CN113984554B - Transmission caustic line-three-dimensional digital image correlation method synchronous experiment system and method - Google Patents
Transmission caustic line-three-dimensional digital image correlation method synchronous experiment system and method Download PDFInfo
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- 230000001360 synchronised effect Effects 0.000 title claims abstract description 23
- 238000002474 experimental method Methods 0.000 title claims abstract description 15
- 239000003518 caustics Substances 0.000 title claims description 51
- 238000012360 testing method Methods 0.000 claims abstract description 81
- 238000005507 spraying Methods 0.000 claims description 15
- 238000005259 measurement Methods 0.000 claims description 14
- 239000002390 adhesive tape Substances 0.000 claims description 10
- 239000003973 paint Substances 0.000 claims description 8
- 238000012937 correction Methods 0.000 claims description 7
- 238000004880 explosion Methods 0.000 claims description 7
- 230000003068 static effect Effects 0.000 claims description 6
- 239000007921 spray Substances 0.000 claims description 5
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- 238000003384 imaging method Methods 0.000 claims description 4
- 230000000977 initiatory effect Effects 0.000 abstract description 7
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
- G01N3/303—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight generated only by free-falling weight
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
- G01N3/068—Special adaptations of indicating or recording means with optical indicating or recording means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/0032—Generation of the force using mechanical means
- G01N2203/0039—Hammer or pendulum
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
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Abstract
The invention relates to a transmission focusThe line-three-dimensional digital image correlation method synchronous experiment system and method comprises a first camera, a second camera, a first flash light source, a second flash light source, a first computer, a second computer, a laser light source, a beam expander, a first field convex lens, a second convex lens, a third camera, a delay signal controller, a drop hammer, an impact head, a test piece, a loading frame and a signal line. The system can simultaneously meet the transmission focusThe method and the three-dimensional digital image correlation method can synchronously measure and collect, the two methods can not interfere with each other, have complementary advantages and mutually verify, can measure stress intensity factors in the whole fracture process of the notch test piece, can measure mechanical parameters such as stress intensity factors of crack tips, crack initiation toughness, crack propagation speed, dynamic fracture toughness and the like, and can accurately and scientifically study the fracture behavior analysis of the test piece.
Description
Technical Field
The invention relates to the field of rock fracture mechanics experiment research, in particular to a transmission caustic line-three-dimensional digital image correlation method synchronous experiment system and method.
Background
The problem of dynamic fracture of rock has been a research hotspot in the fields of mining engineering, civil engineering construction and the like. Therefore, the method has important significance in researching crack initiation, propagation and damage of the rock test piece by adopting an effective means, and is especially suitable for mechanical parameters such as stress intensity factors, crack initiation toughness, crack propagation speed, dynamic fracture toughness and the like of crack tips of rock or rock-like materials.
Different test methods are adopted by students at home and abroad to study the cracking and expanding behaviors of the rock test piece in the dynamic cracking process, and certain achievements are obtained. Among these are mainly the transmissive caustic method and the digital image correlation method. The caustic line method is classified into a transmissive and a reflective caustic line, however, the transmissive caustic line has high measurement accuracy and simple operation compared to the reflective caustic line, and thus it is widely used in the field of experimental mechanics. For the digital image correlation method, the three-dimensional digital image correlation method can measure out-of-plane deformation and has higher measurement accuracy compared with the two-dimensional digital image correlation method. In addition, for the V-notch fracture experiment under mixed loading, the transmission caustic line method can measure the crack stress intensity factor in the expansion process but cannot measure the notch tip stress intensity factor, but the three-dimensional digital image correlation method can accurately measure the notch tip stress intensity factor but cannot accurately measure the stress intensity factor of the crack in the expansion process. The combination of the two methods can measure the change rule of the stress intensity factor of the whole process from the initiation to the expansion of the notch test piece, and provides an experimental technique for researching the whole process of fracture of the notch test piece. Therefore, the method for synchronously measuring the breaking behavior of the test piece by adopting the transmission caustic line method and the three-dimensional digital image correlation method has more important significance based on the advantages of the two methods.
At present, a learner studies the breaking behavior of a test piece based on the combination of a reflected caustic line and a two-dimensional digital image correlation technique, but the digital image correlation method needs to spray speckles on the surface of the test piece to influence the light path propagation of a transmitted caustic line, so that the study of synchronously measuring static and dynamic mechanical parameters in the breaking process of a rock or rock-like test piece by using the transmitted caustic line method and the three-dimensional digital image correlation method has not been performed.
Disclosure of Invention
The invention aims to provide a transmission caustic line-three-dimensional digital image correlation method synchronous experiment system and a transmission caustic line-three-dimensional digital image correlation method synchronous measurement and acquisition, wherein the transmission caustic line method and the three-dimensional digital image correlation method synchronous measurement and acquisition can be simultaneously satisfied, the two methods can be mutually noninterfered, have complementary advantages and mutually verified, can measure stress intensity factors in the whole fracture process of a notch test piece, can measure mechanical parameters such as stress intensity factors, crack initiation toughness, crack propagation speed, dynamic fracture toughness and the like of a crack tip, and can more accurately and scientifically study the fracture behavior analysis of the test piece.
In order to achieve the above object, the present invention provides the following solutions:
a transmission caustic-three-dimensional digital image correlation method synchronous experimental system, the system comprising:
the device comprises a laser light source, a beam expander, a first field convex lens, a loading frame, a test piece, an impact head, a drop hammer, a first flash light source, a second flash light source, a first camera, a second field convex lens, a third camera, a first computer, a second computer and a delay signal controller, wherein the first camera is connected with the first computer;
the laser light source emits light sources which sequentially pass through the beam expander, the first field convex lens, the test piece and the second field convex lens and finally converge on the third camera;
the first camera is connected with the first flash light source, the second flash light source, the delay signal controller, the first computer and the second camera;
the second camera is connected with the first computer;
the third camera is connected with the second computer and the delay signal controller;
the drop hammer and the impact head are connected with the time delay signal controller;
the test piece is located on the loading frame.
Optionally, the system further comprises: the device comprises a servo hydraulic motor, a Hopkinson pressure bar device and an explosion loading device, wherein the servo hydraulic motor is used for applying static load to a test piece, the Hopkinson pressure bar device is used for applying impact load to the test piece, and the explosion loading device is used for applying explosion load to the test piece.
Optionally, the first camera and the second camera form a fixed included angle, and the first camera and the second camera are symmetrically distributed on two sides of the parallel light path of the caustic line.
Optionally, the first camera, the second camera and the third camera are ultra-high speed cameras, the first camera and the main camera, and the second camera is an auxiliary camera.
Optionally, the first camera and the third camera are both in an external trigger mode.
Optionally, the test piece sprays speckle on a surface close to the first camera.
Optionally, spraying the speckles on the surface of the test piece, which is close to the first camera, specifically includes:
firstly, sticking adhesive tape to cover a crack propagation path;
then spraying a layer of white paint on the surface of the test piece, and spraying random uniform black dispersion spots after the white paint is dried;
and finally, the adhesive tape is removed.
Optionally, the test piece is a test piece without a defect or a test piece with a prefabricated crack or a test piece with a prefabricated notch.
The invention also provides a transmission caustic-three-dimensional digital image correlation method synchronous experimental method aiming at the system, which comprises the following steps:
preparing a test piece;
spraying speckle on one surface of the test piece close to the first camera;
adjusting a transmission caustic line system-a three-dimensional digital image correlation method synchronous experimental system to enable the transmission caustic line system to be on the same horizontal straight line;
adjusting the laser height according to the measured position of the test piece, and enabling a light source emitted by a laser light source to finally converge on a third camera through a beam expander, a first field convex lens, the test piece and a second field convex lens in sequence, and adjusting a lens of the third camera to focus on a focal-speckle imaging plane;
focusing the first camera and the second camera to the spot-spraying surface of the test piece;
establishing a three-dimensional coordinate system of the system by using a correction plate, and taking a plurality of effective correction plate photos;
the triggering mode of the delay signal controller is the triggering of an off signal;
adjusting the first camera and the third camera to an external trigger mode;
releasing a drop hammer to strike the impact head, applying load to the test piece, and generating cracks and expanding the test piece;
after the drop hammer contacts the impact head, the delay signal controller generates a trigger signal through the signal wire, and the trigger signal of the delay signal controller triggers the first camera and the third camera through the signal wire;
simultaneously, the first camera triggers the first flash light source, the second flash light source and the second camera by utilizing the signal line;
the third camera starts to collect transmission caustic line experimental data after receiving the trigger signal, and finally the transmission caustic line experimental data is stored by the second computer;
the first camera, the second camera, the first flash light source and the second flash light source work synchronously after receiving the trigger signal, digital image related data are collected and stored and analyzed by the first computer, and finally synchronous measurement of a transmission caustic line method and a three-dimensional digital image related method is realized.
Alternatively, more than 15 valid calibration plate photographs are taken in particular.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the system and the method can simultaneously meet the synchronous measurement and collection of a transmission caustic line method and a three-dimensional digital image correlation method, the two methods can be mutually noninterfere, have complementary advantages and mutually verified, can measure stress intensity factors in the whole fracture process of a notch test piece, can measure mechanical parameters such as stress intensity factors, crack initiation toughness, crack expansion speed, dynamic fracture toughness and the like of a crack tip, and can more accurately and scientifically study the fracture behavior analysis of the test piece.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a transmission caustic-three-dimensional digital image correlation method synchronous experimental system according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a sample structure according to an embodiment of the present invention.
Symbol description:
the device comprises a first camera 1, a second camera 2, a first flash light source 3, a second flash light source 4, a first computer 5, a second computer 6, a laser light source 7, a beam expander 8, a first field convex lens 9, a second convex lens 10, a third camera 11, a delay signal controller 12, a drop hammer 13, an impact head 14, a test piece 15, a loading frame 16, a first signal wire 17, a second signal wire 18, a third signal wire 19, a fourth signal wire 20, a fifth signal wire 21, a sixth signal wire 22, a seventh signal wire 23, an eighth signal wire 24, a ninth signal wire 25, a tenth signal wire 26 and an eleventh signal wire 27.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a transmission caustic line-three-dimensional digital image correlation method synchronous experiment system and a transmission caustic line-three-dimensional digital image correlation method synchronous measurement and acquisition, wherein the transmission caustic line method and the three-dimensional digital image correlation method synchronous measurement and acquisition can be simultaneously satisfied, the two methods can be mutually noninterfered, have complementary advantages and mutually verified, can measure stress intensity factors in the whole fracture process of a notch test piece, can measure mechanical parameters such as stress intensity factors, crack initiation toughness, crack propagation speed, dynamic fracture toughness and the like of a crack tip, and can more accurately and scientifically study the fracture behavior analysis of the test piece.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Fig. 1 is a schematic structural diagram of a transmission caustic line-three-dimensional digital image correlation method synchronous experimental system according to an embodiment of the present invention, and fig. 2 is a schematic structural diagram of a sample according to an embodiment of the present invention, as shown in fig. 1 and 2, the system includes:
the device comprises a laser light source 7, a beam expander 8, a first field convex lens 10, a loading frame 16, a test piece 15, an impact head 14, a drop hammer 13, a first flash light source 3, a second flash light source 4, a first camera 1, a second camera 2, a second field convex lens 10, a third camera 11, a first computer 5, a second computer 6 and a delay signal controller 12;
the laser light source 7 emits light sources which pass through the beam expander, the first field convex lens, the test piece and the second field convex lens in sequence and finally converge on the third camera;
the first camera is connected with the first flash light source, the second flash light source, the delay signal controller, the first computer and the second camera;
the second camera is connected with the first computer;
the third camera is connected with the second computer and the delay signal controller;
the drop hammer and the impact head are connected with the time delay signal controller;
the test piece is located on the loading frame.
Specifically, the first camera, the second camera and the third camera are ultra-high speed cameras.
The transmission caustic line system is on the same horizontal line, and a light source emitted by the laser light source 7 sequentially passes through the beam expander 8, the first field convex lens 9, the test piece 15 and the second convex lens 10, finally converged to the third camera 11, and the lens of the third camera 11 is adjusted to focus on a plane for focal speckle imaging; the third camera 11 and the second computer 6 are connected by a signal line 27. Wherein the first camera 1 is a main camera, and the second camera 2 is an auxiliary camera; the first camera 1 and the second camera 2 form a certain included angle, are symmetrically distributed on two sides of a caustic line parallel light path, and focus the two cameras, namely the first camera 1 and the second camera 2, to the surface of a spray spot of a test piece; the first flash light source 3 and the second flash light source 4 are placed on both sides of the first camera 1 and the second camera 2. The first signal wire 17 and the second signal wire 18 are respectively connected with the drop hammer 13 and the impact head 14, and the triggering mode of the delay signal controller 12 is regulated to be 'off-on' signal triggering; the fourth signal line 20 and the tenth signal line 26 are connected to the first camera 1 and the third camera 11, respectively. Both the first camera 1 and the third camera 11 are brought into an external trigger mode. The first camera 1 is connected to the first flash light source 3 and the second flash light source 4 via the fifth signal line 21 and the sixth signal line 22, respectively, and the second camera 2 is connected to the seventh signal line 23. The eighth signal line 24 connects the first camera 1 and the first computer 5, and the ninth signal line 25 connects the second camera 2 and the first computer 5.
After the drop hammer 13 contacts the impact head 14, the third signal line 19 causes the delay signal controller 12 to generate a trigger signal, and the trigger signal of the delay signal controller 12 triggers the first camera 1 and the third camera 11 through the fourth signal line 20 and the tenth signal line 26. Meanwhile, the first camera 1 activates the first strobe light source 3, the second strobe light source 4 and the second camera 2 with the signal line. After receiving the trigger signal, the third camera 11 starts to collect the transmitted caustic line experimental data, and finally, the transmitted caustic line experimental data is saved by the second computer 6. The first camera 1, the second camera 2, the first flash light source 3 and the second flash light source 4 work synchronously after receiving the trigger signal, collect the related data of the digital image and store and analyze by the first computer 5. And finally, synchronous measurement of a transmission caustic line method and a three-dimensional digital image correlation method is realized.
The transmission caustic line method is combined with the three-dimensional digital image correlation method, the test piece breaking process of the test piece 15 under dynamic and static loading is synchronously recorded, and the test piece breaking behavior is analyzed and studied.
The side of the test piece 15 close to the ultra-high speed camera is sprayed with speckle. To achieve simultaneous measurement of the transmitted caustic and the three-dimensional digital image correlation method, no speckle should be sprayed in the crack propagation path region. The method comprises the following specific steps: when spraying speckles, firstly, sticking an adhesive tape to cover the crack propagation path, wherein the diameter of the adhesive tape is about 1 cm; then spraying a layer of white paint on the surface of the test piece, and spraying random uniform black dispersion spots after the white paint is dried; and finally, the adhesive tape is removed.
The transmission caustic line method can measure various parameters such as stress intensity factors, crack expansion speed, expansion length, expansion acceleration and the like of the crack tip according to focal specks. According to the three-dimensional digital image correlation method, the stress intensity factors, the crack propagation stress intensity factors, the crack periphery displacement field, the strain field and other parameters when the crack or the notch is cracked can be calculated according to the speckle displacement information around the crack propagation path.
The impact head 14 and the drop hammer 13 on the experiment loading table 16 are replaced by a servo hydraulic press, a Hopkinson pressure bar device and an explosion loading device. Static loading, impact loading and blast loading of test piece 15 Shi Jiazhun.
The test piece 15 may be a test piece free of defects, a test piece containing a pre-crack, a test piece containing a pre-cut, or the like.
The system can not only study the behavior analysis of a test piece, but also explore the stress intensity factor of the expansion crack under the static or dynamic load effect by means of the method of the caustic line through the related measurement of the digital image.
Based on the system in the invention, the invention also provides an electric measurement-caustic line-digital speckle correlation method synchronous experiment method, which comprises the following steps:
first, a test piece is prepared. The side of the test piece 15 close to the ultra-high speed camera is sprayed with speckle. In order to achieve simultaneous measurement of the transmitted caustic and the three-dimensional digital image correlation method, no speckle is sprayed in the crack propagation path region. When spraying speckles, firstly, sticking an adhesive tape to cover the crack propagation path, wherein the diameter of the adhesive tape is about 1 cm; then spraying a layer of white paint on the surface of the test piece, and spraying random uniform black dispersion spots after the white paint is dried; and finally, the adhesive tape is removed.
Second, the transmitted caustic system and the three-dimensional digital image correlation system are adjusted. The transmission caustic line system is on the same horizontal line, and the laser height is adjusted according to the position of the measurement test piece. The light source emitted by the laser light source 7 sequentially passes through the beam expander 8, the first field convex lens 9, the test piece 15 and the second convex lens 10, finally converges to the third camera 11, and the lens of the third camera 11 is regulated to focus on a focal speckle imaging plane; the third camera 11 and the second computer 6 are connected by an eleventh signal line 27. In the three-dimensional digital image correlation system, a first camera 1 is a main camera, and a second camera 2 is an auxiliary camera; the first camera 1 and the second camera 2 form a certain included angle, are symmetrically distributed on two sides of a caustic line parallel light path, and focus the two cameras, namely the first camera 1 and the second camera 2, to the surface of a spray spot of a test piece; the first flash light source 3 and the second flash light source 4 are placed on both sides of the first camera 1 and the second camera 2. The signal line 24 connects the first camera 1 and the first computer 5, and the signal line 25 connects the second camera 2 and the first computer 5. When the three-dimensional digital image related system is adjusted, a three-dimensional coordinate system is established by using the correction plate, and more than 15 effective correction plate photos are taken. The triggering mode of the delay signal controller 12 is regulated to be the triggering of an on signal; the first camera 1 and the third camera 11 are adjusted to the external trigger mode.
Finally, the drop hammer 13 is released to strike the impact head 14, a load is applied to the test piece 15, the test piece 15 generates cracks and expands, and the system automatically collects the caustic line experimental data and the three-dimensional digital image related experimental data.
In fig. 2, the area a is a digital image speckle area, and the area B is a digital image speckle-free area.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (6)
1. A transmission caustic-three-dimensional digital image correlation method synchronous experimental system, the system comprising:
the device comprises a laser light source, a beam expander, a first field convex lens, a loading frame, a test piece, an impact head, a drop hammer, a first flash light source, a second flash light source, a first camera, a second field convex lens, a third camera, a first computer, a second computer and a delay signal controller, wherein the first camera is connected with the first computer;
the laser light source emits light sources which sequentially pass through the beam expander, the first field convex lens, the test piece and the second field convex lens and finally converge on the third camera;
the first camera is connected with the first flash light source, the second flash light source, the delay signal controller, the first computer and the second camera;
the second camera is connected with the first computer;
the third camera is connected with the second computer and the delay signal controller;
the drop hammer and the impact head are connected with the time delay signal controller;
the test piece is positioned on the loading frame;
the first camera and the second camera form a fixed included angle, and the first camera and the second camera are symmetrically distributed on two sides of a caustic line parallel light path;
the first flash light source and the second flash light source are arranged on two sides of the first camera and the second camera;
the first camera, the second camera and the third camera are ultra-high speed cameras, the first camera is a main camera, and the second camera is an auxiliary camera;
the test piece sprays speckle on one surface close to the first camera, and specifically comprises:
firstly, sticking adhesive tape to cover a crack propagation path;
then spraying a layer of white paint on the surface of the test piece, and spraying random uniform black dispersion spots after the white paint is dried;
finally, removing the adhesive tape;
after the drop hammer contacts the impact head, the delay signal controller generates a trigger signal, and the trigger signal of the delay signal controller triggers the first camera and the third camera; simultaneously, the first camera triggers the first flash light source, the second flash light source and the second camera; the third camera starts to collect transmission caustic line experimental data after receiving the trigger signal, and the transmission caustic line experimental data is stored by the second computer; the first camera, the second camera, the first flash light source and the second flash light source synchronously work after receiving the trigger signal, collect related data of digital images and store and analyze the related data by the first computer.
2. The transmitted caustic-three dimensional digital image correlation method synchronization experiment system according to claim 1, wherein the system further comprises: the device comprises a servo hydraulic motor, a Hopkinson pressure bar device and an explosion loading device, wherein the servo hydraulic motor is used for applying static load to a test piece, the Hopkinson pressure bar device is used for applying impact load to the test piece, and the explosion loading device is used for applying explosion load to the test piece.
3. The transmissive caustic line-three dimensional digital image correlation method synchronization experiment system according to claim 1, wherein the first camera and the third camera are both in an external trigger mode.
4. The transmitted caustic-three dimensional digital image correlation method synchronous experimental system according to claim 1, wherein the test piece is a defect-free test piece or a pre-crack test piece or a pre-cut-containing test piece.
5. A transmission caustic-three-dimensional digital image correlation method synchronization experiment method, characterized in that the method is applied to the system according to any one of claims 1-4, the method comprising:
preparing a test piece;
spraying speckle on one surface of the test piece close to the first camera;
adjusting a transmission caustic line system-a three-dimensional digital image correlation method synchronous experimental system to enable the transmission caustic line system to be on the same horizontal straight line;
adjusting the laser height according to the measured position of the test piece, and enabling a light source emitted by a laser light source to finally converge on a third camera through a beam expander, a first field convex lens, the test piece and a second field convex lens in sequence, and adjusting a lens of the third camera to focus on a focal-speckle imaging plane;
focusing the first camera and the second camera to the spot-spraying surface of the test piece;
establishing a three-dimensional coordinate system of the system by using a correction plate, and taking a plurality of effective correction plate photos;
the triggering mode of the delay signal controller is the triggering of an off signal;
adjusting the first camera and the third camera to an external trigger mode;
releasing a drop hammer to strike the impact head, applying load to the test piece, and generating cracks and expanding the test piece;
after the drop hammer contacts the impact head, the delay signal controller generates a trigger signal through the signal wire, and the trigger signal of the delay signal controller triggers the first camera and the third camera through the signal wire;
simultaneously, the first camera triggers the first flash light source, the second flash light source and the second camera by utilizing the signal line;
the third camera starts to collect transmission caustic line experimental data after receiving the trigger signal, and finally the transmission caustic line experimental data is stored by the second computer;
the first camera, the second camera, the first flash light source and the second flash light source work synchronously after receiving the trigger signal, digital image related data are collected and stored and analyzed by the first computer, and finally synchronous measurement of a transmission caustic line method and a three-dimensional digital image related method is realized.
6. The method according to claim 5, characterized in that more than 15 effective correction plate pictures are taken.
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Citations (7)
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