A method, apparatus, equipment, and medium for predicting fracture strain in ductile fracture bodies of pipes.

Abstract

This invention relates to the field of ductile fracture identification, and discloses a method, apparatus, equipment, and medium for predicting the fracture strain of ductile fracture bodies in pipes. The method involves acquiring the first, second, and third local principal stresses of the ductile fracture body in the pipe, and determining the first stress invariant, Tresca stress, and Mises stress based on these stresses. The equivalent stress of the ductile fracture body is determined based on the first stress invariant. The stress triaxiality of the ductile fracture body is determined based on the equivalent stress and Mises stress. The stress triaxiality, Mises stress, and Tresca stress are input into a pre-constructed fracture strain prediction model to predict the fracture strain of the ductile fracture body in the pipe. This invention can effectively improve the accuracy of predicting the fracture strain of ductile fracture bodies in pipes.

Description

Technical Field

[0001] This invention relates to the field of ductile fracture identification, and more particularly to a method, apparatus, equipment, and medium for predicting fracture strain of ductile fracture bodies in pipes. Background Technology

[0002] In the process of carbon dioxide pipeline transportation, especially under high-pressure conditions such as transporting dense phase carbon dioxide, ductile fracture is the main failure mode of carbon dioxide transport pipelines.

[0003] Related technologies can use the Gurson damage model to model the damage behavior of carbon dioxide transport pipelines, simulate the initiation and evolution of material damage, and predict the fracture strain of carbon dioxide transport pipelines. However, the Gurson damage model is a local model and cannot effectively couple the plastic deformation and damage changes of carbon dioxide transport pipelines, resulting in low accuracy in fracture strain prediction.

[0004] To ensure the safe operation of carbon dioxide transport pipelines, there is an urgent need for a reliable method to predict pipeline fracture strain. Summary of the Invention

[0005] This invention provides a method, apparatus, equipment, and medium for predicting fracture strain in ductile fracture bodies of pipes, in order to address the shortcomings of low accuracy in fracture strain prediction in related technologies and improve the accuracy of fracture strain prediction.

[0006] In a first aspect, the present invention provides a method for predicting the fracture strain of a ductile fracture body of a pipe, comprising:

[0007] Obtain the first, second, and third local principal stresses of the ductile fracture body of the pipe;

[0008] Based on the first local principal stress, the second local principal stress, and the third local principal stress, the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe are determined.

[0009] Based on the first stress invariant, the equivalent stress of the ductile fracture body of the pipe is determined;

[0010] The stress triaxiality of the ductile fracture body of the pipe is determined based on the equivalent stress and the Mises stress.

[0011] The stress triaxiality, the Mises stress, and the Tresca stress are input into a pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe.

[0012] Optionally, determining the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe based on the first local principal stress, the second local principal stress, and the third local principal stress includes:

[0013] Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant;

[0014] The first local principal stress is subtracted from the third local principal stress to obtain the corresponding difference. The difference is divided by 2 to obtain the corresponding first quotient, and the first quotient is used as the Tresca stress of the ductile fracture body of the pipe.

[0015] The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0016] Optionally, determining the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant includes:

[0017] Divide the first stress invariant by 3 to obtain the corresponding second quotient;

[0018] The second quotient is used as the equivalent stress of the ductile fracture body of the pipe.

[0019] Optionally, determining the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and the Mises stress includes:

[0020] Calculate the ratio of the equivalent stress to the Mises stress;

[0021] The ratio is determined as the stress triaxiality of the ductile fracture body of the pipe.

[0022] Optionally, the fracture strain prediction model is:

[0023]

[0024] Where, ε f The fracture strain is given by τ, where c1, c2, and c3 are material constants. tresca For the Tresca stress, σ mises Let η be the Mises stress, η be the stress triaxiality, and csch be the hyperbolic cosecant function.

[0025] In a second aspect, the present invention provides a fracture strain prediction device for a ductile fracture body of a pipe, comprising:

[0026] The acquisition unit is used to acquire the first local principal stress, the second local principal stress, and the third local principal stress of the ductile fracture body of the pipe.

[0027] The first determining unit is used to determine the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0028] The second determining unit is used to determine the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant.

[0029] The third determining unit is used to determine the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and the Mises stress.

[0030] The prediction unit is used to input the stress triaxiality, the Mises stress and the Tresca stress into a pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe.

[0031] Optionally, the first determining unit is further configured to:

[0032] Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant;

[0033] The first local principal stress is subtracted from the third local principal stress to obtain the corresponding difference. The difference is divided by 2 to obtain the corresponding first quotient, and the first quotient is used as the Tresca stress of the ductile fracture body of the pipe.

[0034] The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0035] Optionally, the fracture strain prediction model is:

[0036]

[0037] Where, ε f The fracture strain is given by τ, where c1, c2, and c3 are material constants. tresca For the Tresca stress, σ mises Let η be the Mises stress, η be the stress triaxiality, and csch be the hyperbolic cosecant function.

[0038] Thirdly, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the fracture strain prediction method for ductile fracture bodies of pipes described in the first aspect or any corresponding embodiment thereof.

[0039] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute the fracture strain prediction method for a ductile fracture body of a pipe according to the first aspect or any corresponding embodiment described above.

[0040] This invention provides a method, apparatus, equipment, and medium for predicting the fracture strain of ductile fracture bodies in pipes. It obtains the first, second, and third local principal stresses of the ductile fracture body. Based on these stresses, it determines the first stress invariant, Tresca stress, and Mises stress. Based on the first stress invariant, it determines the equivalent stress of the ductile fracture body. Based on the equivalent stress and Mises stress, it determines the stress triaxiality of the ductile fracture body. The stress triaxiality, Mises stress, and Tresca stress are input into a pre-constructed fracture strain prediction model to predict the fracture strain of the ductile fracture body. This invention can effectively improve the accuracy of predicting the fracture strain of ductile fracture bodies in pipes. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 A flowchart illustrating a method for predicting the fracture strain of a ductile fracture body in a pipe, provided in an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of experimental and predicted ductile fracture data for X80 pipe steel provided in an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of the structure of a fracture strain prediction device for a ductile fracture body of a pipe provided in an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] The following is combined with Figures 1-2 The present invention describes a method for predicting the fracture strain of ductile fracture bodies in pipes.

[0048] like Figure 1 As shown in the figure, this embodiment proposes a first method for predicting the fracture strain of a ductile fracture body of a pipe, which may include the following steps:

[0049] S101. Obtain the first, second, and third local principal stresses of the ductile fracture body of the pipe.

[0050] Among them, the ductile fracture specimen refers to a pipe that will exhibit ductile fracture. Specifically, the ductile fracture specimen can be a specific pipe for which the ductile fracture strain needs to be predicted.

[0051] Optionally, the pipe ductile fracture material can be a carbon dioxide transport pipe or other types of pipes that are prone to ductile fracture.

[0052] It should be noted that in mechanics, the stress state at any point within an object can be represented by stresses in three mutually perpendicular directions. These three stresses are called the three local principal stresses of the object under that stress state. The three forces are ordered in magnitude as follows: σ1 > σ2 > σ3. In this case, σ1 is the first local principal stress, σ2 is the second local principal stress, and σ3 is the third local principal stress.

[0053] Specifically, this embodiment can perform stress analysis on a ductile fracture body of a pipe in operation to determine the first local principal stress, the second local principal stress, and the third local principal stress of the ductile fracture body of the pipe.

[0054] S102. Based on the first local principal stress, the second local principal stress, and the third local principal stress, determine the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe.

[0055] It should be noted that objects in the field of mechanics possess a first stress invariant, a second stress invariant, and a third stress invariant.

[0056] Among them, Tresca stress is the Tresca equivalent shear stress of the ductile fracture body of the pipe.

[0057] Specifically, the Mises stress is the equivalent stress of the ductile fracture body of the pipe.

[0058] Specifically, in this embodiment, the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe can be determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0059] Optionally, step S102 may include:

[0060] Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant;

[0061] Subtracting the third principal stress from the first local principal stress yields the corresponding difference. Dividing the difference by 2 yields the corresponding first quotient, which is then used as the Tresca stress of the ductile fracture body of the pipe.

[0062] The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0063] Specifically, the formula for calculating the first stress invariant of a ductile fracture body of a pipe can be:

[0064] I1 = σ1 + σ2 + σ3.

[0065] Where I1 is the first stress invariant, and σ1, σ2 and σ3 are the first local principal stress, the second local principal stress and the third local principal stress, respectively.

[0066] Specifically, the formula for calculating the Tresca stress of a ductile fracture body in a pipe can be:

[0067]

[0068] Where, τ tresca For Tresca stress.

[0069] Specifically, the formula for calculating the Mises stress in a ductile fracture body of a pipe can be:

[0070]

[0071] S103. Based on the first stress invariant, determine the equivalent stress of the ductile fracture body of the pipe.

[0072] Specifically, in this embodiment, the equivalent stress of the core fracture body can be determined based on the first stress invariant of the ductile fracture body of the pipe.

[0073] Optionally, step S103 may include:

[0074] Divide the first stress invariant by 3 to obtain the corresponding second quotient;

[0075] The second quotient is used as the equivalent stress of the ductile fracture body of the pipe.

[0076] The formula for calculating the equivalent stress of a ductile fracture body in a pipe can be:

[0077]

[0078] in, The equivalent stress of the ductile fracture body of the pipe.

[0079] S104. Determine the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and Mises stress.

[0080] Specifically, in this embodiment, the stress triaxiality of the ductile fracture body of the pipe can be determined based on the equivalent stress and Mises stress.

[0081] Optionally, step S104 may include:

[0082] Calculate the ratio of equivalent stress to Mises stress;

[0083] The ratio is determined as the stress triaxiality of the ductile fracture body of the pipe.

[0084] Specifically, the formula for calculating the stress triaxiality of a ductile fracture body of a pipe can be:

[0085]

[0086] Where η is the stress triaxiality of the ductile fracture body of the pipe.

[0087] S105. Input the triaxial stress, Mises stress, and Tresca stress into the pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe.

[0088] Specifically, in this embodiment, the stress triaxiality, Mises stress, and Tresca stress of the ductile fracture body of the pipe can be input into the fracture strain prediction model for calculation, and the fracture strain output by the fracture strain prediction model can be obtained.

[0089] Optionally, the fracture strain prediction model is:

[0090]

[0091] Where, ε f τ is the fracture strain, c1, c2, and c3 are material constants, and τ is the fracture strain. tresca For Tresca stress, σ misesLet η be the Mises stress, η be the stress triaxiality, and csch be the hyperbolic cosecant function.

[0092] It should be noted that this embodiment is executed Figure 1 Steps S101 to S105 in the process can predict the fracture strain of the ductile fracture body of the pipe and improve the accuracy of the predicted fracture strain.

[0093] The fracture strain prediction method for ductile fracture bodies of pipes proposed in this embodiment obtains the first, second, and third local principal stresses of the ductile fracture body. Based on these stresses, the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body are determined. The equivalent stress of the ductile fracture body is determined based on the first stress invariant. The stress triaxiality of the ductile fracture body is determined based on the equivalent stress and Mises stress. The stress triaxiality, Mises stress, and Tresca stress are then input into a pre-constructed fracture strain prediction model to predict the fracture strain of the ductile fracture body. This embodiment can effectively improve the accuracy of predicting the fracture strain of ductile fracture bodies of pipes.

[0094] based on Figure 1 In this embodiment, a second method for predicting the fracture strain of a ductile fracture body of a pipe is proposed. In the process of constructing the fracture strain prediction model, the correlation between the stress triaxiality, Mises stress, Tresca stress and fracture strain of the ductile fracture body of the pipe can be determined, and then the fracture strain prediction model can be constructed.

[0095] Specifically, in this embodiment, a strain prediction model for pipe fracture based on a hyperbolic cosine function can be established according to the stress triaxiality, Mises stress, and Tresca stress of the ductile fracture body of the pipe:

[0096]

[0097] Subsequently, this embodiment transforms the pipe fracture strain prediction model based on the hyperbolic cosine function to obtain the aforementioned fracture strain prediction model.

[0098] In practical applications, this embodiment can utilize fracture test data of X80 pipe steel to verify the effectiveness and accuracy of the fracture strain prediction model. The verification process data is as follows: Figure 2 As shown. In the fracture strain prediction model, c1, c2, and c3 can be set to 0.0007, 4.6970, and 0.4541, respectively. This embodiment can use the least squares method for fitting, which minimizes the average absolute value of the model's relative error. The definition of the average absolute value of the relative error is as follows:

[0099]

[0100] Where, ε error This represents the average of the absolute values ​​of the relative errors. The fracture strain predicted by the fracture prediction model. The fracture strain is obtained through the experiment, and N is the total number of test samples.

[0101] The average absolute value of the relative error obtained in this embodiment is about 13%, and the lowest absolute value of the relative error reaches 2%, which can accurately identify and predict the rupture behavior of carbon dioxide pipelines.

[0102] In related technologies, crack propagation in dense-phase carbon dioxide pipelines is a failure mode, and long-range crack propagation can lead to serious consequences. To accurately simulate this process, a reliable material damage model is required. The Gurson damage model, as a classic model of mesoscopic damage, can effectively simulate the initiation and evolution of material damage and has been successfully applied to damage behavior modeling of metallic materials. However, research shows that the Gurson model is a local model and cannot effectively couple the plastic deformation of the material with damage changes. The calculation results are easily affected by the mesh size and arrangement, and the model has many parameters to be determined, resulting in high computational cost and difficulty, which to some extent limits its application accuracy and scope.

[0103] This embodiment optimizes the shortcomings of pipe ductile fracture prediction models in related technologies, improves the model's ability to predict fracture failure behavior of ductile fracture bodies under shear-dominated failure mode, and reduces the parameters required for model calculation. It can more accurately and stably predict the ductile fracture behavior of pipelines, solves the problems of large model damage parameter requirements and high mesh dependence when the damage model is used to simulate crack propagation in pipelines in related technologies, expands the applicability of fracture prediction models, and can more accurately and stably predict the fracture and crack propagation behavior of carbon dioxide pipelines.

[0104] The fracture strain prediction method for ductile fracture bodies of pipes proposed in this embodiment can first construct a fracture strain prediction model and verify the accuracy of the fracture strain prediction model to ensure the prediction accuracy of the fracture strain prediction model.

[0105] like Figure 3 As shown in the figure, this embodiment proposes a fracture strain prediction device for ductile fracture bodies of pipes, which may include:

[0106] The acquisition unit 301 is used to acquire the first local principal stress, the second local principal stress, and the third local principal stress of the ductile fracture body of the pipe.

[0107] The first determining unit 302 is used to determine the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0108] The second determining unit 303 is used to determine the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant.

[0109] The third determining unit 304 is used to determine the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and the Mises stress.

[0110] The prediction unit 305 is used to input the triaxial stress, Mises stress and Tresca stress into the pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe.

[0111] It should be noted that the processing procedures and beneficial effects of the acquisition unit 301, the first determining unit 302, the second determining unit 303, the third determining unit 304, and the prediction unit 305 can be referred to respectively. Figure 1 Steps S101 to S105 are not described in detail here.

[0112] Optionally, the first determining unit 302 is also used for:

[0113] Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant;

[0114] Subtracting the third principal stress from the first local principal stress yields the corresponding difference. Dividing the difference by 2 yields the corresponding first quotient, which is then used as the Tresca stress of the ductile fracture body of the pipe.

[0115] The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

[0116] Optionally, the second determining unit 303 is also used for:

[0117] Divide the first stress invariant by 3 to obtain the corresponding second quotient;

[0118] The second quotient is used as the equivalent stress of the ductile fracture body of the pipe.

[0119] Optionally, the third determining unit 304 is also used for:

[0120] Calculate the ratio of equivalent stress to Mises stress;

[0121] The ratio is determined as the stress triaxiality of the ductile fracture body of the pipe.

[0122] Optionally, the fracture strain prediction model is:

[0123]

[0124] Where, ε f τ is the fracture strain, c1, c2, and c3 are material constants, and τ is the fracture strain. tresca For Tresca stress, σ mises Let η be the Mises stress, η be the stress triaxiality, and csch be the hyperbolic cosecant function.

[0125] The fracture strain prediction device for ductile fracture bodies of pipes proposed in this embodiment acquires the first, second, and third local principal stresses of the ductile fracture body. Based on these stresses, the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body are determined. The equivalent stress of the ductile fracture body is determined based on the first stress invariant. The stress triaxiality of the ductile fracture body is determined based on the equivalent stress and Mises stress. The stress triaxiality, Mises stress, and Tresca stress are input into a pre-constructed fracture strain prediction model to predict the fracture strain of the ductile fracture body. This embodiment can effectively improve the accuracy of predicting the fracture strain of ductile fracture bodies of pipes.

[0126] In this embodiment, the fracture strain prediction device for the ductile fracture body of the pipe is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0127] This invention also provides a computer device having the above-described features. Figure 3 The device shown is for predicting the fracture strain of a ductile fracture body in a pipe.

[0128] Please see Figure 4The present invention provides a schematic diagram of the structure of a computer device according to an optional embodiment. The computer device includes one or more processors 10, a memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components are interconnected via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 4 Take a processor 10 as an example.

[0129] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0130] The memory 20 stores instructions executable by at least one processor 10 to cause at least one processor 10 to perform the method shown in the above embodiments.

[0131] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function. The data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, which can be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0132] Memory 20 may include volatile memory, such as random access memory. Memory may also include non-volatile memory, such as flash memory, hard disk, or solid-state drive. Memory 20 may also include combinations of the above types of memory.

[0133] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0134] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting the fracture strain of a ductile fracture body of a pipe, characterized in that, include: Obtain the first, second, and third local principal stresses of the ductile fracture body of the pipe; Based on the first local principal stress, the second local principal stress, and the third local principal stress, the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe are determined. Based on the first stress invariant, the equivalent stress of the ductile fracture body of the pipe is determined; The stress triaxiality of the ductile fracture body of the pipe is determined based on the equivalent stress and the Mises stress. The stress triaxiality, the Mises stress, and the Tresca stress are input into a pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe. The fracture strain prediction model is as follows: ； The fracture strain is given. For material constants, For the Tresca stress, For the Mises stress, The stress triaxiality, It is a hyperbolic cosecant function.

2. The method according to claim 1, characterized in that, The step of determining the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe based on the first local principal stress, the second local principal stress, and the third local principal stress includes: Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant; The first local principal stress is subtracted from the third local principal stress to obtain the corresponding difference. The difference is divided by 2 to obtain the corresponding first quotient, and the first quotient is used as the Tresca stress of the ductile fracture body of the pipe. The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

3. The method according to claim 1, characterized in that, The determination of the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant includes: Divide the first stress invariant by 3 to obtain the corresponding second quotient; The second quotient is used as the equivalent stress of the ductile fracture body of the pipe.

4. The method according to claim 1, characterized in that, The determination of the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and the Mises stress includes: Calculate the ratio of the equivalent stress to the Mises stress; The ratio is determined as the stress triaxiality of the ductile fracture body of the pipe.

5. A device for predicting the fracture strain of a ductile fracture body of a pipe, characterized in that, include: The acquisition unit is used to acquire the first local principal stress, the second local principal stress, and the third local principal stress of the ductile fracture body of the pipe. The first determining unit is used to determine the first stress invariant, Tresca stress, and Mises stress of the ductile fracture body of the pipe based on the first local principal stress, the second local principal stress, and the third local principal stress. The second determining unit is used to determine the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant. The third determining unit is used to determine the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and the Mises stress. The prediction unit is used to input the stress triaxiality, the Mises stress and the Tresca stress into a pre-built fracture strain prediction model to predict the fracture strain and obtain the fracture strain of the ductile fracture body of the pipe. The fracture strain prediction model is as follows: ； The fracture strain is given. For material constants, For the Tresca stress, For the Mises stress, The stress triaxiality, It is a hyperbolic cosecant function.

6. The apparatus according to claim 5, characterized in that, The first determining unit is further configured to: Calculate the sum of the first local principal stress, the second local principal stress, and the third local principal stress, and use the sum as the first stress invariant; The first local principal stress is subtracted from the third local principal stress to obtain the corresponding difference. The difference is divided by 2 to obtain the corresponding first quotient, and the first quotient is used as the Tresca stress of the ductile fracture body of the pipe. The Mises stress is determined based on the first local principal stress, the second local principal stress, and the third local principal stress.

7. A computer device, characterized in that, include: The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes the computer instructions to perform the fracture strain prediction method for ductile fracture bodies of pipes as described in any one of claims 1 to 4.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the fracture strain prediction method for the ductile fracture body of the pipe as described in any one of claims 1 to 4.

Images