Measure the method for steel construction welding deformation based on grid
Technical field
The present invention relates to the steel construction welding field, particularly a kind of method of measuring the steel construction welding deformation based on grid.
Background technology
Along with the high speed development of construction work, the design of steel construction becomes increasingly complex, and is increasingly high to the welding deformation control requirement, so steel construction measurement of the distortion of generation when welding needs also to increase day by day.The common method of measuring the steel construction welding deformation has: the tape measure and the ruler direct method of measurement, measure drawdown deformation and vertically deflection deformation that welding produces; The foil gauge mensuration is measured structure partial displacement and strain that welding causes; The digital camera mensuration is measured the welded structure drawdown deformation.
The tape measure and the ruler direct method of measurement, its major defect is: method itself is leaned on visualization, causes measuring accuracy low, because be contact type measurement, high-temperature region deflection in the time of therefore can't measuring welding, and can't obtain the deformation data in the welding process.
The normal foil gauge mensuration that adopts in the engineering, its major defect is: paste the quality of back foil gauge and the influence that stability receives substrate, pastes glue and technology for applying, instability appears in Monitoring Data easily, and the problem that is difficult to revise.The size of steel construction itself is very big simultaneously, and the distortion more complicated, and the measurement point of foil gauge is limited, thereby can't obtain to be out of shape global data.
Document: " application of digital camera in the welded structure drawdown deformation is measured " (Zhu Yuanxiang, Zhao Xuerong, Wang Qin. welding; 2003,5:16-18) studied the application of digital camera mensuration in the welded structure drawdown deformation is measured, its major defect is: the camera site of photo; The RP of structure is very big to the error effect of the data processing in later stage; And be difficult to control, and picture do not set up ID according to the time, can't obtain the deformation data in each stage in the steel construction welding process like this.
Summary of the invention
The object of the present invention is to provide a kind of deficiency that overcomes existing measurement steel construction welding deformation mode, satisfy the method based on grid measurement steel construction welding deformation of the requirement of efficient and the welded steel structure Deformation control of industry practice in using.
The technical solution that realizes the object of the invention is:
A kind of method based on gridding method measurement steel construction welding deformation comprises the steps:
Step 1: planning grid: according to the Steel Structural Design difformity and the big or small grid of different size, the parameter of design comprises grid length, width, spacing equidimension;
Step 2: silk screen Mold Making: through mesh design figure, make the silk screen mould, select mold materials, manufacture craft;
Step 3: print grid: selected measuring position, print grid;
Step 4: establishing shot point: at the on-the-spot fixedly digital camera of suitable visual angle of selecting of welding, camera position requires to photograph grid fully;
Step 5: sampling is taken: according to weld interval, welding sequence is selected shooting time and filming frequency;
Step 6: the reorganization gridding information: the numerical imaging that the logarithmic code camera photographs carries out image gray processing, image filtering, and keystone distortion correction, image binaryzation are handled;
Step 7: set up deformation coordinate system: utilize the MATLAB program compiler that above-mentioned image is carried out the grid edge coordinate and extract;
Step 8: the comparison of correspondence image: the image to the different time welding obtains is down set up image I D, and each ID is carried out the comparison of difference gridding coordinate;
Step 9: calculate deflection: according to setting up image I D weld interval according to steel construction in the 8th step, through the comparison of image lattice coordinate, the deflection that calculates every grid is big or small, direction and draw welding deformation change curve in time.
The present invention compared with prior art, its remarkable advantage:
(1) because the present invention uses the mode of serigraphy to carry out the printing of grid, so the grid Mold Making is simple.
(2) because the present invention uses the principle of videographic measurment, can select rational camera site, take grid, so do not receive the restriction of physical dimension size according to the size of measurement structure.
(3) because this method defines Image ID service time, so can measure the welding deformation of different time in the steel construction.
(4) because this method system requirements are simple, and execute-in-place only need be taken pictures and got final product, so cost is relatively low, measurement result is abundant, and survey bureau is sex-limited little, and is very suitable in the steel construction welding deformation is measured.
(5) because the MATLAB process of compilation picture that this method adopts can adopt same program for different tests, so reduced amount of calculation.
Below in conjunction with accompanying drawing the present invention is described in further detail.
Description of drawings
Fig. 1 is the process flow diagram of concrete operations step of the present invention.
Embodiment
When measuring the steel construction welding deformation:
The first step, planning grid: according to the grid that the steel construction and the different welding deformations of different size are measured Demand Design difformity and size, grid configuration can be designed to the dot matrix grid as required, square bar grid, circular grid etc.During like the measured angular seam deformation, should adopt the dot matrix grid, the dot matrix diameter is to be advisable in a thirtieth o'clock of thickness of slab size; During the measurement ring weld seam, adopt circular grid, diameter of a circle is that 1/5th of thickness of slab is advisable; When measuring butt-weld, suitable employing side bar grid, square bar width is that 1/20th of thickness of slab is advisable.
Second step, the silk screen Mold Making: according to mesh design figure, the choose reasonable mold materials, manufacture craft is made mould.When measuring the steel construction deformation position like the dot matrix grid, can select metal material to make the deformable frame, square node and circular grid are measured the two dimension distortion of steel construction, and the wood materials that alternative costs are low is made fixed border.As when measuring the transversely deforming of constrained butt-weld, the silk screen mould can be selected wooden frame for use, utilizes tension and compression equipment that silk screen is fixed to frame, and the grid that will in CAD, design then imports automatic silk screen machine, the grid printing of advancing.
The 3rd step, print grid: selected measuring position, print grid; To select different printing materials according to welding conditions different in the steel construction production to the size that influences of grid material, like printing ink as the distortion scale by print grid in the measuring position; Metallic paint, paint etc.Mainly decide, select metallic paint more than 150 ℃, select printing ink for 40 ℃-150 ℃, select paint below 40 ℃ according to measuring position temperature (temperature field that weld seam exists thermograde to alter a great deal to the mother metal zone in the welding process).
In the 4th step, the establishing shot point: at the on-the-spot fixedly digital camera of suitable visual angle of selecting of welding, camera position requires to photograph grid fully, and angle is for facing.
In the 5th step, sampling is taken: according to the weld job time, welding sequence is selected shooting time and shooting cycle, is starting point before the weldering; Welding process each minute shooting once is advisable; Welding finishes the back took once per five minutes of half an hour, took once in ten minutes after half an hour, took once in 30 minutes after one hour, should continue six hours; Image in that put different weld intervals and different shooting time obtains down at interval should comprise all gridding informations.
In the 6th step, the reorganization gridding information: the numerical imaging that obtains is taken in the sampling in the 5th step carried out image gray processing, image filtering, keystone distortion correction, image binaryzation are handled gradation of image: adopt the imadjust function directly gray scale to be adjusted; Image filtering: adopt linear filter to carry out the local mean value computing, promptly per 1 gray values of pixel points f (x, y) (i j) replaces the average h of the interior each point gray-scale value of its local neighborhood of usefulness; Keystone distortion correction: at first on original image, confirm the known point of relative position in four physical spaces; Most important point is four summits of rectangle; Adopt linear mode of texturing then, with the relative position of four points in image adjust to physical space in relative position identical; Figure binaryzation: confirmed to carry out binary conversion treatment after the threshold value.If node is " deceiving ", each pixel gray scale is made as 0 with its gray scale during less than threshold value, and promptly black is the net region.Otherwise genus background.Based on this criterion, begin from the upper left side of image, from top to bottom line by line or from left to right by column scan, can distinguish each pixel clearly and whether belong to the scale net region.Through this treatment scheme, the raw value picture of taking camera becomes the binaryzation picture.In addition, this treatment scheme should be able to be come out grid profile segmented extraction from numerical imaging.
In the 7th step, set up deformation coordinate system: in the process image of binaryzation, the scale grid is a white, and background is a black.Handle to one-row pixels, scanning from left to right, if certain pixel is a white, promptly numerical value is 1, and the pixel on its left side is black, and promptly numerical value is 0, then it is the left hand edge of a certain scale grid; And if certain pixel is white, and the pixel on its right is black, and then it is the right hand edge of a certain scale grid.Follow above principle image is scanned, and the coordinate of record marginal point.Owing to exist except scale has other white image on the background, n the marginal point that from left to right obtains is the marginal point of n bar scale grid.Set up two coordinates matrixs; Write down the coordinate of left hand edge and right hand edge respectively, line number is identical with the line number of scan image, and columns is the scale quantity in the scan image; Wherein m is capable, the horizontal ordinate of data represented from left to right n scale grid on m is capable of n row.When lining by line scan,, just its horizontal ordinate is recorded among the corresponding coordinates matrix, so that next step processing whenever to a marginal point.When accomplishing the scanning of entire image, the edge coordinate of all scale grids just writes down completion.
In the 8th step, the comparison of correspondence image: the edge coordinate to a last step extracts is handled, and just can obtain the displacement numerical value of each bar scale.It at first is reduced data.Extract through edge coordinate, what obtain is two matrixes, is depositing the horizontal ordinate of left hand edge and right hand edge.Short-cut method is that two matrix data of corresponding positions are averaged; Obtain the centre coordinate matrix of scale grid; Again the non-zero of each row is averaged; Obtain an array that number of elements is identical with scale quantity, wherein the numerical value of n element is represented the center horizontal ordinate mean value of n root scale.Adopt the data of two groups of corresponding scale grids of this method to handle.Next is that data compare.The left side array of grid element center is subtracted each other; Can obtain the respective pixel value of respective coordinates under relative displacement; Introduce the physical distance of adjacent leaf sight range corresponding pixel value and adjacent coordinates again,, just can obtain the physical distance of corresponding scale relative displacement through calculating.
The 9th step; Calculate deflection: according to the picture mesh information of gained in the 8th step, in coordinate, extract the gridding information coordinate values of identical numbering,, calculate the actual pitch value of the different time of same mesh according to the ratio of image vegetarian refreshments and physical size; Draw welding deformation at last and change the three-dimensional curve curve map in time: the X axle is the X value of gridding information; The Y axle is the Y value of gridding information, and Z is a time coordinate, thereby can observe whole steel construction welding deformation over time.