CN114136779B - Method for solving I-II type fracture toughness test of quasi-brittle material - Google Patents
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- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
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Abstract
The invention discloses a method for solving a quasi-brittle material I-II type fracture toughness test, which comprises the following steps: carrying out a three-point bending beam fracture experiment containing a prefabricated notch, and acquiring an image, a macroscopic crack expansion track and full-field strain information corresponding to an interested region under a limit load moment by adopting a discontinuous deformation measurement method; determining a micro-crack expansion track according to the full-field main tensile strain information, wherein the macro-crack expansion track and the micro-crack expansion track form a real crack expansion track; in an image corresponding to an interested region at the moment of limiting load, determining deflection times n according to a real crack propagation track by considering a crack deflection factor, and bringing the obtained effective crack propagation length a into a fracture toughness formula corresponding to an I-II composite fracture mode to obtain the I-II fracture toughness of the quasi-brittle material under the real condition. According to the method, the situation of repeated crack deflection is considered, and only the brittle material needs to be aligned and continuously loaded until fracture and destruction are achieved, so that the test operation flow is simplified.
Description
Technical Field
The invention belongs to the field of fracture mechanics theory, and particularly relates to a method for solving a type I-II fracture toughness test of a quasi-brittle material.
Background
In the fracture mechanics field, 3 fracture failure modes are involved: open type cracks (type I cracks), slide-open type cracks (type II cracks), and tear-open type cracks (type I-II cracks). For common quasi-brittle materials such as rock, ceramic, fiber cement-based composite materials and the like, the fracture damage of the quasi-brittle materials presents a nonlinear fracture behavior due to the existence of a fracture process zone near a fracture propagation tip region, and the knowledge category of the line elastic fracture mechanics can not be used for explanation. Aiming at the problems, related scholars sequentially put forward a double-parameter model, a double-K fracture model, a cohesive fracture model, a fracture zone model, a size effect model and the like. In practice, it is assumed that the crack propagates in a straight line direction (I-type crackSlits) and because matrix media inside the quasi-brittle material have the characteristic of random distribution, cracks on the surface of the material usually have a certain deflection angle with the horizontal or vertical direction when the material is broken and damaged, and the crack is expressed as an I-II type composite breaking and damaging mode. For example, chinese patent ZL201811218409.5 discloses a method for testing fracture performance of a concrete I-II composite type fracture, wherein an angle formed by a fracture propagation track and a vertical axis is introduced as a fracture angle to calculate I, II type fracture instability toughness, and the effective fracture length required to be calculated in calculating I type fracture instability toughness can be calculated according to critical fracture opening displacement CMOD C And the elastic modulus E calculated by the test piece P-CMOD curve. The method is designed for a crack test piece, adopts a theoretical calculation mode, cannot determine the position of a fine crack expansion tip, and cannot meet the actual occurrence process of the actual fracture toughness. Therefore, the method for solving the I-II type fracture toughness test of the quasi-brittle material, which can consider the actual situation of multi-time fracture deflection of the actual fracture propagation track, has important scientific research significance and engineering practical value.
Disclosure of Invention
According to fracture mechanics correlation theory, the invention provides a method for solving the I-II type fracture toughness test of a quasi-brittle material, which can determine the fracture toughness of the quasi-brittle material in an I-II type composite fracture mode by aiming at the brittle material to continuously load to fracture and destroy under the condition of multiple fracture deflection without executing repeated loading and unloading, so that the test operation flow is simplified.
The invention is realized by adopting the following technical scheme:
a method for solving a type I-II fracture toughness test of a quasi-brittle material comprises the following steps:
the first step: carrying out a three-point bending beam fracture experiment containing a prefabricated notch, and acquiring an image, a macroscopic crack expansion track and full-field strain information corresponding to an interested region under a limit load moment by adopting a discontinuous deformation measurement method;
and a second step of: the full-field strain information obtained by the discontinuous deformation measurement method comprises strains in three directions, full-field main tensile strain information of an interested region is obtained according to the strains in the three directions, a micro-crack expansion track is determined according to the full-field main tensile strain information, at the moment, coordinates of any point on the macro-crack expansion track and the micro-crack expansion track are both known values, and the macro-crack expansion track and the micro-crack expansion track form a real crack expansion track;
and a third step of: in an image corresponding to an interested region under the moment of a limit load, determining deflection times n according to a real crack expansion track by considering a crack deflection factor, and calculating an effective crack expansion length a corresponding to the moment of the limit load by adopting a formula (1);
a＝a 0 +a 1 +a 2 +···+a i +···+a n (1)
in the formula (1), a 0 、a i Respectively representing the length of the prefabricated crack and the effective crack extension length corresponding to the ith deflection; a, a n The length between the position of the crack extension tip of the micro-crack extension track and the end position of the n-1 th crack deflection is determined according to the full-field main tensile strain information;
fourth step: bringing the effective crack extension length a obtained in the third step into the corresponding fracture toughness K under the I-II composite fracture mode un In the formula, the I-II type fracture toughness of the quasi-brittle material under the real condition can be obtained.
In the above-described solving method, in the third step, the vertical direction of the trajectory end position of each deflection is the direction of the main tensile strain, and the length between the start and end positions of each crack deflection is directly used as the effective crack propagation length under the deflection.
Under the condition that the prefabricated notch is positioned at the center of the beam, the corresponding fracture toughness K under the I-II composite fracture mode is achieved un The formula is formula (2),
in the formula (2), P max S, B and D represent the span, width and height of the test piece, respectively, representing the ultimate load measured from the fracture test; f (f) 1 For test piecesShape parameters.
The main tensile strain direction corresponding to each coordinate point position on the real crack expansion track in the region of interest is always vertical to the actual expansion direction of the crack tip; firstly, finding out a cracked critical point and an uncracked critical point according to a full-field main tensile strain information cloud chart, wherein the critical point is determined as the position of a crack expansion tip corresponding to the last crack deflection, the main tensile strain direction is perpendicular to the crack expansion direction, and then a is determined according to the position of the n-1 st deflection in a real crack expansion track and the distance between the critical point n Values.
Compared with the prior art, the method has the beneficial effects that:
(1) When the fracture toughness is solved, the factors of repeated deflection of the fracture are considered, the fracture toughness is closer to the actual fracture and damage state of the quasi-brittle material, and the obtained fracture toughness value is more accurate.
(2) According to the method for solving the fracture toughness, the fracture toughness can be solved only by aligning the brittle material and continuously loading the brittle material until fracture damage, repeated loading and unloading processes are not needed, the rigidity requirement on the testing machine is reduced, and the testing operation steps are simplified. The fracture toughness solving method considering multiple fracture deflection is provided directly from the test angle, and the length of each fracture deflection can be directly obtained from the test without complex theoretical deduction calculation.
(3) The solving method is suitable for both the offset test piece and the test piece with the prefabricated crack at the middle position, not only comprises macroscopic crack expansion but also comprises fine crack expansion, and is more in line with the actual crack expansion process, and the deflection times are determined according to the actual crack expansion process, so that the requirement of actual crack detection can be met.
Drawings
FIG. 1 is a schematic illustration of three-point bending beam dimensions (in mm) for use in a fracture test;
FIG. 2 is a schematic diagram of an effective crack propagation length solution for a conventional nonlinear fracture model;
FIG. 3 is a schematic representation of an effective fracture propagation length solution of the present invention;
FIG. 4 is a graph showing the load-crack opening displacement measured in the example;
FIG. 5 shows the measured crack propagation trajectory and deflection angle information for a test piece with a fiber loading of 1.2%;
FIG. 6 shows the measured crack propagation trajectory and deflection angle information for a test piece with a fiber loading of 2.0%;
FIG. 7 is a comparison of measured fracture toughness for the present invention with a dual K fracture model.
Detailed Description
The foregoing is merely an overview of the present invention, and the present invention is further described in detail below with reference to the accompanying drawings, in order to make the purpose and technical solutions of the present invention more clear. The specific embodiments of the present invention are not limited thereto, and any equivalent modifications and improvements made by those skilled in the art without substantial innovation shall fall within the scope of the present invention.
The invention discloses a method for solving a quasi-brittle material I-II type fracture toughness test, which comprises the following steps:
the first step: carrying out a three-point bending beam (the size of a test piece is shown as in figure 1) fracture experiment containing a prefabricated notch, and acquiring an image, a macroscopic crack expansion track and full-field strain information corresponding to an interested region at a limit load moment by adopting a discontinuous deformation measurement method;
and a second step of: the full-field strain information obtained by the discontinuous deformation measurement method comprises strains in three directions, full-field main tensile strain information of an interested region is obtained according to the strains in the three directions, a micro-crack expansion track is determined according to the full-field main tensile strain information, at the moment, coordinates of any point on the macro-crack expansion track and the micro-crack expansion track are both known values, and the macro-crack expansion track and the micro-crack expansion track form a real crack expansion track;
and a third step of: in an image corresponding to an interested region under the limit load moment, according to a real crack expansion track, considering a crack deflection factor, determining the deflection times n, wherein the specific deflection times can be determined according to the actual crack expansion condition, and calculating the effective crack expansion length a corresponding to the limit load moment by adopting a formula (1);
a＝a 0 +a 1 +a 2 +···+a i +···+a n (1)
in the formula (1), a 0 、a i Respectively representing the length of the prefabricated crack and the effective crack extension length corresponding to the ith deflection; a, a n The length between the position of the crack extension tip of the micro-crack extension track and the end position of the n-1 th crack deflection is determined according to the full-field main tensile strain information;
fourth step: bringing the effective crack extension length a obtained in the third step into the corresponding fracture toughness K under the I-II composite fracture mode un In the formula, the I-II type fracture toughness of the quasi-brittle material under the real condition can be obtained.
The embodiment aims at the condition that the prefabricated notch is positioned at the center of the beam, and the corresponding fracture toughness K is in the I-II composite fracture mode un The formula is formula (2),
in the formula (2), P max S, B and D represent the span, width and height of the test piece, respectively, representing the ultimate load measured from the fracture test; f (f) 1 The shape parameter of the test piece can be obtained by the formula (3).
In the first step, before a fracture test starts, a random speckle pattern needs to be manufactured in an interested area on the surface of a test material in advance, then the acquisition frequency of a camera is fixed by fixing the camera in front of the interested area, and the acquisition of the fracture destruction whole process image is completed, so that the image corresponding to the interested area under the limit load moment is acquired. The quasi-brittle material can not generate complete fracture of the whole material when in extreme load, and the crack expansion phenomenon exists at the position of the prefabricated notch. The discontinuous deformation measuring method is a prior application of the applicant, the patent number is ZL201810294857.7, and the macroscopic crack expansion track and full-field strain information of the image at the moment of limiting load can be obtained through the method.
In the second step, the full-field strain information obtained by the discontinuous deformation measurement method comprises strains in three directions (horizontal strain, vertical strain and shearing strain), the full-field main strain information of the region of interest can be obtained according to the strains in the three directions, the expansion track of the micro-crack can be further observed by the full-field main strain information, the real evolution process of the crack can be reflected, and the main tensile strain direction corresponding to each coordinate point position in the region of interest is always vertical to the actual expansion direction of the tip of the crack.
In the third step, a 1 、…、a n-1 Can be directly determined by the true crack propagation trajectory obtained in the second step, for a n Firstly, finding out a cracked critical point and an uncracked critical point according to a full-field main tensile strain information cloud chart, wherein the critical point is determined as the position of a crack expansion tip, the main tensile strain direction is perpendicular to the crack expansion direction, and then determining a according to the distance between the position of the n-1 st deflection in a real crack expansion track and the critical point n Values.
FIG. 2 shows a solution method for the effective crack propagation length of the existing nonlinear fracture model: assuming that the O point is a cracking position, OA is a horizontal coordinate axis, and when cracks generate deflection for more than 1 time, the conventional nonlinear fracture model always transmits a vector BP 1 Sum vector BP 2 As the direction of main tensile strain, the position of the crack extension tip (point B (1 deflection) or point C (crack deflection exceeding 1 time) in FIG. 2) is determined, and the effective crack extension length OB 'or OC' is obtained by solving the projection B 'or C' of the point B or C on the OA axis, so that the length in the length direction of the prefabricated crack is mostly selected as the effective crack extension length in the prior art.
Unlike FIG. 2, the present invention will always be directed perpendicular to the crack propagation tip location (as vector BP in FIG. 3 1 Sum vector BP 2 Or vector CP 1 Sum vector CP 2 ) As the direction of the main tensile strain, thereby being used as effective crackThe basis for the solution of the slit extension length is directly taken as the effective slit extension length under the deflection from the end to the beginning of each deflection position. In addition, the invention marks the lengths of the line segment OB (1 deflection) and the line segment OB+line segment OC (crack deflection more than 1) as effective crack extension lengths, and fully considers the crack deflection factors.
Example 1
The object of this example is a directional steel fiber cement-based composite material with a volume doping amount of 1.2% and 2.0% (wherein, each doping amount is used for manufacturing 1 test piece), and the test purpose is as follows: fracture toughness obtained by adopting a double-K fracture model and the method provided by the invention under the moment of comparison limit load and respectively calculated is respectively denoted as K I And K I+II 。
The three-point bending prefabricated notched beam used in the fracture test has dimensions of B×D×S=100 mm×100mm×400mm, and initial crack length a 0 =40 mm. And a displacement loading control mode is adopted, and the speed is constant at 0.1mm/min. Before the test starts, a camera is fixed in front of the test material, and the region of interest is continuously photographed. The curve of the experimental load-crack opening displacement is shown in fig. 4, and it can be seen that the curve is not subjected to complex loading and unloading processes and is loaded only once.
Fig. 5 and 6 show measured crack propagation trajectories and crack deflection angle information. For the test piece with the volume doping amount of 1.2% in fig. 5, the first left image in fig. 5 is an image corresponding to the region of interest under the limit load moment, and is recorded as an original image, the middle is a crack propagation track image, and the first right image is a main tensile strain cloud image. The macro-crack propagation track obtained by the discontinuous deformation measurement method can obviously see turning points A, B and C, coordinates of the turning points A, B and C can be directly obtained through the macro-crack propagation track, and after three-point coordinates are obtained, the lengths of the line segments AB and BC can be obtained by using the Pythagorean theorem. For the line segment CD, the accurate position of the point D can be obtained by means of the main-pulling strain cloud picture, and then the length of the line segment CD is calculated, so that the effective crack extension length corresponding to the limit load moment is obtained. Similarly, a test piece (see FIG. 6) having a fiber loading of 2.0% can be treated in the same manner.
After determining the corresponding effective crack extension length under the limit load moment, the method brings the corresponding fracture toughness K under the I-II composite fracture mode un In the formula (2),
in the formula (2), P max S, B and D represent the span, width and height of the test piece, respectively, representing the ultimate load measured from the fracture test; f (f) 1 The shape parameter of the test piece can be obtained by the formula (3).
According to the first to third steps of the present invention, the effective crack propagation length a of the test piece increases in consideration of the crack deflection factor, and in addition, since the formula (3) shows an increasing trend with the increase of a/D, the fracture toughness value K calculated by the formula (2) is used un Will increase. As can be seen from the comparison result of the measured fracture toughness of the method and the double-K fracture model (shown in figure 7), the comparison trend of the measured fracture toughness value is consistent with the analysis, and the reliability of the solving method is demonstrated.
When fracture toughness solving is carried out, fracture deflection factors are introduced, fracture damage characteristics of the quasi-brittle material are fully considered, and meanwhile, the method provided by the invention does not need to undergo complex loading and unloading processes, so that the method can be popularized and applied in the fields of scientific research and engineering.
The invention is applicable to the prior art where it is not described.
Claims (4)
1. A method for solving a type I-II fracture toughness test of a quasi-brittle material comprises the following steps:
the first step: carrying out a three-point bending beam fracture experiment containing a prefabricated notch, and obtaining an image, a macroscopic crack expansion track and full-field strain information corresponding to an interested region at the moment of a limit load;
and a second step of: the obtained full-field strain information comprises strains in three directions, full-field main tensile strain information of an interested region is obtained according to the strains in the three directions, a micro-crack expansion track is determined according to the full-field main tensile strain information, at the moment, coordinates of any point on the macro-crack expansion track and the micro-crack expansion track are both known values, and the macro-crack expansion track and the micro-crack expansion track form a real crack expansion track;
and a third step of: in an image corresponding to an interested region under the moment of a limit load, determining deflection times n according to a real crack expansion track by considering a crack deflection factor, and calculating an effective crack expansion length a corresponding to the moment of the limit load by adopting a formula (1);
a＝a 0 +a 1 +a 2 +···+a i +···+a n (1)
in the formula (1), a 0 、a i Respectively representing the length of the prefabricated crack and the effective crack extension length corresponding to the ith deflection; a, a n The length between the position of the crack extension tip of the micro-crack extension track and the end position of the n-1 th crack deflection is determined according to the full-field main tensile strain information;
fourth step: bringing the effective crack extension length a obtained in the third step into the corresponding fracture toughness K under the I-II composite fracture mode un In the formula, the I-II type fracture toughness of the quasi-brittle material under the real condition can be obtained;
the main tensile strain direction corresponding to each coordinate point position on the real crack expansion track in the region of interest is always vertical to the actual expansion direction of the crack tip; firstly, finding out a cracked critical point and an uncracked critical point according to a full-field main tensile strain information cloud chart, wherein the critical point is determined as the position of a crack expansion tip corresponding to the last crack deflection, the main tensile strain direction is perpendicular to the crack expansion direction, and then a is determined according to the position of the n-1 st deflection in a real crack expansion track and the distance between the critical point n Values.
2. The method according to claim 1, wherein in the third step, the vertical direction of the trajectory end position of each deflection is the direction of the main pull strain, and the length between the start and end positions of each crack deflection is directly used as the effective crack propagation length under the deflection.
3. The method of claim 1, wherein,
under the condition that the prefabricated notch is positioned at the center of the beam, the corresponding fracture toughness K under the I-II composite fracture mode is achieved un The formula is formula (2),
in the formula (2), P max S, B and D represent the span, width and height of the test piece, respectively, representing the ultimate load measured from the fracture test; f (f) 1 Is a shape parameter of the test piece.
4. The method according to claim 1, wherein in the first step, before the fracture test starts, a random speckle pattern is required to be made in the region of interest on the surface of the test material in advance, then the acquisition frequency of the camera is fixed by fixing a camera in front of the region of interest, and the acquisition of the fracture destruction whole process image is completed, so that the image corresponding to the region of interest at the moment of limiting load is acquired; and acquiring an image, a macroscopic crack expansion track and full-field strain information corresponding to the region of interest under the limit load moment by adopting a discontinuous deformation measurement method.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007147348A (en) * | 2005-11-25 | 2007-06-14 | Toray Ind Inc | Fracture toughness testing method for light-weight sandwich panel |
| CN102692188A (en) * | 2012-05-08 | 2012-09-26 | 浙江工业大学 | Dynamic crack length measurement method for machine vision fatigue crack propagation test |
| CN103698224A (en) * | 2013-11-11 | 2014-04-02 | 水利部交通运输部国家能源局南京水利科学研究院 | Self-weight influence-free concrete material fracture toughness testing method |
| CN103760036A (en) * | 2014-01-08 | 2014-04-30 | 黄河水利委员会黄河水利科学研究院 | Testing method of steel fiber reinforced concrete fracture test crack initiation load |
| CN108662978A (en) * | 2018-04-04 | 2018-10-16 | 河北工业大学 | A kind of Discontinuous Deformation measurement method |
| CN109493329A (en) * | 2018-11-02 | 2019-03-19 | 河北工业大学 | Digital Image Correlation Method based on local mesh reflnement |
| CN109507041A (en) * | 2018-10-18 | 2019-03-22 | 上海宝冶集团南京建筑有限公司 | A kind of I-II mixed mode fracture property test method of concrete |
| EP3581882A1 (en) * | 2018-06-12 | 2019-12-18 | Technische Universität Wien | Flexion beam flex measurement method and test structure for for carrying out such a method |
| CN111651912A (en) * | 2020-05-09 | 2020-09-11 | 大连理工大学 | Hydraulic fracture propagation path numerical calculation method based on fracture mechanics criterion |
| CN111950209A (en) * | 2020-08-12 | 2020-11-17 | 西安石油大学 | Control method for hydraulic fracturing fracture extension track |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9939359B2 (en) * | 2014-09-25 | 2018-04-10 | East China University Of Science And Technology | Method of measurement and determination on fracture toughness of structural materials at high temperature |
| US11754481B2 (en) * | 2019-06-28 | 2023-09-12 | University Of South Carolina | Method for determining mixed mode dynamic fracture toughness of engineering materials involving forming surface cracks in specimens |
-
2021
- 2021-11-26 CN CN202111417551.4A patent/CN114136779B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007147348A (en) * | 2005-11-25 | 2007-06-14 | Toray Ind Inc | Fracture toughness testing method for light-weight sandwich panel |
| CN102692188A (en) * | 2012-05-08 | 2012-09-26 | 浙江工业大学 | Dynamic crack length measurement method for machine vision fatigue crack propagation test |
| CN103698224A (en) * | 2013-11-11 | 2014-04-02 | 水利部交通运输部国家能源局南京水利科学研究院 | Self-weight influence-free concrete material fracture toughness testing method |
| CN103760036A (en) * | 2014-01-08 | 2014-04-30 | 黄河水利委员会黄河水利科学研究院 | Testing method of steel fiber reinforced concrete fracture test crack initiation load |
| CN108662978A (en) * | 2018-04-04 | 2018-10-16 | 河北工业大学 | A kind of Discontinuous Deformation measurement method |
| EP3581882A1 (en) * | 2018-06-12 | 2019-12-18 | Technische Universität Wien | Flexion beam flex measurement method and test structure for for carrying out such a method |
| CN109507041A (en) * | 2018-10-18 | 2019-03-22 | 上海宝冶集团南京建筑有限公司 | A kind of I-II mixed mode fracture property test method of concrete |
| CN109493329A (en) * | 2018-11-02 | 2019-03-19 | 河北工业大学 | Digital Image Correlation Method based on local mesh reflnement |
| CN111651912A (en) * | 2020-05-09 | 2020-09-11 | 大连理工大学 | Hydraulic fracture propagation path numerical calculation method based on fracture mechanics criterion |
| CN111950209A (en) * | 2020-08-12 | 2020-11-17 | 西安石油大学 | Control method for hydraulic fracturing fracture extension track |
Non-Patent Citations (3)
| Title |
|---|
| Mode II fracture toughness for non-planar frictional cracks;Andrea SPAGNOLI et al.;《Procedia Structural Integrity》;第159-164页 * |
| 定向钢纤维水泥基复合材料起裂特性的细观数值模拟;刘辛丁 等;《混凝土》(第9期);第76-80页 * |
| 定向钢纤维水泥基材料Ⅰ-Ⅱ复合型断裂性能研究;王晓伟 等;《硅酸盐通报》;第37卷(第10期);第3147-3153页 * |
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