Fracture strain prediction method, device and equipment for ductile fracture body of pipe and medium

Abstract

The invention relates to the field of ductile fracture identification, and discloses a fracture strain prediction method, device, equipment and medium for a ductile fracture body of a pipe, and the method comprises the steps: obtaining a first local principal stress, a second local principal stress and a third local principal stress of the ductile fracture body of the pipe, and obtaining the fracture strain of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress and the third local principal stress; and determining a first stress invariant, a Teresta stress and a Miseius stress of the ductile fracture body of the pipe. And determining the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant. And determining the stress triaxial degree of the ductile fracture body of the pipe according to the equivalent stress and the Mises stress. And inputting the stress three-axis degree, the Misess stress and the Teresta stress into a pre-constructed fracture strain prediction model for fracture strain prediction to obtain the fracture strain of the ductile fracture body of the pipe. According to the method, the prediction accuracy of the fracture strain of the ductile fracture body of the pipe can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of ductile fracture identification, and in particular to a method, device, equipment and medium for predicting the fracture strain of a ductile fracture body of a pipe. Background Art

[0002] In the process of CO2 pipeline transportation, especially under high-pressure conditions such as transporting dense-phase CO2, ductile fracture of CO2 transportation pipelines is its main failure mode.

[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. The Gurson damage model is a local model that cannot effectively couple the plastic deformation of carbon dioxide transport pipelines with damage changes, and the fracture strain prediction accuracy is low.

[0004] In order to ensure the safe operation of carbon dioxide transportation pipelines, relevant technologies urgently need a reliable method for predicting pipeline fracture strain. Summary of the invention

[0005] The present invention provides a method, device, equipment and medium for predicting the fracture strain of a ductile fracture body of a pipe, so as to solve the defect of low fracture strain prediction accuracy in the related art and improve the fracture strain prediction accuracy.

[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] Obtaining the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe;

[0008] Determining a first stress invariant, a Tresca stress, and a Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress, and the third local principal stress;

[0009] Determining the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant;

[0010] Determining the stress triaxiality of the ductile fracture body of the pipe according to the equivalent stress and the Mises stress;

[0011] The stress triaxiality, the Mises stress and the Tresca stress are input into a pre-constructed fracture strain prediction model to perform fracture strain prediction, and the fracture strain of the ductile fracture body of the pipe is obtained.

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

[0013] Calculating a sum of the first local principal stress, the second local principal stress and the third local principal stress, and using the sum as the first stress invariant;

[0014] Subtracting the third local principal stress from the first local principal stress to obtain a corresponding difference, dividing the difference by 2 to obtain a corresponding first quotient, and using the first quotient 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 pipe ductile fracture body based on the first stress invariant includes:

[0017] Dividing the first stress invariant by 3 to obtain a corresponding second quotient value;

[0018] The second quotient value 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 according to the equivalent stress and the Mises stress includes:

[0020] Calculating 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 tube.

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

[0023]

[0024] Among them, ε f is the fracture strain, c1, c2 and c3 are material constants, τ tresca is the Tresca stress, σ mises is the Mises stress, η is the stress triaxiality, and csch is the hyperbolic cosecant function.

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

[0026] An acquisition unit, used for acquiring 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] a first determining unit, configured to determine a first stress invariant, a Tresca stress, and a Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress, and the third local principal stress;

[0028] A second determining unit, configured to determine an equivalent stress of the ductile fracture body of the pipe based on the first stress invariant;

[0029] A third determining unit is used to determine the stress triaxiality of the ductile fracture body of the pipe according to 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 perform fracture strain prediction and obtain the fracture strain of the ductile fracture body of the pipe.

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

[0032] Calculating a sum of the first local principal stress, the second local principal stress and the third local principal stress, and using the sum as the first stress invariant;

[0033] Subtracting the third local principal stress from the first local principal stress to obtain a corresponding difference, dividing the difference by 2 to obtain a corresponding first quotient, and using the first quotient 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] Among them, ε f is the fracture strain, c1, c2 and c3 are material constants, τ tresca is the Tresca stress, σ mises is the Mises stress, η is the stress triaxiality, and csch is the hyperbolic cosecant function.

[0038] In a third aspect, 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 method for predicting the fracture strain of a ductile fracture body of a pipe according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0039] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for predicting the fracture strain of a ductile fracture body of a pipe according to the first aspect or any corresponding embodiment thereof.

[0040] The present invention provides a method, device, equipment and medium for predicting the fracture strain of a ductile fracture body of a pipe, obtains the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe, and determines the first stress invariant, the Tresca stress and the Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress and the third local principal stress. Based on the first stress invariant, the equivalent stress of the ductile fracture body of the pipe is determined. According to the equivalent stress and the Mises stress, the stress triaxiality of the ductile fracture body of the pipe is determined. The stress triaxiality, the Mises stress and the Tresca stress are input into a pre-constructed fracture strain prediction model to predict the fracture strain, and the fracture strain of the ductile fracture body of the pipe is obtained. The present invention can effectively improve the prediction accuracy of the fracture strain of the ductile fracture body of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A flow chart of a method for predicting fracture strain of a pipe ductile fracture body provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of X80 pipeline steel test and predicted ductile fracture data provided by an embodiment of the present invention;

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

[0045] Figure 4 A schematic diagram of the structure of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Combine the following Figure 1-Figure 2 The present invention describes the fracture strain prediction method of the pipe ductile fracture body.

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

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

[0050] The pipe ductile fracture body is a pipe that will experience ductile fracture. Specifically, the pipe ductile fracture body may be a pipe for which ductile fracture strain needs to be predicted.

[0051] Optionally, the pipe ductile fracture body may be a carbon dioxide transport pipeline, or may be other types of pipelines that may experience ductile fracture.

[0052] It should be noted that in the field of mechanics, the stress state of any point in an object can be expressed by stresses in three mutually perpendicular directions. The stresses in these three directions are called the three local principal stresses of the object under this stress state. The three forces are sorted by size, σ1>σ2>σ3. At this time, 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 a stress analysis on the ductile fracture body of the 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. Determine the first stress invariant, Tresca stress and Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress and the third local principal stress.

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

[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 Mises equivalent stress of the ductile fracture body of the pipe.

[0058] Specifically, this embodiment can 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 of the ductile fracture body of the pipe, respectively.

[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] Subtract the third local principal stress from the first local principal stress to obtain a corresponding difference, divide the difference by 2 to obtain a corresponding first quotient, and use the first quotient as the Tresca stress of the ductile fracture body of the pipe;

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

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

[0064] I1=σ1+σ2+σ3.

[0065] Among them, I1 is the first stress invariant, 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 calculation formula of the Tresca stress of the ductile fracture body of the pipe can be:

[0067]

[0068] Among them, τ tresca Stress for Tresca.

[0069] Specifically, the calculation formula of the Mises stress of the ductile fracture body of the pipe can be:

[0070]

[0071] S103. Determine the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant.

[0072] Specifically, this embodiment can determine the equivalent stress of the core fracture body according to the first stress invariant of the pipe ductile fracture body.

[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 taken as the equivalent stress of the ductile fracture body of the pipe.

[0076] Among them, the calculation formula for the equivalent stress of the ductile fracture body of the pipe can be:

[0077]

[0078] in, is 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, this embodiment can determine the stress triaxiality of the ductile fracture body of the pipe based on the equivalent stress and Mises stress of the ductile fracture body of the pipe.

[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 calculation formula for the stress triaxiality of the pipe ductile fracture body can be:

[0085]

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

[0087] S105, inputting stress triaxiality, Mises stress and Tresca stress into a pre-built fracture strain prediction model to perform fracture strain prediction, and obtaining 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 to obtain the fracture strain output by the fracture strain prediction model.

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

[0090]

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

[0092] It should be noted that, in this embodiment, by executing Figure 1 Steps S101 to S105 in the method 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 of the ductile fracture body of the pipe proposed in this embodiment obtains the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe. According to the first local principal stress, the second local principal stress and the third local principal stress, the first stress invariant, the Tresca stress and the 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. According to the equivalent stress and the Mises stress, the stress triaxiality of the ductile fracture body of the pipe is determined. The stress triaxiality, the Mises stress and the Tresca stress are input into the pre-constructed fracture strain prediction model to predict the fracture strain, and the fracture strain of the ductile fracture body of the pipe is obtained. This embodiment can effectively improve the prediction accuracy of the fracture strain of the ductile fracture body of the pipe.

[0094] based on Figure 1 In the second method for predicting the fracture strain of a ductile fracture body of a pipe proposed in this embodiment, in the process of constructing a 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, this embodiment can establish a pipe fracture strain prediction model based on a hyperbolic cosine function according to the stress triaxiality, Mises stress and Tresca stress of the pipe ductile fracture body:

[0096]

[0097] Afterwards, this embodiment converts the pipe fracture strain prediction model of the hyperbolic cosine function to obtain the above fracture strain prediction model.

[0098] In practical applications, this embodiment can use the fracture test data of X80 pipeline steel to verify the effectiveness and accuracy of the fracture strain prediction model. Figure 2 As shown. c1, c2 and c3 in the fracture strain prediction model can be set to 0.0007, 4.6970 and 0.4541 respectively. This embodiment can use the least squares method to fit so that the average value of the absolute value of the relative error of the model is minimized. The definition of the average value of the absolute value of the relative error is as follows:

[0099]

[0100] Among them, ε error is the average absolute value of relative error. is the fracture strain predicted by the fracture prediction model, is the fracture strain obtained by the test, and N is the total number of test samples.

[0101] The average absolute value of the relative error verified in this embodiment is about 13%, and the minimum absolute value of the relative error reaches 2%, which can more accurately identify and predict the fracture behavior of the carbon dioxide pipeline.

[0102] In the related technology, crack propagation in dense phase carbon dioxide pipelines is the failure mode of dense phase carbon dioxide transport pipelines, and the long-range propagation of cracks can cause serious consequences. In order to accurately simulate this process, a reliable material damage model is required. As a classic model of mesoscopic damage, the Gurson damage model can well simulate the initiation and evolution of material damage, and has been successfully applied to the damage behavior modeling of metal materials. However, studies have shown that the Gurson model is a local model that cannot effectively couple the plastic deformation of the material with the damage change. The calculation results are easily affected by the mesh size and layout. In addition, there are many parameters to be determined in the model, and the calculation cost and difficulty are high, which to a certain extent limits its application accuracy and scope.

[0103] This embodiment can optimize the deficiencies of the ductile fracture prediction model of the pipe in the related art, improve the model's ability to predict the fracture failure behavior of the ductile fracture body under the shear-dominated failure mode, and reduce the parameters required for the model calculation, so that the ductile fracture behavior of the pipeline can be predicted more accurately and stably, and the problem that the damage model in the related art has a large demand for model damage parameters and high grid dependence when simulating pipeline crack propagation is solved, and the scope of application of the fracture prediction model is expanded, so that the fracture and crack propagation behavior of the carbon dioxide pipeline can be predicted more accurately and stably.

[0104] The fracture strain prediction method for a ductile fracture body of a pipe 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, this embodiment provides a device for predicting the fracture strain of a ductile fracture body of a pipe, and the device may include:

[0106] An acquisition unit 301 is used to acquire a first local principal stress, a second local principal stress and a third local principal stress of a ductile fracture body of a pipe;

[0107] A first determining unit 302 is used to determine a first stress invariant, a Tresca stress and a Mises stress of a ductile fracture body of the pipe according to the first local principal stress, the second local principal stress and the third local principal stress;

[0108] A 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 determination unit 304 is used to determine the stress triaxiality of the ductile fracture body of the pipe according to the equivalent stress and the Mises stress;

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

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

[0112] Optionally, the first determining unit 302 is further configured to:

[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] Subtract the third local principal stress from the first local principal stress to obtain a corresponding difference, divide the difference by 2 to obtain a corresponding first quotient, and use the first quotient as the Tresca stress of the ductile fracture body of the pipe;

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

[0116] Optionally, the second determining unit 303 is further configured to:

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

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

[0119] Optionally, the third determining unit 304 is further configured to:

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

[0125] The fracture strain prediction device for the ductile fracture body of the pipe proposed in this embodiment obtains the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe. According to the first local principal stress, the second local principal stress and the third local principal stress, the first stress invariant, the Tresca stress and the 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. According to the equivalent stress and the Mises stress, the stress triaxiality of the ductile fracture body of the pipe is determined. The stress triaxiality, the Mises stress and the Tresca stress are input into the pre-constructed fracture strain prediction model to predict the fracture strain, and the fracture strain of the ductile fracture body of the pipe is obtained. This embodiment can effectively improve the prediction accuracy of the fracture strain of the ductile fracture body of the pipe.

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

[0127] The embodiment of the present invention also provides a computer device having the above Figure 3 The fracture strain prediction device of the ductile fracture body of the pipe is shown.

[0128] See also Figure 4, a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the computer device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 4 A processor 10 is taken as an example.

[0129] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0130] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0131] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function. The data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage devices. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

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

[0133] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0134] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting fracture strain of a ductile fracture body of a pipe, characterized in that: include: Obtaining the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe; Determining a first stress invariant, a Tresca stress, and a Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress, and the third local principal stress; Determining the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant; Determining the stress triaxiality of the ductile fracture body of the pipe according to the equivalent stress and the Mises stress; The stress triaxiality, the Mises stress and the Tresca stress are input into a pre-constructed fracture strain prediction model to perform fracture strain prediction, and the fracture strain of the ductile fracture body of the pipe is obtained.

2. The method according to claim 1, characterized in that: The determining of the first stress invariant, the Tresca stress and the Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress and the third local principal stress comprises: Calculating a sum of the first local principal stress, the second local principal stress and the third local principal stress, and using the sum as the first stress invariant; Subtracting the third local principal stress from the first local principal stress to obtain a corresponding difference, dividing the difference by 2 to obtain a corresponding first quotient, and using the first quotient 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 determining, based on the first stress invariant, the equivalent stress of the ductile fracture body of the pipe comprises: Dividing the first stress invariant by 3 to obtain a corresponding second quotient value; The second quotient value is used as the equivalent stress of the ductile fracture body of the pipe.

4. The method according to claim 1, characterized in that Determining the stress triaxiality of the ductile fracture body of the pipe according to the equivalent stress and the Mises stress includes: Calculating 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 tube.

5. The method according to claim 1, characterized in that The fracture strain prediction model is: Among them, ε f is the fracture strain, c1, c2 and c3 are material constants, τ tresca is the Tresca stress, σ mises is the Mises stress, η is the stress triaxiality, and csch is the hyperbolic cosecant function.

6. A fracture strain prediction device for a ductile fracture body of a pipe, characterized in that: include: An acquisition unit, used for acquiring the first local principal stress, the second local principal stress and the third local principal stress of the ductile fracture body of the pipe; a first determining unit, configured to determine a first stress invariant, a Tresca stress, and a Mises stress of the ductile fracture body of the pipe according to the first local principal stress, the second local principal stress, and the third local principal stress; A second determining unit is used to determine the equivalent stress of the ductile fracture body of the pipe based on the first stress invariant; A third determining unit is used to determine the stress triaxiality of the ductile fracture body of the pipe according to 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 perform fracture strain prediction and obtain the fracture strain of the ductile fracture body of the pipe.

7. The device according to claim 6, characterized in that The first determining unit is further configured to: Calculating a sum of the first local principal stress, the second local principal stress and the third local principal stress, and using the sum as the first stress invariant; Subtracting the third local principal stress from the first local principal stress to obtain a corresponding difference, dividing the difference by 2 to obtain a corresponding first quotient, and using the first quotient 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.

8. The device according to claim 6, characterized in that The fracture strain prediction model is: Among them, ε f is the fracture strain, c1, c2 and c3 are material constants, τ tresca is the Tresca stress, σ mises is the Mises stress, η is the stress triaxiality, and csch is the hyperbolic cosecant function.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are connected to each other for communication, the memory stores computer instructions, and the processor executes the fracture strain prediction method for a ductile fracture body of a pipe according to any one of claims 1 to 5 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for predicting the fracture strain of a ductile fracture body of a pipe according to any one of claims 1 to 5.

Images