CN110987621B - Method for establishing three-dimensional fracture model of metal material in complex stress state - Google Patents
Method for establishing three-dimensional fracture model of metal material in complex stress state Download PDFInfo
- Publication number
- CN110987621B CN110987621B CN201911311254.4A CN201911311254A CN110987621B CN 110987621 B CN110987621 B CN 110987621B CN 201911311254 A CN201911311254 A CN 201911311254A CN 110987621 B CN110987621 B CN 110987621B
- Authority
- CN
- China
- Prior art keywords
- samples
- group
- stress
- fracture
- sample
- 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.)
- Active
Links
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
- 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
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0067—Fracture or rupture
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0256—Triaxial, i.e. the forces being applied along three normal axes of the specimen
Abstract
The invention provides a method for establishing a three-dimensional fracture model of a metal material in a complex stress state, which comprises the steps of designing a first group of samples and a second group of samples; performing a quasi-static standard tensile test on the first group of samples by adopting nonlinear tensile force to obtain a true stress-shaping strain curve of the first group of samples, inputting the true stress-shaping strain curve of the first group of samples into a material numerical test model corresponding to various sample types in the second group of samples, and obtaining stress triaxial eta and normalized Lord angle parameters corresponding to various sample types in the second group of samples
The method comprises the steps of carrying out a first treatment on the surface of the Carrying out fracture test on various types of samples in the second group of samples by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to various sample types in the second group of samples; normalized Lord angle parameters based on stress triaxial η for each sample type in the second set of samples
And critical fracture strain values to obtain a three-dimensional fracture model of the metal material in a complex stress state.
Description
Technical Field
The invention belongs to the field of automobile informatization, and particularly relates to a method for establishing a three-dimensional fracture model of a metal material under a complex stress state.
Background
In the fracture study of metal materials, a forming limit diagram and a fixed critical fracture strain value are often adopted to simulate the fracture failure of the metal materials. However, when the forming limit diagram is used for judging the occurrence of cracks, crack areas are too conservative, and cracks tend to occur too early or too late; and the forming limit diagram can only be used for predicting the crack condition of the material under the condition of a linear strain path, and in the practical process, the material is accompanied by strong strain path dependence after necking. When the fixed critical fracture strain value is adopted to judge the occurrence of the crack, the influence of the stress state of the material on the critical fracture strain value is not considered. Obviously, the current fracture failure simulation method does not consider the influence of different stress states and nonlinear strain paths on fracture failure at the same time, and can not accurately simulate the fracture failure of the metal material in a complex stress state.
Disclosure of Invention
The invention provides a three-dimensional fracture model building method of a metal material in a complex stress state, which aims to solve the problem that the current fracture failure simulation method does not consider the influence of different stress states and nonlinear strain paths on fracture failure at the same time, so that the fracture failure of the metal material in the complex stress state cannot be accurately simulated.
According to a first aspect of the embodiment of the present invention, there is provided a method for building a three-dimensional fracture model of a metal material in a complex stress state, including:
designing a first group of samples for a quasi-static standard tensile test and a second group of samples for a fracture test for a metal material of the same material, wherein the samples in the second group of samples comprise a plurality of types;
performing quasi-static standard tensile test on the first group of samples by adopting nonlinear tensile force to obtain a true stress-shaping strain curve of the first group of samples, inputting the true stress-shaping strain curve of the first group of samples into a material numerical test model corresponding to various sample types in the second group of samples to obtain stress triaxial eta, lord angle parameter zeta and normalized Lord angle parameter corresponding to various sample types in the second group of samples
Carrying out fracture test on various types of samples in the second group of samples by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to various sample types in the second group of samples;
for each sample type in the second group of samples, the stress triaxial degree eta, the Lord angle parameter zeta and the normalized Lord angle parameter are used for the sample type
Substituting the critical fracture strain value into a corresponding three-dimensional model, establishing a multi-element equation set, and calculating to obtain five unknown coefficients K, C and +_in the three-dimensional fracture model>
f. n, and further obtaining a three-dimensional fracture model of the metal material in a complex stress state.
In an alternative implementation, the first set of samples includes a plurality of samples, and the performing a quasi-static standard tensile test on the first set of samples using a nonlinear tensile force to obtain a true stress-shaping strain curve for the first set of samples includes:
carrying out quasi-static standard tensile test on each sample in the first group of samples by adopting the nonlinear tensile force so as to obtain a true stress-shaping strain curve of each sample in the first group of samples;
a centered one of the true stress-shaping strain curves of each of the first set of samples is selected as the true stress-shaping strain curve of the first set of samples.
In another alternative implementation, each sample type in the second set of samples includes a plurality of samples of that type; the step of performing a fracture test on each type of sample in the second group of samples by using the nonlinear tensile force, the step of obtaining critical fracture strain values corresponding to each type of sample in the second group of samples includes:
and aiming at each sample type in the second group of samples, carrying out corresponding fracture tests on a plurality of samples of the type by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to the number of the samples, calculating the average value of the critical fracture strain values corresponding to the number of the samples, and taking the average value as the critical fracture strain value of the sample type in the second group of samples.
In another alternative implementation, the second set of samples includes five sample types, a pure shear tensile test sample, a center hole unidirectional tensile test sample, an R5 notch tensile test sample, an R10 notch tensile test sample, and a cupping sample, each sample type including a plurality of samples of that type.
In another alternative implementation, the strain to failure of the three-dimensional fracture model is a function of stress triaxial and normalized Lord angle, as follows
Wherein the formula comprises five unknowns, K, C respectively,
f. n, calibrating through a plurality of groups of fracture tests; wherein, by stress triaxial η and normalized Lodet angle parameter->
The stress state of the material is represented, and the values are [ -1,1]The calculation formula is as follows
Stress triaxial degree:
wherein, p is the hydrostatic pressure,
for Mises equivalent stress, sigma 1 、σ 2 、σ 3 Respectively the first, second and third principal stresses, I 1 As the first stress invariant, J 2 Is the second stress deflection invariant;
lomb angle parameter:
in the method, in the process of the invention,
for Mises equivalent stress, J 2 、J 3 The second and third bias stress deflection are respectively invariable;
normalized Lord angle
In the three-dimensional fracture model, the fracture failure of the material is judged by a damage factor D, and when D=1, the material is broken, and the calculation formula is shown as follows
In d epsilon p In order to provide an amount of plastic strain accumulation,
for fracture failure strain corresponding to different stress triaxial and normalized Lord angle, the material is considered in the calculation of the damage factor DIs accumulated in the non-linear strain path.
In another alternative implementation, the DIC equipment is used for real-time strain testing to obtain critical fracture strain values for each sample type in the second set of samples.
The beneficial effects of the invention are as follows:
1. according to the invention, a quasi-static standard tensile test is carried out on the first group of samples by adopting nonlinear tensile force, and a nonlinear strain path is considered when a true stress-shaping strain curve of the first group of samples is obtained; the nonlinear tensile force is adopted in the breaking test, and various types of samples are designed, so that the influence of different stress states on breaking failure is considered; the invention considers the influence of different stress states and nonlinear strain paths on fracture failure, and can accurately simulate the fracture failure of the metal material in a complex stress state;
2. according to the invention, the first group of samples comprise a plurality of samples, the same nonlinear tensile force is adopted to repeatedly perform quasi-static standard tensile test on the plurality of samples in the first group of samples, after the true stress-shaping strain curves of all the samples in the first group of samples are obtained, the middle true stress-shaping strain curve is selected as the true stress-shaping strain curve of the first group of samples, so that the obtained true stress-shaping strain curve of the first group of samples can reflect the deformation of the metal material more accurately;
3. when the invention carries out fracture test on various types of samples, a plurality of samples of the types are subjected to corresponding fracture test (namely, repeated test is carried out on the corresponding fracture test for a plurality of times), the average value of critical fracture strain values obtained by repeated test is obtained, and the average value is taken as the critical fracture strain value of the samples of the types, so that the influence of the fracture sample (namely, the corresponding stress state) on fracture failure can be further accurately corresponding.
Drawings
FIG. 1 is a block diagram of one embodiment of a method for creating a three-dimensional fracture model of a metallic material under complex stress conditions in accordance with the present invention;
FIG. 2 is a schematic diagram of the structure (in mm) of the samples in the first group of samples;
FIG. 3 is a schematic representation of the structure (in mm) of five sample types in the second set of samples;
FIG. 4 is a B-pillar hydrostatic model in three-dimensional fracture model validation;
fig. 5 is a graph comparing static pressure numerical simulation and test results of a 22MnB5 high-strength steel B column in three-dimensional fracture model verification.
Detailed Description
In order to better understand the technical solution in the embodiments of the present invention and make the above objects, features and advantages of the embodiments of the present invention more comprehensible, the technical solution in the embodiments of the present invention is described in further detail below with reference to the accompanying drawings.
In the description of the present invention, unless otherwise specified and defined, it should be noted that the term "connected" should be interpreted broadly, and for example, it may be a mechanical connection or an electrical connection, or may be a connection between two elements, or may be a direct connection or may be an indirect connection through an intermediary, and it will be understood to those skilled in the art that the specific meaning of the term may be interpreted according to the specific circumstances.
Referring to fig. 1, a block diagram of one embodiment of a method for creating a three-dimensional fracture model of a metallic material under complex stress conditions according to the present invention is shown. The method may comprise the steps of:
step S101, designing a first set of samples for a quasi-static standard tensile test and a second set of samples for a fracture test for a metallic material of the same material, wherein the samples in the second set of samples comprise a plurality of types. In this embodiment, the first set of samples may include a plurality of samples, for example, 3 samples, and the structure of the samples in the first set of samples is shown in fig. 2. The second set of samples may include five sample types, a pure shear tensile test sample, a center hole unidirectional tensile test sample, an R5 notch tensile test sample, an R10 notch tensile test sample, and a cupping sample, as shown in fig. 3.
Step S102, performing quasi-static standard tensile test on the first group of samples by adopting nonlinear tensile force to obtain true samples of the first group of samplesInputting the true stress-shaping strain curve of the first group of samples into a material numerical test model corresponding to various sample types in the second group of samples to obtain stress triaxial η, lord angle parameter ζ and normalized Lord angle parameter corresponding to various sample types in the second group of samples
In step S102, performing a quasi-static standard tensile test on the first set of samples by using a nonlinear tensile force, where obtaining a true stress-shaping strain curve of the first set of samples includes: carrying out quasi-static standard tensile test on each sample in the first group of samples by adopting the nonlinear tensile force so as to obtain a true stress-shaping strain curve of each sample in the first group of samples; a centered one of the true stress-shaping strain curves of each of the first set of samples is selected as the true stress-shaping strain curve of the first set of samples. According to the invention, the nonlinear tensile force is adopted to conduct the quasi-static standard tensile test on the first group of samples, the nonlinear strain path is considered when the true stress-shaping strain curve of the first group of samples is obtained, the first group of samples comprise a plurality of samples, the same nonlinear tensile force is adopted to conduct the quasi-static standard tensile test on the plurality of samples in the first group of samples repeatedly, after the true stress-shaping strain curve of each sample in the first group of samples is obtained, the middle true stress-shaping strain curve is selected as the true stress-shaping strain curve of the first group of samples, and the obtained true stress-shaping strain curve of the first group of samples can reflect the deformation of the metal material more accurately. For example, for 3 samples of the structure shown in fig. 2, the same nonlinear strain tensile force was repeated 3 times with a quasi-static standard tensile test to obtain 3 true stress-shaping strain curves, and a centered true stress-shaping strain curve was selected from the 3 true stress-shaping strain curves as the true stress-shaping strain curve of the first set of samples. In this embodiment, a digital image correlation (DIC, digitial Image Correlation) device may be used to perform a real-time strain test when performing a quasi-static standard tensile test, and a nonlinear tensile force may be applied to the test specimen by loading a constant tensile velocity while stretching the test specimen.
In addition, in this embodiment, the samples in the second set of samples include multiple types, and each type corresponds to a material numerical test model, and after obtaining a true stress-shaping strain curve for representing deformation of a metal material, the present invention inputs the true stress-shaping strain curve into the material numerical test models corresponding to the various sample types in the second set of samples, respectively, so as to obtain stress triaxial η, loude angle parameter ζ, normalized Loude angle parameter corresponding to the various sample types in the second set of samples
Stress triaxial η, lord angle parameter ζ and normalized Lord angle parameter corresponding to each sample type>
Are all used for representing a stress state of the metal material, and stress triaxial eta, lord angle parameter xi and normalized Lord angle parameter corresponding to various sample types>
Can be used for respectively representing various stress states of the metal material. In this embodiment, a numerical model of each test may be established based on the sample sizes and test conditions of various types of samples, and the true stress-shaping strain curve of the first set of samples may be input into the mat_24 material numerical test model of ls_dyna.
And step 103, performing fracture test on various types of samples in the second group of samples by adopting the nonlinear tensile force, and performing real-time strain test by adopting digital image correlation (Digitial Image Correlation) equipment to obtain critical fracture strain values corresponding to various sample types in the second group of samples.
Wherein each sample type in the second set of samples comprises a plurality of samples of that type; in step S103, performing a fracture test on each type of sample in the second set of samples by using the nonlinear tensile force, where obtaining critical fracture strain values corresponding to each type of sample in the second set of samples includes: and aiming at each sample type in the second group of samples, carrying out corresponding fracture tests on a plurality of samples of the type by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to the number of the samples, calculating the average value of the critical fracture strain values corresponding to the number of the samples, and taking the average value as the critical fracture strain value of the sample type in the second group of samples. For example, for five sample types shown in fig. 3, each sample type includes 3 samples, and for each sample type, the corresponding breaking test may be repeated 3 times using the same nonlinear strain tensile force as the quasi-static standard tensile test to obtain 3 critical breaking strain values, and an average value of the 3 critical breaking strain values may be obtained as the critical breaking strain value of the sample type. In the invention, when the fracture test is carried out, a plurality of types of samples are designed, the influence of different stress states on fracture failure is considered, and when the fracture test is carried out on various types of samples, the corresponding fracture test is carried out on a plurality of the types of samples (namely, the corresponding fracture test is repeatedly carried out for a plurality of times), the average value of critical fracture strain values obtained by the repeated tests is calculated, and the average value is taken as the critical fracture strain value of the types of samples, so that the influence of the fracture samples (namely, the corresponding stress states) on the fracture failure can be further accurately corresponding.
In this example, a digital image correlation (Digitial Image Correlation) apparatus can be used to perform real-time strain testing while performing quasi-static standard tensile testing and breaking testing, and a nonlinear tensile force can be applied to the test specimen by loading a constant tensile velocity while stretching the test specimen. In addition, the second set of samples includes five sample types, a pure shear tensile test sample, a center hole unidirectional tensile test sample, an R5 notch tensile test sample, an R10 notch tensile test sample, and a cupping sample, each sample type including a plurality of samples of that type. The unidirectional tensile test, the shearing test, the R5 notch tensile test and the R10 notch tensile test are all carried out on a CMT5305 electronic universal tester, and the test rates are 3mm/min, 2.3mm/min, 1.2mm/min and 2.4mm/min respectively. The perforation test was also performed on a CMT5305 electronic universal tester with a punch speed of 1mm/min. In the test process, a 50mm extensometer is selected for unidirectional tensile test, and a 25mm extensometer is selected for shear test, R5 notch tensile test and R10 notch tensile test for relative deformation measurement.
Step S104, for each sample type in the second group of samples, the stress triaxial degree eta, the Rockwell angle parameter zeta and the normalized Rockwell angle parameter are processed
Substituting the critical fracture strain value into a corresponding three-dimensional model, establishing a multi-element equation set, and calculating to obtain five unknown coefficients K, C and +_in the three-dimensional fracture model>
f. n, and further obtaining a three-dimensional fracture model of the metal material in a complex stress state.
In this example, the failure strain of the three-dimensional fracture model is a function of the stress triaxial degree and the normalized Lodet angle, as follows
Wherein the formula comprises five unknowns, K, C respectively,
f. n, the calibration is carried out through a plurality of groups of fracture tests. Wherein, by stress triaxial η and normalized Lodet angle parameter->
The stress state of the material is represented, and the values are [ -1,1]The calculation formula is as follows
Stress triaxial degree:
wherein, p is the hydrostatic pressure,
for Mises equivalent stress, sigma 1 、σ 2 、σ 3 Respectively the first, second and third principal stresses, I 1 As the first stress invariant, J 2 Is the second stress deflection invariant;
lomb angle parameter:
in the method, in the process of the invention,
for Mises equivalent stress, J 2 、J 3 The second and third bias stress deflection are respectively invariable; />
Normalized Lord angle
In the three-dimensional fracture model, the fracture failure of the material is judged by a damage factor D, and when D=1, the fracture occurs, and the calculation formula is as follows:
in d epsilon p In order to provide an amount of plastic strain accumulation,
and in the calculation of the damage factor D, the damage accumulation of a nonlinear strain path of the material is considered for the fracture failure strain corresponding to different stress triaxial degrees and normalized Lord angles. After a three-dimensional fracture model of the metal material in different stress states and under a nonlinear strain path is obtained, determining a fracture curved surface of the metal material in a complex stress state according to the three-dimensional fracture model; or the metal material is formedThe real stress-plastic strain curve and the three-dimensional fracture model under the complex stress state are brought into any working condition model of the metal material to carry out simulation calculation, so that the fracture condition of the metal material is predicted.
From the above embodiments, the present invention performs a quasi-static standard tensile test on the first group of samples by using a nonlinear tensile force, and considers a nonlinear strain path when obtaining a true stress-shaping strain curve of the first group of samples; the nonlinear tensile force is adopted in the breaking test, and various types of samples are designed, so that the influence of different stress states on breaking failure is considered; the invention considers the influence of different stress states and nonlinear strain paths on fracture failure, and can accurately simulate the fracture failure of the metal material in a complex stress state.
The three-dimensional model was verified as follows: in order to verify whether the fracture curved surface obtained by the calibrated 22MnB5 high-strength steel according to the three-dimensional fracture model is applicable or not, the fracture curved surface is applied to a B column static pressure numerical model, a B column static pressure process is simulated, a crack area of the B column after static pressure is predicted, and meanwhile a B column static pressure test is carried out. The grid size of the main deformation area of the B column is 0.5mm, and the two ends of the B column are fixed on the tool.
In the simulation process of the 22MnB5 high-strength steel B column, the two end tools are constrained, the pressure head downwards presses the B column at the speed of 1.85m/s, the stroke of the pressure head is 100mm, and the whole static pressure process is 0.054s. The pressure head and the tooling select a MAT_20 rigid body material constitutive model in LS_DYNA, the B column selects a MAT_24 isotropic material constitutive model, and the MMC fracture curved surface of the 22MnB5 high strength steel is input through MAT_ADD_EROSION without considering the influence of strain rate. In the simulation process, the B-pillar grid is selected for self-adaptive repartition, and the minimum grid size is defined as 0.5mm. Through simulation calculation, after static pressure, the deformation of the 22MnB5 high strength steel B column is shown in the left graph of FIG. 5. From the left graph, the deformation of the region where the B-pillar contacts the ram is maximum after static pressure, and the maximum plastic strain of the B-pillar is 0.857 as shown by the oval circled region in the figure. Meanwhile, a few units are deleted on the back of the position with the maximum deformation of the B column, and microcracks appear.
In the experimental process of the 22MnB5 high strength steel B column, the B column is in an actual loading state of the whole car, the upper end and the lower end of the B column are fixed with a test bed through a tool after being welded with a mounting plate, and the upper end and the lower end of the B column are fully restrained. During the test, the pressure head is adopted to carry out quasi-static loading on the installation position of the door hinge in the middle of the B column, the pressing speed of the pressure head is 2mm/s (namely, nonlinear pressure is applied to the B column), and the pressing displacement of the pressure head is 100mm. The deformations of the 22MnB5 high strength steel B column are shown in the right diagram of fig. 5, respectively. As can be seen from the right graph, after the static pressure experiment, the 22MnB5 high strength steel B column deforms greatly at the contact position with the pressure head, as shown by the oval circle area in the graph; at the same time, microcracks appear on the back of the B pillars. As can be seen from FIG. 5, after static pressure, the 22MnB5 high strength steel B-pillars all deform greatly at the same position, and microcracks are generated at the same position on the back of the B-pillars as shown by the oval circled area in FIG. 5. The matching degree of the numerical simulation result and the experimental result is higher, and the failure condition of the 22MnB5 high strength steel can be accurately predicted by the fracture curved surface obtained through calibration.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the invention is to be governed only by the following claims.
Claims (4)
1. The method for establishing the three-dimensional fracture model of the metal material in the complex stress state is characterized by comprising the following steps of:
designing a first group of samples for a quasi-static standard tensile test and a second group of samples for a fracture test for a metal material of the same material, wherein the samples in the second group of samples comprise a plurality of types;
performing quasi-static standard tensile test on the first group of samples by adopting nonlinear tensile force to obtain a true stress-shaping strain curve of the first group of samples, inputting the true stress-shaping strain curve of the first group of samples into a material numerical test model corresponding to various sample types in the second group of samples to obtain stress triaxial eta, lord angle parameter zeta and normalized Lord angle parameter corresponding to various sample types in the second group of samples
Carrying out fracture test on various types of samples in the second group of samples by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to various sample types in the second group of samples;
for each sample type in the second group of samples, the stress triaxial degree eta, the Lord angle parameter zeta and the normalized Lord angle parameter are used for the sample type
Substituting the critical fracture strain value into a corresponding three-dimensional model, establishing a multi-element equation set, and calculating to obtain five unknown coefficients K, C and +_in the three-dimensional fracture model>
f. n, and further obtaining a three-dimensional fracture model of the metal material in a complex stress state;
the first set of samples comprises a plurality of samples, the quasi-static standard tensile test is performed on the first set of samples by using nonlinear tensile force, and obtaining the true stress-shaping strain curve of the first set of samples comprises:
carrying out quasi-static standard tensile test on each sample in the first group of samples by adopting the nonlinear tensile force so as to obtain a true stress-shaping strain curve of each sample in the first group of samples;
selecting a centered one of the true stress-shaping strain curves of each of the first set of samples as the true stress-shaping strain curve of the first set of samples;
each sample type in the second set of samples comprises a plurality of samples of that type; the step of performing a fracture test on each type of sample in the second group of samples by using the nonlinear tensile force, the step of obtaining critical fracture strain values corresponding to each type of sample in the second group of samples includes:
and aiming at each sample type in the second group of samples, carrying out corresponding fracture tests on a plurality of samples of the type by adopting the nonlinear tensile force to obtain critical fracture strain values corresponding to the number of the samples, calculating the average value of the critical fracture strain values corresponding to the number of the samples, and taking the average value as the critical fracture strain value of the sample type in the second group of samples.
2. The method of claim 1, wherein the second set of samples comprises five sample types, each comprising a plurality of the types of samples, a pure shear tensile test sample, a center hole unidirectional tensile test sample, an R5 notch tensile test sample, an R10 notch tensile test sample, and a cupping test sample.
3. The method for building a three-dimensional fracture model of a metal material under a complex stress state according to claim 1, wherein the failure strain of the three-dimensional fracture model is a function of the stress triaxial degree and the normalized lod angle, as follows
Wherein the formula comprises five unknowns, K, C respectively,
f. n, calibrating through a plurality of groups of fracture tests; wherein, by stress triaxial η and normalized Lodet angle parameter->
The stress state of the material is represented, and the values are [ -1,1]In the formula, the formula is as follows>
Stress triaxial degree:
wherein, p is the hydrostatic pressure,
for Mises equivalent stress, sigma 1 、σ 2 、σ 3 Respectively the first, second and third principal stresses, I 1 As the first stress invariant, J 2 Is the second stress deflection invariant;
lomb angle parameter:
in the method, in the process of the invention,
for Mises equivalent stress, J 2 、J 3 The second and third bias stress deflection are respectively invariable;
normalized Lord angle
In the three-dimensional fracture model, the fracture failure of the material is judged by a damage factor D, and when D=1, the material is broken, and the calculation formula is as follows:
in d epsilon p In order to provide an amount of plastic strain accumulation,
and in the calculation of the damage factor D, the damage accumulation of a nonlinear strain path of the material is considered for the fracture failure strain corresponding to different stress triaxial degrees and normalized Lord angles.
4. The method for building a three-dimensional fracture model of a metal material under a complex stress state according to claim 1, wherein the method is characterized in that a DIC device is used for performing a real-time strain test to obtain critical fracture strain values corresponding to various sample types in the second group of samples.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911311254.4A CN110987621B (en) | 2019-12-18 | 2019-12-18 | Method for establishing three-dimensional fracture model of metal material in complex stress state |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911311254.4A CN110987621B (en) | 2019-12-18 | 2019-12-18 | Method for establishing three-dimensional fracture model of metal material in complex stress state |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110987621A CN110987621A (en) | 2020-04-10 |
| CN110987621B true CN110987621B (en) | 2023-04-25 |
Family
ID=70095509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911311254.4A Active CN110987621B (en) | 2019-12-18 | 2019-12-18 | Method for establishing three-dimensional fracture model of metal material in complex stress state |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110987621B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112067437B (en) * | 2020-08-14 | 2021-12-07 | 南京航空航天大学 | Method for establishing tension-compression asymmetric failure criterion of isotropic material |
| CN112446132A (en) * | 2020-10-19 | 2021-03-05 | 中国石油天然气集团有限公司 | Drawing method of full-quadrant fracture forming limit diagram of material and using method thereof |
| CN112199879A (en) * | 2020-10-22 | 2021-01-08 | 中国石油大学(华东) | Method for establishing and analyzing three-dimensional fracture model of polyethylene under complex stress |
| CN112800645A (en) * | 2021-01-05 | 2021-05-14 | 唐山钢铁集团有限责任公司 | GISSMO material failure model parameter measurement method |
| WO2022181401A1 (en) * | 2021-02-25 | 2022-09-01 | 国立大学法人東京農工大学 | Stress test device, material model identification processing device, material model identification processing network system, material model identification processing method, and material model identification processing program |
| CN113420391B (en) * | 2021-07-02 | 2023-03-10 | 北京理工大学重庆创新中心 | Method for obtaining high-precision hardening model parameters of material under complex stress state |
| CN113642207A (en) * | 2021-07-09 | 2021-11-12 | 恒大新能源技术(深圳)有限公司 | Metal failure model construction method and device, terminal equipment and storage medium |
| CN113673030B (en) * | 2021-08-05 | 2023-07-25 | 河钢股份有限公司 | Simulation analysis method for ductile fracture coupling failure of metal material |
| CN113843326B (en) * | 2021-08-11 | 2022-07-19 | 上海交通大学 | Metal plate stamping forming edge cracking prediction method considering trimming quality |
| CN114509341B (en) * | 2022-02-23 | 2023-08-25 | 北京理工大学重庆创新中心 | Method for measuring stress triaxial degree in tensile fracture test process of material sample |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007232715A (en) * | 2006-02-01 | 2007-09-13 | Nippon Steel Corp | Method and device for breaking estimation, program and recording medium |
| JP2007285832A (en) * | 2006-04-14 | 2007-11-01 | Nippon Steel Corp | System and method for acquiring breaking point, system and method for estimating break, programs and recording media of these method |
| JP2008051768A (en) * | 2006-08-28 | 2008-03-06 | Shinji Tanimura | Material simulation system, material simulation method, and material simulation program |
| CN105095962A (en) * | 2015-07-27 | 2015-11-25 | 中国汽车工程研究院股份有限公司 | Method for predicting dynamic mechanical property of material based on BP artificial neural network |
| CN106644711A (en) * | 2016-11-17 | 2017-05-10 | 西南交通大学 | Test method for uniaxial constitutive relation of ductile material |
| CN107655768A (en) * | 2017-08-04 | 2018-02-02 | 中车青岛四方机车车辆股份有限公司 | Damage model parameter calibration method based on tensile shear and notch tension test |
| CN108169040A (en) * | 2017-12-14 | 2018-06-15 | 中国人民解放军空军工程大学 | The parameter identification method of material constitutive and failure model under a kind of Under High Strain rate |
| CN110147618A (en) * | 2019-05-22 | 2019-08-20 | 电子科技大学 | Aero engine turbine blades reliability estimation method based on fracture mechanics |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2641174C (en) * | 2006-02-01 | 2014-03-04 | Nippon Steel Corporation | Fracture prediction method |
| JP4329848B2 (en) * | 2007-06-15 | 2009-09-09 | トヨタ自動車株式会社 | Structure analysis apparatus and structure analysis method |
-
2019
- 2019-12-18 CN CN201911311254.4A patent/CN110987621B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007232715A (en) * | 2006-02-01 | 2007-09-13 | Nippon Steel Corp | Method and device for breaking estimation, program and recording medium |
| JP2007285832A (en) * | 2006-04-14 | 2007-11-01 | Nippon Steel Corp | System and method for acquiring breaking point, system and method for estimating break, programs and recording media of these method |
| JP2008051768A (en) * | 2006-08-28 | 2008-03-06 | Shinji Tanimura | Material simulation system, material simulation method, and material simulation program |
| CN105095962A (en) * | 2015-07-27 | 2015-11-25 | 中国汽车工程研究院股份有限公司 | Method for predicting dynamic mechanical property of material based on BP artificial neural network |
| CN106644711A (en) * | 2016-11-17 | 2017-05-10 | 西南交通大学 | Test method for uniaxial constitutive relation of ductile material |
| CN107655768A (en) * | 2017-08-04 | 2018-02-02 | 中车青岛四方机车车辆股份有限公司 | Damage model parameter calibration method based on tensile shear and notch tension test |
| CN108169040A (en) * | 2017-12-14 | 2018-06-15 | 中国人民解放军空军工程大学 | The parameter identification method of material constitutive and failure model under a kind of Under High Strain rate |
| CN110147618A (en) * | 2019-05-22 | 2019-08-20 | 电子科技大学 | Aero engine turbine blades reliability estimation method based on fracture mechanics |
Non-Patent Citations (2)
| Title |
|---|
| 于思淼 ; 蔡力勋 ; 姚迪 ; 包陈 ; 陈辉 ; 彭云强 ; 韩光照 ; .准静态条件下金属材料的临界断裂准则研究.力学学报.2018,(05),95-112. * |
| 梁宾.基于Gissmo失效模型的6016铝合金板材断裂行为研究及应用.《机械工程学报》.2019,53-61. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110987621A (en) | 2020-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110987621B (en) | Method for establishing three-dimensional fracture model of metal material in complex stress state | |
| CN108645704B (en) | Method for calibrating microstructure parameters of metal material based on nanoindentation and finite element simulation inversion | |
| JP4818786B2 (en) | Fracture limit acquisition system and method, fracture prediction system and method, program and recording medium for these methods | |
| KR101707492B1 (en) | Evaluating Method Of The Fracture Toughness Using Instrumented indentation testing | |
| Hambli et al. | Finite element modeling of sheet-metal blanking operations with experimental verification | |
| CN103345558B (en) | A kind of method and system controlling high-strength steel bending | |
| CN111339703A (en) | Virtual prediction method for material hardening behavior under large strain condition | |
| JP6958521B2 (en) | Stress-strain relationship estimation method | |
| Achouri et al. | Experimental and numerical analysis of micromechanical damage in the punching process for High-Strength Low-Alloy steels | |
| Vorkov et al. | Springback prediction of high-strength steels in large radius air bending using finite element modeling approach | |
| JP2020134348A (en) | Stress-strain relation estimation method | |
| Abbasi et al. | Analytical method for prediction of weld line movement during stretch forming of tailor-welded blanks | |
| Achouri et al. | Influence of the edge rounding process on the behaviour of blanked parts: numerical predictions with experimental correlation | |
| CN110749510A (en) | Method for detecting bending property of metal material based on finite element simulation | |
| Noh et al. | Inverse parameter estimation of the Cowper-Symonds material model for electromagnetic free bulge forming | |
| Ailinei et al. | Influence of anisotropy on the cold bending of S600MC sheet metal | |
| CN113843326B (en) | Metal plate stamping forming edge cracking prediction method considering trimming quality | |
| CN114414376B (en) | Method for determining fracture strain of hot stamping part | |
| Hawryluk et al. | Application of physical modeling with the use of soft model materials for the analysis and optimization of metal extrusion processes | |
| Tantideeravit et al. | An application of FEM in the determination of tensile properties for work-hardened carbon steel by means of small punch test | |
| Gavrus et al. | An inverse analysis approach of the Erichsen test starting from a finite element model | |
| Abbasnejad Dizaji et al. | Effect of hardening models on different ductile fracture criteria in sheet metal forming | |
| CN112685947A (en) | Method and device for optimizing parameters of sheet material resilience model, terminal and storage medium | |
| JP4622688B2 (en) | Method and apparatus for predicting surface strain of press-formed product | |
| Groseclose et al. | Determination of biaxial flow stress using frictionless dome test |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |