Optimum analysis method and device for joint position of vehicle body

Abstract

The optimal analysis method for the joint position of the vehicle body of the present invention determines the optimal joint position of the component group in the vehicle body model (37). In the optimal analysis method for the joint position of the vehicle body, a joint candidate (P1) is set at a position that is a candidate for joining the component group. For each component group, at least four fixed joint points or fixed joint parts (P5) are selected based on the distance between the joint candidates. The optimal analysis is performed by setting the selected fixed joint points or fixed joint parts and the optimal joint candidates that are the objects of the optimal analysis in the vehicle body model (37). The optimal analysis determines the optimal joint or joint part (P7) for joining the component group.

Description

Technical Field

[0001] This invention relates to an optimized analysis method and apparatus for the joining position of an automotive body, and particularly to an optimized analysis method and apparatus for the joining position of an automotive body to improve the dynamic stiffness related to the vibration characteristics of the vehicle body. Background Technology

[0002] In structural body stiffness, there are indices for static stiffness and dynamic stiffness. According to Hooke's law, static stiffness increases with increasing the spring constant, regardless of the mass of the structure. In contrast, the shape of the structure changes periodically due to the input of a periodic load from the vibration point, thus dynamic stiffness is related to its vibrational characteristics. For example, the dynamic stiffness in the vibration of a single-degree-of-freedom system is determined by using the stiffness K of the structure (equivalent to the stiffness matrix in the case of a multi-degree-of-freedom system) and the mass M of the structure, using ω = (K / M). 0.5 The dynamic stiffness is evaluated by the vibration frequency ω. If the vibration frequency ω is increased by increasing the stiffness K, then the dynamic stiffness is improved.

[0003] However, there are many cases where increasing the structure's stiffness K does not increase the vibration frequency ω if the mass M is increased, and in such cases, the dynamic stiffness does not improve. Therefore, to improve dynamic stiffness, it is necessary to reduce the weight of the structure (reduce the mass M) to increase the stiffness K. However, usually, increasing the mass M also increases the stiffness K, so increasing the stiffness K and reducing the mass are often contradictory, making it very difficult to achieve both simultaneously. Therefore, in the past, repeated experiments have been conducted to optimize the vibration characteristics of the structure and improve the dynamic stiffness.

[0004] In recent years, especially in the automotive industry, the trend towards lighter vehicle bodies due to environmental concerns has been driven. Computer-aided engineering (CAE) analysis has become an indispensable technology in vehicle body design. CAE analysis is known to employ optimization techniques such as mathematical optimization, sheet thickness optimization, shape optimization, and topology optimization to improve the rigidity and reduce the weight of structural components. For example, it is frequently used in the structural optimization of castings such as engine blocks.

[0005] In optimization techniques, topology optimization is receiving particular attention. Topology optimization is a method that involves setting up a design space of a certain size for the structure, introducing three-dimensional elements into this design space, and retaining only the portion of the three-dimensional elements that meet the required conditions and are the minimum necessary size, thus forming the optimal shape that satisfies the conditions. Therefore, topology optimization uses a method of directly constraining and directly applying loads to the three-dimensional elements that form the design space.

[0006] As a technology related to such topology optimization, Patent Document 1 discloses a method for topology optimization of components of complex structures. Furthermore, Patent Document 2 discloses a method for determining the optimal positions for point joining or continuous joining of multiple parts constituting a vehicle body through topology optimization, with the aim of minimizing the amount of joining through welding and other methods and improving the overall rigidity of the vehicle body.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-250818

[0008] Patent Document 2: Japanese Patent Application Publication No. 2013-25593

[0009] In the method of Patent Document 2, an optimization analysis is performed to improve the static stiffness of the vehicle body. In this optimization analysis, multiple components in the structural model of the vehicle body are grouped together as parts assemblies, and at least one fixed joining point is designated. However, the optimization analysis disclosed in Patent Document 2 does not aim to improve the dynamic stiffness of the vehicle body, and it does not directly optimize the bonding positions of the vehicle body by targeting a vehicle body that vibrates under periodic loads. Furthermore, the determined bonding positions are effective for static stiffness, but may not be the optimal bonding positions for improving the dynamic stiffness of the vehicle body.

[0010] To improve the dynamic stiffness of the vehicle body and determine the optimal engagement position, dynamic analysis of the vehicle body's dynamic behavior under vibration is required. Therefore, similar to the method in Patent Document 2, using a vehicle body model obtained by grouping multiple components and engaging them, firstly, as... Figure 8 As shown, a fixed joint point 57 was selected from the joining points 55 within the flange portion 53 of component group 51. Additionally, one fixed joint point was set for each component group, and dynamic analysis of the vehicle model was performed. However, dynamic analysis presents the following problems: the components constituting the component group experience flapping, increasing vibration and resulting in significant component deviations; or some component groups become disorganized, making proper dynamic analysis impossible.

[0011] To prevent component swaying during dynamic analysis, a method is considered: preserving all pre-defined joint points of the component group in the vehicle model, maintaining this state while performing dynamic analysis, and determining the optimal joint point to add and join. However, this method of determining such additional joint points has limitations on the number and location of the additional joint points or joining areas that become the target of optimization analysis. This makes it impossible to sufficiently reduce the overall joint amount of the vehicle body according to the objective, thus hindering the achievement of both improved dynamic rigidity and weight reduction. Summary of the Invention

[0012] The present invention was made in view of the above-mentioned problems, and its object is to provide an optimal analysis method and apparatus for the joint position of a vehicle body, which prevents the component group from shaking, shifting, or becoming disordered in the dynamic analysis of dynamic rigidity related to improving the vibration characteristics of the vehicle body, thereby achieving both dynamic rigidity and lightweight vehicle body, and determining the optimal position of the joint point or joint portion for joining the component group of the vehicle body.

[0013] The inventors of this invention carefully studied a method to solve the aforementioned problems. First, in the method described in Patent Document 2, because only one fixed joint point is selected, the component assembly may wobble, shift, or become disorganized. Therefore, four or more fixed joint points are added. That is, with two fixed joint points, deviations may occur at one flange of the component assembly or one end of the component, causing the component assembly to wobble and easily shift or become disorganized. Furthermore, even with three fixed joint points, setting two fixed joint points at one end of the component and one fixed joint point at the other end still results in deviations and easily causes the component assembly to wobble. Therefore, setting four or more fixed joint points is considered to minimize deviations. Based on this, the components are reliably fixed to each other beforehand, thus focusing on the strain energy at the joint points, thereby achieving… Figure 9 As shown in (a), static analysis, such as stiffness analysis, is performed on the vehicle body model of the component group 51, which has pre-set joint points 55 on the flange portion 53. For the component group 51, four or more fixed joint points 57 are selected from the joint points 55 in order of the largest strain energy.

[0014] However, even in this method of setting more than four fixed joint points in order of large strain energy, taking four fixed joint points as an example, the four fixed joint points 57 are also as follows: Figure 9 (b) shows the flange 53, which is selected to be biased towards the center of its length direction as the part where it joins the component assembly 51. Figure 9 (b)(i)), or selected as a flange portion 53 biased to one side. Figure 9 (b)(ii) and (iii)). Moreover, if the vehicle body model with such biased fixed joint point 57 is dynamically analyzed, the following problems occur as described above: the parts that are joined to the part group shake and become messy, resulting in a large offset of the parts from the part group joint, or a part of the part group becoming messy, etc.

[0015] Therefore, the inventors of this invention carefully studied methods to solve problems such as component swaying during dynamic analysis. As a result, they conceived of setting four or more fixed joint points in each component group, and selecting the distances between these four or more fixed joint points as far as possible. Furthermore, they realized that if a vehicle model is set in such a way that the distances between the four or more fixed joint points are increasingly greater than each other, the components will not shift from the parts to be joined in the component group, thus enabling dynamic analysis.

[0016] This invention is based on the following insights and is specifically composed of the following structure.

[0017] The optimal analysis method for the joining positions of a vehicle body according to the present invention is for a vehicle body model having multiple components that are joined as component groups through joining points or joining portions. The computer performs the following steps to determine the optimal positions for point joining or continuous joining of the component groups. The optimal analysis method for the joining positions of the vehicle body includes: a joining candidate setting step, in which joining candidates are set at positions that are candidates for joining the component groups; and a fixed joining selection step, in which four or more fixed joining points or fixed joining portions that must be joined in each component group are selected from the joining candidates set in each component group. The process includes an area); and a joint optimization analysis step, in which the vehicle model is set to include fixed joint points or fixed joint portions selected for each component group that are not the object of the optimization analysis, and optimal joint candidates that are the object of the optimization analysis. Optimization analysis is performed on the vehicle model other than on the fixed joint points or fixed joint portions selected for each component group. This optimization analysis determines the optimal joint point or joint portion in the vehicle model for joining the component group. The fixed joint selection step includes: a first fixed joint selection step, in which static or dynamic analysis is performed on the vehicle model with the joint candidates set. Based on the results of the static or dynamic analysis, a first fixed joint point or first fixed joint portion is selected from the joint candidates for each component group; a second... The fixed joint selection step involves selecting, from the aforementioned component group, the joint candidate that is furthest from the first fixed joint point or the first fixed joint portion as the second fixed joint point or the second fixed joint portion; the third fixed joint selection step involves selecting, from the aforementioned component group, the joint candidate that is furthest from the midpoint of the straight line connecting the first fixed joint point or the first fixed joint portion and the second fixed joint point or the second fixed joint portion as the third fixed joint point or the third fixed joint portion; and the fourth fixed joint selection step involves selecting, from the aforementioned joint candidates other than the first fixed joint point or the first fixed joint portion and the second fixed joint point or the second fixed joint portion, the joint candidate that is furthest from the third fixed joint point or the third fixed joint portion as the fourth fixed joint point or the fourth fixed joint portion.

[0018] The first fixed joint selection step in the above-mentioned fixed joint selection process can also select the joint candidate with the largest strain energy as the first fixed joint point or the first fixed joint part.

[0019] The first fixed joint selection step in the above-mentioned fixed joint selection process can also select the joint candidate with the largest resultant force of tensile stress and sheared stress as the first fixed joint point or the first fixed joint part.

[0020] The above-mentioned fixed joint selection process can also take the center of the above-mentioned joint candidate as a representative point and calculate the above-mentioned distance in a cyclical manner for the above-mentioned joint candidates in each of the above-mentioned component groups.

[0021] The vehicle body joint position optimization analysis apparatus of the present invention performs optimization analysis on a vehicle body model having multiple components and joining the multiple components as a group of components through joint points or joint portions. This optimization analysis determines the optimal position for point joints or continuous joints used for the joints of the aforementioned component groups. The vehicle body joint position optimization analysis apparatus includes: a joint candidate setting unit that sets joint candidates at positions that are candidate positions for joining the aforementioned component groups; and a fixed joint selection unit that selects from the aforementioned positions set in each of the aforementioned component groups. Among the candidate joints, at least four fixed joint points or fixed joint portions that must be joined in each component group are selected; and a joint optimization analysis unit is used, which, in the above-mentioned vehicle body model, focuses on the fixed joint points or fixed joint portions selected in each component group that are not the object of the optimization analysis, and on the best candidate joints that are the object of the optimization analysis, except for the fixed joint points or fixed joint portions selected in each component group, to perform optimization analysis, and the optimization analysis finds the best joint point or joint portion in the above-mentioned vehicle body model for joining the above-mentioned component group. The fixed engagement selection unit comprises: a first fixed engagement selection unit, which performs static or dynamic analysis on the vehicle model with the engagement candidates set, and selects a first fixed engagement point or a first fixed engagement part from the engagement candidates for each component group based on the results of the static or dynamic analysis; a second fixed engagement selection unit, which selects the engagement candidate that is furthest from the first fixed engagement point or the first fixed engagement part from the component group as a second fixed engagement point or a second fixed engagement part; and a third fixed engagement selection unit, which... The third fixed joint selection unit selects the joint candidate that is furthest from the midpoint of the straight line connecting the first fixed joint point or the first fixed joint and the second fixed joint point or the second fixed joint as the third fixed joint point or the third fixed joint; and the fourth fixed joint selection unit selects the joint candidate that is furthest from the joint candidates other than the first fixed joint point or the first fixed joint and the second fixed joint point or the second fixed joint as the fourth fixed joint point or the fourth fixed joint.

[0022] The first fixed joint selection part of the aforementioned fixed joint selection unit can also select the joint candidate with the largest strain energy as the first fixed joint point or the first fixed joint part.

[0023] The first fixed joint selection part of the aforementioned fixed joint selection unit can also select the joint candidate with the largest resultant force of tensile stress and shear stress as the first fixed joint point or the first fixed joint part.

[0024] The aforementioned fixed joint selection unit may also take the center of the aforementioned joint candidate as a representative point and calculate the aforementioned distance in a cyclical manner for the aforementioned joint candidates in each of the aforementioned component groups.

[0025] According to the present invention, the shaking of components, the offset of components, and the becoming disordered can be suppressed in the dynamic analysis for the optimization analysis of the engagement position, so as to improve the dynamic rigidity of the vehicle body or to make the vehicle body lighter while maintaining or improving the dynamic rigidity, and thus the optimal engagement position can be determined. Attached Figure Description

[0026] Figure 1 This is a block diagram illustrating the structure of the vehicle body's engagement position optimization analysis device, taking the case of selecting four fixed engagement points or fixed engagement portions as an example, according to an embodiment of the present invention.

[0027] Figure 2 This diagram represents the vehicle body model that is the object of analysis in an embodiment of the present invention, and the docking candidate set on the vehicle body model.

[0028] Figure 3 This is an explanatory diagram illustrating the process of selecting the first to fourth fixed joint points in the vehicle body model where the component groups must be joined, as an example of an embodiment of the present invention.

[0029] Figure 4 This is a flowchart illustrating the process flow of an optimization analysis method for the joint position of a vehicle body, taking the case of selecting four fixed joint points or fixed joint portions as an example, according to an embodiment of the present invention.

[0030] Figure 5 This is a diagram illustrating the optimized analytical model for dynamic analysis used in the optimization analysis of the joint position in the embodiment. Figure 5 (a) is Comparative Example 1. Figure 5 (b) is a comparative example 2. Figure 5 (c) is Invention Example 1).

[0031] Figure 6 This is a diagram illustrating the optimized analytical model in the dynamic analysis used for optimization analysis at the joint position in the embodiment, during deformation. Figure 6 (a) is Comparative Example 1. Figure 6 (b) is a comparative example 2. Figure 6 (c) is Invention Example 1).

[0032] Figure 7 This is a diagram showing the optimized analytical model after deformation in the dynamic analysis used for the optimization analysis at the joint position in the embodiment. Figure 7 (a) is Comparative Example 1. Figure 7(b) is a comparative example 2. Figure 7 (c) is Invention Example 1).

[0033] Figure 8 This diagram illustrates an example of a case where, according to existing technology, one fixed joint point is selected in each component group.

[0034] Figure 9 This diagram illustrates an example of a case where four fixed joint points are selected for each component group without applying the present invention. Detailed Implementation

[0035] The following is for reference Figures 1-4 The method and apparatus for optimizing the joint position of a vehicle body according to an embodiment of the present invention will be described. Before describing the method and apparatus for optimizing the joint position of a vehicle body, a vehicle body model that is the subject of this invention will be described. A joint point refers to a spot welding point, and a joint portion refers to a part obtained by continuous welding such as laser beam welding or electric arc welding. In the following description, the case of a joint point will be mainly used as an example. However, the present invention can also be applied to the case of a joint portion.

[0036] <Vehicle Model>

[0037] The vehicle model used in this invention has multiple parts, which are joined together as a component group through joint points or joints. These multiple parts refer to body frame parts, chassis parts, etc.

[0038] Figure 2 An example of a vehicle body model 37 is shown. The components in the vehicle body model 37 are modeled using planar elements and / or solid elements, and fixed joint points are set at the locations where these components are grouped together and joined by spot welding.

[0039] The deformation and vibration behaviors of the vehicle body model 37 under load are analyzed, and therefore, each component in the vehicle body model 37 is modeled as an elastic body, a viscoelastic body, or an elastoplastic body. Furthermore, the material properties, element information, and even information related to each component group of the vehicle body model 37 are stored in the vehicle body model file 23 (see below). Figure 1 )middle.

[0040] <Optimization Analysis Device for Vehicle Body Joint Position>

[0041] The optimization analysis device 1 (hereinafter referred to as "optimization analysis device 1") of this embodiment performs optimization analysis on the vehicle body model 37, and the optimization analysis determines the optimal positions for point joints or continuous joints used for the joints of each component group. For example Figure 1 As shown, the optimization analysis device 1 is composed of a PC (personal computer) and includes a display device 3, an input device 5, a memory storage device 7, a working data memory 9, and an arithmetic processing unit 11. Furthermore, the display device 3, input device 5, memory storage device 7, and working data memory 9 are connected to the arithmetic processing unit 11 and execute their respective functions according to instructions from the arithmetic processing unit 11.

[0042] The following uses Figure 2 The function of each component of the optimization analysis device 1 in this embodiment will be explained based on the example of finding the fixed joint points and additional optimal joint points for joining the component groups in the vehicle body model 37 shown.

[0043] Display Devices

[0044] Display device 3 is used for displaying analysis results, etc., and is composed of a liquid crystal display (LCD monitor) or the like.

[0045] Input Device

[0046] The input device 5 is used for displaying instructions on the vehicle model file 23 and for operator input, and consists of a keyboard, mouse, etc.

[0047] Storage Devices

[0048] Storage device 7 is used for storing various files such as vehicle model file 23, and is composed of a hard disk, etc.

[0049] Data Storage for Job Operations

[0050] The operational data storage 9 is used for temporary storage and processing of data used by the arithmetic processing unit 11, and is composed of RAM (Random Access Memory) and the like.

[0051] Computational Processing Department

[0052] like Figure 1 As shown, the arithmetic processing unit 11 includes a connection candidate setting unit 13, a fixed connection selection unit 17, and a connection optimization analysis unit 19, and is composed of a CPU (central processing unit) such as a PC. Each of these units performs its function by executing a predetermined program through the CPU. The functions of each unit of the arithmetic processing unit 11 will be explained below.

[0053] (Connecting candidate setting unit)

[0054] The engagement candidate setting unit 13 in the vehicle body model 37 serves as the position setting engagement candidate for the engagement of each component group.

[0055] An example of the specific processing performed by the engagement candidate setting unit 13 is described below. Figure 2 As shown, in the component group (not shown) formed by joining multiple components that constitute the vehicle body model 37, joint candidates 35 are densely generated at specified intervals.

[0056] (Fixed joint selected unit)

[0057] The fixed joint selection unit 17 selects, from the joint candidates set in each component group of the vehicle body model 37, at least four fixed joint points or fixed joint parts that must be joined in each component group. Figure 1 This indicates the case of four fixed joint points or fixed joint portions. The fixed joint selection unit 17 has a first fixed joint selection section 17a, a second fixed joint selection section 17b, a third fixed joint selection section 17c, and a fourth fixed joint selection section 17d. When five or more fixed joint points or fixed joint portions are selected, a fifth fixed joint selection section, etc., can be added to the arithmetic processing unit.

[0058] The fixed joint points or fixed joint portions selected by the fixed joint selection unit 17 are joint points or joint portions that are not the objects of the optimization analysis of the joint position described later, but are the joint points or joint portions that each component group must join. Moreover, as a preprocessing step for the optimization analysis, four fixed joint points or fixed joint portions are selected for each component group by the first fixed joint selection unit 17a to the fourth fixed joint selection unit 17d, thereby enabling appropriate optimization analysis of the joint position.

[0059] The following is based on Figure 3 Taking component group 39 as an example, the process of selecting the first fixed joint point 43a, the second fixed joint point 43b, the third fixed joint point 43c, and the fourth fixed joint point 43d from the joint candidates 41 will be explained. Furthermore, if more than five fixed joint points are determined, the joint candidate that is most separated from all four fixed joint points can be selected. Alternatively, joint candidates that do not overlap with the first to fourth fixed joint points can be selected, and determined from these in the same manner as the first to fourth fixed joint points described below.

[0060] [First Fixed Joint Selection Section]

[0061] The first fixed joint selection unit 17a performs static or dynamic analysis on the vehicle model 37 for which joint candidates 41 are set in each component group 39, and selects the first fixed joint point 43a from the joint candidates 41 in each component group 39 based on the results of the static or dynamic analysis.

[0062] Static analysis determines the displacement, load, etc., of a structural model under a load condition that applies a constant load to a specified location on the structural model. In this embodiment, static analysis can be applied, for example, simple structural analysis (such as rigid analysis) that applies a load condition that causes a static load to act on the structural model, or topology optimization as described later.

[0063] For example, if the first fixed joint point 43a is selected based on the results of simple structural analysis, firstly, the stress, strain, strain energy, load, etc., of each joint candidate 41 in each component group 39 are calculated. Next, based on these calculated values, the joint candidates 41 in each component group 39 are sorted, and the joint candidate 41 with the highest ranking is selected as the first fixed joint point 43a in that component group 39.

[0064] For example, when based on strain energy, the candidate 41 with the highest strain energy among the component groups can be selected as the first fixed joint point 43a. Alternatively, when based on stress, the candidate 41 with the highest resultant force of tensile stress and shear stress among the component groups can be selected as the first fixed joint point 43a. Furthermore, regardless of whether it is strain energy or stress (the resultant force of tensile stress and shear stress), the first fixed joint selection unit 17a can appropriately select the first fixed joint point 43a.

[0065] Alternatively, the first fixed joint point 43a can be selected based on the results of topology optimization. For example, topology optimization can be performed by setting design variables (e.g., density) for each joint candidate 41, and the joint candidates 41 within each component group 39 can be sorted and the first fixed joint point 43a selected based on the values ​​of the design variables obtained for each joint candidate 41.

[0066] On the other hand, dynamic analysis is used to determine the vibration characteristics of a structural model under periodic loads, including frequency response analysis, eigenvalue analysis, and transient characteristic analysis.

[0067] Furthermore, as a dynamic analysis for determining the first fixed joint point 43a, for example, in the case of frequency response analysis, similarly to the simple construction analysis described above, stress, strain, strain energy, load, etc. are calculated for each joint candidate 41, and the first fixed joint point 43a is selected based on the calculated values.

[0068] However, the values ​​of strain energy, etc., in each bonding candidate 41 calculated by frequency response analysis are periodically varying values, so the ranking of bonding candidates can be done, for example, based on the peak value of strain energy, etc.

[0069] [Second Fixed Joint Selection Section]

[0070] For each component group 39, the second fixed engagement selection unit 17b selects the engagement candidate 41 that is furthest away from the first fixed engagement point 43a from the engagement candidates 41 as the second fixed engagement point 43b.

[0071] [Third Fixed Joint Selection Section]

[0072] For each component group 39, the third fixed joint selection unit 17c selects the joint candidate 41 that is furthest away from the midpoint M of the straight line connecting the first fixed joint point 43a and the second fixed joint point 43b from the joint candidates 41 other than the first fixed joint point 43a and the second fixed joint point 43b, and uses it as the third fixed joint point 43c.

[0073] [Fourth Fixed Joint Selection Section]

[0074] The fourth fixed engagement selection unit 17d selects the engagement candidate 41 that is furthest away from the third fixed engagement point 43c from the engagement candidates 41 other than the first fixed engagement point 43a and the second fixed engagement point 43b as the fourth fixed engagement point 43d.

[0075] Furthermore, the second fixed joint selection unit 17b, the third fixed joint selection unit 17c, and the fourth fixed joint selection unit 17d preferably calculate the distance in a cyclical manner for each joint candidate 41 in the component group 39. In the distance calculation, for example, it is sufficient to use the coordinate value of the center point obtained from the node coordinates of the element set as a joint candidate 41 and the element selected as the first fixed joint point 43a to the third fixed joint point 43c.

[0076] Furthermore, in the selection of the third fixed joint point 43c performed by the third fixed joint selection unit 17c, the coordinates of the midpoint M can be calculated simply by using the coordinates of the representative points of the first fixed joint point 43a and the second fixed joint point 43b.

[0077] Alternatively, when a fifth fixed joint point is selected, the joint candidate that is most separated from all four fixed joint points can also be selected. For example, the distances to the first to fourth fixed joint points can be calculated and the most separated joint candidate can be selected cyclically, or the midpoint between the first and fourth fixed joint points can be determined and the joint candidate most separated from that midpoint can be selected. Alternatively, similar to the case where the first fixed joint point is selected, the fifth fixed joint point can be selected from the joint candidates 41 other than the first to fourth fixed joint points based on the results of static or dynamic analysis.

[0078] In addition, when the sixth fixed joint point is selected, the joint candidate that is furthest away from the fifth fixed joint point can be selected from the joint candidates other than the first to fifth fixed joint points, just as the second fixed joint point was selected above.

[0079] Furthermore, if a sixth or higher fixed joint point is selected and fixed, the number of remaining joint candidates for optimization is significantly reduced, thereby diminishing the effectiveness of optimizing joint points or joints to minimize the amount of jointing required and improve the overall rigidity of the vehicle body. Therefore, temporarily stopping at selecting the fifth fixed joint point is effective in achieving the original objective.

[0080] (Combined Optimized Analysis Unit)

[0081] The joint optimization analysis unit 19 generates an optimization analysis model (not shown). This optimization analysis model sets the first to fourth fixed joint points selected by the fixed joint selection unit 17 for each component group and the best joint candidates that become the objects of optimization analysis in the vehicle body model. Moreover, the joint optimization analysis unit 19 performs optimization analysis, which determines the best joint points or joints for joining the component groups in the optimization analysis model.

[0082] In this embodiment, such as Figure 1 As shown, the optimization analysis unit 19 includes a frequency response analysis unit 19a, a load condition determination unit 19b, an optimization analysis model generation unit 19c, an optimization analysis condition setting unit 19d, and an optimization analysis unit 19e.

[0083] [Frequency Response Analysis Section]

[0084] The frequency response analysis unit 19a applies a specified excitation condition to the fixed joint setting vehicle body model (not shown) with the first to fourth fixed joint points set in each component group and performs frequency response analysis to determine the vibration mode generated in the fixed joint setting vehicle body model and the deformation state under the vibration mode.

[0085] Frequency response analysis is a type of dynamic analysis, and it is an analytical method for determining the vibration modes and deformation patterns of a structure in response to a constant sinusoidal load applied to it. Furthermore, as an excitation condition in frequency response analysis, a sinusoidal load is often applied to the left and right rear suspension mounting sections of a fixedly attached vehicle model above the vehicle body.

[0086] [Load Condition Determination Department]

[0087] The load condition determination unit 19b determines the load conditions applied to the fixed-joint vehicle body model corresponding to the deformation mode under the vibration mode obtained by the frequency response analysis unit 19a. Moreover, the deformation mode under the vibration mode can be, for example, the deformation of the fixed-joint vehicle body model at the moment when the total displacement of the fixed-joint vehicle body model is maximized.

[0088] [Optimized Analytical Model Generation Department]

[0089] The optimal analytical model generation unit 19c sets the first to fourth fixed joint points and the optimal joining candidate that becomes the object of optimal analysis in the vehicle body model and generates the optimal analytical model.

[0090] In this embodiment, the optimization analysis model generation unit 19c sets the joint candidate 35 set on the vehicle body model 37 as the best joint candidate. However, the first fixed joint point to the fourth fixed joint point (up to the fifth fixed joint point depending on the situation) selected by the fixed joint selection unit 17 are removed from the best joint candidates.

[0091] [Optimization Analysis Condition Setting Department]

[0092] The optimization analysis condition setting unit 19d sets the optimization analysis conditions for performing optimization analysis on the object optimized by the optimal combination candidate in the optimization analysis model generated by the optimization analysis model generation unit 19c.

[0093] As optimization conditions, two types are set: objective conditions and constraints. Objective conditions are set according to the purpose of the optimization analysis, such as minimizing strain energy, maximizing absorbed energy, and minimizing generated stress. Only one objective condition is set. Constraint conditions are restrictions imposed on aspects of the optimization analysis, such as the optimized model having a specified stiffness. Multiple constraints can be set.

[0094] [Optimization Analysis Department]

[0095] The optimization analysis unit 19e applies the load conditions determined by the load condition determination unit 19b to the optimization analysis model and performs optimization analysis to find the best engagement candidate that satisfies the optimization analysis conditions set by the optimization analysis condition setting unit 19d as the best engagement point or engagement part for engaging each component group.

[0096] Furthermore, topology optimization can be applied in the optimization analysis performed by the optimization analysis unit 19e. Moreover, when using the density method in topology optimization, if there are many intermediate densities, it is preferable to perform discretization as shown in equation (1).

[0097] [Formula 1]

[0098] K′(ρ)=ρ p K

[0099] in,

[0100] K': A rigid matrix for which a penalty has been imposed on the elements.

[0101] K: The rigid matrix of the elements

[0102] ρ: Normalized density

[0103] p: Penalty coefficient

[0104] In discretization, a penalty coefficient of 2 or higher is often used, but in the optimization of the joining position in this invention, a penalty coefficient of 4 or higher is preferred.

[0105] Furthermore, the optimization analysis unit 19e can perform optimization processing based on topology optimization, or optimization processing based on other calculation methods. Moreover, as the optimization analysis unit 19e, commercially available optimization analysis software utilizing the finite element method can be used, for example.

[0106] Furthermore, in the optimization analysis performed in the optimization analysis section 19e, the inertia force acting on the vehicle during movement can also be considered using the inertia relief method. The inertia relief method is an analytical method for determining stress and strain based on the forces acting on an object undergoing constant acceleration motion, such as the force acting on the object in a state of free support (where the object is supported at a support point that serves as the reference for the coordinates of the inertia force). It is used for the static analysis of moving aircraft and ships.

[0107] <Optimization Analysis Method for Vehicle Body Joint Position>

[0108] The optimization analysis method for the joint position of the vehicle body according to the embodiments of the present invention (hereinafter referred to as the "optimization analysis method") is applied to the vehicle body model 37 of the automobile. Figure 2 An optimization analysis is performed to determine the optimal positions for point or continuous joints used in the joints of each component group. The optimization analysis method is as follows: Figure 4 As shown in the example up to the fourth fixed joint selection step, the process includes a joint candidate setting step P1, a fixed joint selection step P5, and a joint optimization analysis step P7. These steps will be described below. Furthermore, each step is performed by an optimization analysis device 1 composed of a computer (…). Figure 1 )conduct.

[0109] "Joining Candidate Setting Process"

[0110] In the vehicle model 37, the process of setting up candidate positions for joining various component groups (P1) becomes the setting of candidate positions for joining components. Figure 1 In the optimization analysis device 1 shown, the optimization is performed by the candidate setting unit 13.

[0111] Fixed Joint Selection Process

[0112] In the fixed joint selection process P5, for each component group of the vehicle model 37, at least four fixed joint points or fixed joint parts that must be joined in each component group are selected from the joint candidates set in each component group. Figure 1 The optimization analysis device 1 shown is performed by the fixed-joint selection unit 17.

[0113] Moreover, such as Figure 4 As shown, the fixed joint selection process P5 includes a first fixed joint selection step S5a, a second fixed joint selection step S5b, a third fixed joint selection step S5c, and a fourth fixed joint selection step S5d. Alternatively, it may include a fifth and subsequent fixed joint selection steps.

[0114] (First fixed joint selection step)

[0115] The first fixed joint selection step S5a performs static or dynamic analysis on the vehicle body model 37, and based on the results of the static or dynamic analysis, such as Figure 3 As shown, a first fixed engagement point 43a is selected from the engagement candidates 41 within each component group 39. Figure 1 The optimization analysis device 1 shown is performed by the first fixed joint selection unit 17a.

[0116] In the first fixed connection selection step S5a, as a static analysis, simple construction analysis, topology optimization, etc. can be applied, and as a dynamic analysis, frequency response analysis, etc. can be applied.

[0117] For example, in the case of a simple structural analysis performed as a static analysis, firstly, the stress, strain, strain energy, load, etc., are calculated for each joint candidate 41 within each component group 39. Next, based on the magnitude of these calculated values, the joint candidates 41 within each component group 39 are ranked, and the joint candidate 41 with the highest ranking is selected as the first fixed joint point 43a within that component group 39 (see reference). Figure 3 ).

[0118] On the other hand, in the case of frequency response analysis as a dynamic analysis, similar to simple structural analysis, the peak values ​​of stress, strain, strain energy, load, etc., are calculated for each joint candidate 41. Based on these calculated values, the joint candidates 41 in each component group 39 are sorted and the first fixed joint point 43a is selected (refer to...). Figure 3 ).

[0119] (Second fixed joint selection step)

[0120] like Figure 3 As shown, in the second fixed engagement selection step S5b, for each component group 39, the engagement candidate 41 that is furthest from the first fixed engagement point 43a is selected as the second fixed engagement point 43b. Figure 1 The optimization analysis device 1 shown is performed by the second fixed joint selection unit 17b.

[0121] (Third fixed joint selection step)

[0122] like Figure 3 As shown, in the third fixed joint selection step S5c, for each component group 39, from the joint candidates 41 other than the first fixed joint point 43a and the second fixed joint point 43b, the joint candidate 41 that is farthest from the midpoint M of the straight line connecting the first fixed joint point 43a and the second fixed joint point 43b is selected as the third fixed joint point 43c. The third fixed joint selection step S5c is in... Figure 1 The optimization analysis device 1 shown is performed by the third fixed joint selection unit 17c.

[0123] (Fourth fixed joint selection step)

[0124] like Figure 3 As shown, in the fourth fixed joint selection step S5d, for each component group 39, the joint candidate 41 that is furthest from the third fixed joint point 43c is selected as the fourth fixed joint point 43d from the joint candidates 41 other than the first fixed joint point 43a and the second fixed joint point 43b. The fourth fixed joint selection step S5d is in... Figure 1 The optimization analysis device 1 shown is performed by the fourth fixed joint selection unit 17d.

[0125] Alternatively, when a fifth fixed joint point is selected, the joint candidate that is most separated from all four fixed joint points can also be selected. For example, the distances to the first to fourth fixed joint points can be calculated and the most separated joint candidate can be selected cyclically, or the midpoint between the first and fourth fixed joint points can be determined and the joint candidate most separated from that midpoint can be selected. Or, similar to the first fixed joint selection step S5a described above, the fifth fixed joint point can be selected from the joint candidates 41 other than the first to fourth fixed joint points based on the results of static or dynamic analysis.

[0126] In addition, when the sixth fixed joint point is selected, the joint candidate that is furthest away from the fifth fixed joint point can be selected from the joint candidates other than the first to fifth fixed joint points as the sixth fixed joint point, similar to the second fixed joint selection step S5b described above.

[0127] Furthermore, if a sixth or higher fixed joint point is selected and fixed, the number of remaining joint candidates for optimization is significantly reduced, thereby diminishing the effectiveness of optimizing joint points or joints to minimize the amount of jointing required and improve the overall rigidity of the vehicle body. Therefore, temporarily stopping at selecting the fifth fixed joint point is effective in achieving the original objective.

[0128] Furthermore, the second fixed engagement selection step S5b, the third fixed engagement selection step S5c, and the fourth fixed engagement selection step S5d preferably calculate the distance in a cyclical manner for the engagement candidates 41 in each component group 39.

[0129] "Joint Optimization Analysis Process"

[0130] The joint optimization analysis process P7 generates an optimized analysis model (not shown). This optimized analysis model, based on the vehicle body model, sets the first to fourth fixed joint points selected for each component group in the fixed joint selection process P5, and the best joint candidates that become the objects of optimization analysis. The optimization analysis then determines the optimal joint point or joint portion for joining the component group within the optimized analysis model. The joint optimization analysis process P7... Figure 1 The optimization analysis device 1 shown is performed by the joint optimization analysis unit 19.

[0131] In this embodiment, such as Figure 4 As shown, the optimization analysis process P7 includes a frequency response analysis step S7a, a load condition determination step S7b, an optimization analysis model generation step S7c, an optimization analysis condition setting step S7d, and an optimization analysis step S7e.

[0132] (Frequency response analysis steps)

[0133] Frequency response analysis step S7a applies specified excitation conditions to a fixed-joint vehicle model (not shown) with first to fourth fixed joint points set in each component group, and performs frequency response analysis to determine the vibration modes generated in the fixed-joint vehicle model and the deformation morphology under these vibration modes. Frequency response analysis step S7a... Figure 1 The optimization analysis device 1 shown is performed by the frequency response analysis unit 19a.

[0134] (Load conditions determine the steps)

[0135] The load condition determination step S7b determines the load conditions applied to the fixed-joint vehicle model corresponding to the deformation mode of the vibration mode obtained in the frequency response analysis step S7a. Figure 1 The optimization analysis device 1 shown is performed by the load condition determination unit 19b. When the load condition is determined in the load condition determination step S7b, the deformation mode under the vibration mode can be, for example, the deformation of the fixed-joint set car body model at the moment when the total displacement of the fixed-joint set car body model is the maximum.

[0136] (Steps for generating the optimized analytical model)

[0137] Step S7c generates an optimized analytical model (not shown). This optimized analytical model sets the first to fourth fixed joint points on the vehicle body model, and identifies the best joint candidates that become the objects of optimized analysis. Figure 1 The optimization analysis device 1 shown is performed by the optimization analysis model generation unit 19c.

[0138] Furthermore, in the optimal analytical model generation step S7c, the joining candidate 35 set on the vehicle body model 37 is set as the best joining candidate. However, the first to fourth fixed joining points (up to the fifth fixed joining point, depending on the situation) selected in the fixed joining selection step P5 are removed from the best joining candidates.

[0139] (Steps for setting optimal analysis conditions)

[0140] The optimization analysis condition setting step S7d sets the optimization analysis conditions for the objects optimized in the optimization analysis model generated in the optimization analysis model generation step S7c, with the best joining candidate as the optimized object. Figure 1 The optimization analysis device 1 shown is operated by the optimization analysis condition setting unit 19d.

[0141] As optimization analysis conditions, there are two types: objective conditions and constraint conditions. Objective conditions are optimization analysis conditions set according to the purpose of the optimization analysis, such as minimizing strain energy, maximizing absorbed energy, and minimizing generated stress. Only one objective condition can be set. Constraint conditions are restrictions imposed on aspects of the optimization analysis, such as the optimized analysis model having a specified stiffness. Multiple constraint conditions can be set.

[0142] (Optimization analysis steps)

[0143] The optimization analysis step S7e applies the load conditions determined in the load condition determination step S7b to the optimization analysis model and performs optimization analysis to find the best joint candidate that satisfies the optimization analysis conditions set in the optimization analysis condition setting step S7d as the best joint point or joint for joining each component group.

[0144] Topology optimization can be applied in the optimization analysis within the optimization analysis step S7e. Moreover, when using the density method in topology optimization, if there are many intermediate densities, it is preferable to discretize as shown in the above equation (1).

[0145] Furthermore, the optimization analysis step S7e can perform optimization processing based on topology optimization, or it can perform optimization processing based on other calculation methods. Moreover, the optimization processing within the optimization analysis step S7e can be performed, for example, using commercially available optimization analysis software that utilizes the finite element method.

[0146] In addition, during the optimization analysis in step S7e, the inertial force acting on the optimization analysis model can also be considered using the inertial release method.

[0147] The vehicle body engagement position optimization analysis method and apparatus according to embodiments of the present invention can appropriately set four or more fixed engagement points or fixed engagement portions in each component group even during dynamic analysis for engagement position optimization. Therefore, it is possible to suppress the shaking, displacement, and disorder of components during dynamic analysis, and to determine the optimal engagement position in order to improve the dynamic rigidity of the vehicle body or to reduce the weight of the vehicle body while maintaining dynamic rigidity.

[0148] In addition, such as Figure 3 As shown above, the above description selects the first fixed joint point 43a to the fourth fixed joint point 43d for each component group 39 for optimization analysis, but the present invention can also select more than 5 fixed joint points for optimization analysis.

[0149] When a fifth fixed joint point is selected, the joint candidate that is most separated from all four fixed joint points can also be selected. Alternatively, the fifth fixed joint point can be selected from joint candidates other than the first to fourth fixed joint points based on the results of static or dynamic analysis. Furthermore, the fifth fixed joint point can be determined, for example, simply by finding the midpoint of the straight line connecting the third and fourth fixed joint points, and selecting the joint candidate farthest from this midpoint from the joint candidates that have excluded the already selected fixed joint points. Alternatively, the distances to the first to fourth fixed joint points can be calculated and the most separated joint candidate selected iteratively. For the sixth and subsequent fixed joint points, the same steps as for the fifth fixed joint point can be repeated.

[0150] Furthermore, if a sixth or higher fixed joint point is selected and fixed, the number of remaining joint candidates for optimization is significantly reduced, thereby diminishing the effectiveness of optimizing joint points or joints to minimize the amount of jointing required and improve the overall rigidity of the vehicle body. Therefore, temporarily stopping at selecting the fifth fixed joint point is effective in achieving the original objective.

[0151] Furthermore, the above description describes the case where engagement candidates 35 are automatically generated at predetermined intervals, but the present invention is not limited to this. For example, the operator may also generate engagement candidates 35 by manually inputting using the input device 5.

[0152] Furthermore, the above description describes the generation of fixed joints on the vehicle body model 37 that are joined by spot welding. However, the present invention can also generate fixed joints on the vehicle body model 37 that are continuously joined by laser welding, arc welding, etc.

[0153] Furthermore, when selecting fixed joints for each component group using such a vehicle body model, the representative point of the joint can be determined using the node coordinates of one or more planar or solid elements constituting each joint, and the distance to other joint candidates, already selected fixed joints, or fixed joints can be calculated.

[0154] Furthermore, the optimization analysis method and apparatus for the vehicle body joint position in this embodiment, when determining the load conditions in the optimization analysis, calculates the deformation mode under the vibration mode generated by the vehicle body model with a fixed joint setting by performing frequency response analysis as a dynamic analysis. However, the present invention may also use intrinsic value analysis instead of frequency response analysis as a dynamic analysis to calculate the deformation mode under the vibration mode generated by the vehicle body model with a fixed joint setting.

[0155] Natural value analysis is an analytical method for determining the natural frequencies and eigenmodes (modes of vibration) of a structure. Furthermore, since natural value analysis always determines the vibration characteristics, it can determine the deformation patterns within the vibration modes without requiring excitation conditions.

[0156] Example

[0157] The effectiveness of the present invention has been confirmed through analysis, and therefore will be described below. In this embodiment, a vehicle body model 37 in which multiple components are joined as component groups through joint points is used. Figure 2 The optimal joint point for improving dynamic stiffness was determined through optimization analysis.

[0158] First, for each component group of the vehicle body model 37, four or five fixed joint points are selected using the following method. For example... Figure 2 As shown, dynamic analysis is performed on the vehicle body model 37 with designated joint candidates 35, and the peak value of strain energy is calculated for each joint candidate 35. In this embodiment, frequency response analysis is applied as the dynamic analysis used to select fixed joint points.

[0159] Then, for each component group, the candidate joint 35 with the largest peak strain energy was selected as the first fixed joint point. After selecting the first fixed joint point, for each component group, the second to fourth or fifth fixed joint points were selected sequentially according to the order described in the embodiment. In the selection of the second to fourth or fifth fixed joint points, the distance for the joint candidates of each component group was calculated in a cyclical manner.

[0160] Next, using more than four fixed joint points selected for each component group, the optimal joint position for joining each component group was analyzed.

[0161] During the optimization analysis, firstly, a dynamic analysis of a fixed-joint vehicle model with fixed joint points is performed to determine the deformation pattern under the vibration mode generated by the fixed-joint vehicle model. In this embodiment, intrinsic value analysis is performed as the dynamic analysis used to determine the deformation pattern under the vibration mode.

[0162] Then, the load conditions applied to the fixed-joint vehicle model corresponding to the deformation mode in the vibration mode were determined. Here, the load conditions corresponding to the deformation mode of the torsional mode, which is one of the vibration modes, were determined.

[0163] Next, the vehicle body model 37 is densely generated at specified intervals (10mm) as the best joining candidate.

[0164] Then, an optimized analytical model was generated, with fixed joint points and optimal joint candidates set in the vehicle body model, and the joint position was optimized. In the optimization analysis, topology optimization was applied, and objective and constraint conditions were set as optimization analysis conditions in the optimized analytical model. In this embodiment, the objective condition is the minimization of compliance (maximization of rigidity), and the constraint condition is the proportion (number) of remaining joint candidates.

[0165] Furthermore, the optimized analytical model is dynamically analyzed, and the load conditions are used for optimization analysis to find the best candidate joints that satisfy the optimization analysis conditions as the optimal joint points. In the optimization analysis, the number of optimal joint points is 3949.

[0166] In this embodiment, an example is taken as an invention example where four or five fixed joint points are selected for each component group according to the above method, and the optimal joint point is obtained by setting the optimal analysis of the selected four or five fixed joint points. As shown below, the deformation of the vehicle body model in dynamic analysis and the vibration characteristics of the optimized analytical model with the optimal joint point obtained by the optimal analysis are obtained are calculated. In addition, Invention Example 1 selects and sets four fixed joint points, and Invention Example 2 selects and sets five fixed joint points.

[0167] Furthermore, as a comparison, static analysis (simple construction analysis) of a vehicle body model with joint points as joint candidates was performed according to the method described in Patent Document 2. Examples of one or four fixed joint points selected based solely on the magnitude of strain energy obtained for the joint candidates of each component group were used as comparative examples. Moreover, even in the comparative examples, the deformation and vibration characteristics of the vehicle body model based on dynamic analysis were obtained, similar to the inventive examples.

[0168] Figures 5-7 The results of dynamic analysis (intrinsic value analysis) using a fixed-joint vehicle body model 45 with fixed joint points are shown to obtain the deformation shape produced by the fixed-joint vehicle body model 45. Figure 5 Indicates the period before deformation begins. Figure 6 Indicates the middle of the transformation. Figure 7 This indicates the shape of the fixed joint setting of the vehicle body model 45 after the deformation is completed.

[0169] Comparative Example 1 ( Figure 5 of (a), Figure 6 (a) and Figure 7In (a) of the example, a fixed joint point is set in each component group. As deformation progresses, the component will wobble, causing the floor panel (the part enclosed by the dashed ellipse in the figure) to deviate downwards from the middle of the deformation. Comparative Example 2 ( Figure 5 (b) Figure 6 (b) and Figure 7 (b) Four fixed joint points are selected for each component group based solely on the order of strain energy. The four fixed joint points are biased towards one side of the component, so as deformation progresses, the component will wobble, and at the end of deformation, some of the components will shift from the jointing point of the component group (the area enclosed by the dashed ellipse in the figure).

[0170] In Invention Example 1 ( Figure 5 (c) Figure 6 (c) and Figure 7 In (c), four fixed joint points are set in each component group, so that the components will not wobble or shift. In addition, the components will not become messy. Torsional deformation is generated in the vehicle model 45 with fixed joint setting.

[0171] Next, for both the inventive and comparative examples, intrinsic values ​​of the optimized analytical models for the optimal joint points, obtained through optimized analysis, were analyzed to determine the frequencies of the vibration modes that become torsional modes. The results of determining the frequencies of the torsional modes are shown in Table 1.

[0172] [Table 1]

[0173]

[0174] As shown in Table 1, compared to the frequency (30.07 Hz) in Comparative Example 1 where one fixed joint point was set in each component group, the frequency in Comparative Example 2, Invention Example 1 and Invention Example 2 where four or five fixed joint points were set was higher, and the dynamic rigidity was improved.

[0175] However, in Comparative Example 2, which sets four fixed joint points selected solely based on strain energy, such as Figure 5 (b) Figure 7 As shown in (b), in the dynamic analysis of the fixed joint setting vehicle model with 4 fixed joint points, some parts wobbled and caused obstacles.

[0176] On the other hand, in Invention Examples 1 and 2, no component wobbling, displacement, or disorder occurs during dynamic analysis, allowing for the appropriate determination of the vibration mode frequency. Furthermore, in Invention Examples 1 and 2, compared to the comparative example, the frequency of the torsional vibration mode is higher, thus improving dynamic stiffness.

[0177] Industrial availability

[0178] According to the present invention, an optimal analysis method and apparatus for the joint position of a vehicle body can be provided, which, in the dynamic analysis of dynamic stiffness related to improving the vibration characteristics of the vehicle body, prevents the component assembly from swaying, shifting, or becoming disordered, thereby achieving both dynamic stiffness and lightweighting of the vehicle body, and determines the optimal position of the joint point or joint portion for joining the component assembly of the vehicle body.

[0179] Explanation of reference numerals in the attached figures

[0180] 1…Optimization analysis unit; 3…Display device; 5…Input device; 7…Storage device; 9…Working data memory; 11…Arithmetic processing unit; 13…Joining candidate setting unit; 17…Fixed joining selection unit; 17a…First fixed joining selection unit; 17b…Second fixed joining selection unit; 17c…Third fixed joining selection unit; 17d…Fourth fixed joining selection unit; 19…Joining optimization analysis unit; 19a…Frequency response analysis unit; 19b…Load condition determination unit; 19c…Optimization Analytical model generation unit; 19d… Optimized analytical condition setting unit; 19e… Optimized analytical unit; 23… Vehicle body model file; 35… Joining candidate; 37… Vehicle body model; 39… Component group; 41… Joining candidate; 43… Fixed joining point; 43a… First fixed joining point; 43b… Second fixed joining point; 43c… Third fixed joining point; 43d… Fourth fixed joining point; 45… Fixed joining setting vehicle body model; 51… Component group; 53… Flange; 55… Joining point; 57… Fixed joining point.

Claims

1. An optimization analysis method for the joint position of a vehicle body, wherein for a vehicle body model having multiple components and the multiple components being joined as a component group through joint points or joint portions, a computer performs the following steps to perform optimization analysis, which determines the optimal position for point joints or continuous joints used for the joints of the component group. The method for optimizing the engagement position of the vehicle body is characterized by including: A candidate engagement setting process, in which a candidate engagement is set at a position that will be an engagement of the component assembly; A fixed engagement selection process, in which at least four fixed engagement points or fixed engagement portions that must be engaged in each component group are selected from the engagement candidates set in each component group; and The process involves an optimal engagement analysis step. In this step, the vehicle body model is configured to exclude the fixed engagement points or fixed engagement portions selected from each component group from the optimization analysis, and to identify the optimal engagement candidates that will be the focus of the optimization analysis. Optimization analysis is then performed on the components other than the selected fixed engagement points or fixed engagement portions. This optimization analysis determines the optimal engagement points or engagement portions in the vehicle body model for engaging the component groups. The fixed joint selection process includes: In the first fixed joint selection step, static or dynamic analysis is performed on the vehicle model with the joint candidates set. Based on the results of the static or dynamic analysis, a first fixed joint point or a first fixed joint portion is selected from the joint candidates for each component group. In the second fixed engagement selection step, the engagement candidate that is furthest from the first fixed engagement point or the first fixed engagement portion is selected from the component group as the second fixed engagement point or the second fixed engagement portion. The third fixed joint selection step involves selecting the joint candidate that is furthest from the midpoint of the straight line connecting the first fixed joint point or the first fixed joint portion and the second fixed joint point or the second fixed joint portion as the third fixed joint point or the third fixed joint portion; and The fourth fixed joint selection step involves selecting, from among the joint candidates other than the first fixed joint point or the first fixed joint portion and the second fixed joint point or the second fixed joint portion, the joint candidate that is furthest from the third fixed joint point or the third fixed joint portion as the fourth fixed joint point or the fourth fixed joint portion.

2. The method for optimizing the joint position of the vehicle body according to claim 1, characterized in that, The first fixed joint selection step of the fixed joint selection process selects the joint candidate with the largest strain energy as the first fixed joint point or the first fixed joint part.

3. The method for optimizing the joint position of the vehicle body according to claim 1, characterized in that, The first fixed joint selection step of the fixed joint selection process selects the joint candidate with the largest resultant force of tensile stress and shear stress as the first fixed joint point or the first fixed joint part.

4. The method for optimizing the joint position of the vehicle body according to any one of claims 1 to 3, characterized in that, The fixed joint selection process uses the center of the joint candidate as a representative point and calculates the distance for the joint candidates in each component group in a cyclical manner.

5. An optimization analysis apparatus for the joint position of a vehicle body, performing optimization analysis on a vehicle body model having multiple components that are joined as a component group through joint points or joint portions, the optimization analysis determining the optimal position for point joints or continuous joints used for the joints of the component group. The device for optimizing the engagement position of the vehicle body is characterized by having: A joining candidate setting unit sets a joining candidate at a position that is a candidate for joining the component group. A fixed engagement selection unit selects from the engagement candidates set in each component group at least four fixed engagement points or fixed engagement portions that must be engaged in each component group; and A joint optimization analysis unit is configured to perform optimization analysis on the vehicle body model, specifically on the fixed joint points or fixed joint portions selected from each component group that are not the targets of the optimization analysis, and on the optimal joint candidates that are the targets of the optimization analysis. This optimization analysis determines the optimal joint points or joint portions in the vehicle body model for joining the component groups. The fixed engagement selection unit includes: The first fixed joint selection part performs static or dynamic analysis on the vehicle model with the joint candidates set, and selects a first fixed joint point or a first fixed joint part from the joint candidates for each component group based on the results of the static or dynamic analysis. The second fixed engagement selection part selects the engagement candidate that is furthest away from the first fixed engagement point or the first fixed engagement part as the second fixed engagement point or the second fixed engagement part in the component group. A third fixed engagement selection section selects the engagement candidate that is furthest from the midpoint of the straight line connecting the first fixed engagement point or the first fixed engagement portion and the second fixed engagement point or the second fixed engagement portion as the third fixed engagement point or the third fixed engagement portion; and The fourth fixed joint selection unit selects the joint candidate that is furthest away from the third fixed joint point or the third fixed joint from the joint candidates other than the first fixed joint point or the first fixed joint and the second fixed joint point or the second fixed joint.

6. The optimization analysis apparatus for the joint position of the vehicle body according to claim 5, characterized in that, The first fixed joint selection part of the fixed joint selection unit selects the joint candidate with the largest strain energy as the first fixed joint point or the first fixed joint part.

7. The optimization analysis apparatus for the joint position of the vehicle body according to claim 5, characterized in that, The first fixed joint selection part of the fixed joint selection unit selects the joint candidate with the largest resultant force of tensile stress and shear stress as the first fixed joint point or the first fixed joint part.

8. The apparatus for optimizing the engagement position of the vehicle body according to any one of claims 5 to 7, characterized in that, The fixed joint selection unit uses the center of the joint candidate as a representative point and calculates the distance for the joint candidates in each component group in a cyclical manner.

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