CN117371272A - Method for calculating crack length and fracture performance of clamping type unilateral notch tensile test sample applicable to different anisotropic materials and sizes - Google Patents

Method for calculating crack length and fracture performance of clamping type unilateral notch tensile test sample applicable to different anisotropic materials and sizes Download PDF

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CN117371272A
CN117371272A CN202311231329.4A CN202311231329A CN117371272A CN 117371272 A CN117371272 A CN 117371272A CN 202311231329 A CN202311231329 A CN 202311231329A CN 117371272 A CN117371272 A CN 117371272A
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crack
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刘争
王靖惠
陈旭
张喆
李吉康
靳鹏飞
刘明昊
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Abstract

The invention relates to a method for calculating crack length and fracture performance of a clamping type unilateral notch tensile sample suitable for different anisotropic materials and sizes, which comprises the following steps: 1) Establishing a two-dimensional plane stress model of the clamping type SENT sample, respectively establishing reference points at the upper and lower parts outside the clamping type SENT sample, and establishing coupling constraint between the reference points and the clamping ends of the sample; 2) Performing grid division on the model; 3) Calculating displacement, strain and stress field to obtain stress intensity factors and flexibility under different initial crack lengths, spans and anisotropic material parameters; 4) And according to finite element simulation results, establishing the relation between the normalized stress intensity factors and the normalized flexibility of the clamping type SENT test sample under different spans and the initial crack length and anisotropic material parameters, and the relation between the initial crack length and the normalized flexibility. The invention can effectively improve the crack monitoring and reliability evaluation precision of the clamping type unilateral notch tensile sample structure, and reduce the safety and economic risks caused by unreasonable calculation.

Description

Method for calculating crack length and fracture performance of clamping type unilateral notch tensile test sample applicable to different anisotropic materials and sizes
Technical Field
The invention belongs to the technical field of fracture mechanical property detection, and particularly relates to a method for calculating crack length and fracture property of a clamping type single-side notch tensile sample applicable to different anisotropic materials and sizes.
Background
Anisotropic materials refer to materials that exhibit different characteristics in different directions of mechanical, physical, and chemical properties, such as unidirectionally rolled metal sheets, composite materials, single crystal and additive manufacturing materials, and are widely used in the aerospace and other process industries. The structural members made of anisotropic materials inevitably exhibit crack initiation and propagation during service, thus accurately monitoring the crack length and fracture properties (K IC 、G IC ) Is the key of safe operation and maintenance. The clamping type unilateral notch Stretching (SENT) sample is widely used for measuring the fracture performance of an engineering structure because the stress state of the crack tip is similar to that of a pipeline and a pressure-bearing container containing defects.
However, the formulas related to the clamping type SENT test sample developed at present are all aimed at isotropic materials, and the fracture behavior of the isotropic materials cannot be calculated. On the other hand, aiming at the fracture and fatigue crack propagation test of the composite material based on the clamping SENT sample, the current method for measuring the instantaneous crack length by adopting the optical microscopy is limited by the measurement precision of a lens and the size of a window, and other human errors are easy to introduce by visual and manual acquisition, so that the method can not be applied to corrosive solutions, high-temperature boxes and other closed environments.
In order to solve the existing problems, numerical analysis methods are often adopted to calculate stress intensity factors and flexibility under different anisotropic material parameters and sample geometric dimensions, and corresponding formulas are fitted. However, the results reported at present are only the calculation of stress intensity factors and flexibility of compact tensile samples, three-point bending samples and eccentric loading SENT samples, and no study on the fracture performance of the clamping SENT samples applied to anisotropic materials is yet seen at present, and a crack length prediction formula based on a flexibility method is not established yet.
In view of the above, it is needed to solve the flexibility and stress intensity factors of the clamped SENT sample under a wide range of anisotropic material parameters (0.02-40, 0.1-10), different spans (H/W=2-10) and initial crack lengths (a/W=0.2-0.9) by adopting a numerical analysis method, develop stress intensity factors and flexibility calculation formulas and crack length monitoring formulas based on the flexibility method, and finally realize the accurate calculation of crack lengths and fracture properties of the clamped SENT sample of different anisotropic materials and structural sizes.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a method for calculating crack length and fracture performance of a clamping type unilateral notch tensile sample suitable for different anisotropic materials and sizes, establishes calculation formulas of stress intensity factors and flexibility under different initial crack length, span and anisotropic material parameters aiming at a clamping type unilateral notch tensile (SENT) sample, realizes accurate prediction of the crack length of the clamping type SENT sample considering the anisotropic material, and accurately evaluates the fracture performance (K) of the anisotropic material IC 、G IC )。
The invention solves the technical problems by the following technical proposal:
a method for calculating crack length and fracture performance of clamping type unilateral notch tensile test samples suitable for different anisotropic materials and sizes is characterized by comprising the following steps: the method comprises the following steps:
1) Adopting finite element analysis software Abaqus to establish a two-dimensional plane stress model of a clamping type SENT sample, and inputting the different directionsElastic modulus E of the sexual material 1 、E 2 Poisson's ratio v 12 And shear modulus G 12 Respectively establishing reference points at the upper part and the lower part of the outer part of the clamping type SENT sample, and establishing coupling constraint of the reference points and the clamping ends of the sample in a motion coupling constraint mode, wherein an external load P is respectively applied to the upper reference point and the lower reference point;
2) Dividing a two-dimensional plane stress model into grids by adopting 8-node quadrilateral units (CPS 8R) with reduced integral, encrypting grids at crack tips, introducing singular units and adopting focusing ring grids;
3) Calculating displacement, strain and stress fields by an implicit solver carried by Abaqus to obtain stress intensity factors and flexibility under different initial crack lengths, spans and anisotropic material parameters;
4) According to the finite element simulation result, establishing normalized stress intensity factors of clamping type SENT samples under different spans (H/W)And normalized compliance->Relationship with initial crack length α, anisotropic material parameters (λ, ρ), and initial crack length α and normalized compliance +.>Is the relation of:
normalized stress intensity factor for anisotropic materialsThe calculation formula is as follows:
wherein: α=a/W, a is the initial crack length, W is the specimen width;
f (α, λ, ρ) is calculated by:
q i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
R ij fitting parameters;
normalized compliance versus crack length:
wherein: p (α, λ, ρ) is calculated by:
p i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
S ij fitting parameters;
the crack length prediction formula based on compliance is as follows:
wherein:
t i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
M ij is a fitting parameter.
Elastic modulus E of anisotropic Material 1 、E 2 Poisson's ratio v 12 And shear modulus G 12 Defined by the characterization in-plane anisotropic material parameters λ, ρ:
wherein: e (E) 1 、E 2 Is the elastic modulus of the material, v 12 Is the Poisson's ratio of the material, G 12 Is the shear modulus of the material.
The structural dimensions of the clamping type single-side notch tensile sample in the step 1) are specifically as follows:
the width W of the sample gauge length section is 12mm;
the length of the sample of the gauge length section perpendicular to the crack direction is H, the ratio of the span H to the width W of the test piece can be changed by adjusting the boundary length H of the surface of the clamping section which is in power coupling with the reference point, and the analysis comprises 5 different spans, namely H/W=2, 4, 6, 8 and 10;
the crack is in the middle of the sample, the analysis matrix contains 9 different crack lengths α=a/W, α=0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9;
finite element model analysis investigated a broad range of orthotropic parameters including 16 λ values, i.e. λ=0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 10, 20, 40 and 5 ρ values, ρ=0.1, 1, 4, 8, 10 for a total of 80 sets of materials.
The specific calculation steps of the flexibility and stress intensity factor in the step 3) are as follows:
the stress intensity factor along the crack front can be calculated by a contour integration method and directly output from the dat file of Abaqus;
the output of the crack apex node is obtained from the odb file of Abaqus, resulting in an opening displacement (V) at the upper and lower points of the crack, and the compliance is obtained from the ratio of the opening displacement (V) to the applied force (P), i.e., c=v/P.
Moreover, the normalized stress intensity factor in step 4)And normalized compliance->The specific expression is as follows:
wherein: k is a stress intensity factor output by software;
b is the model sample thickness (b=1 mm);
w is the width of the model sample;
p=2000N is the applied load;
wherein: e (E) * For an equivalent elastic modulus of the material, for an anisotropic material,
b is the thickness (1 mm) of the model sample;
c is the flexibility obtained by the software output.
The invention has the advantages and beneficial effects that:
1. the invention provides an anisotropic material fracture performance test method aiming at a clamping type unilateral notch tensile sample, provides a calculation formula of normalized stress intensity factors and flexibility under different anisotropic material parameters, spans and initial crack lengths, can be used for calculating the anisotropic material fracture performance based on the clamping type unilateral notch tensile sample, and has the advantages of simple formula covering a wide range of materials and geometric dimensions and easy use.
2. The crack length prediction formula based on flexibility can effectively avoid the defects of optical crack length measurement such as optical microscopy, visual method and the like, can rapidly and accurately measure the real-time crack length through the flexibility, and can be applied to complex and severe experimental environments.
3. The method for solving the stress intensity factor and the flexibility and the crack length prediction formula based on the flexibility can effectively improve the crack monitoring and reliability evaluation precision of the clamping type single-side notch tensile sample and reduce the safety and economic risks caused by unreasonable evaluation.
Drawings
FIG. 1 is a schematic illustration of the geometry of a clamped single-sided notched tensile specimen for testing of the present invention;
FIG. 2 is a schematic representation of the sampling pattern of a test specimen of the present invention on a unidirectional carbon fiber composite laminate;
FIG. 3 is a graph of load displacement obtained from the test of the present invention;
FIG. 4 is a geometric schematic of a finite element model of the present invention;
FIG. 5 is a finite element mesh diagram of a clamped single-sided notched tensile specimen;
FIG. 6 is a graph of normalized stress intensity factor versus initial crack length, span and anisotropy parameters calculated for the finite element of the present invention;
FIG. 7 is a graph of normalized compliance calculated for the finite element of the present invention versus initial crack length, span and anisotropy parameters.
Detailed Description
The invention is further illustrated by the following examples, which are intended to be illustrative only and not limiting in any way.
The method for calculating crack length and fracture performance of clamping type unilateral notch tensile test samples suitable for different anisotropic materials and sizes is characterized by comprising the following innovation steps: the method comprises the following steps:
1) Adopting finite element analysis software Abaqus to establish a two-dimensional plane stress model of a clamping SENT sample, and inputting the elastic modulus E of an anisotropic material 1 、E 2 Poisson's ratio v 12 And shear modulus G 12 Respectively establishing reference points at the upper part and the lower part of the outer part of the clamping type SENT sample, and establishing coupling constraint of the reference points and the clamping ends of the sample in a motion coupling constraint mode, wherein an external load P is respectively applied to the upper reference point and the lower reference point;
the structural dimensions of the clamping type unilateral notch tensile sample are specifically as follows:
the width W of the sample gauge length section is 12mm;
the length of the sample of the gauge length section perpendicular to the crack direction is H, the ratio of the span H to the width W of the test piece can be changed by adjusting the boundary length H of the surface of the clamping section which is in power coupling with the reference point, and the analysis comprises 5 different spans, namely H/W=2, 4, 6, 8 and 10;
the crack is in the middle of the sample, the analysis matrix contains 9 different crack lengths α=a/W, α=0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9;
finite element model analysis investigated a broad range of orthotropic parameters including 16 λ values, i.e. λ=0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 10, 20, 40 and 5 ρ values, ρ=0.1, 1, 4, 8, 10 for a total of 80 sets of materials.
2) Dividing a two-dimensional plane stress model into grids by adopting 8-node quadrilateral units (CPS 8R) with reduced integral, encrypting grids at crack tips, introducing singular units and adopting focusing ring grids;
3) Calculating displacement, strain and stress fields by an implicit solver carried by Abaqus to obtain stress intensity factors and flexibility under different initial crack lengths, spans and anisotropic material parameters;
the specific calculation steps of the flexibility and stress intensity factor are as follows:
the stress intensity factor along the crack front can be calculated by a contour integration method and directly output from the dat file of Abaqus;
to determine the displacement field, consider the output of the crack apex node, the compliance is obtained by the ratio of the opening displacement (V) at the upper and lower points of the crack to the applied force (P), i.e., c=v/P.
4) According to the finite element simulation result, establishing normalized stress intensity factors of clamping type SENT samples under different spans (H/W)And normalized compliance->Relationship with initial crack length α, anisotropic material parameters (λ, ρ), and initial crack length α and normalized compliance +.>Is the relation of:
normalized stress intensity factor for anisotropic materialsThe calculation formula is as follows:
wherein: α=a/W, a is the initial crack length, W is the specimen width;
f (α, λ, ρ) is calculated by:
q i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
R ij to fit parameters, parameters R at different spans H/W ij Listed in tables 1-3;
table 1 span H/w=2 and 4 parameter R in equation (3) below ij
Table 2 span H/w=6 and 8 parameter R in equation (3) below ij
Table 3 span H/w=10 parameter R in equation (3) below ij
Normalized compliance versus crack length:
wherein: p (α, λ, ρ) is calculated by:
p i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
S ij to fit parameters, parameters S at different spans H/W ij Listed in tables 4-6;
table 4 span H/w=2 and 4 parameter S in equation (6) below ij
Table 5 stride H/w=6 and 8 parameter S in equation (6) below ij
Table 6 span H/w=10 parameter S in equation (6) below ij
The crack length prediction formula based on compliance is as follows:
wherein:
t i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
M ij to fit parameters, parameters M at different spans H/W ij As shown in tables 7-9.
Table 7 spans H/w=2 and 4 parameter M in equation (8) below ij
Table 8 span H/w=6 and 8 parameter M in equation (8) below ij
Table 9 span H/w=10 parameter M in equation (8) below ij
Elastic modulus E of anisotropic Material 1 、E 2 Poisson's ratio v 12 And shear modulus G 12 Defined by the characterization in-plane anisotropic material parameters λ, ρ:
wherein: e (E) 1 、E 2 Is the elastic modulus of the material, v 12 Is the Poisson's ratio of the material, G 12 Is the shear modulus of the material.
Normalized stress intensity factorAnd normalized compliance->The specific expression is as follows:
wherein: k is a stress intensity factor output by software;
b is the model sample thickness (b=1 mm);
w is the width of the model sample;
p=2000N is the applied load;
wherein: e (E) * For an equivalent elastic modulus of the material, for an anisotropic material,
b is the thickness (1 mm) of the model sample;
c is the flexibility obtained by the software output.
Taking unidirectional T300-12K carbon fiber reinforced epoxy resin material produced by Guangwei composite company as an example, the method provided by the invention is used for obtaining the accurate crack length and the fracture performance. The basic mechanical properties of the composite material are measured by a uniaxial tensile test and a shearing test: modulus of elasticity E in the fiber direction (X-direction) 1 Is 86300MPa, perpendicular to the fiber direction (Y direction)Modulus of elasticity E of (2) 2 7370MPa, poisson's ratio v 12 0.266, shear modulus G 12 For 6517MPa, in-plane orthotropic parameters λ and ρ can be calculated from equation (9) and equation (10), resulting in λ= 0.0854, ρ= 1.8571.
In the following, the crack length and fracture properties of the composite material will be accurately calculated according to the method of the present invention.
(1) Sample design and processing
The clamping type single-side notch tensile sample is adopted, the normalized initial crack length alpha=0.5, the span H/W is 4, and the geometric schematic diagram is shown in figure 1. The test specimen width W was 12mm, the initial crack length a was 5.858mm, the actual normalized initial crack length α=0.488, the gauge length h=48 mm, and the specimen both end holding portions H * The length is 20mm. The crack direction was consistent with the fiber direction, thickness b=3.08 mm. The SENT specimen was cut on the X-Y side of the laminate composite plate, and as shown in FIG. 2, the crack propagation direction was the fiber direction (X direction).
(2) Fracture experiment procedure
Fracture experiments were performed on a MTS 370.02 pull-torsion fatigue tester. And (3) carrying out quasi-static load stretching in a displacement control mode (0.1 mm/min) at room temperature, measuring crack opening displacement by adopting a DIC technology, and recording the external load and the crack opening displacement of the test piece in the test process. The crack length is monitored in real time through a high-power camera, a sample photo is taken every 1s by the camera for monitoring the crack length, and after the sample is completely broken, the test is stopped. The load displacement curve obtained by the test is shown in FIG. 3, in which the critical load P max ＝268.059N。
(3) Test data processing
Two types of data are collected in the experimental process, namely a photo of the surface of the sample taken by a camera, and text data collected by an MTS tester, including time, load, opening displacement and the like. And obtaining the flexibility through the ratio of the displacement to the load, and finally obtaining the flexibility and the crack length under the corresponding condition at each moment.
(4) Finite elements establish stress intensity factors and the relationship between compliance and crack length
Using finite element software Abaqus, a two-dimensional planar stress model of a clamped single-edge notched tensile specimen was established as shown in fig. 4, wherein specimen width W was 12mm, total length l=h+2h * The analysis matrix contained 9 different normalized crack lengths α, i.e., α=a/w=0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, =88 mm.
Modulus of elasticity E of input carbon fiber composite material 1 ＝86300MPa，E 2 =7370 MPa, poisson ratio v 12 =0.266, shear modulus G 12 =6517 MPa. The model is gridded by adopting 8-node quadrilateral cells with reduced integral, the grids at the crack tips are encrypted and singular cells are introduced, and the focusing ring type grids are adopted, so that the finite element grid model is shown in figure 5. Normalized stress intensity factors and flexibility under different anisotropic material parameters, spans and crack lengths are calculated, the results are shown in fig. 6 and 7, and fitted empirical formulas are shown in formula (1) and formula (4).
From equation (7), the corresponding crack length for each compliance of the clamped send sample under the span H/w=4 condition can be obtained when the anisotropic material parameter is λ= 0.0854, ρ= 1.8571. The test shows that the normalized flexibility corresponding to the crack initiation time of the test sample is 5.9958, the predicted crack length is obtained by the formula (7), and the current developed crack length prediction method based on the flexibility is found to be effective by comparing the predicted crack length with the initial crack length alpha=0.488 of the sample shot by the camera (table 10).
Table 10 comparison of test and predicted normalized crack lengths
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On the other hand, substituting the measured normalized initial crack length α=0.488 into equation (1), the normalized stress intensity factor corresponding to the sample with the span H/w=4 can be calculatedLet p=p again max The formula (11) is substituted by 268.059N, B =3.08 mm and w=12.07 mmObtaining the fracture toughness at break>
For composite materials, critical strain energy release rates, i.e., fracture toughness (G IC ) To characterize its resistance to damage. The critical strain energy release rate can be calculated using the difference between the compliance C and the crack length a:
wherein: p is the ultimate load (N) of crack propagation, B is the sample thickness (m),is the difference of the compliance curve fit.
The relationship (4) of the compliance obtained from the SENT specimen with known crack length to the crack length was constructed by Abaqus. And determining a flexibility curve according to the discrete crack length range under finite element modeling. By plotting the relation between the flexibility (mm/N) and the crack length (mm), the method can obtainWill limit load P max ＝268.059N、B＝3.08mm、The fracture toughness G finally obtained by carrying out the test in the formula (13) IC ＝729.385N/m。
Although the embodiments of the present invention and the accompanying drawings have been disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the embodiments and the disclosure of the drawings.

Claims (4)

1. A method for calculating crack length and fracture performance of clamping type unilateral notch tensile test samples suitable for different anisotropic materials and sizes is characterized by comprising the following steps: the method comprises the following steps:
1) Adopting finite element analysis software Abaqus to establish a two-dimensional plane stress model of a clamping SENT sample, and inputting the elastic modulus E of an anisotropic material 1 、E 2 Poisson ratio v and shear modulus G 12 Respectively establishing reference points at the upper part and the lower part of the outer part of the clamping type SENT sample, and establishing coupling constraint of the reference points and the clamping ends of the sample in a motion coupling constraint mode, wherein an external load P is respectively applied to the upper reference point and the lower reference point;
2) Dividing a two-dimensional plane stress model into grids by adopting 8-node quadrilateral units (CPS 8R) with reduced integral, encrypting grids at crack tips, introducing singular units and adopting focusing ring grids;
3) Calculating displacement, strain and stress fields by an implicit solver carried by Abaqus to obtain stress intensity factors and flexibility under different initial crack lengths, spans and anisotropic material parameters;
4) According to the finite element simulation result, establishing normalized stress intensity factors of clamping type SENT samples under different spans (H/W)And normalized compliance->Relationship with initial crack length α, anisotropic material parameters (λ, ρ), and initial crack length α and normalized compliance +.>Is the relation of:
normalized stress intensity factor for anisotropic materialsThe calculation formula is as follows:
wherein: α=a/W, a is the initial crack length, W is the specimen width;
f (α, λ, ρ) is calculated by:
q i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
R ij fitting parameters;
normalized compliance versus crack length:
wherein: p (α, λ, ρ) is calculated by:
p i (lambda, p) is fitThe coefficient is determined by material parameters lambda and rho, and the calculation formula is as follows:
wherein:
S ij fitting parameters;
the crack length prediction formula based on compliance is as follows:
wherein:
t i (lambda, ρ) is a fitting coefficient, determined by the material parameters lambda, ρ, and the calculation formula is:
wherein:
M ij fitting parameters;
anisotropic materialModulus of elasticity E of (2) 1 、E 2 Poisson's ratio v 12 And shear modulus G 12 Defined by the characterization in-plane anisotropic material parameters λ, ρ:
wherein: e (E) 1 、E 2 Is the elastic modulus of the material, v 12 Is the Poisson's ratio of the material, G 12 Is the shear modulus of the material.
2. The method for calculating crack length and fracture performance of clamping type single-side notch tensile test samples applicable to different anisotropic materials and sizes according to claim 1, wherein the method comprises the following steps: the structural dimensions of the clamping type unilateral notch tensile sample in the step 1) are specifically as follows:
the width W of the sample gauge length section is 12mm;
the length of the sample of the gauge length section perpendicular to the crack direction is H, the ratio of the span H to the width W of the test piece can be changed by adjusting the boundary length H of the surface of the clamping section which is in power coupling with the reference point, and the analysis comprises 5 different spans, namely H/W=2, 4, 6, 8 and 10;
the crack is in the middle of the sample, the analysis matrix contains 9 different crack lengths α=a/W, α=0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9;
finite element model analysis investigated a broad range of orthotropic parameters including 16 λ values, i.e. λ=0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 10, 20, 40 and 5 ρ values, ρ=0.1, 1, 4, 8, 10 for a total of 80 sets of materials.
3. The method for calculating crack length and fracture performance of clamping type single-side notch tensile test samples applicable to different anisotropic materials and sizes according to claim 1, wherein the method comprises the following steps: the specific calculation steps of the flexibility and stress intensity factors in the step 3) are as follows:
the stress intensity factor along the crack front can be calculated by a contour integration method and directly output from the dat file of Abaqus;
the output of the crack apex node is obtained from the odb file of Abaqus, resulting in an opening displacement (V) at the upper and lower points of the crack, and the compliance is obtained from the ratio of the opening displacement (V) to the applied force (P), i.e., c=v/P.
4. The method for calculating crack length and fracture performance of clamping type single-side notch tensile test samples applicable to different anisotropic materials and sizes according to claim 1, wherein the method comprises the following steps: the normalized stress intensity factor in step 4)And normalized compliance->The specific expression is as follows:
wherein: k is a stress intensity factor output by software;
b is the model sample thickness (b=1 mm);
w is the width of the model;
p=2000N is the applied load;
wherein: e (E) * For an equivalent elastic modulus of the material, for an anisotropic material,b is the thickness (1 mm) of the model sample;
c is the flexibility obtained by the software output.
CN202311231329.4A 2023-09-22 2023-09-22 Method for calculating crack length and fracture performance of clamping type unilateral notch tensile test sample applicable to different anisotropic materials and sizes Active CN117371272B (en)

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