Method for calculating fracture surface ratio, information processing device, and program

Abstract

To improve a calculation technique of a fracture rate of a material.SOLUTION: A fracture rate calculation method includes an acquisition step for acquiring three-dimensional point group data of a fracture shape of a material having a vertical fracture when a direction perpendicular to a fracture of the material is regarded as a Z axis, a crack propagation direction of the material as a Y axis, and a direction perpendicular to a surface formed by a Y axis-Z axis as an X axis, a first creation step for creating shape data of a two-dimensional (X, Z) cross section and shape data of a two-dimensional (Y, Z) cross section on the basis of the three-dimensional point group data, a first extraction step for extracting a boundary point between a brittle region and a ductile region in each cross section on the basis of height information of the shape data of the two-dimensional (X, Z) cross section and the shape data of the two-dimensional (Y, Z) cross section, and a calculation step for calculating an area of the brittle region on the basis of the boundary point and calculating a fracture rate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a method for calculating a fracture surface ratio of a material, an information processing apparatus, and a program.

Background Art

[0002] Conventionally, as a means for evaluating the fracture toughness of a metallic material, the Charpy impact test has been widely applied. The Charpy impact test is a test in which an impact is applied with a hammer to a test piece (Charpy test piece) with a notch to break it, and the energy absorbed by the test, lateral bulging, and fracture surface ratio are determined.

[0003] The fracture surface ratio is calculated as a brittle fracture surface ratio indicating the ratio of the area of the brittle fracture surface to the total area of the fracture surface, or a ductile fracture surface ratio indicating the ratio of the area of the ductile fracture surface to the total area of the fracture surface. Here, the brittle fracture surface refers to a fracture surface in which many crystal grains are cleaved or intergranularly fractured and appear shiny. On the other hand, the ductile fracture surface refers to a fracture surface that is sheared in a fibrous shape and has a dull and non-shiny appearance.

[0004] So far, the fracture surface ratio has been determined, for example, in accordance with Appendix C (Provisions) "Method for Determining Fracture Surface Ratio" of JIS Z2242:2018 "Charpy Impact Test Method for Metallic Materials". After the metallic material fractured in the Charpy impact test, an inspector visually determined the regions of the brittle fracture surface and the ductile fracture surface on the fracture surface of the metallic material and measured their areas. However, when measuring the fracture surface ratio by visual determination, there was a problem that the values of the fracture surface ratio varied among inspectors. This problem is considered to be caused by the variation in the boundary position between the ductile fracture surface and the brittle fracture surface determined by the inspector when inspecting the fracture surface of the test piece. Therefore, a highly accurate method for measuring the fracture surface ratio that does not depend on individual differences of inspectors has been desired.

[0005] For example, Patent Document 1 discloses a steel fracture surface discrimination device comprising: a three-dimensional shape measuring device for measuring the shape of the fracture surface of a steel material; a discrimination means for acquiring three-dimensional point cloud data of the fracture surface shape measured by the three-dimensional shape measuring device, extracting two-dimensional cross-sectional shape data obtained by cutting the steel material with a plane perpendicular to the crack propagation direction from the three-dimensional point cloud data, and determining whether the range of a line segment is a brittle fracture area or a ductile fracture area based on the absolute value of the slope of the line segment between adjacent points and the absolute value of the difference in the slopes of adjacent line segments in the extracted two-dimensional cross-sectional shape data. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-148453 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, when the fracture surface discrimination device for steel materials described in Patent Document 1 was used to evaluate the fracture surface ratio of steel materials, it was found that the accuracy was insufficient. In other words, there was room for improvement in the technology for calculating the fracture surface ratio of materials.

[0008] In light of these circumstances, the purpose of this disclosure is to improve the technique for calculating the fracture surface ratio of materials. [Means for solving the problem]

[0009] (1) A method according to one embodiment of the present disclosure is In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the aforementioned three-dimensional point cloud data. A first extraction step extracts the boundary points between the brittle region and the ductile region in each cross-section based on the height information of the shape data of the two-dimensional (X,Z) cross-section and the height information of the shape data of the two-dimensional (Y,Z) cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, It is equipped with.

[0010] (2) A method according to one embodiment of the present disclosure is the method described in (1), A second creation step involves creating a group of endpoint data (X,Y) in the Y-axis direction for the endpoints of the fracture surface in the X-axis direction from the three-dimensional point cloud data, A second extraction step involves creating approximate lines for each predetermined number of points using the endpoint data (X,Y) group, and extracting the boundary line in the X-axis direction between the brittle region and the ductile region based on the angle formed by adjacent approximate lines. Furthermore, In the calculation step, if the angle between the X-axis boundary line of the brittle region extracted in the second extraction step and the X-axis is less than a predetermined value, the area of ​​the brittle region is calculated based on the X-axis boundary line extracted in the second extraction step and the boundary point.

[0011] (3) A method according to one embodiment of the present disclosure is a method according to (1) or (2), This includes the step of converting the aforementioned three-dimensional point cloud data into polygon mesh data and calculating the normal vector of each face, In the first creation step, shape data for a two-dimensional (X,Z) cross-section and shape data for a two-dimensional (Y,Z) cross-section are created based on the three-dimensional point cloud data filtered by the normal vectors of each surface.

[0012] (4) An information processing apparatus according to one embodiment of the present disclosure is An information processing device comprising a control unit for calculating fracture surface ratio, wherein the control unit is In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the aforementioned three-dimensional point cloud data. A first extraction step extracts the boundary points between the brittle region and the ductile region in each cross-section based on the height information of the shape data of the two-dimensional (X,Z) cross-section and the height information of the shape data of the two-dimensional (Y,Z) cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, Execute this.

[0013] (5) A program according to one embodiment of the present disclosure is A program for calculating fracture surface ratio, which is used by a computer. In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the aforementioned three-dimensional point cloud data. A first extraction step extracts the boundary points between the brittle region and the ductile region in each cross-section based on the height information of the shape data of the two-dimensional (X,Z) cross-section and the height information of the shape data of the two-dimensional (Y,Z) cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, A calculation step to calculate the area of ​​the region enclosed by the aforementioned boundary points and calculate the brittle fracture ratio, Make it run. [Effects of the Invention]

[0014] According to one embodiment of the present disclosure, the technique for calculating the fracture surface ratio of a material can be improved.

Brief Description of the Drawings

[0015] [Figure 1] It is a block diagram showing a schematic configuration of a fracture rate calculation system according to an embodiment of the present disclosure. [Figure 2] It is a conceptual diagram showing a fracture surface of a material according to an embodiment of the present disclosure. [Figure 3] It is a flowchart showing the operation of an information processing apparatus according to an embodiment of the present disclosure. [Figure 4] It is a diagram showing the concept of the first extraction step. [Figure 5] An example of each step of the first extraction step is shown. [Figure 6] It is a conceptual diagram showing an overview of a calculation step according to an embodiment of the present disclosure. [Figure 7] It is a diagram showing an overview of the first modification example. [Figure 8] It is a flowchart showing the operation of an information processing apparatus according to the first modification example. [Figure 9] It is a diagram showing the concept of the second extraction step. [Figure 10] It is a flowchart showing the operation of an information processing apparatus according to the second modification example. [Figure 11] It is a diagram showing an overview of the calculation process of the normal vector. [Figure 12] It is a flowchart showing the operation of an information processing apparatus according to the third modification example.

Modes for Carrying Out the Invention

[0016] Hereinafter, a fracture rate calculation system 1 for a material according to an embodiment of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0017] Referring to FIG. 1, the outline and configuration of the fracture rate calculation system 1 according to this embodiment will be described.

[0018] The fracture surface ratio calculation system 1 according to this embodiment comprises a three-dimensional shape measuring device 10 and an information processing device 20. The three-dimensional shape measuring device 10 and the information processing device 20 are connected, for example, via a network for communication.

[0019] The 3D shape measuring device 10 is installed above the fractured steel material and measures the shape of the fracture surface of the steel material. For example, an LED-based measuring instrument (3D scanner) can be used as the 3D shape measuring device 10. The 3D shape measuring device 10 performs distance measurement by optical means, for example. The distance measurement method used by the 3D shape measuring device 10 may be any method such as triangulation or phase difference distance measurement.

[0020] The information processing device 20 is any device used by the user. For example, a personal computer, a server computer, a general-purpose electronic device, or a dedicated electronic device can be used as the information processing device 20. The information processing device 20 processes the three-dimensional point cloud data of the fracture surface shape measured by the three-dimensional shape measuring device 10 and calculates the fracture surface ratio.

[0021] First, an overview of this embodiment will be described, and details will be discussed later. Figure 2 shows a conceptual diagram representing the fracture surface of the material. The direction perpendicular to the fracture surface of the material is the Z-axis, the crack propagation direction of the material is the Y-axis, and the direction perpendicular to the plane formed by the Y-axis and Z-axis is the X-axis. The fracture surface of the material shown in Figure 2 has a notch 31, a ductile region 32, and a brittle region 33. In general terms, the fracture surface ratio calculation method according to this embodiment involves extracting the boundary points between the ductile region 32 and the brittle region 33 in the fracture surface, calculating the area of ​​the region defined by the extracted boundary points, and then calculating the brittle fracture surface ratio. Specifically, the extracted boundary points are used to define, for example, boundary lines A1 and A2 in the Y-axis direction and boundary lines B1 and B2 in the X-axis direction in Figure 2. The fracture surface ratio is then calculated based on the area of ​​the region enclosed by these boundary lines A1, A2, B1, and B2. The fracture surface ratio calculated in this embodiment includes both the brittle fracture surface ratio and the ductile fracture surface ratio. The following description of this embodiment focuses on the calculation of the brittle fracture surface ratio, but is not limited to this case.

[0022] More specifically, in the fracture surface ratio calculation method according to this embodiment, the information processing device 20 acquires three-dimensional point cloud data of the fracture surface shape of a material having a fracture surface from the three-dimensional shape measuring device 10. In addition, in the fracture surface ratio calculation method according to this embodiment, the information processing device 20 creates two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the three-dimensional point cloud data. In addition, in the fracture surface ratio calculation method according to this embodiment, the information processing device 20 extracts the boundary points between the brittle region and the ductile region in each cross-section based on the height information of the two-dimensional (X,Z) cross-sectional shape data and the height information of the two-dimensional (Y,Z) cross-sectional shape data. Then, in the fracture surface ratio calculation method according to this embodiment, the information processing device 20 calculates the area of ​​the brittle region based on the extracted boundary points and calculates the brittle fracture surface ratio.

[0023] Thus, according to this embodiment, the information processing device 20 extracts boundary points between the brittle region and the ductile region in the two-dimensional (X,Z) cross-section and the two-dimensional (Y,Z) cross-section based on the shape data of the two-dimensional (X,Z) cross-section and the shape data of the two-dimensional (Y,Z) cross-section, calculates the area of ​​the brittle region based on the boundary points, and calculates the brittle fracture surface ratio. In other words, since the boundary points are determined based on the shape data of the two-dimensional (X,Z) cross-section and the shape data of the two-dimensional (Y,Z) cross-section, the technique for calculating the fracture surface ratio of the material can be improved.

[0024] Next, we will describe in detail the various components of the information processing device 20 in the fracture surface ratio calculation system 1.

[0025] (Configuration of the information processing device 20) As shown in Figure 1, the information processing device 20 comprises a control unit 21, a storage unit 22, a communication unit 23, an input unit 24, and an output unit 25.

[0026] The control unit 21 includes at least one processor, at least one dedicated circuit, or a combination thereof. The processor is a general-purpose processor such as a CPU (central processing unit) or GPU (graphics processing unit), or a dedicated processor specialized for a specific process. The dedicated circuit is, for example, an FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit). The control unit 21 controls each part of the information processing device 20 and executes processes related to the operation of the information processing device 20.

[0027] The storage unit 22 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or at least two combinations thereof. The semiconductor memory is, for example, RAM (random access memory) or ROM (read-only memory). The RAM is, for example, SRAM (static random access memory) or DRAM (dynamic random access memory). The ROM is, for example, EEPROM (electrically erasable programmable read-only memory). The storage unit 22 functions, for example, as a main memory, auxiliary memory, or cache memory. The storage unit 22 stores data used for the operation of the information processing device 20 and data obtained by the operation of the information processing device 20.

[0028] The communication unit 23 includes at least one external communication interface. The communication interface may be either a wired or wireless communication interface. In the case of wired communication, the communication interface may be, for example, a LAN (Local Area Network) interface or a USB (Universal Serial Bus) interface. In the case of wireless communication, the communication interface may be, for example, an interface compatible with mobile communication standards such as LTE (Long Term Evolution), 4G (4th generation), or 5G (5th generation), or an interface compatible with short-range wireless communication such as Bluetooth (registered trademark). The communication unit 23 receives data used for the operation of the information processing device 20 and transmits data obtained by the operation of the information processing device 20.

[0029] The input unit 24 includes at least one input interface. The input interface may be, for example, a physical key, a capacitive key, a pointing device, or a touchscreen integrated with a display. Alternatively, the input interface may be, for example, a microphone that accepts voice input or a camera that accepts gesture input. The input unit 24 accepts operations to input data used for the operation of the information processing device 20. Instead of being integrated into the information processing device 20, the input unit 24 may be connected to the information processing device 20 as an external input device. Any connection method can be used, for example, USB (Universal Serial Bus), HDMI (registered trademark) (High-Definition Multimedia Interface), or Bluetooth (registered trademark).

[0030] The output unit 25 includes at least one output interface. The output interface is, for example, a display that outputs information as video, or a speaker that outputs information as sound. The display is, for example, an LCD (liquid crystal display) or an organic EL (electroluminescence) display. The output unit 25 displays and outputs data obtained by the operation of the information processing device 20. Instead of being provided in the information processing device 20, the output unit 25 may be connected to the information processing device 20 as an external output device. Any connection method can be used, for example, USB, HDMI (registered trademark), or Bluetooth (registered trademark).

[0031] The functions of the information processing device 20 are realized by executing the program according to this embodiment on a processor corresponding to the information processing device 20. In other words, the functions of the information processing device 20 are realized by software. The program causes the computer to perform the operations of the information processing device 20, thereby causing the computer to function as the information processing device 20. That is, the computer functions as the information processing device 20 by performing the operations of the information processing device 20 according to the program.

[0032] In this embodiment, the program can be recorded on a computer-readable recording medium. The computer-readable recording medium includes non-temporary computer-readable media, such as magnetic recording devices, optical discs, magneto-optical recording media, or semiconductor memory. The program can be distributed, for example, by selling, transferring, or lending portable recording media such as DVDs (digital versatile discs) or CD-ROMs (compact disc read-only memory) on which the program is recorded. Alternatively, the program may be distributed by storing it on the storage of an external server and transmitting it from the external server to other computers. The program may also be provided as a program product.

[0033] (Operation of information processing device) The operation of the information processing device 20 according to this embodiment will be described with reference to Figure 3. Figure 3 is a flowchart showing an example of a method executed by the information processing device 20 according to this embodiment.

[0034] Step S100: The control unit 21 of the information processing device 20 acquires three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface from the three-dimensional shape measuring device 10. Hereinafter, this step will also be referred to as the acquisition step.

[0035] Step S110: The control unit 21 creates two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the three-dimensional point cloud data acquired in the acquisition step. Hereinafter, this step will also be referred to as the first creation step. In the first creation step, multiple cross-sectional shape data are generated at predetermined pitches in both the X-axis and Y-axis directions based on the three-dimensional point cloud data. The predetermined pitch is, for example, 1 mm.

[0036] Step S120: The control unit 21 extracts the boundary points between the brittle region and the ductile region in each cross-section based on the height information of the two-dimensional (X,Z) cross-sectional shape data and the height information of the two-dimensional (Y,Z) cross-sectional shape data created in the first creation step. Hereinafter, this step will also be referred to as the first extraction step. Details of the first extraction step will be described later.

[0037] Step S200: The control unit 21 calculates the area of ​​the brittle region and the brittle fracture surface ratio based on the boundary points extracted in the first extraction step. Hereinafter, this step will also be referred to as the first calculation step. Details of the calculation step will be described later.

[0038] The following describes in detail an example of the first extraction process mentioned above.

[0039] (First extraction step) In the first extraction step, the boundary points between the brittle region and the ductile region in each cross-section are extracted from the shape data of the two-dimensional (X,Z) cross-section and the shape data of the two-dimensional (Y,Z) cross-section. Figure 4 shows a conceptual diagram of the first extraction step. Figure 4 shows the shape data of the two-dimensional (X,Z) cross-section as an example. As shown in Figure 4, in the first extraction step, a part of the cross-sectional shape is approximated by a straight line based on the height information (Z value) of the shape data of the two-dimensional (X,Z) cross-section, and the endpoints of the line segments are extracted as boundary points. Here, an example of extracting boundary points based on the shape data of the two-dimensional (X,Z) cross-section is shown, but the same method can be used to extract boundary points based on the shape data of the two-dimensional (Y,Z) cross-section.

[0040] Figure 5 shows an example of each step in the first extraction process. From the shape data of the two-dimensional (X,Z) cross section, the difference in height (difference in Z) between adjacent plots in the X direction is calculated, starting with plot 401, which is the point with the smallest X value. If the difference in height is less than or equal to a predetermined threshold (hereinafter also called the height threshold), these plots are determined to be a group that forms an approximate straight line. This determination process is repeated until the difference exceeds the height threshold (in this case, up to plot 411). Based on the X and Z values ​​of the plots included in the group, an approximate straight line is created, for example, by the least squares method (step S121).

[0041] When an approximate line is created, a process is performed to determine whether or not to delete the approximate line (hereinafter also referred to as the deletion process). Specifically, the angle between the approximate line and the X-axis is determined, and if this angle exceeds a predetermined angle (hereinafter also referred to as the angle tolerance), the approximate line is deleted. In addition, the length of the approximate line in the X-axis direction is determined, and if this length is less than or equal to a predetermined threshold (hereinafter also referred to as the length threshold), the approximate line is deleted. The length of the approximate line in the X-axis direction may be determined by the number of plots in the group that forms the approximate line. If the angle between the approximate line and the X-axis is less than or equal to the angle tolerance, and the length of the approximate line in the X-axis direction exceeds the length threshold, the approximate line is not deleted. In this case, approximate line 501 in Figure 5 is not deleted because the angle between the approximate line and the X-axis is less than or equal to the angle tolerance, and the length of the approximate line in the X-axis direction exceeds the length threshold.

[0042] If the height difference exceeds the height threshold, the process proceeds to the determination of the next group of plots, and approximation lines are similarly created for these plots. For example, as shown in Figure 5, the height difference between adjacent plots in the X direction is calculated sequentially, starting with the plot whose height difference exceeds the height threshold (in this case, plot 412). If the height difference is less than or equal to the height threshold, these plots are determined to be a group that forms an approximation line. This determination process is repeated until the height difference exceeds the height threshold. In this case, since both plot 413 and plot 414 exceed the height threshold, no approximation line is drawn (step S123).

[0043] Following step S123, the process proceeds to the determination of the next group of plots, and approximation lines for these plots are similarly created (step S124). Specifically, as shown in Figure 5, the difference in height between adjacent plots in the X direction is calculated sequentially, starting with plots adjacent to plots that form an approximation line whose angle exceeds the angle tolerance (in this case, plot 415). If the height difference is less than or equal to the height threshold, these plots are determined to be a group that forms an approximation line. This determination process is repeated until the height threshold is exceeded. Based on the X and Z values ​​of the plots included in the group, an approximation line is created, for example, by the least squares method. Subsequently, a deletion process is performed. In Figure 5, approximation line 503 is not deleted because the angle between the approximation line and the X axis is less than or equal to the angle tolerance, and the length of the approximation line in the X direction exceeds the length threshold.

[0044] Following step S124, the process proceeds to the determination of the next group of plots, and similarly, approximation lines are created for these plots. For example, as shown in Figure 5, the height difference between adjacent plots in the X direction is calculated, starting with the plot whose height difference exceeds the height threshold (in this case, plot 426). In this case, since both plot 427 and plot 428 exceed the height threshold, no approximation lines are drawn (step S125).

[0045] Next, the plots that form the remaining approximation line (the approximation line that has not been deleted) are extracted, specifically those with the minimum and maximum X values. These are designated as the boundary points of the brittle region. In other words, the endpoints of the line segments of the approximation line are extracted as boundary points. In the example in Figure 5, plots 401 and 425 are extracted as boundary points.

[0046] The following provides a detailed explanation of an example of the calculation process described above.

[0047] (First calculation step) In the calculation process, the area of ​​the brittle region is calculated based on the boundary points extracted in the first extraction process, and the brittle fracture surface ratio is calculated based on this area.

[0048] Figure 6 is a conceptual diagram showing an overview of the calculation process. In the calculation process, the area enclosed by multiple boundary points extracted in the first extraction process is defined as the brittle region, and the area of ​​this region is calculated. Various methods can be used to calculate the area of ​​this region. For example, approximate straight lines for boundary lines A1 and A2, and boundary lines B1 and B2, may be defined using multiple boundary points, and the area enclosed by these boundary lines may be calculated. Alternatively, the brittle fracture ratio may be calculated by dividing this area by the total fracture surface area.

[0049] As described above, according to this embodiment, the information processing device 20 extracts boundary points between the brittle region and the ductile region in each cross-section based on the shape data of the two-dimensional (X,Z) cross-section and the shape data of the two-dimensional (Y,Z) cross-section, calculates the area of ​​the brittle region based on the boundary points, and calculates the brittle fracture surface ratio. In other words, since the boundary points are determined based on the shape data of the two-dimensional (X,Z) cross-section and the shape data of the two-dimensional (Y,Z) cross-section, the technique for calculating the fracture surface ratio of the material can be improved.

[0050] (First variation) Referring to Figures 7 and 8, a first modification of this embodiment will be described. In the first modification, as shown in Figure 7, inflection points BL1, BR1, BL2, and BR2 on the side surface of the fracture are used. Specifically, in the first modification, boundary line B1' connecting inflection points BL1 and BR1, and boundary line B2' connecting inflection points BL2 and BR2 are used instead of boundary lines B1 and B2. When inflection points (hereinafter also referred to as constrictions) of an angle less than a certain angle occur in the fracture surface shape, the calculation accuracy is improved by calculating the fracture surface ratio based on boundary lines connecting the constrictions rather than boundary points extracted based on the first extraction process.

[0051] Figure 8 is a flowchart showing an example of a modified method performed by the information processing device 20 according to this embodiment. Steps S100 to S120 are the same as in the flowchart of Figure 3, so the same reference numerals are used and their explanation is omitted.

[0052] Step S130: The control unit 21 of the information processing device 20 creates a group of endpoint data (X,Y) in the Y-axis direction for the endpoints of the fracture surface in the X-axis direction from the three-dimensional point cloud data. Hereinafter, this step will also be referred to as the second creation step.

[0053] Step S140: The control unit 21 creates approximate lines for each predetermined number of points using the endpoint data (X,Y) group created in the second creation step, and extracts the boundary line in the X direction between the brittle region and the ductile region based on the angle information formed by adjacent approximate lines. Hereinafter, this step will also be referred to as the second extraction step.

[0054] Figure 9 shows a conceptual diagram of the second extraction process. Here, an example of defining BL1 and BL2 is shown, but BR1 and BR2 can be defined using a similar method.

[0055] As shown in Figure 9, for example, a straight line is created for each set of adjacent plots (e.g., five plots) using endpoint data (X,Y). The straight line may be determined, for example, by the least squares method. Next, the angle information of adjacent straight lines is determined. If the angle is less than a predetermined angle (hereinafter also referred to as the first angle threshold), the intersection of these adjacent straight lines is determined to be a constriction (BL1 and BL2). In other words, if the angle information of adjacent straight lines is acuter than the first angle threshold, the intersection of these adjacent straight lines is determined to be a constriction (BL1 and BL2). If multiple intersections of straight lines satisfying the above conditions are detected, the outermost one (the intersection with the minimum and maximum Y values) is determined to be the constriction. The first angle threshold is set appropriately depending on the material (steel type).

[0056] As shown in Figure 9, detection of BL1 may be performed by detecting an intersection that satisfies the above conditions from the notch 31 side. Similarly, detection of BL2 may be performed by detecting an intersection that satisfies the above conditions from the opposite side of the notch 31.

[0057] After BL1, BR1, BL2, and BR2 are determined by the method described above, the straight line connecting BL1 and BR1 is extracted as the boundary line B1' in the X direction. Similarly, the straight line connecting BL2 and BR2 is extracted as the boundary line B2' in the X direction.

[0058] Step S150: The control unit 21 determines whether the angle between the X-boundary (boundary B1' and boundary B2') of the extracted brittle region and the X-axis is less than a predetermined angle (hereinafter also referred to as the second angle threshold). If the angle between the X-boundary of the brittle region and the X-axis is less than the second angle threshold, the process proceeds to step S210. On the other hand, if the angle between the X-boundary of the brittle region and the X-axis is greater than or equal to the second angle threshold, the process proceeds to step S220. The second angle threshold is set appropriately depending on the material (steel type).

[0059] Step S210: If the angle between the X-axis boundary lines (boundary lines B1' and B2') of the brittle region extracted in the second extraction step and the X-axis is less than the second angle threshold, the area of ​​the brittle region is calculated based on the X-axis boundary lines (boundary lines B1' and B2') extracted in the second extraction step and the boundary points extracted in the first extraction step. In other words, boundary lines A1 and A2 are determined by multiple boundary points. Boundary lines B1' and B2' are determined based on the X-axis boundary lines extracted in the second extraction step. The area enclosed by these boundary lines is calculated, and the brittle fracture ratio is calculated by dividing this area by the total fracture surface area.

[0060] Step S220: If the angle between the X-axis boundary line (at least one of boundary line B1' or boundary line B2') of the brittle region extracted in the second extraction step and the X-axis is greater than or equal to the second angle threshold, the area of ​​the brittle region is calculated based on the boundary points extracted in the first extraction step. That is, boundary lines A1 and A2, and boundary lines B1 and B2 are all defined by multiple boundary points. The area enclosed by these boundary lines is calculated, and the brittle fracture ratio is calculated by dividing this area by the total fracture area.

[0061] (Second variation) A second modification of this embodiment will be described below. In the second modification, the accuracy of the fracture surface ratio is improved by filtering the point cloud data corresponding to Sherlip from the three-dimensional point cloud data used in the above embodiment.

[0062] Figure 10 is a flowchart showing an example of a second modified method performed by the information processing device 20 according to this embodiment. Steps S100 and S120 are the same as in the flowchart of Figure 3, so they are denoted by the same reference numerals and their explanation is omitted.

[0063] Step S101: The control unit 21 of the information processing device 20 converts the 3D point cloud data into polygon mesh data and calculates the normal vector of each face. Figure 11 shows a conceptual diagram of the normal vector calculation process. As shown in Figure 11, in the conversion process to polygon mesh data, the control unit 21 extracts triangular faces from three adjacent plots of the 3D point cloud data. The normal vector of the triangle is calculated by the control unit 21.

[0064] Step S111: The control unit 21 creates two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data based on the three-dimensional point cloud data filtered by the normal vector of each face. Specifically, based on the angle between the normal vector and the Z axis, the three-dimensional point cloud data is filtered to include only a portion of the point cloud data based on whether this angle is less than a predetermined angle (hereinafter also referred to as the third angle threshold). Then, based on the filtered portion of three-dimensional point cloud data, two-dimensional (X,Z) cross-sectional shape data and two-dimensional (Y,Z) cross-sectional shape data are created. Specifically, in the above filtering process, if the angle between the normal vector of a certain face and the Z axis is less than the third angle threshold, the three plots forming that face are included in the portion of the point cloud data. This makes it possible to efficiently exclude point cloud data corresponding to Sherlip.

[0065] (Third variation) A third modification of this embodiment will be described below. In the third modification, the accuracy of the fracture surface ratio is improved by filtering the point cloud data corresponding to the shear rip from the three-dimensional point cloud data used in the first modification described above. Figure 12 is a flowchart showing an example of the method according to the third modification executed by the information processing device 20 according to this embodiment. Each step is the same as in the flowcharts of Figures 8 and 11, so the same reference numerals are used and their explanation is omitted. In this way, even when there is a certain degree of constriction in the fracture surface shape, the accuracy of calculating the fracture surface ratio can be improved by filtering the point cloud data corresponding to the shear rip.

[0066] While this disclosure has been described based on the drawings and embodiments, it should be noted that those skilled in the art will find it easy to make various modifications and alterations based on this disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of this disclosure. For example, the functions, etc., included in each means or each step, etc., can be rearranged in a logically consistent manner, and multiple means or steps, etc., can be combined into one or divided. [Explanation of Symbols]

[0067] 1. Fracture surface ratio calculation system 1 10 3D shape measuring device 20 Information Processing Devices 21 Control Unit 22 Memory section 23 Communications Department 24 Input section 25 Output section 31 Notches 32. Ductility region 33 Brittle region Plots 401, 411, 412, 413, 414, 415, 425, 426, 427, 428 501, 503 Approximate straight line A1, A2, B1, B2, B1', B2' border BL1, BL2, BR1, BR2 Inflection points (constrictions)

Claims

1. In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X, Z) cross-sectional shape data and two-dimensional (Y, Z) cross-sectional shape data based on the three-dimensional point cloud data, A first extraction step involves creating an approximate line for each point group where the difference in height between adjacent points is less than or equal to a predetermined height threshold, for each of the two-dimensional (X, Z) cross-sectional shape data and the two-dimensional (Y, Z) cross-sectional shape data, and extracting the endpoints of the approximate lines created where the angle with the X axis or the Y axis is less than or equal to a predetermined angle tolerance, as the boundary points between the brittle region and the ductile region in each cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, A method for calculating the fracture surface ratio of a material comprising the following features.

2. A second creation step involves creating a set of endpoint data (X, Y) in the Y-axis direction for endpoints that are points having the minimum and maximum values ​​in the X-axis direction for each Y-coordinate, from the aforementioned three-dimensional point cloud data. A second extraction step involves creating approximate lines for each predetermined number of points using the endpoint data (X, Y) group, and extracting the boundary line in the X-axis direction between the brittle region and the ductile region based on the angle formed by adjacent approximate lines. Furthermore, The method for calculating the fracture surface ratio of a material according to claim 1, wherein, in the calculation step, if the angle between the boundary line in the X-axis direction of the brittle region extracted in the second extraction step and the X-axis is less than a predetermined angle, the area of ​​the brittle region is calculated based on the boundary line in the X-axis direction extracted in the second extraction step and the boundary point.

3. This includes the step of converting the three-dimensional point cloud data into polygon mesh data and calculating the normal vector of each face, The fracture surface ratio calculation method according to claim 1 or claim 2, wherein in the first creation step, shape data of a two-dimensional (X, Z) cross-section and shape data of a two-dimensional (Y, Z) cross-section are created based on the three-dimensional point cloud data filtered by the normal vector of each surface.

4. An information processing device comprising a control unit for calculating fracture surface ratio, wherein the control unit is In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X, Z) cross-sectional shape data and two-dimensional (Y, Z) cross-sectional shape data based on the three-dimensional point cloud data, A first extraction step involves creating an approximate line for each point group where the difference in height between adjacent points is less than or equal to a predetermined height threshold, for each of the two-dimensional (X, Z) cross-sectional shape data and the two-dimensional (Y, Z) cross-sectional shape data, and extracting the endpoints of the approximate lines created where the angle with the X axis or the Y axis is less than or equal to a predetermined angle tolerance, as the boundary points between the brittle region and the ductile region in each cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, An information processing device that performs this task.

5. A program for calculating fracture surface ratio, which is used by a computer. In a material having a fracture surface, the Z-axis is defined as the direction perpendicular to the fracture surface of the material, the Y-axis as the crack propagation direction of the material, and the X-axis is defined as the direction perpendicular to the plane formed by the Y-axis and Z-axis. The process involves acquiring three-dimensional point cloud data of the fracture surface shape of the material having a fracture surface. A first creation step involves creating two-dimensional (X, Z) cross-sectional shape data and two-dimensional (Y, Z) cross-sectional shape data based on the three-dimensional point cloud data, A first extraction step involves creating an approximate line for each point group where the difference in height between adjacent points is less than or equal to a predetermined height threshold, for each of the two-dimensional (X, Z) cross-sectional shape data and the two-dimensional (Y, Z) cross-sectional shape data, and extracting the endpoints of the approximate lines created where the angle with the X axis or the Y axis is less than or equal to a predetermined angle tolerance, as the boundary points between the brittle region and the ductile region in each cross-section. A calculation step of calculating the area of ​​the brittle region based on the boundary point and calculating the fracture surface ratio, A program that executes the command.

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