CN116296798A - Method and system for determining constitutive relation of tensile concrete based on DIC technology - Google Patents
Method and system for determining constitutive relation of tensile concrete based on DIC technology Download PDFInfo
- Publication number
- CN116296798A CN116296798A CN202310117273.3A CN202310117273A CN116296798A CN 116296798 A CN116296798 A CN 116296798A CN 202310117273 A CN202310117273 A CN 202310117273A CN 116296798 A CN116296798 A CN 116296798A
- Authority
- CN
- China
- Prior art keywords
- tensile
- strain
- concrete
- damage
- local
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 73
- 238000005516 engineering process Methods 0.000 title claims abstract description 60
- 230000008569 process Effects 0.000 claims abstract description 32
- 238000004458 analytical method Methods 0.000 claims abstract description 11
- 238000005315 distribution function Methods 0.000 claims description 12
- 230000006735 deficit Effects 0.000 claims description 9
- 238000012937 correction Methods 0.000 claims description 6
- 238000010276 construction Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 description 24
- 238000012360 testing method Methods 0.000 description 11
- 238000013001 point bending Methods 0.000 description 8
- 238000006073 displacement reaction Methods 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 239000000654 additive Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Images
Classifications
-
- 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
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
-
- 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
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
-
- 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
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a method and a system for determining a constitutive relation of a tensile concrete based on a DIC technology, wherein the system comprises a DIC data acquisition module, a constitutive relation analysis module and an output module; the data acquisition module comprises an integral tensile strain data acquisition unit and/or a local tensile strain data acquisition unit, the constitutive relation analysis module comprises a microscopic tensile damage model of integral tensile concrete and/or a microscopic tensile damage model of local tensile concrete, the method acquires integral tensile strain data of the integral tensile process of the concrete and/or local tensile strain data of the local tensile process of the concrete in real time through a digital image technology, and a strain-time curve is output; and inputting the whole tensile strain data into a mesoscopic tensile damage model of the whole tensile concrete and/or inputting the partial tensile strain data into a mesoscopic tensile damage model of the partial tensile concrete, calculating to obtain the stress of a specific part of the tensile concrete, and outputting a stress-time curve and a strain-stress relation curve.
Description
Technical Field
The invention relates to the technical field of concrete construction, in particular to a method and a system for measuring a constitutive relation of a tensile concrete based on a DIC technology.
Background
A digital image correlation technique (DIC), which is a computer vision capturing technique, is often applied to observe the strain state of a material surface, and a high-speed camera photographs an image of the material surface during loading and calculates the strain of any point of the image; compared with the strain gauge and the extensometer for measuring the strain or displacement of the material, the DIC technology can achieve completely non-contact measurement, and the influence of the contact state of the measuring equipment and the material on the test result is greatly avoided.
Currently, the existing DIC technology is an advanced technology for analyzing cracking states or strain change rules of materials such as concrete, metal, rubber and the like when the materials are loaded, and a recognition method for a crack propagation mode of a rock body in a field hole is invented by a patent CN106248672A (DIC technology-based recognition method and system for a crack propagation mode of the rock body in the field hole), and a drilling and shooting technology is combined with the DIC technology, so that the rock body is excavated and unloaded and the original crack are effectively distinguished, and the method has the advantages of convenience in operation, reliability in monitoring and high precision; patent CN201710693040.2, method for measuring part strain in real time in additive manufacturing process, discloses a method for measuring part strain in real time in additive manufacturing process, and strain distribution cloud patterns at different moments are obtained to reveal strain distribution and evolution rule in additive manufacturing process; patent CN201910801202.9 (a test and calculation method for measuring the plastic strain ratio of a metal material) discloses a method for measuring the plastic strain ratio of the metal material, obtains the plastic strain ratio of the metal material under the gauge length of 1.0mm, improves the accuracy, reliability and objectivity of the measurement of the strain ratio, and reduces the test cost; patent CN113466066B 'a method for measuring fatigue deformation and crack width of a concrete material based on DIC technology' discloses a method for measuring fatigue deformation and crack width of a concrete material based on DIC technology, and analysis of crack width, height and number under specific fatigue life is realized.
However, the invention can only measure the change rule of cracks, displacement or strain of the material, and can not directly reveal the constitutive relation of the material in the loading process, and the following problems still exist:
(1) Only the displacement and strain law of the material can be measured: the existing DIC technology utilizes the gray value difference of images before and after loading to analyze the displacement field or the strain field of the material, and has great limitation on the concrete material needing to analyze the stress and strain relation in the loading process;
(2) Constitutive relation of specific parts of materials cannot be described: the DIC technology has the advantages that strain rules of different parts of the material can be described, strain cloud charts are generated, but the stress-strain relationship calculated in the prior art is the same as the stress-strain principle obtained by the testing machine through load-displacement curve calculation, and only constitutive relationships of the whole material can be described;
(3) Lack of a system capable of directly outputting the constitutive relationship of a material: the current DIC technology can only directly output strain cloud pictures of materials or strain data of different parts, but cannot directly output stress-strain curves describing constitutive relations of different parts of the materials;
(4) DIC technology measurement is aided by other equipment: if the existing method is to establish the stress-strain relation of the material based on the measurement of the strain of the material by the DIC technology, the test process is more complicated by the results output by other devices such as a displacement extensometer, a testing machine output load and the like, and the subsequent results are not easy to process.
Therefore, how to provide a method and a system for determining the constitutive relation of a tensile concrete based on the DIC technology is a problem to be solved by the person skilled in the art.
Disclosure of Invention
In view of the above, the invention provides a method and a system for determining the constitutive relation of a tensile concrete based on the DIC technology, which solve the problems that the constitutive relation of a specific part of a material cannot be described only by the DIC technology, the stress-strain relation of the material is established on the basis of measuring the strain of the material by the DIC technology, the stress-strain relation is assisted by other equipment, the process is complicated, and the subsequent result processing is not facilitated.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a method for determining a constitutive relation of a tensioned concrete based on DIC technology, comprising:
acquiring overall tensile strain data of the overall concrete tensile process in real time through a digital image technology, and outputting a strain-time curve; inputting the whole tensile strain data into a constructed mesoscopic tensile damage model of the whole tensile concrete, calculating to obtain the stress of a specific part of the whole tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve;
and/or
Acquiring local tensile strain data of a concrete local tensile process in real time through a digital image technology, and outputting a strain-time curve; and inputting the local tensile strain data into a constructed microscopic tensile damage model of the local tensile concrete, calculating to obtain the stress of the specific part of the local tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve.
Preferably, the construction method of the microscopic tensile damage model of the integral tensile concrete comprises the following steps:
obtaining a probability density function of yield strain, a probability density function of fracture strain, a probability distribution function of yield strain and a probability distribution function of fracture strain of the concrete under integral stretching;
obtaining an elastic modulus damage value caused by fracture strain and an elastic modulus damage caused by yield strain;
and constructing a mesoscopic tensile damage model of the whole tensile concrete.
Preferably, the mesoscopic tensile damage model of the whole tensile concrete is as follows:
σ N ＝E 0 ε(1-D' y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R The modulus of elasticity damage value caused by fracture strain is epsilon, which is the tensile strain of the whole concrete at a certain moment in the tensile process.
Preferably, the probability density function of the yield strain comprises probability density functions of an elastic phase, an elastoplastic phase and a plastic phase, in particular:
wherein p (ε) is a probability density function of yield strain; epsilon is the tensile strain of the concrete at a certain moment in the whole tensile process; epsilon 0 The initial strain of the concrete before loading is set; epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
the probability density function of the fracture strain is:
wherein q (ε) is a probability density function of strain at break; h is a fracture accumulated damage value corresponding to the maximum yield strain;
the probability distribution function of yield strain is:
wherein D is y Probability density function as yield strain;
the probability distribution function of the fracture strain is:
wherein D is R The probability density function of fracture strain, namely the elastic modulus damage value caused by the fracture strain;
the elastic modulus damage caused by the yield strain is:
wherein D is y ' is the elastic modulus damage value caused by the yield strain.
Preferably, the mesoscopic tensile damage model of the local tensile concrete is:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the concrete at a certain moment in the local tensile process, and D is the damage variable of the local tensile concrete.
Preferably, the damage variables of the local tensile concrete are:
wherein D is a damage variable of the local tensile concrete; a is a damage correction coefficient; epsilon is the strain measured by DIC; zeta and lambda are random field parameters of the impairment variables;
the random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnεpr
wherein E is 0 The initial tensile elastic modulus of the concrete; epsilon pr Is the ultimate tensile strain of the concrete; sigma (sigma) pr Is the ultimate tensile stress of the concrete.
A system for measuring a constitutive relation of a tensile concrete based on a DIC technology comprises a DIC data acquisition module, a constitutive relation analysis module and an output module;
the data acquisition module comprises an integral tensile strain data acquisition unit and/or a local tensile strain data acquisition unit, and the constitutive relation analysis module comprises a microscopic tensile damage model of integral tensile concrete and/or a microscopic tensile damage model of local tensile concrete.
The whole tensile strain data acquisition unit is used for acquiring whole tensile strain data of the whole concrete tensile process in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the whole tensile concrete is used for calculating the input whole tensile strain data to obtain the stress of a specific part of the whole tensile concrete;
the local tensile strain data acquisition unit is used for acquiring local tensile strain data of a local tensile process of the concrete in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the local tensile concrete is used for calculating the input local tensile strain data to obtain the stress of a specific part of the local tensile concrete;
and the output module is used for outputting a stress-time curve according to the strain-time curve and the specific part stress and outputting a strain-stress relation curve.
Preferably, the mesoscopic tensile damage model of the whole tensile concrete is as follows:
σ N ＝E 0 ε(1-D' y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R For breaking offThe damage value of the elastic modulus caused by the change is epsilon, which is the tensile strain of the concrete at a certain moment in the whole tensile process;
wherein D is y As a probability density function of yield strain, D y ' is the damage value of elastic modulus caused by yield strain, D R The probability density function of the fracture strain is used, namely the elastic modulus damage value caused by the fracture strain, q (epsilon) is used as the probability density function of the fracture strain, and p (epsilon) is used as the probability density function of the yield strain;
the probability density function of the yield strain comprises probability density functions of an elastic stage, an elastoplastic stage and a plastic stage, and specifically comprises the following steps:
wherein epsilon is the tensile strain of concrete at a certain moment 0 For initial strain of the concrete before loading epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
wherein H is the accumulated damage value of fracture corresponding to the maximum yield strain.
Preferably, the mesoscopic tensile damage model of the local tensile concrete is:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the local tensile concrete, and D is the damage variable of the local tensile concrete;
wherein D is a damage variable of the local tensile concrete, a is a damage correction coefficient, epsilon is the strain measured by DIC, and zeta and lambda are random field parameters of the damage variable;
the random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnεpr
wherein E is 0 For initial tensile modulus, ε of concrete pr For the ultimate tensile strain, sigma, of concrete pr Is the ultimate tensile stress of the concrete.
Compared with the prior art, the invention discloses a method and a system for determining the constitutive relation of the tensile concrete based on the DIC technology, which have the following beneficial effects:
1. on the basis of the DIC technology measurement strain rule, stress-strain curves of different positions of the tensile concrete are obtained through a microscopic tensile damage model of the tensile concrete, and the stress-time, stress-time and stress-strain relation curves of the concrete can be directly output on the premise of not using load data of a loading tester, so that the method has the advantages of strong applicability, simplicity and convenience in operation and high intelligent degree;
2. the stress-strain relation data output by the invention is the constitutive relation of any position of the tensile concrete on a microscopic scale reflected by the strain law and the tensile damage constitutive model obtained by combining the DIC technology, can be used for analyzing the constitutive relation of a concrete tensile region under the action of bending loads such as three-point bending or four-point bending, can also be used for analyzing the constitutive relation of the interlayer position of the ballastless track overlapping structure, and has wide application prospect.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a method for determining the constitutive relation of a tensioned concrete according to the present invention;
FIG. 2 is a schematic diagram of a system for determining the constitutive relation of a tensioned concrete according to the present invention;
FIG. 3 is a schematic view of strain versus time curves of a locally tensioned concrete according to an embodiment of the present invention;
FIG. 4 is a schematic view of the damage variables of a locally pulled concrete according to an embodiment of the present invention;
FIG. 5 is a diagram showing the comparison between the calculated results and the actual measured results of the local tensile concrete constitutive relation provided by the embodiment of the invention;
the system comprises a 1-concrete test piece, a 2-camera, a 3-data acquisition unit, a 4-constitutive relation analysis module and a 5-tripod.
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 embodiment of the invention discloses a method for measuring a constitutive relation of a tensile concrete based on a DIC technology, which comprises the following steps:
acquiring overall tensile strain data of the overall concrete tensile process in real time through a digital image technology, and outputting a strain-time curve; inputting the whole tensile strain data into a constructed mesoscopic tensile damage model of the whole tensile concrete, calculating to obtain the stress of a specific part of the whole tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve;
and/or
Acquiring local tensile strain data of a concrete local tensile process in real time through a digital image technology, and outputting a strain-time curve; and inputting the local tensile strain data into a constructed microscopic tensile damage model of the local tensile concrete, calculating to obtain the stress of the specific part of the local tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve.
In practical application, a camera is adopted to aim at a concrete measurement position, speckles on the surface of the concrete are calibrated through a calibration plate, a high-speed camera is adopted to shoot the concrete at the frequency of 50 Hz-10000 Hz, and the whole tensile strain data of the whole tensile process of the concrete and/or the local tensile strain data of the local tensile process of the concrete are collected in real time.
In order to further implement the technical scheme, the construction method of the microscopic tensile damage model of the whole tensile concrete comprises the following steps:
obtaining a probability density function of yield strain, a probability density function of fracture strain, a probability distribution function of yield strain and a probability distribution function of fracture strain of the concrete under integral stretching;
obtaining an elastic modulus damage value caused by fracture strain and an elastic modulus damage caused by yield strain;
and constructing a mesoscopic tensile damage model of the whole tensile concrete.
In order to further implement the technical scheme, the microscopic tensile damage model of the whole tensile concrete is as follows:
σ N ＝E 0 ε(1-D' y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R The modulus of elasticity damage value caused by fracture strain is epsilon, which is the tensile strain of the whole concrete at a certain moment in the tensile process.
In order to further implement the above technical solution, the probability density function of the yield strain includes probability density functions of an elastic phase, an elastoplastic phase and a plastic phase, specifically:
wherein p (ε) is a probability density function of yield strain; epsilon is the tensile strain of the concrete at a certain moment in the whole tensile process; epsilon 0 The initial strain of the concrete before loading is set; epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
the probability density function of the fracture strain is:
wherein q (ε) is a probability density function of strain at break; h is a fracture accumulated damage value corresponding to the maximum yield strain;
the probability distribution function of yield strain is:
wherein D is y Probability density function as yield strain;
the probability distribution function of the fracture strain is:
wherein D is R The probability density function of fracture strain, namely the elastic modulus damage value caused by the fracture strain;
the elastic modulus damage caused by the yield strain is:
wherein D is y ' is the elastic modulus damage value caused by the yield strain.
In order to further implement the technical scheme, the microscopic tensile damage model of the local tensile concrete is as follows:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the concrete at a certain moment in the local tensile process, and D is the damage variable of the local tensile concrete.
In order to further implement the technical scheme, the damage variables of the local tensile concrete are as follows:
wherein D is a damage variable of the local tensile concrete; a is a damage correction coefficient; epsilon is the strain measured by DIC; zeta and lambda are random field parameters of the impairment variables;
the random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnεpr
wherein E is 0 Is mixed withInitial tensile elastic modulus of the concrete; epsilon pr Is the ultimate tensile strain of the concrete; sigma (sigma) pr Is the ultimate tensile stress of the concrete.
A system for measuring a constitutive relation of a tensile concrete based on a DIC technology comprises a DIC data acquisition module, a constitutive relation analysis module and an output module;
the data acquisition module comprises an integral tensile strain data acquisition unit and/or a local tensile strain data acquisition unit, and the constitutive relation analysis module comprises a microscopic tensile damage model of integral tensile concrete and/or a microscopic tensile damage model of local tensile concrete.
The whole tensile strain data acquisition unit is used for acquiring whole tensile strain data of the whole concrete tensile process in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the whole tensile concrete is used for calculating the input whole tensile strain data to obtain the stress of a specific part of the whole tensile concrete;
the local tensile strain data acquisition unit is used for acquiring local tensile strain data of a local tensile process of the concrete in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the local tensile concrete is used for calculating the input local tensile strain data to obtain the stress of a specific part of the local tensile concrete;
and the output module is used for outputting a stress-time curve according to the strain-time curve and the specific part stress and outputting a strain-stress relation curve.
In order to further implement the technical scheme, the microscopic tensile damage model of the whole tensile concrete is as follows:
σ N ＝E 0 ε(1-D' y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R For the modulus of elasticity damage value caused by fracture strain, ε is the blendingTensile strain at a certain moment in the whole tensile process of the concrete;
wherein D is y As a probability density function of yield strain, D y ' is the damage value of elastic modulus caused by yield strain, D R The probability density function of the fracture strain is used, namely the elastic modulus damage value caused by the fracture strain, q (epsilon) is used as the probability density function of the fracture strain, and p (epsilon) is used as the probability density function of the yield strain;
the probability density function of the yield strain comprises probability density functions of an elastic stage, an elastoplastic stage and a plastic stage, and specifically comprises the following steps:
wherein epsilon is the tensile strain of concrete at a certain moment 0 For initial strain of the concrete before loading epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
wherein H is the accumulated damage value of fracture corresponding to the maximum yield strain.
In order to further implement the technical scheme, the microscopic tensile damage model of the local tensile concrete is as follows:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the local tensile concrete, and D is the damage variable of the local tensile concrete;
wherein D is a damage variable of the local tensile concrete, a is a damage correction coefficient, epsilon is the strain measured by DIC, and zeta and lambda are random field parameters of the damage variable;
in the present embodiment, a=1×10 135 ，ζ＝0.4，λ＝2.7。
The random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnεpr
wherein E is 0 For initial tensile modulus, ε of concrete pr For the ultimate tensile strain, sigma, of concrete pr Is the ultimate tensile stress of the concrete.
In this embodiment, the DIC data acquisition module comprises a high-speed camera, a calibration plate and a data acquisition unit;
placing a concrete test piece with the length of 100mm multiplied by 400mm subjected to speckle treatment in a universal servo press to perform tensile tests such as uniaxial tension, three-point bending, four-point bending and split tension, connecting a high-speed camera with a data analysis system, and directly facing the concrete test piece, and calibrating the camera by adopting a calibration plate; shooting a concrete test piece with a high-speed camera at the frequency of 60Hz while loading is started until the test piece is broken, guiding an image into a structural relation analysis module through a data acquisition device to output a strain-time curve, a stress-time curve and a stress-strain curve, taking three-point bending and stretching as an example, wherein the three-point bending and stretching is a strain-time curve of the three-point bending local tensile concrete, the strain-time curve is used for calculating to obtain the change rule of a damage variable of the three-point bending local tensile concrete, the strain-time curve is used for calculating to obtain the change rule of the stress of the middle-span bottom of the concrete test piece, and the stress-time curve is derived, and the strain-time curve is shown in the figure 5;
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. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A method for determining a constitutive relation of a tensioned concrete based on DIC technology, comprising:
acquiring overall tensile strain data of the overall concrete tensile process in real time through a digital image technology, and outputting a strain-time curve; inputting the whole tensile strain data into a constructed mesoscopic tensile damage model of the whole tensile concrete, calculating to obtain the stress of a specific part of the whole tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve;
and/or
Acquiring local tensile strain data of a concrete local tensile process in real time through a digital image technology, and outputting a strain-time curve; and inputting the local tensile strain data into a constructed microscopic tensile damage model of the local tensile concrete, calculating to obtain the stress of the specific part of the local tensile concrete, outputting a stress-time curve, and outputting a strain-stress relation curve.
2. The method for determining the constitutive relation of the tensile concrete based on the DIC technology according to claim 1, wherein the construction method of the microscopic tensile damage model of the whole tensile concrete is as follows:
obtaining a probability density function of yield strain, a probability density function of fracture strain, a probability distribution function of yield strain and a probability distribution function of fracture strain of the concrete under integral stretching;
obtaining an elastic modulus damage value caused by fracture strain and an elastic modulus damage caused by yield strain;
and constructing a mesoscopic tensile damage model of the whole tensile concrete.
3. The method for determining the constitutive relation of a tensile concrete based on DIC technology according to claim 2, wherein the microscopic tensile damage model of the overall tensile concrete is:
σ N ＝E 0 ε(1-D′ y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R The modulus of elasticity damage value caused by fracture strain is epsilon, which is the tensile strain of the whole concrete at a certain moment in the tensile process.
4. The method for determining the constitutive relation of a tensile concrete based on DIC technology according to claim 2, characterized in that the probability density function of the yield strain comprises probability density functions of elastic phase, elastoplastic phase and plastic phase, in particular:
wherein p (ε) is a probability density function of yield strain; epsilon is the tensile strain of the concrete at a certain moment in the whole tensile process; epsilon 0 The initial strain of the concrete before loading is set; epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
the probability density function of the fracture strain is:
wherein q (ε) is a probability density function of strain at break; h is the accumulated damage value of fracture corresponding to the maximum yield strain;
the probability distribution function of yield strain is:
wherein D is y Probability density function as yield strain;
the probability distribution function of the fracture strain is:
wherein D is R The probability density function of fracture strain, namely the elastic modulus damage value caused by the fracture strain;
the elastic modulus damage caused by the yield strain is:
wherein D is y ' is the elastic modulus damage value caused by the yield strain.
5. The method for determining the constitutive relation of a tensile concrete based on DIC technology according to claim 1, wherein the model of the microscopic tensile damage of the local tensile concrete is:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the concrete at a certain moment in the local tensile process, and D is the damage variable of the local tensile concrete.
6. The method for determining the constitutive relation of a tensile concrete based on the DIC technique according to claim 5, wherein the local damage variable of the tensile concrete is:
wherein D is a damage variable of the local tensile concrete; a is a damage correction coefficient; epsilon is the strain measured by DIC; zeta and lambda are random field parameters of the impairment variables;
the random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnε pr
wherein E is 0 The initial tensile elastic modulus of the concrete; epsilon pr Is the ultimate tensile strain of the concrete; sigma (sigma) pr Is the ultimate tensile stress of the concrete.
7. A system for determining a constitutive relation of a tensile concrete based on a DIC technique, a method for determining a constitutive relation of a tensile concrete based on a DIC technique according to any one of claims 1-6, characterized by comprising a DIC data acquisition module, a constitutive relation analysis module and an output module;
the data acquisition module comprises an integral tensile strain data acquisition unit and/or a local tensile strain data acquisition unit, and the constitutive relation analysis module comprises a microscopic tensile damage model of integral tensile concrete and/or a microscopic tensile damage model of local tensile concrete.
The whole tensile strain data acquisition unit is used for acquiring whole tensile strain data of the whole concrete tensile process in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the whole tensile concrete is used for calculating the input whole tensile strain data to obtain the stress of a specific part of the whole tensile concrete;
the local tensile strain data acquisition unit is used for acquiring local tensile strain data of a local tensile process of the concrete in real time through a digital image technology and outputting a strain-time curve;
the mesoscopic tensile damage model of the local tensile concrete is used for calculating the input local tensile strain data to obtain the stress of a specific part of the local tensile concrete;
and the output module is used for outputting a stress-time curve according to the strain-time curve and the specific part stress and outputting a strain-stress relation curve.
8. The system for determining the constitutive relation of a tensile concrete based on DIC technology according to claim 7, wherein the microscopic tensile damage model of the overall tensile concrete is:
σ N ＝E 0 ε(1-D' y )(1-D R )
wherein sigma N To stress a certain position of the tensioned concrete E 0 For the initial tensile elastic modulus of the concrete, D y ' is the damage value of elastic modulus caused by yield strain, D R For the elastic modulus damage value caused by fracture strain, epsilon is the whole tensile strength of the concreteA tensile strain at Cheng Mouyi;
wherein D is y As a probability density function of yield strain, D y ' is the damage value of elastic modulus caused by yield strain, D R The probability density function of the fracture strain is used, namely the elastic modulus damage value caused by the fracture strain, q (epsilon) is used as the probability density function of the fracture strain, and p (epsilon) is used as the probability density function of the yield strain;
the probability density function of the yield strain comprises probability density functions of an elastic stage, an elastoplastic stage and a plastic stage, and specifically comprises the following steps:
wherein epsilon is the tensile strain of concrete at a certain moment 0 For initial strain of the concrete before loading epsilon 1 The limit strain of the concrete in the elastic stage is calculated by the DIC technology; epsilon 2 The limit strain of the concrete in the elastoplastic stage is calculated by the DIC technology; epsilon 3 For the ultimate strain of concrete in the plastic stage, the strain exceeds epsilon ymax Concrete fracture, calculated by DIC technique;
wherein H is the accumulated damage value of fracture corresponding to the maximum yield strain.
9. The system for determining the constitutive relation of a tensile concrete based on DIC technology according to claim 7, wherein the model of the microscopic tensile damage of the local tensile concrete is:
σ＝E 0 ε(1-D)
wherein sigma is the tensile stress of the local tensile concrete, epsilon is the tensile strain of the local tensile concrete, and D is the damage variable of the local tensile concrete;
wherein D is a damage variable of the local tensile concrete, a is a damage correction coefficient, epsilon is the strain measured by DIC, and zeta and lambda are random field parameters of the damage variable;
the random field parameters ζ and λ of the impairment variables are respectively:
λ＝lnεpr
wherein E is 0 For initial tensile modulus, ε of concrete pr For the ultimate tensile strain, sigma, of concrete pr Is the ultimate tensile stress of the concrete.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310117273.3A CN116296798A (en) | 2023-02-15 | 2023-02-15 | Method and system for determining constitutive relation of tensile concrete based on DIC technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310117273.3A CN116296798A (en) | 2023-02-15 | 2023-02-15 | Method and system for determining constitutive relation of tensile concrete based on DIC technology |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116296798A true CN116296798A (en) | 2023-06-23 |
Family
ID=86782564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310117273.3A Pending CN116296798A (en) | 2023-02-15 | 2023-02-15 | Method and system for determining constitutive relation of tensile concrete based on DIC technology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116296798A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2839056A1 (en) * | 2013-03-01 | 2014-09-01 | Simco Technologies Inc. | Method and system for planning maintenance activities for concrete structures |
| CN105089698A (en) * | 2014-05-13 | 2015-11-25 | 中国铁道科学研究院城市轨道交通中心 | Settlement control method in process of enabling subway tunnel to penetrate through existing railway |
| CN110220980A (en) * | 2019-06-10 | 2019-09-10 | 南京工业大学 | Test method based on acoustic emission measurement concrete in uniaxial tension damage evolution equation |
| CN112964580A (en) * | 2021-03-17 | 2021-06-15 | 哈尔滨工业大学 | Concrete tensile impact performance test device and impact test method thereof |
| CN113466066A (en) * | 2021-06-30 | 2021-10-01 | 山东大学 | DIC technology-based method for measuring fatigue deformation and crack width of concrete material |
| US20220042901A1 (en) * | 2018-10-01 | 2022-02-10 | Nippon Telegraph And Telephone Corporation | Hydrogen Embrittlement Progress Evaluation Method and Hydrogen Embrittlement Progress Evaluation Device |
| CN115455806A (en) * | 2022-08-12 | 2022-12-09 | 华北水利水电大学 | Concrete statistical damage constitutive model parameter determination method |
-
2023
- 2023-02-15 CN CN202310117273.3A patent/CN116296798A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2839056A1 (en) * | 2013-03-01 | 2014-09-01 | Simco Technologies Inc. | Method and system for planning maintenance activities for concrete structures |
| CN105089698A (en) * | 2014-05-13 | 2015-11-25 | 中国铁道科学研究院城市轨道交通中心 | Settlement control method in process of enabling subway tunnel to penetrate through existing railway |
| US20220042901A1 (en) * | 2018-10-01 | 2022-02-10 | Nippon Telegraph And Telephone Corporation | Hydrogen Embrittlement Progress Evaluation Method and Hydrogen Embrittlement Progress Evaluation Device |
| CN110220980A (en) * | 2019-06-10 | 2019-09-10 | 南京工业大学 | Test method based on acoustic emission measurement concrete in uniaxial tension damage evolution equation |
| CN112964580A (en) * | 2021-03-17 | 2021-06-15 | 哈尔滨工业大学 | Concrete tensile impact performance test device and impact test method thereof |
| CN113466066A (en) * | 2021-06-30 | 2021-10-01 | 山东大学 | DIC technology-based method for measuring fatigue deformation and crack width of concrete material |
| CN115455806A (en) * | 2022-08-12 | 2022-12-09 | 华北水利水电大学 | Concrete statistical damage constitutive model parameter determination method |
Non-Patent Citations (6)
| Title |
|---|
| LI, J: "Research on the stochastic damage constitutive model of concrete materials", 《ICACS 2003: INTERNATIONAL CONFERENCE ON ADVANCES IN CONCRETE AND STRUCTURES》, vol. 32, 1 January 2003 (2003-01-01), pages 44 - 54 * |
| 徐丽海: "基于DIC类岩石材料损伤演化研究", 《贵州大学学报（自然科学版）》, vol. 35, no. 3, 30 June 2018 (2018-06-30), pages 110 - 115 * |
| 李杰: "混凝土随机损伤本构关系工程参数标定与应用", 《同济大学学报（自然科学版）》, vol. 45, no. 8, 31 August 2017 (2017-08-31), pages 1100 - 1107 * |
| 白卫峰: "考虑围压效应的混凝土统计损伤模型", 《应用基础与工程学学报》, vol. 29, no. 6, 30 December 2021 (2021-12-30), pages 1500 - 1511 * |
| 白卫峰;孙胜男;管俊峰;陈健云;: "基于统计损伤理论的混凝土双轴拉-压本构模型研究", 应用基础与工程科学学报, no. 05, 15 October 2015 (2015-10-15), pages 1 - 4 * |
| 邹德磊: "飞射物撞击LNG储罐穹顶的试验与数值仿真分析", 《自然灾害学报》, vol. 26, no. 6, 15 December 2017 (2017-12-15), pages 13 - 21 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| NL2026165B1 (en) | Method for analyzing tensile failure performance of 3d printing sample | |
| KR20160077704A (en) | Method of obtaining reliable true stress-strain curves in a large range of strains in tensile testing using digital image correlation | |
| US20140283619A1 (en) | Method for evaluating corrosion-fatigue life of steel material | |
| CN110411836A (en) | A kind of test and calculation method measuring metal material plastic strain ratio | |
| JPWO2020065815A1 (en) | Material tester | |
| CN116738780B (en) | Compact tensile sample fatigue crack propagation length and rate calculation method considering crack deflection | |
| CA2246705C (en) | Process and device for checking the solidity of vertically anchored masts | |
| CN107271273B (en) | A kind of method of cross tensile pre-deformation load measurement yield surface | |
| Huang et al. | Method for visualizing the shear process of rock joints using 3D laser scanning and 3D printing techniques | |
| CN116296798A (en) | Method and system for determining constitutive relation of tensile concrete based on DIC technology | |
| CN104122205B (en) | A kind of method utilizing impression uplift capacity to measure residual stress | |
| CN112927185A (en) | True stress-true strain curve test calculation method based on digital image correlation method | |
| Matvienko et al. | The effect of low-cycle fatigue parameters on damage accumulation near a hole | |
| JP3312298B2 (en) | How to measure stress intensity factor | |
| CN114518289A (en) | Control method for deformation strain control by video acquisition | |
| Gilat et al. | Full field strain measurement during a tensile split Hopkinson bar experiment | |
| JP2014085243A (en) | True stress measuring method and apparatus | |
| Tran et al. | Experimental analysis of the extension to shear fracture transition in a rock analogue material using digital image correlation method | |
| Panwitt et al. | Automated crack length measurement for mixed mode fatigue cracks using digital image correlation | |
| CN110082207A (en) | Detect method and apparatus, system and the storage medium of coating material strain failure | |
| Xiufeng et al. | Research on Application of Digital Image Correlation Method | |
| KR102653004B1 (en) | Method for tracing displacement fields and stress fields at structures containing discontinuous regions using non-ordinary state-based peridynamics and digital image correlation | |
| RU2319945C1 (en) | Method of building diagram of deforamtion of material | |
| Rajinikanth et al. | Strain Measurement Using Digital Image Correlation Technique | |
| CAO et al. | Digital image correlation based high-speed crack tip locating method and its application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |