrete localization method is: first, obtain the degree of depth of user's specified cross-section, and the third direction maximum coordinates value of node in metal construction three-dimensional finite element model, deduct again the actual grade of user's input by this third direction maximum coordinates value, just can obtain the third direction coordinate of user's specified cross-section, navigate on user's specified cross-section;

2) temperature value of each node on calculating user specified cross-section, concrete grammar is: for any point on user's specified cross-section, find the corresponding node that transverse and longitudinal coordinate is identical with the transverse and longitudinal coordinate of this point according to its transverse and longitudinal coordinate in the front and rear surfaces structured data of the three-dimensional finite element model of metal construction; Then, from metal construction data, obtain their third direction coordinate; Utilize again the method for second step according to these two corresponding node coordinates, obtain their temperature value, utilize formula (3), calculate the temperature value of this node:

T _i＝T _iq+(T _iq-T _ih)|Z-Z _iq|/|Z _iq-Z _ih| (3)

Wherein, T _ifor the temperature of any point on user's specified cross-section, T _iq, T _ihthe temperature that is respectively the corresponding node of temperature and rear surface of the corresponding node of front surface of the three-dimensional finite element model of metal construction, Z is user's specified cross-section third direction coordinate, Z _iq, Z _ihbe respectively the third direction coordinate of corresponding node in the front and rear surfaces of three-dimensional finite element model of metal construction; Finally, according to same method, calculate the temperature value of all nodes on user's specified cross-section;

3) utilize formula (1), find corresponding pixel points in X-Y scheme by all nodes on user's specified cross-section, and compose step 2 to corresponding pixel points) temperature value that obtains; Utilize the method for neighbor point interpolation, obtain the temperature value of other pixel on user's specified cross-section, draw the two-dimension temperature distribution plan of user's specified cross-section;

4) the two-dimension temperature distribution plan of the inner all user's specified cross-sections of metal construction is combined, just obtain the three-dimensional temperature field of metal construction inside.