KR20210044927A - Apparatus for evaluating fatigue life of welds - Google Patents

Abstract

Provided is a device for evaluating a fatigue lifespan of a welding unit to input a design lifespan by calculating a fatigue lifespan and calculating a critical initial crack size satisfying the design lifespan when inputting a crack size. According to one embodiment of the present invention, the device for evaluating the fatigue lifespan of the welding unit may comprise: an input unit selecting a function and receiving a parameter related to the selected function from a user; a fatigue lifespan calculation unit receiving the selected function of the user from the input unit and receiving a crack dimension, a crack condition, and a load condition of the welding unit from the input unit to calculate a fatigue lifespan of the welding unit; and an initial crack search unit receiving the selected function of the user from the input unit and receiving a design lifespan and a crack radius ratio of the welding unit from the input unit to repeatedly calculate the fatigue lifespan by calculating an initial crack dimension.

Description

Welding fatigue life evaluation device {APPARATUS FOR EVALUATING FATIGUE LIFE OF WELDS}

The present invention relates to a welding part fatigue life evaluation apparatus for evaluating the fatigue life of the welding part.

In general, a device for evaluating the fatigue life of a crack near a weld can calculate the fatigue life for a given initial crack and dynamic load, but conversely, when the design life required by the manufacturer is entered, a satisfactory critical initial crack size is determined. It does not perform the function of calculating.

Accordingly, when a crack is found immediately after fabrication, there is a problem in that it is necessary to perform fatigue life calculations one by one.

Republic of Korea Patent Publication No. 10-2011-0098668

According to an embodiment of the present invention, when a crack size is input, a fatigue life evaluation apparatus for a welded part is provided that calculates a fatigue life, inputs a design life, and calculates a critical initial crack size satisfying the fatigue life.

In order to solve the above-described problem of the present invention, the apparatus for evaluating fatigue life of a welded part according to an embodiment of the present invention includes an input unit that receives a function selection and a parameter related to the selected function from a user, and receives the user's function selection through the input unit. , A fatigue life calculation unit that calculates the fatigue life of the weld by receiving the crack dimensions, crack conditions, and load conditions of the weld from the input unit, and receives the user's function selection from the input unit, and receives the design life and crack half of the welding unit from the input unit. It may include an initial crack search unit that receives the input cost and calculates the initial crack dimension to repeatedly calculate the fatigue life.

According to an embodiment of the present invention, there is an effect of securing a welding quality that satisfies a reference fatigue life.

1 is a schematic configuration diagram of a welding fatigue life evaluation apparatus according to an embodiment of the present invention.
2 is a schematic flowchart of an operation of an initial crack search unit of the apparatus for evaluating fatigue life of a weld according to an embodiment of the present invention.
3 is a graph showing the load condition of the apparatus for evaluating fatigue life of a weld according to an embodiment of the present invention.
4 is a graph showing a relationship between a crack radius and an accumulation cycle of the apparatus for evaluating fatigue life of a weld according to an embodiment of the present invention.
5 is a diagram illustrating an exemplary computing environment in which one or more embodiments disclosed herein may be implemented.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention.

1 is a schematic configuration diagram of a welding fatigue life evaluation apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a welding fatigue life evaluation apparatus 100 according to an embodiment of the present invention may include an input unit 110, a fatigue life calculation unit 120, and an initial crack search unit 130.

The input unit 110 may receive a function selection and a parameter related to the selected function from the user.

That is, the user can input the function selection of the fatigue life calculation unit 120 or the initial crack search unit through the input unit 110, and the parameters or details for performing the function of the selected fatigue life calculation unit 120 or the initial crack search unit You can enter a function selection.

The fatigue life calculation unit 120 may receive a user's function selection through the input unit 110, and receive a crack dimension, a crack condition, and a load condition of the weld through the input unit 110 to calculate the fatigue life of the weld. .

The fatigue life calculation unit 120 may include a generation unit 121 and a first output unit 122.

The generation unit 121 may receive the crack dimension, the crack condition, and the load condition, calculate the fatigue life of the welding portion, and generate an array of change in the crack dimension.

The first output unit 122 may output the calculated fatigue life.

The input unit 110 may receive a type and size of a crack, and a dimension of a welding part with respect to the crack size. For example, as for the type of crack, one of a total of three types of crack shapes (surface, embedded, and corner) can be selected and input. The crack dimension may include a crack depth of the weld, a crack width, a distance from a surface of an internal crack, a width and thickness of a plate including a crack, and a gap between toe of the weld. The crack condition may be a condition in which a crack propagation parameter is selected from a user or directly inputted, and the load condition may include a load in the form of a constant stress fluctuation width, a load-time history, and a constant stress fluctuation cycle.

For the load in the form of a constant stress fluctuation width, the input unit 110 directly receives the fluctuation widths of the membrane stress and the bending stress obtained through stress linearization from the structural analysis result. I can.

The load-time history corresponds to the stress range obtained from the result by applying a rainflow-counting technique to the time history data of stress obtained directly from the plate surface. It can be used when you want to enter the number of cycles to be performed.

The constant stress range-cycle includes the load-time history or constant stress range-cycle data obtained by the rainflow-counting technique from the input unit 110 directly from the user. Can be input.

That is, the above-described crack dimension, the crack condition, and the load condition may be selected by the user through the input unit 110 or directly input the dimensions.

For example, when the user wants to evaluate the fatigue life of the welding part through the input unit 110, the fatigue life calculation unit 120 is operated by inputting the above-described crack dimension, the crack condition, and the load condition to reduce the fatigue of the welding part. Life can be calculated and printed.

Conversely, when the user wants to find the initial crack size for the design life through the input unit 110, the user can click the'find initial crack' check box. At this time, the input section of the crack dimension, the crack condition, and the load condition in the fatigue life output valve 120 and the input unit 110 may be deactivated.

Referring back to FIG. 1, the initial crack search unit 130 receives the user's function selection through the input unit 110, receives the design life and the crack radius ratio of the welding unit from the input unit, and calculates the initial crack size to calculate the fatigue life. Can be iteratively calculated.

The initial crack search unit 130 may include an execution unit 131 and a second output unit 132.

The execution unit 131 may repeatedly calculate the fatigue life as many times as a set number of times according to the initial crack depth and initial crack width according to the design life and the calculated initial crack dimensions, and the second output unit 132 relates to the initial crack. The calculated fatigue life graph can be printed.

2 is a schematic operation flowchart of an initial crack search unit of the apparatus for evaluating fatigue life of a weldment according to an embodiment of the present invention, and FIG. 3 is a graph showing a load condition of the apparatus for evaluating fatigue life of a welded part according to an embodiment of the present invention. , FIG. 4 is a graph showing the relationship between the crack radius and the cumulative cycle of the apparatus for evaluating fatigue life of a weld according to an embodiment of the present invention.

First, referring to FIG. 1 and FIG. 2, the execution unit 131 of the initial crack search unit 130 of the welding fatigue life evaluation apparatus 100 according to an embodiment of the present invention is provided through the input unit 110. The design life and the crack radius ratio of the weld can be input (S10). At this time, the initial crack size may be set arbitrarily (S20). Thereafter, the execution unit 131 may calculate the fatigue life (S30) and repeatedly calculate the fatigue life until it meets the reference condition (S40, S50, S60, S70, S90). If the crack dimension is greater than or equal to the reference value (0.8T), the crack condition and the load condition may be modified and input (S80).

Thereafter, the crack depth and width (a,c) of the crack radius ratio can be output and terminated.

The execution unit 131 may apply an initial crack depth and an initial crack width satisfying the following equation.

(Equation)

Where a is the initial crack depth, c is the initial crack width, i is the number of settings, N is the number of repetitions of the load, L is the design life, Ni is the ith accumulated repetition cycle, and Nc is the final accumulated cycle (fatigue life). .

When the load conditions are set as shown in the table below, it can be expressed as in the graph of FIG. 3.

(table)

Referring to FIG. 4, it is clear that the crack dimension a is a function of increasing N, but since the dominant differential equation is a nonlinear equation that is almost impossible to obtain a clear solution, the following exact quantitative relationship cannot be grasped.

f(a, N) = 0

However, it is assumed that the mode of f(a, N) = 0 will not change significantly depending on the initial crack size setting value, and a rough estimate is made.

5 is a diagram illustrating an exemplary computing environment in which one or more embodiments disclosed herein may be implemented.

Shows an example of a system 1000 including a computing device 1100 configured to implement one or more of the embodiments described above. For example, the computing device 1100 may be a personal computer, a server computer, a handheld or laptop device, a mobile device (mobile phone, PDA, media player, etc.), a multiprocessor system, a consumer electronic device, a mini computer, a mainframe computer, Distributed computing environments including, but not limited to, any of the aforementioned systems or devices.

The computing device 1100 may include at least one processing unit 1110 and a memory 1120. Here, the processing unit 1110 may include, for example, a central processing unit (CPU), a graphic processing unit (GPU), a microprocessor, an application specific integrated circuit (ASIC), and Field Programmable Gate Arrays (FPGA). It can be, and can have a plurality of cores. The memory 1120 may be a volatile memory (eg, RAM, etc.), a nonvolatile memory (eg, ROM, flash memory, etc.), or a combination thereof.

Additionally, the computing device 1100 may include an additional storage 1130. Storage 1130 includes, but is not limited to, magnetic storage, optical storage, and the like. The storage 1130 may store computer-readable instructions for implementing one or more embodiments disclosed herein, and other computer-readable instructions for implementing an operating system, an application program, and the like. Computer-readable instructions stored in storage 1130 may be loaded into memory 1120 for execution by processing unit 1110.

Further, the computing device 1100 may include an input device(s) 1140 and an output device(s) 1150. Here, the input device(s) 1140 may include, for example, a keyboard, a mouse, a pen, a voice input device, a touch input device, an infrared camera, a video input device, or any other input device. Further, the output device(s) 1150 may include, for example, one or more displays, speakers, printers, or any other output device, and the like. Further, the computing device 1100 may use an input device or an output device provided in another computing device as the input device(s) 1140 or the output device(s) 1150.

In addition, computing device 1100 may include communication connection(s) 1160 that enable communication with other devices (eg, computing device 1300) via network 1200. Here, the communication connection(s) 1160 is a modem, a network interface card (NIC), an integrated network interface, a radio frequency transmitter/receiver, an infrared port, a USB connection, or other computing device for connecting the computing device 1100 to another computing device. May include an interface. Further, the communication connection(s) 1160 may include a wired connection or a wireless connection.

Each component of the above-described computing device 1100 may be connected by various interconnections such as a bus (e.g., peripheral component interconnection (PCI), USB, firmware (IEEE 1394), optical bus structure, etc.). And may be interconnected by a network.

As used herein, terms such as "input part", "fatigue life calculation part", "initial crack search part", etc. generally refer to a computer-related entity that is hardware, a combination of hardware and software, software, or software that is running. . For example, a component may be, but is not limited to, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. For example, both the controller and the application running on the controller may be components. One or more components may exist within a process and/or thread of execution, and a component may be localized on one computer or distributed between two or more computers.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, but is limited by the claims to be described later, and the configuration of the present invention is varied within the scope not departing from the technical spirit of the present invention. It can be easily understood by those of ordinary skill in the art that the present invention can be changed and modified.

100: welding fatigue life evaluation device
110: input unit
120: fatigue life calculation unit
121: generation unit
122: first output unit
130: initial crack search unit
131: executive
132: second output unit

Claims (5)

An input unit for receiving a function selection and a parameter related to the selected function from a user;
A fatigue life calculation unit that receives a user's function selection through the input unit and receives a crack dimension, a crack condition, and a load condition of the welding unit from the input unit to calculate a fatigue life of the welding unit; And
An initial crack search unit that receives the user's function selection through the input unit, receives the design life and crack radius ratio of the welding unit from the input unit, calculates the initial crack dimension, and repeatedly calculates the fatigue life
Welding fatigue life evaluation device comprising a.
The method of claim 1,
The fatigue life calculation unit
A generator configured to receive the crack dimension, the crack condition, and the load condition, calculate a fatigue life of the welded portion, and generate an array of varying crack dimensions; And
1st output to output the calculated fatigue life
Welding fatigue life evaluation device comprising a.
The method of claim 1,
The initial crack search unit
A performing unit that repeatedly calculates the fatigue life by a set number of times according to the initial crack depth and the initial crack width according to the design life and the calculated initial crack dimensions; And
The second output section that outputs the fatigue life graph calculated for the initial crack
Welding fatigue life evaluation device comprising a.
The method of claim 1,
The crack dimensions include the depth of the crack of the weld, the width of the crack, the distance from the surface of the internal crack, the width and thickness of the plate containing the crack, and the gap between the toe of the weld,
The crack condition is a condition in which a crack propagation parameter is selected or directly input from a user,
The load condition is a welding fatigue life evaluation apparatus including a load in the form of a constant stress fluctuation width, a load-time history, and a constant stress fluctuation cycle.
The method of claim 1,
The apparatus for evaluating fatigue life of a welded part applying the initial crack depth and the initial crack width satisfying the following equation.
Equation)

Where a is the initial crack depth, c is the initial crack width, i is the number of settings, N is the number of repetitions of the load, L is the design life, Ni is the ith accumulated repetition cycle, and Nc is the final accumulation cycle (fatigue life).

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