CN102818732B - Method and apparatus for simultaneous determination of post-buckling deformation parameters and elastic moduli of elastomeric material - Google Patents
Method and apparatus for simultaneous determination of post-buckling deformation parameters and elastic moduli of elastomeric material Download PDFInfo
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Abstract
The invention discloses a method and an apparatus for simultaneous determination of post-buckling deformation parameters and elastic moduli of an elastomeric material. The method is as follows: a PLC controller controls a linear stepping motor through a driver, a movable supporting baffle plate is pushed by the linear stepping motor so as to allow a sample to undergo post-buckling deformation, a scanner acquires a post-buckling deformation image of the sample and transfers the image to a notebook computer, and image processing analysis software is used to process the sample so as to obtain the skeleton of the post-buckling deformation image; a coordinate of a point at a leftmost end of the sample and a coordinate of a point at a rightmost end of the sample are determined according to the skeleton of the post-buckling deformation image, a coordinate of the midpoint of chord length between the leftmost end point coordinate and the rightmost end point coordinate is calculated, and then flexibility of the midpoint, corners at the ends and elastic moduli are calculated. According to the invention, synchronous determination of the elastic moduli in a pressure bar post-buckling method and the post-buckling deformation parameters of the pressure bar are realized, which enables the processes of determination and calculation of the elastic moduli to be simplified; test operation is simple, determination precision is improved, and miniaturization, intelligentization and automation of the apparatus are realized.
Description
Technical field
The invention belongs to construction material physical characteristics detection field, relate to method and the integration unit of a kind of resilient material pressure lever post-buckling deformation behavioral parameters and elastic modulus Simultaneously test, particularly relate to resilient material pressure lever post-buckling end axial displacement, the method for midway deflection and end corner and elastic modulus Simultaneously test and device.
Background technology
It is engineering is developed the gordian technique in some particular component process that pressure lever post-buckling large deflection mechanical characteristic analysis calculates, in slender compression bar geometrical nonlinear analysis, model simplification can be made under certain assumed condition, analysis result can engineering demands well, for engineering design provides theory support.Such as: pressure lever post-buckling theory of large-deflection plate is successfully applied to the alternate composite insulation conductor spacer design of high-pressure delivery line, is applied to microelectromechanical systems (MEMS) flexible structure large deflection bistable state change point, is applied to Wicresoft's intervene operation active catheter design etc., the core of these design and devdlop is post-buckling deformation behavior and the elastic modulus of these component materials, therefore, the post-buckling deformation behavior of convenience, noncontact, intelligentized resilient material and the mensuration of elastic modulus are crucial.
Liang Jun (food science and technology, 1991, (1): the simple and easy fine dried noodle bending of the midway deflection and end axial displacement that 28) utilize crossfoot and linear foot have developed to measure vermicelli post-bucklings breaks bar detector, but manually measures with range estimation, and precision is low, operation is inconvenient.The special special post-buckling deformation parameter adding carrier aircraft and contact-cup anemometer mensuration slender type depression bar is utilized in " engineering mechanics (1) " (P340-342) of Higher Education Publishing House's publication in 2002 of Fan Qinshan chief editor, but specimen size is large, need specially specially to add carrier aircraft, add that carrier aircraft size is very huge, complex structure, and the employing of midway deflection mensuration has contact measurement, measuring accuracy is low, is only applicable to the large sample of size, is not suitable for the sample that size is little.
At present, China Patent No. is ZL200810243157.1, name is called " fine dried noodle bending breaking rate measuring method and analyzer based on axial compression amount ", end axial displacement is adopted to replace end corner to measure the bending resistance of vermicelli, but the midway deflection of vermicelli and end corner remain to be measured by range estimation by scale and angle index line, and measuring accuracy is low, operation is inconvenient.China Patent No. is ZL200910030016.6, name is called " fine dried noodles elasticity modulus measuring method based on pressure lever post-buckling ", utilize general physical property instrument mensuration based on the assay method of the fine dried noodles elasticity modulus of pressure lever post-buckling, but do not relate to the measurement of vermicelli deformation parameter.China Patent No. is ZL200920231756.1, name is called " fine dried noodle bending based on end axial displacement fracture rate intelligent determination instrument ", utilize touch screen technology on the basis of above-mentioned patent ZL200810243157.1, step-by-step linear electric motor drive technology and PLC control technology replace end corner to measure the bending resistance of vermicelli to end axial displacement, and the parameters input of analyzer is exported, the aspects such as the drive method that end axial displacement realizes and control method are improved, but the elastic modulus of sample can not be measured and resolve sample post-buckling deformation parameter.
Above-mentionedly relate in the document of resilient material post-buckling deformation parameter and elastic modulus detection, all do not relate to resilient material post-buckling deformation parameter midway deflection and end corner high precision, contactless mensuration and deformation parameter and elastic modulus Simultaneously test and have that power measures, the analyzer of the collection of post-buckling strain image and analytical capabilities.Above-mentioned relate to vermicelli bending resistance and elastic modulus document in, all do not relate to the post-buckling deformation parameter of Other Engineering resilient material and the mensuration of elastic modulus, the elastic modulus detection of current Other Engineering resilient material (metal material, plastics, compound substance etc.) has generally adopted pulling method, compression method and three-point bending method, has no and adopts post-buckling method to measure its elastic modulus.Therefore, about utilizing image treating to measure resilient material post-buckling deformation parameter midway deflection and end corner, and the method for Simultaneously test elastic modulus has no bibliographical information.
Summary of the invention
The object of this invention is to provide a kind of resilient material post-buckling deformation parameter and elastic modulus Simultaneously test device and method, utilize image treating, high precision, contactless Simultaneously test resilient material post-buckling deformation parameter midway deflection, end corner and elastic modulus, device is simple, volume is little, cost is low, control and detect automaticity high.
For achieving the above object, the technical scheme that resilient material post-buckling deformation parameter of the present invention and elastic modulus Simultaneously test device adopt is: on base, be provided with quiet supporting baffle and dynamic supporting baffle, the both ends of sample lay respectively in the groove in quiet supporting baffle and dynamic supporting baffle, arrange and the straight line stepper moving supporting baffle and be directly connected relative to the opposite side of sample in dynamic supporting baffle, quiet supporting baffle side arranges the force snesor obtaining sample imposed load, straight line stepper connects PLC through driver, PLC is by analog to digital conversion block connection signal amplifier, signal amplifier connects with force snesor, immediately below quiet supporting baffle and dynamic supporting baffle, arrange scanner, scanner connects external notebook computer, notebook computer Built-in Image treatment and analyses software.
The technical scheme that resilient material post-buckling deformation parameter of the present invention and elastic modulus Simultaneously test method adopt has following steps: 1) by PLC through driver control linear stepping motor, promoting dynamic supporting baffle by linear stepping motor makes sample produce post-buckling deformation, when dynamic supporting baffle arrives end axial displacement setting, linear stepping motor stops automatically, scanner gathers the image of the post-buckling deformation of sample and is sent to notebook computer, medium filtering denoising is carried out by the post-buckling strain image of image processing and analyzing software to sample, thresholding and Thinning process, obtain the post-buckling strain image skeleton of sample, 2) the high order end point coordinate of sample is determined from post-buckling strain image skeleton
f i,jwith low order end point coordinate
f m,n, according to formula
, calculate left end point coordinate
f i,jwith right endpoint coordinate
f m,nbetween chord length
lmiddle point coordinate
f x,y,
3) middle point coordinate is gone out according to formulae discovery
f x,ythe bee-line of each point pixel to the post-buckling strain image skeleton of sample
d emin
i.e. midway deflection
; K is that pixel value is converted into physical length coefficient, is the ratio of 25.4mm and scanner scanning resolution; 4) to set from low order end point on sample post-buckling strain image skeleton H pixel as
f a,b, go out end corner according to formulae discovery
;
5) gathered the load p added by post-buckling deformation of sample by force snesor, load p is sent to PLC after the analog to digital conversion of signal amplifier amplification, analog to digital conversion block, calculates end axial displacement
Δ l = l-lthe elastic modulus value at place
,
lfor the length of sample,
ifor sample inertia square,
for the elliptic integral value relevant with end corner,
,
θfor sample end corner.
The present invention has following superiority:
1, the present invention utilizes scanner in conjunction with special image process software, measure pressure lever post-buckling midway deflection and end corner two deformation parameters, achieve pressure lever post-buckling method elastic modulus and pressure lever post-buckling deformation parameter Simultaneous Determination, for non-contact measurement, corner, specific bent end measurement and calculation elastic modulus can be selected, elastic modulus detection and computation process are simplified, and test operation is simple, improves estimating precision; Device achieves miniaturization, intellectuality and robotization.
2, the present invention is applicable to various uniform cross section elongated straight type and thin long and straight type elasticity sample, as samples such as tinsel (sheet), composite silk (sheet), plastic wire (sheet), bamboo matter silk (sheet), wooden thin bar (thin slice), papery thin slice, vertical bar type dehydrated foods.Sample raw material length is unrestricted, and specimen length general control is at 40-300 mm.
3, the six large technological synthesiss such as human-computer interaction technology, PLC technology, scanning technique, power measuring technique, notebook computer image processing techniques and linear stepping motor Driving technique are applied to the mensuration of pressure lever post-buckling deformation parameter and elastic modulus by apparatus of the present invention, there is power mensuration, the collection of post-buckling strain image and analytical capabilities, drastically increase the robotization of device, intellectuality, standardization degree.
Accompanying drawing explanation
Fig. 1 is the front view of resilient material post-buckling deformation parameter of the present invention and elastic modulus Simultaneously test device;
Fig. 2 is the vertical view of Fig. 1;
Fig. 3 is post-buckling strain image skeleton and the unique point parameter schematic diagram of sample 4 in Fig. 1-2;
Fig. 4 is Fig. 1 elastomeric material post-buckling deformation geometric parameter relation and suffered load schematic;
In figure: 1. base; 2. force snesor; 3. quiet supporting baffle; 4. sample; 5. scanner; 6. dynamic supporting baffle; 7. straight line stepper; 8. driver; 9.PLC controller; 10. analog to digital conversion block; 11. touch-screen systems; 12. signal amplifiers; 13. power supplys; 14. notebook computers;
l for specimen length (mm);
Δ l for end axial displacement (mm);
w for midway deflection (mm);
θ for end corner (°);
p for the load (N) applied.
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.
Embodiment
As depicted in figs. 1 and 2, the bottom of resilient material post-buckling deformation parameter of the present invention and elastic modulus Simultaneously test device is base 1, at quiet supporting baffle 3 side, force snesor 2 is set, quiet supporting baffle 3 is fixedly connected with the force side of force snesor 2, indirectly be fixed on base 1 by the installation end of force snesor 2 again, like this, force snesor 3 can obtain the load applied sample 4.Dynamic supporting baffle 6 is fixedly connected dynamic with the output screw of straight line stepper 7, is more indirectly fixed on base 1 by the installation end of straight line stepper 7.Sample 4 is between quiet supporting baffle 3 and dynamic supporting baffle 6, and the groove in quiet supporting baffle 3 and dynamic supporting baffle 6 is put at the both ends of sample 4 respectively.
Arranging relative to the opposite side of sample 4 in dynamic supporting baffle 6 is the straight line stepper 7 be directly connected with dynamic supporting baffle 6, and be fixedly connected the output screw of straight line stepper 7 dynamic supporting baffle 6.Straight line stepper 7 also connects PLC 9 through driver 8 simultaneously, PLC 9 is by analog to digital conversion block 10 connection signal amplifier 12, power supply 13 is connection signal amplifier 12, analog to digital conversion block 10 and touch-screen system 11 respectively, there is provided respective power supply, touch-screen system 11 connects PLC 9.Signal amplifier 12 connects with force snesor 2, the load that sample 4 is applied obtained by force snesor 3, be transferred to PLC 9 through signal amplifier 12, analog to digital conversion block 10, calculate elastic mould value through PLC 9, then be transferred to touch-screen 11 by PLC 9 and show.
Immediately below quiet supporting baffle 3 and dynamic supporting baffle 6, scanner 5 is set, dynamic supporting baffle 6 by immediately below the scanner 5 that arranges support and form and be slidably connected.Perform region by quiet supporting baffle 3 and dynamic supporting baffle 6 faces the scanning work region of scanner 5, and scanner 5 connects external notebook computer 14.The strain image of sample 4 is obtained by scanner 5, strain image is transferred to external notebook computer 14 by scanner 5, notebook computer 14 Built-in Image treatment and analyses software, image processing and analysis software can resolve the deformation parameter of the strain image of sample 4, and analysis result is presented on the interface of software.
Resilient material post-buckling deformation parameter of the present invention and elastic modulus Simultaneously test device are when measuring, input/output information, control information and metrical information process are completed by PLC 9, touch-screen 11 and notebook computer 14, image scanning and disposal system are made up of scanner 5 and notebook computer 14 and image processing and analysis software, and dynamometric system is made up of force snesor 2, signal amplifier 12 and analog to digital conversion block 10 and PLC 9.Concrete determination step is as follows:
Control linear stepping motor 7 by PLC 9 and driver 8 to work, promoting dynamic supporting baffle 6 by linear stepping motor 7 makes sample produce post-buckling deformation, when dynamic supporting baffle 6 arrives end axial displacement setting, linear stepping motor 7 stops automatically, now start scanner 5, the image of the post-buckling deformation of sample 4 is gathered by scanner 5, be sent to notebook computer 14 to store, medium filtering denoising is carried out by the post-buckling strain image of special image Treatment Analysis software to sample 4, thresholding and Thinning process, obtain the post-buckling strain image skeleton of sample 4, as shown in Figure 3.From the sample post-buckling strain image skeleton of Fig. 3, obtain unique point coordinate, specifically determine the coordinate of leftmost side pixel
f i,jthe coordinate of (left end point of sample 4)
f i,jwith the coordinate of rightmost side pixel (right endpoint of sample 4)
f m,n, then, calculate the chord length between leftmost side pixel and rightmost side pixel according to geometric relationship
lmiddle point coordinate
f x,y, computing formula is as follows:
。
According to chord length
l'smiddle point coordinate
, point coordinate in calculating
f x,ythe distance of each point pixel to the post-buckling strain image skeleton of sample 4, wherein bee-line
d emin
for midway deflection
w, computing formula is as follows:
Wherein: k is that pixel value is converted into physical length coefficient (mm/pixel), is 25.4mm(1 inch) with the ratio of scanner scanning resolution.
Be wired near linear according to the pixel within the scope of tens pixels in inner side, two ends (leftmost side point and rightmost side point) on sample post-buckling strain image skeleton, the angle between the line of this near linear and high order end point and low order end point is end corner
θ.If H pixel is from rightmost side point on sample post-buckling strain image skeleton
f a,b, then
f a,
b with rightmost side point
f m,nline and the line between high order end point and low order end point between angle be end corner
θ(°), computing formula is as follows:
.
Gather the image of sample post-buckling deformation at scanner 5 while, gathered the load p added by post-buckling deformation of sample 4 by force snesor 2, as shown in Figure 4.Suffered by the post-buckling deformation of sample 4, load is gathered by force snesor, amplify through signal amplifier 12, the analog to digital conversion of analog to digital conversion block 10, finally be sent to PLC 9 to store, again according to the basic parameter of sample 4 and the end axial displacement parameter of setting, calculate this end axial displacement through PLC 9
Δ l the elastic mould value at place,
Δ l= l-l, l for specimen length
, l for chord length, elastic modulus computing formula is as follows:
Wherein:
efor sample elasticity modulus (N/mm
2),
pfor end axle pressure (N), namely end axis is to the load applied,
lfor the length (mm) of sample,
ifor sample inertia square (mm
4),
for the elliptic integral value relevant with end corner, wherein
,
θfor sample end corner (°).
Owing to tending towards stability with after load sample post-buckling end corner 10 °, corner, specific post-buckling end measurement and calculation elastic modulus can be selected, reduce elliptic integral value
selection, elastic modulus detection and computation process are simplified.
integrated use Modern Tracking Technology's of the present invention, drive technology, Image Acquisition and Treatment Analysis technology, synthesis measuring while establishing the midway deflection of pressure lever post-buckling deformation parameter and end corner and elastic modulus, evaluates for resilient material pressure lever post-buckling deformation behavior determination and mechanics of materials texture characteristic.
3 embodiments of the present invention are below provided:
embodiment 1
Randomly draw the length samples that certain radical is cut into regulation.Start the device of Fig. 1 and Fig. 2, and initialization and check and correction are carried out to device, inputted the basic parameters such as sample name, thickness, width and length by touch-screen 11, and the axial displacement determined according to specimen length and the F corresponding with axial displacement (
a, pi/2) and the setup parameter such as (as table 1); According to specimen length, dynamic supporting baffle 6 is positioned; To get between the quiet supporting baffle 2 of sample 4 embedding device and dynamic supporting baffle 6 as shown in Figure 1, start test macro, linear stepping motor 7 is started working, promoting dynamic supporting baffle 6 by the screw rod of linear stepping motor 7 with 0.01-1.0 mm/s speed makes sample produce post-buckling deformation, and when dynamic supporting baffle 6 arrives end axial displacement setting, linear stepping motor 7 stops automatically; Now start scanner 5, carry out scanning to sample post-buckling deformation now obtain sample post-buckling strain image and be transferred to notebook computer 14, then analyze with notebook computer 14 special image process software, extract midway deflection and the end corner of the deformation of sample post-buckling, shown test results by special image process software again and error compared with theoretical value (see table 1), and preserve Measurement and Computation result; The load meanwhile applied is transferred to PLC 9 by force snesor 3 through signal amplifier 12, analog to digital conversion block 10, again according to the imposed load that the basic parameter of sample and the setup parameter of test and dynamometric system gather, calculated the elastic mould value of sample by PLC 9, and shown by touch-screen 11.
With special image Treatment Analysis software, medium filtering denoising, thresholding and Thinning process are carried out to the sample post-buckling strain image that scanner in device 5 gathers, obtain sample post-buckling strain image skeleton (Fig. 3), from image framework, obtain unique point coordinate, calculate according to coordinate figure and converse midway deflection value and end corner value; Gather the load made added by the deformation of sample post-buckling simultaneously, draw the elastic modulus of sample through computing, specifically measure according to following step:
One, the midway deflection of sample post-buckling deformation and the mensuration of end corner
1, chord length
lthe calculating of middle point coordinate
Sample post-buckling strain image skeleton is determined the coordinate of leftmost side pixel (sample left end point)
f i,jwith the coordinate of rightmost side pixel (sample right endpoint)
f m,n, calculate chord length according to geometric relationship
lmiddle point coordinate
f x,y, computing formula is as follows:
2, midway deflection
wcalculating
According to chord length
lmiddle point coordinate
, calculate chord length mid point
the distance of each point pixel to sample post-buckling strain image skeleton, wherein bee-line
d emin
for midway deflection
w, computing formula is as follows:
Wherein: k is that pixel value is converted into physical length coefficient (mm/pixel), and arranging scanner scanning resolution is 300ppi, then the length of a pixel is about 0.0847mm, and therefore k is 0.0847mm/pixel.
3, end corner
θcalculating
Be wired near linear according to the pixel within the scope of the certain pixel in inner side, two ends (high order end point and low order end point) on sample post-buckling strain image skeleton, the angle between the line of this near linear and leftmost side point and rightmost side point is end corner.If H pixel is from rightmost side point on sample post-buckling strain image skeleton
f a,b, then
f a,bwith rightmost side point
f m,nline and the line of leftmost side point and rightmost side point between angle be end corner
θ(°), computing formula is as follows:
。
Two, the mensuration of sample elasticity modulus
Gather the image of sample post-buckling deformation at scanner while, sample is made to produce the load p of post-buckling deformation by dynamometric system measurement, through force snesor, signal amplifier, analog to digital conversion Bulk transport to PLC, again according to the basic parameter of sample and end axial displacement parameter (Fig. 4) of setting, calculate the elastic mould value at this axial displacement place, end through PLC 9.Elastic modulus computing formula is as follows:
，
Wherein:
efor sample elasticity modulus (N/mm
2),
pfor end axle pressure (N),
lfor the length (mm) of sample,
ifor sample inertia square (mm
4),
for the elliptic integral value relevant with end corner.
The corresponding relation of table 1 different length sample deformation parameter theoretical value and calculating parameter
embodiment 2
The assay method of 65Mn steel disc pressure lever post-buckling midway deflection and end corner and elastic modulus: randomly draw the sample that 3 are cut into length 180mm.Starter gear, and initialization and check and correction are carried out to instrument, inputted by touch-screen 10 that sample name is 65Mn steel disc, thickness is 0.3mm, width is 12.5mm and length is the basic parameters such as 180mm, and the axial displacement corresponding to the elastic modulus detection determined according to specimen length 180mm be 12.14mm and the F corresponding with axial displacement (
a, pi/2) and (as table 1) be 1.5981 setup parameters such as grade; According to specimen length, dynamic supporting baffle 6 is positioned.
To get between the quiet supporting baffle 2 of sample 4 embedding device and dynamic supporting baffle 6 as shown in Figure 1, start test macro, linear electric motors 7 are started working, promoting dynamic supporting baffle 6 by linear stepping motor screw rod with 0.1mm/s speed makes sample produce post-buckling deformation, is equivalent to relative to end corner 30 ° when dynamic supporting baffle 6 arrives end axial displacement setting 12.14 mm() time linear stepping motor 7 automatically stop; Now start scanner 5, scanning is carried out to sample post-buckling deformation now and obtains sample post-buckling strain image, then notebook computer 13 special image process software is used to carry out medium filtering denoising, thresholding and Thinning process to the sample post-buckling strain image of scanner collection in device (Fig. 1), obtain sample post-buckling strain image skeleton (Fig. 3), from image framework, obtain unique point coordinate, calculate according to coordinate figure and converse midway deflection value and end corner value; Gather the load p (Fig. 4) made added by the deformation of sample post-buckling, draw the elastic modulus of sample through computing, concrete calculation procedure is as follows simultaneously:
One, the midway deflection of sample post-buckling deformation and the mensuration of end corner
1, chord length
lthe calculating of middle point coordinate
The coordinate of leftmost side pixel (sample left end point) on sample post-buckling strain image skeleton can be obtained by special image process software
f i,jfor (156,733), the coordinate of rightmost side pixel (sample right endpoint)
f m,nfor (2138,733), calculate chord length according to geometric relationship
lmiddle point coordinate
f x,yfor (1147,733).
2, midway deflection
wcalculating
According to chord length
lmiddle point coordinate
, calculate chord length mid point
the bee-line of each point pixel and midway deflection to sample post-buckling strain image skeleton
wfor 29.35mm, wherein pixel value is converted into physical length coefficient k (mm/pixel) is 0.0847mm/pixel.
3, end corner
θcalculating
If the 55th pixel coordinate from rightmost side point on sample post-buckling strain image skeleton
f a,bfor (2085,702), then
f a,bwith rightmost side point
f m,nline and the line of leftmost side point and rightmost side point between angle be end corner
θit is 30.3 °
Two, the mensuration of sample elasticity modulus
Gather the image of sample post-buckling deformation at scanner while, the load p making sample produce post-buckling deformation by dynamometric system measurement is 1.846N, through force snesor, signal amplifier, analog to digital conversion Bulk transport to PLC, again according to the basic parameter of said sample and the end axial displacement parameter of setting, the elastic mould value calculating this axial displacement place, end through PLC is 208.2 × 10
9n/m
2.
embodiment 3
The assay method of vermicelli pressure lever post-buckling midway deflection and end corner and elastic modulus: randomly draw the sample that 3 are cut into length 150mm.Starter gear, and initialization and check and correction are carried out to instrument, inputted by touch-screen 11 that sample name is vermicelli, thickness is 0.840mm, width is 3.813mm and length is the basic parameters such as 150mm, and the axial displacement corresponding to the elastic modulus detection determined according to specimen length 150mm be 7.09mm and the F corresponding with axial displacement (
a, pi/2) and (as table 1) be 1.5898 setup parameters such as grade; According to specimen length, dynamic supporting baffle 6 is positioned.
To get between the quiet supporting baffle 2 of sample 4 embedding device and dynamic supporting baffle 6 as shown in Figure 1, start test macro, linear electric motors 7 are started working, promoting dynamic supporting baffle 6 by linear stepping motor screw rod with 0.1mm/s speed makes sample produce post-buckling deformation, is equivalent to relative to end corner 25 ° when dynamic supporting baffle 6 arrives end axial displacement setting 7.09 mm() time linear stepping motor 7 automatically stop; Now start scanner 5, scanning is carried out to sample post-buckling deformation now and obtains sample post-buckling strain image, then notebook computer 14 special image process software is used to carry out medium filtering denoising, thresholding and Thinning process to the sample post-buckling strain image of scanner collection in device (Fig. 1), obtain sample post-buckling strain image skeleton (Fig. 3), from image framework, obtain unique point coordinate, calculate according to coordinate figure and converse midway deflection value and end corner value; Gather the load p (Fig. 4) made added by the deformation of sample post-buckling simultaneously, draw the elastic modulus of sample through computing, concrete calculation procedure is as follows:
One, the midway deflection of sample post-buckling deformation and the mensuration of end corner
1, chord length
lthe calculating of middle point coordinate
The coordinate of leftmost side pixel (sample left end point) on sample post-buckling strain image skeleton can be obtained by special image process software
f i,jfor (201,540), the coordinate of rightmost side pixel (sample right endpoint)
f m,nfor (1889,540), calculate chord length according to geometric relationship
lmiddle point coordinate
f x,yfor (1045,540).
2, midway deflection
wcalculating
According to chord length
lmiddle point coordinate
, calculate chord length mid point
the bee-line of each point pixel and midway deflection to sample post-buckling strain image skeleton
wfor 20.32mm, wherein pixel value is converted into physical length coefficient k (mm/pixel) is 0.0847mm/pixel.
3, end corner
θcalculating
If the 50th pixel coordinate from rightmost side point on sample post-buckling strain image skeleton
f a,bfor (1839,517), then
f a,bwith rightmost side point
f m,nline and the line of leftmost side point and rightmost side point between angle be end corner
θit is 24.7 °
Two, the mensuration of sample elasticity modulus
Gather the image of sample post-buckling deformation at scanner 5 while, the load p making sample produce post-buckling deformation by dynamometric system measurement is 0.250N, PLC 9 is transferred to through force snesor 2, signal amplifier 12, analog to digital conversion block 10, again according to the basic parameter of said sample 4 and the end axial displacement parameter of setting, the elastic mould value calculating this axial displacement place, end through PLC 9 is 2.954 × 10
9n/m
2.
Claims (1)
1. a resilient material post-buckling deformation parameter and elastic modulus Simultaneously test method, adopt resilient material post-buckling deformation parameter and elastic modulus Simultaneously test device, this determinator is provided with quiet supporting baffle (3) and dynamic supporting baffle (6) on base (1), the both ends of sample (4) lay respectively in the groove in quiet supporting baffle (3) and dynamic supporting baffle (6), arrange and the linear stepping motor (7) moving supporting baffle (6) and be directly connected relative to the opposite side of sample (4) in dynamic supporting baffle (6), quiet supporting baffle (3) side arranges the force snesor (2) obtaining sample (4) imposed load, linear stepping motor (7) connects PLC (9) through driver (8), PLC (9) is by analog to digital conversion block (10) connection signal amplifier (12), signal amplifier (12) connects with force snesor (2), immediately below quiet supporting baffle (3) and dynamic supporting baffle (6), arrange scanner (5), scanner (5) connects external notebook computer (14), and notebook computer (14) Built-in Image treatment and analyses software, is characterized in that having following steps:
1) linear stepping motor (7) is controlled by PLC (9) through driver (8), promoting dynamic supporting baffle (6) by linear stepping motor (7) makes sample (4) produce post-buckling deformation, when dynamic supporting baffle (6) arrives end axial displacement setting, linear stepping motor (7) stops automatically, scanner (5) gathers the image of the post-buckling deformation of sample (4) and is sent to notebook computer (14), medium filtering denoising is carried out by the post-buckling strain image of special image treatment and analyses software to sample (4), thresholding and Thinning process, obtain the post-buckling strain image skeleton of sample (4),
2) the high order end point coordinate of sample (4) is determined from post-buckling strain image skeleton
f i,jwith low order end point coordinate
f m,n, according to formula
, calculate high order end point coordinate
f i,jwith low order end point coordinate
f m,nbetween chord length
lmiddle point coordinate
f x,y;
3) middle point coordinate is gone out according to formulae discovery
f x,ythe bee-line of each point pixel to the post-buckling strain image skeleton of sample
d emin
, midway deflection
, k is that pixel value is converted into physical length coefficient, is the ratio of 25.4mm and scanner scanning resolution;
4) to set from low order end point on sample post-buckling strain image skeleton H pixel as
f a,b, go out end corner according to formulae discovery
;
5) gathered the load p added by post-buckling deformation of sample (4) by force snesor (2), load p is sent to PLC (9) after the analog to digital conversion of signal amplifier (12) amplification, analog to digital conversion block (10), calculates end axial displacement
Δ l= l-lthe elastic mould value at place
,
lfor the length of sample,
ifor sample inertia square,
for the elliptic integral value relevant with end corner,
,
θfor sample end corner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210261139.2A CN102818732B (en) | 2012-07-26 | 2012-07-26 | Method and apparatus for simultaneous determination of post-buckling deformation parameters and elastic moduli of elastomeric material |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210261139.2A CN102818732B (en) | 2012-07-26 | 2012-07-26 | Method and apparatus for simultaneous determination of post-buckling deformation parameters and elastic moduli of elastomeric material |
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| Publication Number | Publication Date |
|---|---|
| CN102818732A CN102818732A (en) | 2012-12-12 |
| CN102818732B true CN102818732B (en) | 2015-02-04 |
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| KR101861994B1 (en) | 2012-08-13 | 2018-05-29 | 한국전력공사 | Test apparatus for buckling load |
| CN104344789A (en) * | 2013-07-23 | 2015-02-11 | 国家电网公司 | System and method for monitoring member deflection in bearing capacity test |
| CN103728074B (en) * | 2013-12-09 | 2015-08-12 | 清华大学 | A kind of micro-nano material mechanics properties testing structure |
| CN104729929B (en) * | 2013-12-18 | 2017-12-05 | 昆山工研院新型平板显示技术中心有限公司 | flexible screen bending method and system |
| CN103983559B (en) * | 2014-04-16 | 2016-07-13 | 深圳大学 | Reinforcing bar plays suggestion device and the reminding method of rust and chlorine ion concentration limit state |
| CN107179253B (en) * | 2017-07-04 | 2019-05-07 | 河南理工大学 | A kind of measurement method of rod-like articles elasticity modulus |
| CN108181184A (en) * | 2017-11-28 | 2018-06-19 | 中铝材料应用研究院有限公司 | A kind of evaluating apparatus and application method of sheet metal buckling performance |
| CN108132209A (en) * | 2017-12-22 | 2018-06-08 | 陈益德 | A kind of moisture resistance properties test device of aqueous woodware paint |
| CN109100236B (en) * | 2018-07-09 | 2021-01-12 | 武汉钢铁有限公司 | Thin-specification high-strength pure steel bending test system and test method for automobile |
| CN113029802B (en) * | 2021-04-20 | 2022-10-18 | 中南大学 | High-precision testing method for equivalent elastic statics parameters of dot matrix material |
| CN113970305B (en) * | 2021-06-16 | 2023-07-28 | 广西大学 | Method for measuring axial displacement of compression bar through deflection |
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| CN101451934B (en) * | 2008-12-09 | 2011-01-05 | 江苏大学 | Fine dried noodle bending and breaking rate measuring method and determinator based on axial compression amount |
| CN101526456B (en) * | 2009-03-31 | 2011-01-05 | 江苏大学 | Fine dried noodles elasticity modulus measuring method based on pressure lever post-buckling |
| CN101929933B (en) * | 2009-10-09 | 2012-08-15 | 江苏大学 | Method for measuring mechanical texture characteristic of dried rice noodle |
| CN201564899U (en) * | 2009-10-12 | 2010-09-01 | 上海金塔医用器材有限公司 | Puncture outfit for bottle stopper of infusion apparatus |
| CN102607447B (en) * | 2012-03-08 | 2014-08-20 | 北京北科安地科技发展有限公司 | Method for rapidly monitoring deformation by aid of ground-based three-dimensional laser scanner |
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