Stress analysis device, stress analysis method, and program

Abstract

A stress analysis device and the like are provided that can prevent failure of a simulation analysis when analyzing, by simulation, stress when an object having an inclined portion is fitted with another object. [Solution] A stress analysis device 100 has a first object model showing the shape of a first object, which has a first parallel surface parallel to a predetermined direction, and a second object model showing the shape of a second object, which has a second parallel surface parallel to the predetermined direction and an inclined surface inclined relative to the predetermined direction. In stress analysis, the stress analysis device 100 performs an initial analysis of stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface (S31), and after completion of the initial analysis, re-analyzes stress using a second contact setting that enables contact between each of the second parallel surface and the inclined surface in the second object model and the first parallel surface (S32), thereby calculating the final stress.

Description

[Technical Field]

[0001] The present disclosure relates to a stress analysis device, a stress analysis method, and a program. [Background technology]

[0002] Patent Document 1 discloses a crack estimation device that estimates internal cracks based on stress distribution in an object that has a structure to which internal pressure is applied, such as a shrink-fitted part, and whose surface shape changes when a crack occurs inside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6789452 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, objects fitted together by shrink fitting or the like may include objects that have, at the contact portion, a portion that is parallel to the contact surface of the object being fitted and a portion that is inclined relative to the contact surface of the object being fitted. Because the direction of stress in such an inclined portion is complex, for example, when calculating stress during fitting by shrink fitting using the method of Patent Document 1, the stress may not be calculated. In other words, a simulation analysis of stress during fitting by shrink fitting may fail.

[0005] Therefore, the present disclosure provides a stress analysis device, a stress analysis method, and a program that can prevent failure of a simulation analysis when analyzing the stress that occurs when an object having an inclined portion is fitted with another object. [Means for solving the problem]

[0006] A stress analysis device according to one aspect of the present disclosure is a stress analysis device that analyzes, by simulation, stress occurring at a contact surface between a first object and a second object when the first object and the second object are fitted together, wherein a first object model representing the shape of the first object has a first parallel surface parallel to a predetermined direction, and a second object model representing the shape of the second object has a second parallel surface parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surface and is inclined with respect to the predetermined direction, and when the first object and the second object are fitted together, the first parallel surface comes into contact with at least the second parallel surface, and in the stress analysis, the stress analysis device performs an initial analysis of the stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface, and after completion of the initial analysis, re-analyzes the stress using a second contact setting that enables contact between each of the second parallel surface and the inclined surface in the second object model and the first parallel surface, thereby calculating a final stress.

[0007] A stress analysis method according to one aspect of the present disclosure is a stress analysis method executed by a stress analysis device that analyzes, by simulation, stress generated at a contact surface between a first object and a second object when the first object and the second object are fitted together, wherein a first object model representing the shape of the first object has a first parallel surface parallel to a predetermined direction, and a second object model representing the shape of the second object has a second parallel surface parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surface and is inclined with respect to the predetermined direction, and when the first object and the second object are fitted together, the first parallel surface comes into contact with at least the second parallel surface, and the stress analysis method performs an initial analysis of the stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface, and after completion of the initial analysis, re-analyzes the stress using a second contact setting that enables contact between each of the second parallel surface and the inclined surface in the second object model and the first parallel surface, thereby calculating a final stress.

[0008] A program according to one aspect of the present disclosure is a program for causing a computer to execute the above-described stress analysis method. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, it is possible to realize a stress analysis device or the like that can prevent failure of a simulation analysis when analyzing stresses that occur when an object having an inclined portion is mated with another object through simulation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of a stress analysis system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an object on which a shrink fitting analysis according to the embodiment is performed. [Figure 3] FIG. 3 is a flowchart showing the operation performed by the stress analysis device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing the initial state of a 3D model on analysis software before a shrink fitting analysis according to the embodiment is performed. [Figure 5] FIG. 5 is a diagram showing a screen for performing contact settings in the stress analysis device according to the embodiment. [Figure 6A] FIG. 6A is a diagram showing that the upper inclined surface is selected as the surface of the holder for contact setting. [Figure 6B] FIG. 6B is a diagram illustrating contact settings set on an inclined surface according to an embodiment. [Figure 6C] FIG. 6C is a diagram showing that the lower inclined surface is selected as the surface of the holder for contact setting. [Figure 7A] FIG. 7A is a diagram showing that a parallel surface is selected as the surface of the holder for contact setting. [Figure 7B] FIG. 7B is a diagram illustrating contact settings set for parallel surfaces according to an embodiment. [Figure 8] FIG. 8 is a diagram schematically illustrating the first contact setting according to the embodiment. [Figure 9] FIG. 9 is a diagram schematically showing the shape of the holder in the first contact setting according to the embodiment. [Figure 10] FIG. 10 is a diagram showing the analysis results for each mesh width when the method according to the embodiment is used. [Figure 11] FIG. 11 is a diagram showing a first example of a screen that is displayed when analysis fails when the conventional method is used. [Figure 12] FIG. 12 is a diagram showing a second example of a screen displayed when analysis fails when the conventional method is used. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Background to the invention) As described in the "Problem to be Solved by the Invention" section above, simulations have been conducted to analyze the stresses that occur at the contact surfaces of objects fitted together by shrink fitting (hereinafter referred to as shrink fitting analysis). Shrink fitting is a process of firmly joining two objects by utilizing the thermal expansion properties of metals and other materials. Specifically, shrink fitting analysis involves incorporating a 3D model into analysis software, initially providing a penetration (overlap) of the 3D model by an amount equal to the interference, and then calculating the stresses that act when the components are pushed back to release the penetration during the analysis, assuming that this is equivalent to the restraining force (internal force) that would occur when shrink fitting is performed in the real world. In shrink fitting analysis, contact definitions are typically applied to all contact surfaces in the model's penetration area (especially the C-face between the holder and seal ring).

[0012] Ansys Mechanical (manufactured by ANSYS, Inc.) is often used as analysis software, and the analysis results in this specification are also generated using this software. The analysis software is not limited to Ansys Mechanical, and any other software that performs stress analysis may be used.

[0013] However, when the contact surface of a shrink-fitted part includes a C-surface (chamfered slope), the residuals of the nonlinear equations based on the Newton-Raphson method become high, causing the calculation to diverge. For this reason, with conventional methods, the analysis cannot be completed, making it difficult to quantitatively evaluate the retention force (stress) generated in the shrink-fitted part. For example, simulation analysis may fail.

[0014] This failure of the analysis is thought to be due to the fact that the C-face is inclined compared to the other parallel contact faces, and therefore the direction of the stress is complex when the initial penetration on the C-face is pushed back during the analysis.

[0015] Therefore, the inventors of the present application have conducted extensive research into stress analysis devices and the like that can prevent simulation analysis failures when analyzing stresses that occur when an object having an inclined portion is fitted to another object by shrink fitting or the like, and have devised the stress analysis device and the like described below.

[0016] A stress analysis device according to a first aspect of the present disclosure is a stress analysis device that analyzes, by simulation, stress generated at a contact surface between a first object and a second object when the first object and the second object are fitted together, wherein a first object model representing the shape of the first object has first parallel surfaces parallel to a predetermined direction, and a second object model representing the shape of the second object has second parallel surfaces parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surfaces and is inclined with respect to the predetermined direction, and when the first object and the second object are fitted together, the first parallel surfaces come into contact with at least the second parallel surfaces, and in the stress analysis, the stress analysis device performs an initial analysis of the stress using a first contact setting that enables contact between the second parallel surfaces and the first parallel surfaces in the second object model and disables contact between the inclined surfaces and the first parallel surfaces, and after completion of the initial analysis, re-analyzes the stress using a second contact setting that enables contact between each of the second parallel surfaces and the inclined surfaces in the second object model and the first parallel surfaces, thereby calculating a final stress.

[0017] This allows the initial analysis to eliminate calculations for inclined surfaces, which have complex stress directions and require complex calculations, thereby reducing the residual error of the Newton-Raphson method and enabling the solution to converge. Therefore, the stress analysis device can prevent simulation analysis failures when analyzing stresses that occur when an object with an inclined portion is fitted to another object. Furthermore, since the inclined surface is taken into account in the reanalysis, it is possible to obtain stresses that more accurately reproduce reality.

[0018] Furthermore, for example, a stress analysis device according to a second aspect may be the stress analysis device according to the first aspect, wherein in an initial state of the simulation, a part of the second object model including the second parallel surface and the inclined surface has an overlap with the first object model according to a tightening margin, and the initial analysis may be completed at a point in time when, in the simulation, the second object model is pushed back so as to eliminate the overlap between the first object model and the second object model, and the overlap between the first object model and the second object model is eliminated.

[0019] This makes it possible to eliminate the need for calculation of inclined surfaces, which requires complex calculations, from the calculations from the initial state until the overlap between the first object model and the second object model is resolved.

[0020] Furthermore, for example, the stress analysis device according to the third aspect may be the stress analysis device according to the first or second aspect, and may separately acquire information indicating whether contact between the second parallel surface and the first parallel surface is valid or invalid and information indicating whether contact between the inclined surface and the first parallel surface is valid or invalid.

[0021] This allows for effective contact settings to be obtained between the second parallel surface and the inclined surface.

[0022] Furthermore, for example, a stress analysis device according to a fourth aspect may be a stress analysis device according to any one of the first to third aspects, wherein the inclined surfaces are provided at both ends of the second parallel surface, the first contact setting includes disabling contact between the first parallel surface and each of the inclined surfaces provided at both ends of the second parallel surface, and the second contact setting includes enabling contact between the second parallel surface and each of the inclined surfaces provided at both ends of the second parallel surface and the first parallel surface.

[0023] This makes it possible to prevent the simulation analysis from failing when the first object has a configuration in which both ends of the second parallel plane have inclined surfaces.

[0024] Furthermore, for example, a stress analysis device according to a fifth aspect may be a stress analysis device according to any one of the first to third aspects, wherein the inclined surface is provided only at one end of the second parallel surface, the first contact setting includes disabling contact between the inclined surface provided at one end of the second parallel surface and the first parallel surface, and the second contact setting includes enabling contact between the second parallel surface and the inclined surface provided at one end of the second parallel surface and the first parallel surface.

[0025] This makes it possible to prevent the simulation analysis from failing when the first object has a configuration in which one end of the second parallel surface has an inclined surface.

[0026] Furthermore, for example, a stress analysis device according to a sixth aspect may be the stress analysis device according to any one of the first to fifth aspects, in which the first object is a seal ring and the second object is a holder that holds the seal ring.

[0027] This makes it possible to prevent failure of the simulation analysis of the stress that occurs when the holder and the seal ring are fitted together.

[0028] Furthermore, for example, a stress analysis device according to a seventh aspect may be a stress analysis device according to any one of the first to sixth aspects, in which the first object is made of a non-metal and the second object is made of a metal.

[0029] This makes it possible to prevent failure of the simulation analysis of the stress that occurs when a metal and a non-metal are fitted together.

[0030] Furthermore, a stress analysis method according to an eighth aspect of the present disclosure is a stress analysis method executed by a stress analysis device that analyzes, by simulation, stress generated at a contact surface between a first object and a second object when the first object and the second object are fitted together, wherein a first object model representing the shape of the first object has a first parallel surface parallel to a predetermined direction, and a second object model representing the shape of the second object has a second parallel surface parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surface and is inclined with respect to the predetermined direction, and when the first object and the second object are fitted together, the first parallel surface comes into contact with at least the second parallel surface, and the stress analysis method performs an initial analysis of the stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface, and after completion of the initial analysis, re-analyzes the stress using a second contact setting that enables contact between each of the second parallel surface and the inclined surface in the second object model and the first parallel surface, thereby calculating a final stress.

[0031] This provides the same effects as the above-mentioned stress analysis device.

[0032] A program according to a ninth aspect of the present disclosure is a program for causing a computer to execute the stress analysis method according to the eighth aspect.

[0033] This provides the same effects as the above-mentioned stress analysis device.

[0034] These general or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or as any combination of the system, method, integrated circuit, computer program, or recording medium. The program may be pre-stored in the recording medium, or may be supplied to the recording medium via a wide area communication network including the Internet.

[0035] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0036] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in independent claims are described as optional components.

[0037] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and duplicate explanations may be omitted or simplified.

[0038] In this specification and the drawings, the X-axis and Y-axis represent two of the three axes of a right-handed three-dimensional Cartesian coordinate system.

[0039] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel and equal, terms indicating the shape of elements, such as quadrangle, numerical values, and numerical ranges are not expressions that only express the strict meaning, but are expressions that also mean a substantially equivalent range, for example, including a difference of about several percent (or about 10%).

[0040] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., do not refer to the number or order of elements unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing elements of the same type. Note that ordinal numbers ("first," "second," etc.) may be interchanged as appropriate.

[0041] (Embodiment) The stress analysis device according to this embodiment will be described below with reference to FIGS.

[0042] [1. Configuration of stress analysis equipment] First, the configuration of a stress analysis system including a stress analysis device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of a stress analysis system 10 according to this embodiment. Note that Fig. 1 shows an exemplary functional configuration of the stress analysis system 10, and the functional configuration of the stress analysis system 10 is not limited to that shown in Fig. 1.

[0043] As shown in FIG. 1, the stress analysis system 10 includes a stress analysis device 100 and a display device 200.

[0044] The stress analysis device 100 is an information processing device that uses the finite element method to evaluate the shrink-fitting force (retention force) at the fitting portion (contact portion) of two objects (in this embodiment, a holder 310 and a seal ring 320 shown in FIG. 2, which will be described later), and analyzes by simulation the stress that occurs at the contact surface of the objects that are fitted by shrink fitting. It can also be said that the stress analysis device 100 uses shrink fitting, which fits two objects together using a temperature difference, to analyze by simulation the stress that occurs when surfaces that cannot contact each other before shrink fitting come into contact due to shrink fitting (stress that occurs at the contact surface after shrink fitting).

[0045] The stress analysis apparatus 100 includes a setting acquisition unit 110, an analysis execution unit 120, an output unit 130, and a storage unit 140. The stress analysis apparatus 100 also includes a processor and a memory as hardware components. The memory may be a read-only memory (ROM) or a random access memory (RAM), and can store programs executed by the processor. Each function of the stress analysis apparatus 100 is implemented by a processor that executes programs stored in the memory. The stress analysis apparatus 100 may be implemented by a desktop personal computer (PC), a mobile terminal such as a smartphone or tablet, a server device, or a combination of two or more of these.

[0046] The setting acquisition unit 110 is a processing unit that is communicatively connected to an input acceptance unit such as a mouse, keyboard, or touch panel, and acquires user input via the input acceptance unit. The input acceptance unit may have a microphone, and the setting acquisition unit 110 may acquire voice information as user input. The setting acquisition unit 110 may be configured to include, for example, a communication circuit.

[0047] In this embodiment, the setting acquisition unit 110 acquires settings used in the shrink fitting analysis. The settings include a setting for enabling or disabling contact between contact surfaces of two objects in the shrink fitting analysis. More specifically, the settings include a setting for enabling or disabling contact between an inclined surface of one object and a surface of the other object.

[0048] When enabled, stress calculations are performed assuming that the specified surface exists. When disabled, stress calculations are performed assuming that the disabled surface does not exist.

[0049] The setting acquisition unit 110 may acquire the contact setting by automatically determining whether to enable or disable the contact setting based on the shape of the 3D model (for example, whether the 3D model has an inclined surface). For example, the setting acquisition unit 110 may determine whether or not a target range of the shrink fit analysis (a range including a contact portion, which is a shrink fit analysis range shown in FIG. 2 to be described later) has an inclined surface based on the shape of the 3D model, and if one object has an inclined surface in the target range, it may determine to disable the contact setting of the inclined surface until a parallel surface of one object is pushed back to the outside of the other object in the shrink fit analysis, and to change the contact setting of the inclined surface to valid after the parallel surface of one object is pushed back to the outside of the other object.

[0050] The analysis execution unit 120 is a processing unit that calculates the stress distribution at the contact point formed when two objects are shrink-fitted, based on the shapes of 3D models of the two objects to be fitted together by shrink fitting. In this embodiment, the analysis execution unit 120 calculates the stress distribution using the finite element method. In this embodiment, the analysis execution unit 120 also performs the shrink-fit analysis using Ansys Mechanical as analysis software. The finite element method calculates a solution by iterative calculation.

[0051] The output unit 130 is a processing unit that outputs the analysis results of the analysis execution unit 120 to an external device (in this embodiment, the display device 200). The output unit 130 may be configured to include, for example, a communication circuit.

[0052] The storage unit 140 is a storage device that stores various types of information. The storage unit 140 stores a 3D model of an object to be subjected to shrink fitting analysis, analysis software, etc. The storage unit 140 is realized by a non-volatile storage device (SSD (Solid State Drive) or HDD (Hard Disk Drive)), etc.

[0053] The display device 200 is connected to the stress analysis device 100 and displays information generated by the stress analysis device 100. For example, the display device 200 displays a setting screen for performing a shrink fitting analysis before the shrink fitting analysis is started, and displays the analysis results after the shrink fitting analysis is completed.

[0054] The display device 200 may be, but is not limited to, a liquid crystal display device, an organic EL (Electro-Luminescence) display device, etc. The display device 200 may also be a stationary monitor, or a display unit provided in a mobile terminal such as a tablet or a smartphone.

[0055] Here, the configuration of an object for which shrink fitting analysis is performed will be described with reference to Fig. 2. Fig. 2 is a diagram showing an object for which shrink fitting analysis according to this embodiment is performed. In Fig. 2, cross sections are hatched. Note that the object shown in Fig. 2 is an example, and is not limited to this.

[0056] 2, the object on which the shrink fitting analysis is performed includes a holder 310 and a seal ring 320. The holder 310 and the seal ring 320 are also referred to as sliding members.

[0057] Holder 310 is an example of the second object, and holds seal ring 320. Holder 310 is made of a metal such as titanium. However, holder 310 is not limited to being made of a metal, and may be made of other materials that have thermal expansion properties.

[0058] Seal ring 320 is an example of a first object, and is made of a non-metal such as SiC (silicon carbide). Seal ring 320 is an annular object, and is fitted by shrink fitting into an annular recess provided in holder 310. The width of holder 310 is larger than the width of the annular region provided in holder 310, and is fitted by shrink fitting. Note that seal ring 320 may be made of a non-metal other than SiC, or may be made of a metal.

[0059] 2 is a target range for performing shrink fitting analysis. In this range, the holder 310 and the side surfaces of the seal ring 320 come into contact (e.g., surface contact) due to shrink fitting. The shrink fitting analysis range is a range that includes the overlapping portion of the 3D model (second object model) of the holder 310 and the 3D model (first object model) of the seal ring 320. The shrink fitting analysis range may be set by the user or may be set by the analysis execution unit 120 based on the shape of the 3D model.

[0060] [2. Operation of the stress analysis device] Next, the operation of the stress analysis system 10 configured as above will be described with reference to Figures 3 to 12. Figure 3 is a flowchart showing the operation (stress analysis method) executed by the stress analysis device 100 according to this embodiment.

[0061] 3, the analysis execution unit 120 of the stress analysis device 100 acquires a target model, which is a 3D model of an object for which a shrink fitting analysis is to be performed (S10). The analysis execution unit 120 may acquire the target 3D model by reading it from the storage unit 140, for example, or may acquire the target 3D model from an external device via communication or the like. In this embodiment, the analysis execution unit 120 acquires 3D models of a holder 310 and a seal ring 320 shown in FIG. 2.

[0062] Next, the setting acquisition unit 110 acquires contact settings for performing shrink fit analysis (S20). In this embodiment, the setting acquisition unit 110 receives a setting from the user as to whether contact between the contact surfaces of the holder 310 and the seal ring 320 within the shrink fit analysis range is to be enabled or disabled.

[0063] Fig. 4 is a diagram showing the initial state of a 3D model on analysis software before performing a shrink fitting analysis according to this embodiment. Fig. 4 shows an enlarged cross-sectional view of an area including parallel surface 311 and inclined surfaces 312a and 312b. For convenience, hatching indicating the cross-section is omitted.

[0064] 4 shows a state in which an area R of the holder 310 indicated by a broken line is biting into the seal ring 320. The biting area R corresponds to the interference portion.

[0065] Holder 310 has parallel surface 311, which is a parallel contact surface that is in parallel contact with side surface 321, and inclined surfaces 312a and 312b formed on both ends of parallel surface 311 in the Y-axis direction. Side surface 321 and parallel surface 311 are surfaces parallel to the Y-axis, and inclined surfaces 312a and 312b are surfaces that intersect with the Y-axis. Note that intersecting here does not include being perpendicular.

[0066] In addition, inclined surfaces 312a and 312b and parallel surface 311 are formed continuously in the Y-axis direction. Side surface 321 is an example of a first parallel surface, and parallel surface 311 is an example of a second parallel surface. In addition, the Y-axis direction is an example of a predetermined direction.

[0067] Although the inclined surfaces 312a and 312b are C-surfaces, they may be R-surfaces (i.e., curved surfaces). The shapes of the inclined surfaces 312a and 312b are not particularly limited as long as they are, for example, chamfered surfaces. Furthermore, the inclined surfaces 312a and 312b may be disposed at only one end of the parallel surface 311, rather than at both ends.

[0068] The setting of whether the contact between the side surface 321 and each of the parallel surface 311 and the inclined surfaces 312a and 312b is valid or invalid in the simulation will be described with reference to FIGS.

[0069] Fig. 5 is a diagram showing a screen for making contact settings in the stress analysis system 100 according to this embodiment. The screen shown in Fig. 5 is a screen for setting whether contact between the holder 310 and the seal ring 320 in a shrink fit analysis is enabled or disabled. The stress analysis system 100 displays the screen shown in Fig. 5 on the display device 200, thereby allowing the user to input settings.

[0070] As shown in FIG. 5, the stress analysis device 100 displays an item column and the appearance of the holder 310 and the seal ring 320 on the display device 200 as a screen for performing contact settings.

[0071] In step S20, the setting acquisition unit 110 acquires the settings of the items shown in the dashed boxes Fa and Fb in the item column.

[0072] The dashed frame Fa indicates the surface for which contact setting is performed. "Side_upper C" indicates the inclined surface 312a, which is the C surface located on the positive side of the Y axis, "side_middle" indicates the parallel surface 311, and "side_lower C" indicates the inclined surface 312b, which is the C surface located on the negative side of the Y axis.

[0073] The dashed frame Fb shows the contact settings (contact step control and contact step control 2) for each of the two steps for stress analysis. Contact step control shows the contact settings (first contact settings) when performing an initial analysis as a shrink fit analysis, and contact step control 2 shows the contact settings (second contact settings) when performing a re-analysis after the initial analysis.

[0074] Here, an example of a method for setting whether contact on each surface is valid or invalid will be described with reference to Figures 6A to 7B. Selection of a surface for which contact setting is to be performed will be described using Figures 6A, 6C, and 7A, and the details of the contact setting set on the selected surface will be described using Figures 6B and 7B.

[0075] Conventionally, the three surfaces of holder 310 are set together as a contact setting with the surface of seal ring 320, and a common contact setting is applied to each surface. As explained above, the stress direction on surface C is complicated, which may cause the analysis to fail, so in this embodiment, the contact setting is set individually for the three surfaces of holder 310.

[0076] Fig. 6A is a diagram showing that upper inclined surface 312a has been selected as the surface of holder 310 for which contact setting will be performed. A solid arrow A1 and a dashed frame F1 in Fig. 6A indicate the currently selected surface (here, inclined surface 312a) among the surfaces of holder 310 for which contact setting will be performed, and this is also true in Figs. 6C and 7A, which will be described later. Also, a dashed arrow B in Fig. 6A indicates the surface of seal ring 320 that comes into contact with the surface of holder 310 for which contact setting will be performed.

[0077] Fig. 6A shows that "side surface_upper C" within the dashed-line frame Fa in Fig. 5 has been selected. In this case, the setting acquisition unit 110 acquires information indicating that the inclined surface 312a corresponding to "side surface_upper C" has been selected, and causes the display device 200 to display a screen for selecting whether to enable or disable contact between the inclined surface 312a and the side surface 321. Then, the setting acquisition unit 110 acquires a contact setting for the inclined surface 312a from the user.

[0078] FIG. 6B is a diagram showing contact settings made for the inclined surface 312a according to this embodiment. The screen shown in FIG. 6B is a screen for setting (e.g., switching) whether contact is enabled or disabled. Step 1 indicates a step calculated using the contact step control shown in FIG. 5, and is a step for performing an analysis (initial analysis) until the holder 310 completely comes out of the seal ring 320 in the shrink fitting analysis. Here, "comes out" means a state in which the holder 310 no longer bites into the seal ring 320 (e.g., a state in which the side surface 321 and the parallel surface 311 face each other and are in contact). Furthermore, the holder 310 completely coming out of the seal ring 320 means that the shrink fitting stage is complete.

[0079] 5, and is a step for performing analysis after the holder 310 has completely come out of the seal ring 320 in the shrink fitting analysis. Step 1 corresponds to step S31 shown in FIG. 3, which will be described later, and step 2 corresponds to step S32 shown in FIG. 3, which will be described later.

[0080] 6B, in step 1, contact between inclined surface 312a and side surface 321 is set to "invalid," and in step 2, contact between inclined surface 312a and side surface 321 is set to "valid." That is, in the initial analysis, the analysis is performed assuming that inclined surface 312a and side surface 321 do not come into contact with each other (i.e., no force exchange occurs between inclined surface 312a and side surface 321), and in the reanalysis, the analysis is performed assuming that inclined surface 312a and side surface 321 do come into contact with each other (i.e., force exchange occurs between inclined surface 312a and side surface 321).

[0081] Fig. 6C is a diagram showing that lower inclined surface 312b has been selected as the surface of holder 310 for which contact setting is to be performed. A solid arrow A2 and a dashed frame F2 in Fig. 6C indicate the currently selected surface (here, inclined surface 312b) among the surfaces of holder 310 for which contact setting is to be performed.

[0082] Fig. 6C shows that "side surface_bottom C" has been selected within the dashed-line frame Fa in Fig. 5. In this case, the setting acquisition unit 110 acquires information indicating that the inclined surface 312b corresponding to "side surface_bottom C" has been selected, and causes the display device 200 to display a screen for selecting whether to enable or disable contact between the inclined surface 312b and the side surface 321. Then, the setting acquisition unit 110 acquires a contact setting for the inclined surface 312b from the user.

[0083] In this embodiment, the contact settings for the inclined surfaces 312a and 312b are the same, so the same contact settings as in FIG. 6B are obtained for the inclined surface 312b.

[0084] 7A is a diagram showing that parallel surface 311 has been selected as the surface of holder 310 for which contact setting is to be performed. A solid arrow A3 and a dashed frame F3 in Fig. 7A indicate the surface (here, parallel surface 311) currently selected among the surfaces of holder 310 for which contact setting is to be performed.

[0085] 7A shows that "Side_Middle" has been selected within the dashed-line frame Fa in Fig. 5. In this case, the setting acquisition unit 110 acquires information indicating that the parallel surface 311 corresponding to "Side_Middle" has been selected, and causes the display device 200 to display a screen for selecting whether to enable or disable contact between the parallel surface 311 and the side surface 321. Then, the setting acquisition unit 110 acquires a contact setting for the parallel surface 311 from the user.

[0086] FIG. 7B is a diagram showing contact settings made on parallel surface 311 according to this embodiment.

[0087] 7B, in both steps 1 and 2, contact between parallel surface 311 and side surface 321 is "enabled." In other words, both the initial analysis and the reanalysis are set to perform the analysis assuming that parallel surface 311 and side surface 321 are in contact (i.e., force is exchanged between parallel surface 311 and side surface 321).

[0088] In this way, contact settings are acquired for each of parallel surface 311 and inclined surfaces 312a and 312b. The order in which the contact settings for each surface are acquired is not particularly limited.

[0089] Although the above describes an example in which the setting acquisition unit 110 acquires contact settings input by a user, the present invention is not limited to this, and the setting acquisition unit 110 may automatically set the contact settings based on the shape of the 3D model. For example, when an inclined surface exists within the shrink-fit analysis range on at least one of the holder 310 and the seal ring 320, the setting acquisition unit 110 may set the contact settings for the inclined surfaces to the conditions shown in Fig. 6B and the contact settings for the parallel surfaces to the conditions shown in Fig. 7B.

[0090] 3 again, next, the analysis executing unit 120 executes a shrink-fitting analysis (S30). Specifically, the analysis executing unit 120 executes an initial analysis from an initial state in which the holder 310 is biting into the seal ring 320 until the holder 310 completely moves out of the seal ring 320, with the C-face (here, the inclined faces 312a and 312b) disabled (S31), and after executing step S31, executes a re-analysis after the holder 310 completely moves out of the seal ring 320, with the C-face (here, the inclined faces 312a and 312b) enabled (S32).

[0091] In this way, the analysis executing unit 120 performs the shrink fitting analysis in two steps (S31 and S32) with different contact settings. The analysis executing unit 120 first performs the analysis (for example, solves equations) assuming that the holder 310 has the parallel surface 311 and only the parallel surface 311 of the inclined surfaces 312a and 312b, and then continues the analysis (for example, solves equations) assuming that the inclined surfaces 312a and 312b are restored and the holder 310 has the inclined surfaces 312a and 312b.

[0092] This makes it possible to eliminate calculations for the inclined surfaces 312a and 312b, which have complex stress directions and require complex calculations, in step S31 (for example, the residual error of the Newton-Raphson method becomes smaller), allowing the solution to converge and be solved. Also, since the stresses on the inclined surfaces 312a and 312b can be included in the calculations in step S32, it becomes possible to obtain stresses that more accurately reproduce reality.

[0093] In step S31, an example will be described in which the side surface 321 of the seal ring 320 is not deformed when the holder 310 is completely outside the seal ring 320, but the side surface 321 of the seal ring 320 may be deformed.

[0094] 8 is a diagram schematically illustrating a first contact setting according to the present embodiment. In FIG. 8, the portion where the contact setting is valid (parallel surface 311) is indicated by a thick line, and the portion where the contact setting is invalid (inclined surfaces 312a and 312b) is indicated by a dashed line. The schematic diagram of FIG. 8 is created based on the contact setting of step 1 shown in FIGS. 6B and 7B. The schematic diagram shown in FIG. 8 may be displayed to the user via display device 200.

[0095] As shown in FIG. 8, in step S31, the shrink-fit analysis is performed with the contact setting of the parallel surface 311 enabled and the contact setting of the inclined surfaces 312a and 312b disabled.

[0096] FIG. 9 is a diagram schematically showing the shape of holder 310 in the first contact setting according to this embodiment.

[0097] 9, in step S31, a shrink-fit analysis is performed using holder 310 that does not have inclined surfaces 312a and 312b that are disabled in the first contact setting. That is, in step S31, both ends of parallel surface 311 have a shape that is bent at 90 degrees relative to parallel surface 311. In this case, holder 310, which is initially wedged into seal ring 320, is pushed back to release the wedged state, and stress acting during the push-back occurs only in parallel surface 311. Note that the length of parallel surface 311 in the Y-axis direction shown in FIG. 9 is equal to the length of parallel surface 311 in the Y-axis direction shown in FIG. 8, but this is not limited to this.

[0098] In step S31, the holder 310, which has the shape shown in Fig. 9 in the initial state, bites into the seal ring 320 by the amount of interference, and the stress acting when the holder 310 is pushed back to release the bite is analyzed. The stress analysis can be performed using a parallel plane (simple plane) between the holder 310 and the seal ring 320, making the calculation simple.

[0099] In step S32, a shrink-fit analysis is performed using a holder 310 having inclined surfaces 312a and 312b, as shown in FIG. 4 and other figures.

[0100] 3 again, the output unit 130 outputs the analysis result obtained by the analysis execution unit 120 performing the shrink fitting analysis in step S30 (S40). In the present embodiment, the output unit 130 outputs the analysis result to the display device 200.

[0101] Fig. 10 shows the analysis results calculated using the method according to the present embodiment, and Fig. 11 and Fig. 12 show the analysis results of a conventional method in which parallel surface 311 and inclined surfaces 312a and 312b are effective. In both cases, Ansys Mechanical was used as the analysis software, and holder 310 and seal ring 320 were used as the objects to be shrink fitted.

[0102] FIG. 10 shows analysis results for each mesh width when using the method according to this embodiment. FIG. 10 shows analysis results for four mesh widths: 0.02 mm, 0.0125 mm, 0.01 mm, 0.01 mm, and 0.0075 mm. The normal stress in FIG. 10 represents the force with which the holder 310 holds the seal ring 320, i.e., the force with which the holder 310 presses the seal ring 320 toward the negative side of the X-axis. The shape of the mesh is not limited to a square. The range bar shown in FIG. 10 represents the normal stress inside the holder 310. The shading outside the holder 310 is meaningless due to image processing for grayscale display and is unrelated to the shading of the range bar.

[0103] As shown in Figure 10, the magnitude of normal stress is almost constant when the mesh width is changed. Specifically, the differences between the mesh widths are 0.2%, 2.3%, and 4.8%, which are less than 5%. This means that the equation for calculating normal stress has been solved. Note that there are no particular limitations on the equation used, and any known equation may be used.

[0104] Generally, when the change in normal stress relative to the change in mesh width when the mesh width is reduced is sufficiently small, it can be determined that the analysis will reach a constant value (converge). For example, when the mesh width is reduced from 0.02 mm to 0.01 mm, the change in normal stress (here, about 2.5%) is sufficiently small compared to the change in mesh width (here, 50%). Therefore, from the analysis results shown in FIG. 10, it can be determined that the analysis results will reach a constant value (converge) according to the method of this embodiment. In other words, the stress analysis device 100 can prevent failure of the simulation analysis when a stress occurring when an object having an inclined portion is fitted to another object by shrink fitting.

[0105] 11 and 12 are diagrams showing examples of screens displayed when an analysis fails using a conventional method. FIG. 11 shows an example where a solution is obtained but does not converge (for example, the solution does not converge when the mesh width is reduced), and FIG. 12 shows an example where a solution is not obtained. The force convergence judgment value shown in FIG. 11 indicates a threshold (upper limit) for judging whether the solution has converged. If the force convergence is smaller than the convergence judgment value, the analysis execution unit 120 judges that the solution has converged (i.e., the analysis is successful). Note that FIG. 12 omits the illustration of stress distribution and shows only the object shape.

[0106] The horizontal axis in Figure 11 indicates cumulative iterations (number of iterations), the vertical axis of the upper graph indicates force (normal stress), and the vertical axis of the lower graph indicates time. Time here refers to time increments. In static structural analysis, an analysis is divided into multiple steps, and different load conditions or boundary conditions are applied in stages. Within each step, calculations are not performed all at once, but rather in small increments, with the calculation being repeated to check whether convergence occurs, and the time increment indicates the size of these increments. Time increments are set large if convergence is good, and small if convergence is poor. For example, in the lower graph, the time increment is large initially (1st to 2nd iterations), but then becomes smaller. This means that convergence of the analysis is becoming difficult.

[0107] As shown in FIG. 11, in the conventional setting, the calculation result "force convergence" line (solid line) becomes larger than the "convergence judgment value" line (dashed line), and the analysis fails.

[0108] 12 shows an example in which the holder 310 does not come out of the seal ring 320 and remains embedded (overlapped), i.e., the analysis has failed. An error message indicating that the analysis has failed is displayed in text on the display device 200. In FIG. 12, the error message displayed is an error and a warning.

[0109] Errors include, for example, that the nonlinear analysis calculations did not converge due to constraint conditions, that elements within the body are significantly distorted (for example, above a threshold), or that the current contact settings cannot be used with the current license.

[0110] The warning may, for example, indicate that the analysis failed at all time points and how to deal with this (in the example of Figure 12, restart points can be used), or that some results were not obtained at some time points.

[0111] The analysis executing unit 120 generates an error or warning message depending on the stress distribution result, such as whether the holder 310 is biting into the seal ring 320, and displays the generated error or warning message on the display device 200 as the analysis result. For example, a table in which the stress distribution result and the error or warning message to be displayed are associated with each other may be stored in the storage unit 140, and the analysis executing unit 120 may use the table to determine the content of the error or warning message. Furthermore, if the analysis fails, the analysis executing unit 120 may check the contact settings used in the analysis, determine whether the inclined surface is set to invalid in the contact settings used in the initial analysis, and, if not, suggest to the user that the contact settings be revised.

[0112] (Other embodiments) The stress analysis device 100 according to one or more aspects has been described above based on the embodiments, but the present disclosure is not limited to these embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by those skilled in the art to the present embodiments and embodiments constructed by combining components of different embodiments may also be included in the present disclosure.

[0113] For example, in the above embodiment, an example has been described in which the stress analysis device 100 and the display device 200 are separate devices, but the present invention is not limited to this, and the stress analysis device 100 and the display device 200 may be an integrated device.

[0114] In the above embodiment, an example in which the holder 310 is deformed has been described, but the present invention is not limited to this, and the seal ring 320 may also be changed in addition to the holder 310. In this case, at least a portion of the inclined surfaces 312a and 312b of the holder 310 may be in contact with the seal ring 320 after the shrink fitting analysis is completed.

[0115] Furthermore, in the above embodiment, an example has been described in which this method is used for shrink fitting analysis of shrink fitting, but this method may also be used for shrink fitting analysis of chill fitting (also called cold fitting). This method may also be used when two objects are fitted together by utilizing a volume change (e.g., expansion or contraction) of at least one object due to the application of temperature. Furthermore, this method may also be used when two objects are fitted together by a method other than shrink fitting or chill fitting.

[0116] In the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0117] The order in which the steps in the flowchart are executed is merely an example for specifically explaining the present disclosure, and an order other than the above may be used. Also, some of the steps may be executed simultaneously (in parallel) with other steps, or some of the steps may not be executed.

[0118] The division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as a single functional block, one functional block may be divided into multiple blocks, or some functions may be moved to another functional block.Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0119] Furthermore, the stress analysis apparatus 100 according to the above embodiment may be realized as a single apparatus or may be realized by multiple apparatuses. When the stress analysis apparatus 100 is realized by multiple apparatuses, the components of the stress analysis apparatus 100 may be distributed among the multiple apparatuses in any manner. For example, the stress analysis apparatus 100 may be realized by cloud computing or edge computing. When the stress analysis apparatus 100 is realized by multiple apparatuses, the communication method between the multiple apparatuses is not particularly limited, and may be wireless communication or wired communication. Furthermore, wireless communication and wired communication may be combined between the apparatuses.

[0120] Furthermore, each component described in the above embodiments may be implemented as software or, typically, as an LSI, an integrated circuit. These components may be integrated individually on a single chip, or some or all of them may be integrated on a single chip. While LSI is used here, it may also be referred to as an IC, system LSI, super LSI, or ultra LSI depending on the level of integration. Furthermore, the integration method is not limited to LSI; it may be implemented using a dedicated circuit (a general-purpose circuit that executes a dedicated program) or a general-purpose processor. It is also possible to use a field programmable gate array (FPGA), which can be programmed after LSI fabrication, or a reconfigurable processor, which allows the connection or settings of circuit cells within an LSI to be reconfigured. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or a derivative technology, that technology may naturally be used to integrate the components.

[0121] A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple processing units on a single chip, and is specifically a computer system consisting of a microprocessor, ROM, RAM, etc. The ROM stores computer programs. The system LSI achieves its functions when the microprocessor operates in accordance with the computer programs.

[0122] Another aspect of the present disclosure may be a computer program that causes a computer to execute each of the characteristic steps included in the stress analysis method shown in FIG.

[0123] Furthermore, for example, the program may be a program to be executed by a computer. Another aspect of the present disclosure may be a computer-readable non-transitory recording medium on which such a program is recorded. For example, such a program may be recorded on a recording medium and distributed or circulated. For example, the distributed program may be installed in a device having another processor, and the program may be executed by the processor, thereby causing the device to perform each of the above processes. [Industrial Applicability]

[0124] The present disclosure is useful for an information processing device or the like that performs shrink fitting analysis. [Explanation of symbols]

[0125] 10 Stress analysis system 100 Stress analysis device 110 Setting acquisition unit 120 Analysis Execution Department 130 Output section 140 Storage section 200 Display device 310 Holder (second object) 311 Parallel plane (second parallel plane) 312a, 312b sloped surface 320 Seal Ring (First Object) 321 Side (first parallel surface) A1, A2, A3, B arrows F1, F2, F3, Fa, Fb dashed frame R area

Claims

1. 1. A stress analysis device that analyzes, by simulation, stress generated at a contact surface between a first object and a second object when the first object and the second object are fitted together, the device comprising: a first object model representing a shape of the first object has a first parallel surface parallel to a predetermined direction; a second object model representing a shape of the second object has a second parallel surface parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surface and is inclined with respect to the predetermined direction; When the first object and the second object are fitted together, the first parallel surface is in contact with at least the second parallel surface; In the stress analysis, the stress analysis device performing an initial analysis of the stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface; After the initial analysis is completed, a final stress is calculated by re-analyzing the stress using a second contact setting that enables contact between the second parallel surface and the inclined surface of the second object model and the first parallel surface. Stress analysis equipment.

2. in an initial state of the simulation, a portion of the second object model including the second parallel surface and the inclined surface overlaps with the first object model by an amount corresponding to an interference; The initial analysis is completed when the second object model is pushed back in the simulation so as to eliminate the overlap between the first object model and the second object model, and the overlap between the first object model and the second object model is eliminated. The stress analysis device according to claim 1 .

3. Information indicating whether contact between the second parallel surface and the first parallel surface is valid or invalid and information indicating whether contact between the inclined surface and the first parallel surface is valid or invalid are separately obtained.

3. The stress analysis device according to claim 1 or 2.

4. the inclined surfaces are provided on both ends of the second parallel surface, the first contact setting includes disabling contact between the first parallel surface and each of the inclined surfaces provided at both ends of the second parallel surface; The second contact setting includes validating contact between the first parallel surface and each of the second parallel surface and the inclined surfaces provided at both ends of the second parallel surface.

3. The stress analysis device according to claim 1 or 2.

5. the inclined surface is provided only on one end of the second parallel surface, the first contact setting includes disabling contact between the inclined surface provided at one end of the second parallel surface and the first parallel surface, The second contact setting includes validating contact between the second parallel surface and the inclined surface provided at one end of the second parallel surface and the first parallel surface.

3. The stress analysis device according to claim 1 or 2.

6. 1. A stress analysis method executed by a stress analysis device that analyzes, by simulation, stress occurring at a contact surface between a first object and a second object when the first object and the second object are fitted together, the method comprising: a first object model representing a shape of the first object has a first parallel surface parallel to a predetermined direction; a second object model representing a shape of the second object has a second parallel surface parallel to the predetermined direction and an inclined surface that is continuous with the second parallel surface and is inclined with respect to the predetermined direction; When the first object and the second object are fitted together, the first parallel surface is in contact with at least the second parallel surface; In the stress analysis method, performing an initial analysis of the stress using a first contact setting that enables contact between the second parallel surface and the first parallel surface in the second object model and disables contact between the inclined surface and the first parallel surface; After the initial analysis is completed, a final stress is calculated by re-analyzing the stress using a second contact setting that enables contact between the second parallel surface and the inclined surface of the second object model and the first parallel surface. Stress analysis methods.

7. A program for causing a computer to execute the stress analysis method according to claim 6.

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