Quadratic Hosford-Coulomb ductile fracture identification method and device

Abstract

The invention discloses a quadratic Hosford-Coulomb ductile fracture identification method. The quadratic Hosford-Coulomb ductile fracture identification method comprises the following steps: calculating the principal stress of a stress body to be evaluated; calculating the Hosford shear stress of the stress body to be evaluated; calculating a stress invariant of the to-be-evaluated stress body; the Mises equivalent stress of the stress body to be evaluated is calculated; calculating stress state parameters of the to-be-evaluated stress body; the principal stress of the to-be-evaluated stress body is converted to a stress state parameter space; a quadratic form Hosford-Coulomb stress fracture criterion is constructed according to the stress fracture criterion; selecting a power finger type strain hardening model; and a quadratic Hosford-Coulomb stress fracture criterion is converted to a stress strain parameter space. According to the method, the application range of the linear Hosford-Coulomb criterion is expanded, and the ductile fracture of the metal material can be predicted more accurately and stably compared with the linear Hosford-Coulomb criterion.

Description

Technical Field

[0001] The present invention relates to the technical field of ductile fracture identification, and in particular to a secondary Hosford-Coulomb ductile fracture identification system method and device. Background Art

[0002] With the development of metal material preparation technology, a large number of ductile metal materials have been widely used due to their excellent performance, especially in the oil and gas storage and transportation industry. The application of a large number of high-ductility and high-strength steel pipes has created new demands for large-scale yield deformation in the design and operation stages of pipelines. Therefore, clarifying the ductile fracture boundary of the material is an important limit state of the metal material structure. In order to evaluate the ductile fracture of metal materials, scholars in the industry have proposed the linear Hosford-Coulomb fracture criterion. The linear Hosford-Coulomb fracture criterion assumes that when the linear combination of the Hosford shear stress and the normal stress corresponding to the maximum shear force reaches a certain critical value, the material is damaged, and it has the following form in the Haigh-Westergaard stress space:

[0003] Σ HF +c(Σ I +Σ 3 )=b

[0004] In the formula, Σ I and Σ 3 are the first and third principal stresses; c and b are material parameters; Σ HF is the Hosford shear stress.

[0005] However, in the high stress triaxiality range, the Hosford-Coulomb criterion has a large error in predicting ductile fracture. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a secondary Hosford-Coulomb ductile fracture identification method, which aims to improve the adaptability of the linear Hosford-Coulomb criterion and solve the problem that the linear Hosford-Coulomb criterion has a large ductile fracture prediction error in the high stress triaxiality range.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for identifying a secondary Hosford-Coulomb ductile fracture, comprising the following steps:

[0009] Calculate the principal stresses of the load-bearing body to be evaluated;

[0010] Based on the principal stress of the load-bearing body to be evaluated, the Hosford shear stress of the load-bearing body to be evaluated is calculated;

[0011] Based on the principal stress of the load-bearing body to be evaluated, the stress invariant of the load-bearing body to be evaluated is calculated;

[0012] Based on the principal stress of the load-bearing body to be evaluated, the Mises equivalent stress of the load-bearing body to be evaluated is calculated:

[0013] Based on the stress invariant and Mises equivalent stress of the load-bearing body to be evaluated, the stress state parameters of the load-bearing body to be evaluated are calculated;

[0014] Based on the Mises equivalent stress and stress state parameters of the load-bearing body to be evaluated, the principal stress of the load-bearing body to be evaluated is converted into the stress state parameter space;

[0015] Based on Hosford shear stress and linear Hosford-Coulomb criterion, a quadratic Hosford-Coulomb stress fracture criterion is constructed;

[0016] Select the power-finger strain hardening model;

[0017] Based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted to the stress state parameter space, the quadratic Hosford-Coulomb stress fracture criterion is converted to the stress-strain parameter space, and the quadratic Hosford-Coulomb ductile fracture identification criterion is obtained, which can predict the fracture trajectory of the load-bearing body to be evaluated.

[0018] As a preferred embodiment, the Hosford shear stress of the load-bearing body to be evaluated is calculated by the following formula:

[0019]

[0020] In the formula, Σ HF is the Hosford shear stress of the load body to be evaluated; Σ 1 ,Σ 2 and Σ 3 are the first, second and third principal stresses of the load-bearing body to be evaluated; a is the material parameter.

[0021] Preferably, the stress invariant of the load-bearing body to be evaluated is calculated by the following formula:

[0022]

[0023] In the formula, I 1 , J 2 and J 3 are the first, second and third stress invariants of the load-bearing body to be evaluated.

[0024] As a preference, the Mises equivalent stress of the load-bearing body to be evaluated is calculated by the following formula:

[0025]

[0026] In the formula, Σ eq is the Mises equivalent stress of the load body to be evaluated.

[0027] Preferably, the stress state parameters of the load-bearing body to be evaluated include stress triaxiality and Rhodes angle parameters, which are calculated by the following formula:

[0028]

[0029] Where η is the stress triaxiality and ξ is the Rhodes angle parameter.

[0030] As a preferred embodiment, the expression after converting the principal stress of the load-bearing body to be evaluated into the stress state parameter space is as follows:

[0031] Σ 1 =Σ eq (η+f 1 )

[0032] Σ 2 =Σ eq (η+f 2 )

[0033] Σ 3 =Σ eq (η+f 3 )

[0034] in,

[0035]

[0036] In the formula, f 1 、f 2 and f 3 All are intermediate parameters.

[0037] As a preferred embodiment, the “constructing a quadratic stress combination fracture criterion based on Hosford shear stress and linear Hosford-Coulomb criterion” is specifically:

[0038] ① Based on the Hosford shear stress and the linear Hosford-Coulomb criterion, a quadratic stress combination fracture criterion is constructed. The specific form is: in the positive normal stress interval, the Hosford shear stress and the normal stress are in an elliptical relationship, and in the negative normal stress interval, the Hosford shear stress and the normal stress are in a hyperbolic relationship:

[0039]

[0040] In the formula, m 1 、m 2 and b are material constants;

[0041] ② Combining the above two equations, we can get the secondary stress combination fracture criterion:

[0042]

[0043] In the formula, c 1 、c 2 and b are material constants, c 1 ≥0, c 2 ≤0; <x>is a piecewise function. When x ≥ 0, <x>= x, otherwise <x>=0.

[0044] Preferably, the expression of the power-finger strain hardening model is as follows:

[0045]

[0046] Where A is the material hardening coefficient; n is the material hardening index; ε p is the plastic strain.

[0047] Preferably, the expression of the secondary Hosford-Coulomb ductile fracture identification criterion is as follows:

[0048]

[0049] In the formula, ε f is the plastic strain of the load-bearing body to be evaluated at the beginning of fracture.

[0050] In a second aspect, the present invention provides a secondary Hosford-Coulomb ductile fracture identification device, comprising:

[0051] The first processing unit is used to calculate the principal stress of the load-bearing body to be evaluated;

[0052] The second processing unit is used to calculate the Hosford shear stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated;

[0053] A third processing unit is used to calculate the stress invariant of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated;

[0054] The fourth processing unit is used to calculate the Mises equivalent stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated:

[0055] A fifth processing unit, configured to calculate stress state parameters of the load-bearing body to be evaluated based on the stress invariant and the Mises equivalent stress of the load-bearing body to be evaluated;

[0056] A sixth processing unit, configured to convert the principal stress of the load-bearing body to be evaluated into a stress state parameter space based on the Mises equivalent stress and the stress state parameter of the load-bearing body to be evaluated;

[0057] The seventh processing unit is used to construct a quadratic Hosford-Coulomb stress fracture criterion based on the Hosford shear stress and the linear Hosford-Coulomb criterion;

[0058] The eighth processing unit is used to select a power-finger strain hardening model.

[0059] The ninth processing unit is used to convert the quadratic Hosford-Coulomb stress fracture criterion into the stress-strain parameter space based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted into the stress state parameter space, and obtain the quadratic Hosford-Coulomb ductile fracture identification criterion, so as to predict the fracture trajectory of the load-bearing body to be evaluated.

[0060] The present invention adopts the above technical solution, which has the following advantages:

[0061] The mean of the absolute value of the relative error of the ductile fracture identification criterion proposed by the present invention is reduced by 9% compared with the linear Hosford-Coulomb stress combination criterion, and the standard deviation of the error is reduced by 18%. Moreover, the error of the present invention in the high stress triaxiality interval is reduced by 79% compared with the linear Hosford-Coulomb stress combination criterion, which can effectively reduce the fracture prediction error of the high stress triaxiality stress state.

[0062] In summary, the ductile fracture criterion model proposed in the present invention expands the applicable scope of the linear Hosford-Coulomb stress combination criterion and can predict the ductile fracture of alloys more accurately and stably than the linear Hosford-Coulomb stress combination criterion. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0064] Figure 1 A flow chart of a method for identifying a quadratic Hosford-Coulomb fracture provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0066] The quadratic Hosford-Coulomb fracture identification method provided by the present invention comprises: calculating the principal stress of the load-bearing body to be evaluated; calculating the Hosford shear stress of the load-bearing body to be evaluated; calculating the stress invariant of the load-bearing body to be evaluated; calculating the Mises equivalent stress of the load-bearing body to be evaluated; calculating the stress state parameter of the load-bearing body to be evaluated; converting the principal stress of the load-bearing body to be evaluated into the stress state parameter space; constructing the quadratic Hosford-Coulomb stress fracture criterion; selecting the power-exponential strain hardening model; converting the quadratic Hosford-Coulomb stress fracture criterion into the stress-strain parameter space. The present invention expands the application scope of the linear Hosford-Coulomb criterion, and can more accurately and stably predict the ductile fracture of metal materials than the linear Hosford-Coulomb criterion.

[0067] The secondary Hosford-Coulomb fracture identification method and device provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0068] See also Figure 1 , a secondary Hosford-Coulomb fracture identification method provided in this embodiment includes the following steps:

[0069] S1. Calculate the principal stress of the load-bearing body to be evaluated. The principal stress of the load-bearing body to be evaluated of simple components and structures can be solved by analytical methods, and the principal stress of the load-bearing body to be evaluated of complex components and structures can be solved by finite element method and other numerical approximate calculation methods. Since both belong to common knowledge of those skilled in the art, they will not be described in detail.

[0070] S2. According to the principal stress of the load-bearing body to be evaluated obtained in step S1, the Hosford shear stress of the load-bearing body to be evaluated is calculated by the following formula:

[0071]

[0072] In the formula, Σ HF is the Hosford shear stress of the load body to be evaluated; Σ 1 ,Σ 2 and Σ 3 are the first, second and third principal stresses of the load-bearing body to be evaluated; a is the material parameter.

[0073] S3. According to the principal stress of the load-bearing body to be evaluated obtained in step S1, the stress invariant of the load-bearing body to be evaluated is calculated by the following formula:

[0074] I 1 =Σ 1 +Σ 2 +Σ 3

[0075]

[0076] In the formula, I 1 , J 2 and J 3 are the first, second and third stress invariants of the load-bearing body to be evaluated.

[0077] S4. According to the principal stress of the load-bearing body to be evaluated obtained in step S1, the Mises equivalent stress of the load-bearing body to be evaluated is calculated by the following formula:

[0078]

[0079] In the formula, Σ eq is the Mises equivalent stress of the load body to be evaluated.

[0080] S5. According to the stress invariant of the load-bearing body to be evaluated obtained in step S3, the stress state parameters of the load-bearing body to be evaluated are calculated by the following formula, including stress triaxiality and Rhodes angle parameters:

[0081]

[0082] Where η is the stress triaxiality and ξ is the Rhodes angle parameter.

[0083] S6. Based on the Mises equivalent stress of the load-bearing body to be evaluated obtained in step S4 and the stress state parameter obtained in step S5, the principal stress of the load-bearing body to be evaluated is converted into the stress state parameter space:

[0084] Σ 1 =Σ eq (η+f 1 )

[0085] Σ 2 =Σ eq (η+f 2 )

[0086] Σ 3 =Σ eq (η+f 3 )

[0087] in,

[0088]

[0089] In the formula, f 1 、f 2 and f 3 All are intermediate parameters.

[0090] S7. Based on Hosford shear stress and linear Hosford-Coulomb criterion, a quadratic stress combination fracture criterion is constructed, which is:

[0091] ① Based on the Hosford shear stress and the linear Hosford-Coulomb criterion, a quadratic stress combination fracture criterion is constructed. The specific form is: in the positive normal stress interval, the Hosford shear stress and the normal stress are in an elliptical relationship, and in the negative normal stress interval, the Hosford shear stress and the normal stress are in a hyperbolic relationship:

[0092]

[0093] In the formula, m 1 、m 2 and b are material constants;

[0094] ② Combining the above two equations, we can get the secondary stress combination fracture criterion:

[0095]

[0096] In the formula, c 1 、c 2 and b are material constants, c 1 ≥0, c 2 ≤0; <x>is a piecewise function. When x ≥ 0, <x>= x, otherwise <x>=0.

[0097] S8. Select the power-type strain hardening model, and the expression is as follows:

[0098]

[0099] Where A is the material hardening coefficient; n is the material hardening index; ε p is the plastic strain.

[0100] S9. Based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted to the stress state parameter space, the quadratic Hosford-Coulomb stress fracture criterion is converted to the stress-strain parameter space to obtain the quadratic Hosford-Coulomb ductile fracture identification criterion, which can predict the fracture trajectory of the load-bearing body to be evaluated. The expression of the quadratic Hosford-Coulomb ductile fracture identification criterion is as follows:

[0101]

[0102] In the formula, ε f is the plastic strain of the load-bearing body to be evaluated at the beginning of fracture.

[0103] In order to demonstrate the effect of the method of the present invention, the present invention uses the fracture test data of X80 pipeline steel (see Table 1) to verify the effectiveness of the ductile fracture criterion of the present invention. Since the amount of test data is sufficient, the least square method is used to minimize the average value of the absolute value of the relative error, and the model calibration results are shown in Table 2. The absolute value of the relative error is defined as follows:

[0104]

[0105] In the formula, and are the predicted and experimental fracture strains, respectively; N is the number of experimental samples.

[0106] Table 1 Experimental and predicted fracture strain data of X80 pipeline steel

[0107]

[0108]

[0109] Table 2 Fracture model parameters of X80 pipeline steel

[0110]

[0111] From the comparison results, it can be seen that the mean of the absolute value of the relative error of the ductile fracture identification criterion proposed by the present invention is reduced by 9% compared with the linear Hosford-Coulomb criterion, and the standard deviation of the error is up to 18%. In addition, the error of the present invention in the high stress triaxiality interval is reduced by 79% compared with the linear Hosford-Coulomb criterion, which can effectively reduce the fracture prediction error of the high stress triaxiality stress state.

[0112] Embodiment 2:

[0113] The above-mentioned embodiment 1 provides a secondary Hosford-Coulomb ductile fracture identification method, and correspondingly, this embodiment provides a secondary Hosford-Coulomb ductile fracture identification device. The secondary ductile fracture identification device provided in this embodiment can implement the secondary ductile fracture identification method of embodiment 1, and the secondary ductile fracture identification device can be implemented by software, hardware, or a combination of software and hardware. For example, the secondary ductile fracture identification device may include integrated or separate functional modules or functional units to execute the corresponding steps in each method of embodiment 1. Since the secondary ductile fracture identification device of this embodiment is basically similar to the method embodiment, the process described in this embodiment is relatively simple, and the relevant parts can refer to the partial description of embodiment 1. The secondary ductile fracture identification device of this embodiment is merely schematic.

[0114] The secondary Hosford-Coulomb ductile fracture identification device provided in this embodiment includes:

[0115] The first processing unit is used to calculate the principal stress of the load-bearing body to be evaluated;

[0116] The second processing unit is used to calculate the Hosford shear stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated;

[0117] A third processing unit is used to calculate the stress invariant of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated;

[0118] The fourth processing unit is used to calculate the Mises equivalent stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated:

[0119] A fifth processing unit, configured to calculate stress state parameters of the load-bearing body to be evaluated based on the stress invariant and the Mises equivalent stress of the load-bearing body to be evaluated;

[0120] A sixth processing unit, configured to convert the principal stress of the load-bearing body to be evaluated into a stress state parameter space based on the Mises equivalent stress and the stress state parameter of the load-bearing body to be evaluated;

[0121] The seventh processing unit is used to construct a quadratic Hosford-Coulomb stress fracture criterion based on the Hosford shear stress and the linear Hosford-Coulomb criterion;

[0122] The eighth processing unit is used to select a power-finger strain hardening model.

[0123] The ninth processing unit is used to convert the quadratic Hosford-Coulomb stress fracture criterion into the stress-strain parameter space based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted into the stress state parameter space, and obtain the quadratic Hosford-Coulomb ductile fracture identification criterion, so as to predict the fracture trajectory of the load-bearing body to be evaluated.

[0124] Embodiment 3:

[0125] This embodiment provides a processing device for implementing the secondary Hosford-Coulomb ductile fracture identification method provided in this embodiment 1. The processing device can be a processing device for a client, such as a mobile phone, a laptop computer, a tablet computer, a desktop computer, etc., to execute the method of embodiment 1.

[0126] The processing device includes a processor, a memory, a communication interface and a bus, and the processor, the memory and the communication interface are connected through the bus to complete mutual communication. The memory stores a computer program that can be run on the processor, and the processor executes the secondary Hosford-Coulomb ductile fracture identification method provided in this embodiment 1 when running the computer program.

[0127] Preferably, the memory may be a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0128] Preferably, the processor may be a central processing unit (CPU), a digital signal processor (DSP) or other general-purpose processors of various types, which are not limited here.

[0129] Embodiment 4:

[0130] The secondary Hosford-Coulomb ductile fracture identification method of the present embodiment 1 may be specifically implemented as a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for executing the method described in the present embodiment 1.

[0131] Computer readable storage media can be tangible devices that hold and store instructions used by instruction execution devices. Computer readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any combination thereof.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.< / x> < / x> < / x> < / x> < / x> < / x>

Claims

1. A secondary Hosford-Coulomb ductile fracture identification method, characterized in that: The following steps are involved: Calculate the principal stresses of the load-bearing body to be evaluated; Based on the principal stress of the load-bearing body to be evaluated, the Hosford shear stress of the load-bearing body to be evaluated is calculated; Based on the principal stress of the load-bearing body to be evaluated, the stress invariant of the load-bearing body to be evaluated is calculated; Based on the principal stress of the load-bearing body to be evaluated, the Mises equivalent stress of the load-bearing body to be evaluated is calculated: Based on the stress invariant and Mises equivalent stress of the load-bearing body to be evaluated, the stress state parameters of the load-bearing body to be evaluated are calculated; Based on the Mises equivalent stress and stress state parameters of the load-bearing body to be evaluated, the principal stress of the load-bearing body to be evaluated is converted into the stress state parameter space; Based on Hosford shear stress and linear Hosford-Coulomb criterion, a quadratic Hosford-Coulomb stress fracture criterion is constructed; Select the power-finger strain hardening model; Based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted to the stress state parameter space, the quadratic Hosford-Coulomb stress fracture criterion is converted to the stress-strain parameter space, and the quadratic Hosford-Coulomb ductile fracture identification criterion is obtained, which can predict the fracture trajectory of the load-bearing body to be evaluated.

2. The secondary Hosford-Coulomb ductile fracture identification method according to claim 1, characterized in that: The Hosford shear stress of the load-bearing body to be evaluated is calculated by the following formula: In the formula, Σ HF is the Hosford shear stress of the load-bearing body to be evaluated; Σ1, Σ2 and Σ3 are the first, second and third principal stresses of the load-bearing body to be evaluated respectively; a is the material parameter.

3. The secondary Hosford-Coulomb ductile fracture identification method according to claim 2, characterized in that: The stress invariant of the load-bearing body to be evaluated is calculated by the following formula: I1=Σ1+Σ2+Σ3 Where I1, J2 and J3 are the first, second and third stress invariants of the load-bearing body to be evaluated, respectively.

4. The secondary Hosford-Coulomb ductile fracture identification method according to claim 3, characterized in that: The Mises equivalent stress of the load-bearing body to be evaluated is calculated by the following formula: In the formula, Σ eq is the Mises equivalent stress of the load body to be evaluated.

5. The secondary Hosford-Coulomb ductile fracture identification method according to claim 4, characterized in that: The stress state parameters of the load-bearing body to be evaluated include stress triaxiality and Rhodes angle parameters, which are calculated by the following formula: Where η is the stress triaxiality and ξ is the Rhodes angle parameter.

6. The secondary Hosford-Coulomb ductile fracture identification method according to claim 5, characterized in that: The expression after converting the principal stress of the load-bearing body to be evaluated into the stress state parameter space is as follows: S1=S eq (n+f1) S2=S eq (n+f2) S3=S eq (n+f3) in, Where f1, f2 and f3 are all intermediate parameters.

7. The secondary Hosford-Coulomb ductile fracture identification method according to claim 6, characterized in that: The "construction of a quadratic stress combination fracture criterion based on Hosford shear stress and linear Hosford-Coulomb criterion" is specifically: ① Based on the Hosford shear stress and the linear Hosford-Coulomb criterion, a quadratic stress combination fracture criterion is constructed. The specific form is: in the positive normal stress interval, the Hosford shear stress and the normal stress are in an elliptical relationship, and in the negative normal stress interval, the Hosford shear stress and the normal stress are in a hyperbolic relationship: Where m1, m2 and b are material constants; ② Combining the above two equations, we can get the secondary stress combination fracture criterion: Where c1, c2 and b are material constants, c1≥0, c2≤0; <x>is a piecewise function. When x ≥ 0, <x>= x, otherwise <x> ＝0。< / x> < / x> < / x> 8. The secondary Hosford-Coulomb ductile fracture identification method according to claim 7, characterized in that: The expression of the power-finger strain hardening model is as follows: Where A is the material hardening coefficient; n is the material hardening index; ε p is the plastic strain.

9. The secondary Hosford-Coulomb ductile fracture identification method according to claim 8, characterized in that: The expression of the secondary Hosford-Coulomb ductile fracture identification criterion is as follows: F1(η,ξ)=<2η+f1+f3> 2 F2(η,ξ)=(2η+f1+f3) 2 In the formula, ε f is the plastic strain of the load-bearing body to be evaluated at the beginning of fracture.

10. A secondary Hosford-Coulomb ductile fracture identification device, characterized in that: include: The first processing unit is used to calculate the principal stress of the load-bearing body to be evaluated; The second processing unit is used to calculate the Hosford shear stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated; A third processing unit is used to calculate the stress invariant of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated; The fourth processing unit is used to calculate the Mises equivalent stress of the load-bearing body to be evaluated based on the principal stress of the load-bearing body to be evaluated: A fifth processing unit, configured to calculate stress state parameters of the load-bearing body to be evaluated based on the stress invariant and the Mises equivalent stress of the load-bearing body to be evaluated; A sixth processing unit, configured to convert the principal stress of the load-bearing body to be evaluated into a stress state parameter space based on the Mises equivalent stress and the stress state parameter of the load-bearing body to be evaluated; The seventh processing unit is used to construct a quadratic Hosford-Coulomb stress fracture criterion based on the Hosford shear stress and the linear Hosford-Coulomb criterion; An eighth processing unit is used to select a power-finger strain hardening model; The ninth processing unit is used to convert the quadratic Hosford-Coulomb stress fracture criterion into the stress-strain parameter space based on the principal stress and power-exponential strain hardening model of the load-bearing body to be evaluated converted into the stress state parameter space, and obtain the quadratic Hosford-Coulomb ductile fracture identification criterion, so as to predict the fracture trajectory of the load-bearing body to be evaluated.

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