JP5440773B2 - Vehicle planning support system - Google Patents

Description

  The present invention relates to a vehicle planning support system, and more particularly to a vehicle planning support system that supports vehicle planning using a reference vehicle model having a predetermined vehicle specification value.

In the initial stage of vehicle development, a vehicle plan for examining vehicle packaging or the like is usually performed, and after this vehicle plan, a specific detailed design or production drawing is made.
When performing vehicle strength analysis in such vehicle planning, CAE (Computer Aided Engineering) is used. However, if the calculation is performed by a normal method, the vehicle model used for the analysis becomes complicated and large-scale. Moreover, in order to improve the analysis accuracy, a long time was required for the analysis.

  Conventionally, various planning support systems for supporting the vehicle planning have been proposed. For example, in Patent Document 1, for a vehicle component (center pillar), a plurality of vehicle design plans are created from a database having a plurality of parts (center pillar outer, etc.) information, and a structural analysis is performed for each vehicle design plan. A vehicle shape determination device that performs vehicle evaluation based on the vehicle evaluation and creates at least one vehicle design proposal from a plurality of vehicle design proposals to create an optimal vehicle design proposal. It is disclosed.

  Patent Document 2 reproduces the vibration of a typical vehicle body frame in a frequency band that is dominant with respect to the stress generated in the exhaust pipe, simplifies the vehicle body frame model, and reduces calculation time while ensuring analysis accuracy. A significantly reduced exhaust pipe strength analysis method is disclosed.

  In Patent Document 3, when creating a model used when simulating a system used in a vehicle, a model template and parameters of a plurality of parts constituting the system are stored, and these are read to create a model. A model creation support system that shortens the development period and improves the work efficiency by improving the reusability of information such as parts accumulated in automobile development has been disclosed.

JP 2002-366606 A JP 2004-53313 A JP 2006-343858 A

On the other hand, in the vehicle planning in the initial development stage of a new vehicle, when the specification value of the vehicle is changed, it is necessary to grasp the influence of the changed specification value on the rigidity performance. However, it is not easy to grasp this influence at the early stage of development, so it is necessary to add a reinforcing material at the end of development.
Such a problem can be avoided if the specification value of the vehicle is changed and the influence of the changed specification value on the rigidity performance can be easily grasped in the early stage of development.

  However, in the above-described conventional technology, when setting the vehicle specification values, the rigidity performance comparison is not performed for a combination of a plurality of types of vehicle specification values, and appropriate specification values are set based on the rigidity performance. Therefore, the above-mentioned problem cannot be solved.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle planning support system capable of grasping the influence of specification values on rigidity performance at an early stage of development and avoiding the addition of a reinforcing material at the end of development. It is said.

In order to achieve the above object, the present invention is a vehicle planning support system for supporting planning of a vehicle using a reference vehicle model having a predetermined vehicle specification value, and is a predetermined range with respect to the reference vehicle model. A plurality of concept vehicle models comprising a vehicle specification value creation means for creating a plurality of vehicle specification values and a plurality of vehicle body skeleton frame members having vehicle specification values created by the vehicle specification value creation means A concept vehicle model creation means, a plurality of concept vehicle models for performing strength analysis from a plurality of concept vehicle models, and an analysis vehicle model creation means for creating a vehicle model for analysis of the plurality of concept vehicle models; A vehicle body stiffness calculation means for calculating vehicle body stiffness values of a plurality of analysis vehicle models, and compares the stiffness calculation value with a target stiffness value stored in advance in a storage device, and selects one of a plurality of concept vehicle models Possess a concept vehicle model selecting means for selecting, a vehicle body rigidity calculation means is a static rigidity flexural rigidity and torsional rigidity, and calculates the dynamic stiffness in the following low-frequency region predetermined frequency, the vehicle body rigidity calculation means When calculating the dynamic stiffness in the low-frequency region, calculate the amount of displacement in the excitation direction of the single suspension mounting portion when the single suspension mounting portion in the vehicle model for analysis is unit-vibrated. The displacement amount is calculated as a compliance value, and the dynamic stiffness is calculated based on a frequency response curve in which the compliance value of one suspension mounting portion with respect to a unit excitation frequency is plotted .
In the present invention configured as described above, the vehicle specification value creation means creates a plurality of vehicle specification values within a predetermined range with respect to the reference vehicle model, and the conceptual vehicle model creation means creates these vehicle specification values. A plurality of concept vehicle models composed of a plurality of vehicle body skeleton frame members having a plurality of concept vehicle models, and the analysis vehicle model creation means selects a plurality of concept vehicle models for strength analysis from the plurality of concept vehicle models, and A vehicle model for analysis of the vehicle model is created, the vehicle body stiffness calculation means calculates the vehicle body stiffness values of a plurality of vehicle models for analysis, and the concept vehicle model selection means stores the stiffness calculation value and the target stored in the storage device in advance. Compared to the stiffness value, one of the multiple concept vehicle models is selected, so the vehicle stiffness performance by changing the vehicle specification values in the initial development stage of the new vehicle is compared to the reference vehicle model. Relative evaluation is possible, so it is possible to grasp the effect of vehicle specification values on rigidity performance in a short period of time, and as a result, it is possible to avoid unnecessary work such as adding reinforcement materials at the end of development, which was done in the past I can do it.
Furthermore, according to the present invention, the vehicle body package using the vehicle body specification values considering the bending rigidity and torsional rigidity, which are the static rigidity of the vehicle body, and the low-frequency region dynamic rigidity deeply related to the steering performance, It is possible to examine the structure plan. In particular, by calculating the dynamic stiffness in the low-frequency region that is closely related to the steering performance, the dynamic stiffness of the vehicle body skeleton frame member that affects the steering performance of the vehicle can be verified with high accuracy.
According to the present invention, in calculating the dynamic rigidity, the dynamic rigidity of the vehicle when simplified by a single point and unit input is calculated. That is, during actual vehicle travel, various forces that change in size and direction from moment to moment are applied to the vehicle body from the suspension mounting portion, but it is difficult to manage the dynamic rigidity. Therefore, in the present invention, paying attention to one suspension mounting portion in the vehicle model for analysis, unit vibration is applied to the one suspension mounting portion, the displacement amount in the same point and the same direction is calculated, and the displacement amount per unit input is calculated. Dynamic stiffness is calculated based on a certain compliance. Thereby, in this invention, it can simplify and can verify dynamic rigidity.

In the present invention, preferably, the vehicle body stiffness calculating means estimates a compliance value when the unit excitation frequency is 0 Hz from the frequency response curve, and calculates the dynamic stiffness from the compliance value.
According to the present invention configured as described above, it is possible to calculate the vehicle body rigidity when simplified by a single point and unit input.

In the present invention, preferably, the vehicle specification value is obtained by changing the vehicle specification value related to the wheel base and the vehicle specification value related to the vehicle height for each predetermined value.
(Function and effect)
According to the present invention configured as described above, it is possible to grasp the tendency of the vehicle body rigidity performance with respect to main vehicle specification values that greatly affect the design and comfort of the vehicle, and to select appropriate vehicle specification values. I can do it.

In the present invention, preferably, a plurality of conceptual vehicle models for performing strength analysis are selected by an experimental design method.
According to the present invention configured as described above, since the concept vehicle model for strength analysis is selected by the experimental design method, the number of concept vehicle models for strength analysis is minimized, and the vehicle body stiffness performance with respect to the vehicle specification values Can be grasped.

The present invention preferably further includes a vehicle body weight calculating means for calculating vehicle body weights of a plurality of analysis vehicle models, and a display device for displaying the calculated vehicle body rigidity values and vehicle body weights of the plurality of analysis vehicle models. Have.
In the present invention configured as described above, the weights of a plurality of vehicle models for analysis can be calculated, and further, the vehicle body rigidity value and the vehicle body weight can be displayed and compared relatively. Judgment can be made.

In the present invention, preferably, when calculating the bending rigidity, the vehicle body rigidity calculating means inputs the restraining reaction force to the second predetermined portion and the bending load to the third predetermined portion after constraining the first predetermined portion. The amount of displacement at the measurement site is calculated.
According to the present invention configured as described above, the degree of coincidence with the actual vehicle is high, and the calculation result of the bending rigidity can be obtained with high accuracy.

In the present invention, preferably, when calculating torsional rigidity, the vehicle body rigidity calculating means calculates a torsion angle amount at a measurement part when a torque load is input to the second predetermined part after constraining the first predetermined part. To do.
According to the present invention configured as described above, the degree of coincidence with the actual vehicle is high, and the calculation result of the torsional rigidity can be obtained with high accuracy.

In the present invention, preferably, the vehicle body rigidity calculating means calculates the dynamic rigidity in a low frequency region below a predetermined frequency when the vibration of a low frequency below the predetermined frequency is inputted to the vehicle model for analysis. The displacement amount is calculated.
According to the present invention configured as described above, it is possible to accurately evaluate the steering performance by evaluating only the low frequency that is closely related to the steering performance.

The present invention preferably further includes plate thickness optimizing means for optimizing the plate thickness of the vehicle body skeleton frame member based on the increase in the weight of the vehicle model for analysis due to the change of the specification value.
According to the present invention configured as described above, the increase in the vehicle weight accompanying the change in the vehicle specification value can be reduced by reducing the plate thickness of the vehicle body skeleton frame member.

  According to the vehicle planning support system of the present invention, it is possible to grasp the influence of the specification value on the rigidity performance and to avoid the addition of a reinforcing material at the end of development.

It is a block diagram which shows the basic composition of the plan assistance system by embodiment of this invention. It is a block diagram which shows the various programs and database servers for plan support which the vehicle plan support system by embodiment of this invention uses. It is a flowchart which shows the basic flow of the vehicle plan assistance system by embodiment of this invention. It is drawing which shows the display part of the computer at the time of the input of the specification value etc. of the reference | standard vehicle model by embodiment of this invention. It is a figure which shows the reference | standard vehicle model created by the vehicle planning assistance system by embodiment of this invention, and the several concept vehicle model (concept vehicle model 1-6) in which intensity | strength analysis is performed. 1 is a perspective view showing a vehicle body skeleton frame of a conceptual vehicle body model created by a vehicle planning support system according to an embodiment of the present invention. It is a perspective view which shows the concept vehicle model made from the vehicle body frame | skeleton frame of FIG. It is a perspective view which shows the vehicle model for analysis produced by the vehicle planning assistance system by embodiment of this invention. It is the perspective view which looked at the analytical vehicle model for demonstrating the calculation method of the "bending rigidity" performed in the vehicle planning assistance system by embodiment of this invention from the diagonal back side direction. It is the perspective view which looked at the analysis vehicle model for demonstrating the calculation method of the "torsional rigidity" performed in the vehicle planning assistance system by embodiment of this invention from the diagonal back side direction. It is a diagram for explaining a calculation method of “dynamic stiffness in a low frequency region” executed in the vehicle planning support system according to the embodiment of the present invention. FIG. 4 is a diagram showing a “bending displacement amount of a reference vehicle model” and a “range of a target bending displacement amount obtained from a bending displacement amount of a reference vehicle model” in a vehicle planning support system according to an embodiment of the present invention. FIG. 4 is a diagram showing “a torsional angle displacement amount of a reference vehicle model” and “a range of a target torsional angle displacement amount obtained from a torsion angle displacement amount of a reference vehicle model” in a vehicle planning support system according to an embodiment of the present invention. It is a perspective view of a vehicle model for analysis showing board thickness distribution by a vehicle planning support system by an embodiment of the present invention. It is the figure which displayed the analysis result of static stiffness by the planning support system of vehicles by the embodiment of the present invention.

Hereinafter, a planning support system according to an embodiment of the present invention will be described with reference to the drawings.
First, the basic configuration of the planning support system according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the basic configuration of a planning support system according to an embodiment of the present invention, and FIG. 2 shows various programs and database servers for planning support used by the vehicle planning support system according to the embodiment of the present invention. It is a block diagram.

  As shown in FIG. 1, the vehicle planning support system 1 according to the present embodiment includes a computer 2 and a database server 4. The computer 2 includes a CPU 8, a ROM 10, a RAM 12, a storage unit 14, an input unit 16, a display unit 18, and a communication unit 22, which are connected to each other by a system bus 6.

  The CPU 8 is a central processing unit that executes processing by the planning support program 22 shown in FIG. 2 in addition to general computer processing. The ROM 10 stores a boot program for starting the computer 2 and the like. The RAM 12 includes a program area for temporarily storing a planning support program 22 executed in the vehicle planning support system 1 and various data, and a data area for writing and reading data.

  The storage unit 14 is a storage device such as a hard disk drive. The storage unit 14 has a plan support program storage unit, and stores a plan support program 22 shown in FIG. The input unit 16 is a keyboard, a mouse, or the like for inputting commands and data from the outside. The display unit 18 is a liquid crystal display or the like. The communication unit 20 transmits and receives information between the database server 4 and another computer (not shown) via a wireless or wired communication line.

Here, before explaining the planning support program 22, the outline of the planning support system according to the present embodiment will be described. The planning support system of the present embodiment creates a reference vehicle model that serves as a reference when planning support is performed in advance, and next, a plurality of reference vehicle models and vehicle specification values within a predetermined range (range). By comparing the vehicle body stiffness values of these concept vehicle models with the target values and performing a relative evaluation of the vehicle body stiffness performance by changing the vehicle specification values with respect to the reference vehicle model, The concept vehicle model is selected. Here, it is verified in advance that the reference vehicle model matches the actual vehicle with high accuracy.
In addition, the verification target of the planning support system according to the present embodiment is a vehicle body structure model (concept vehicle model) composed of a vehicle body skeleton frame member (see FIG. 7 and the like).

  Next, the outline of the planning support program 22 and the outline of the flow of vehicle planning will be described with reference to FIG. As shown in FIG. 2, the plan support program 22 receives the vehicle specification value of the reference vehicle model and the range for the concept vehicle model (change allowance range of the specification value) that are used as a reference when performing the planning support. An input program 24 and a vehicle specification value generation program 26 for the concept vehicle model are included.

  Further, the planning support program 22 includes a reference vehicle model generation program (including an analysis reference vehicle model generation program) 28, a rigidity calculation program 30, a weight calculation program 32, a 3D shape (3) for the reference vehicle model. A (dimensional shape) creation program 34 and a plate thickness suitability program 36 are included.

Similarly, the planning support program 22 includes a concept vehicle model generation program (including an analysis concept vehicle model generation program) 38, a rigidity calculation program 40, a weight calculation program 42, and a 3D shape (for a concept vehicle model). A three-dimensional shape) creation program 44 and a plate thickness suitability program 46 are included.
Further, the planning support program 22 includes a target stiffness value input receiving program 48 for the concept vehicle model.

  Next, the database server 4 stores the vehicle specification values of the reference vehicle model and the range data 50 of the concept vehicle model, the stiffness calculation value data 52 of the reference vehicle model and the concept vehicle model, the weights of the reference vehicle model and the concept vehicle model. The calculated value data 54, the reference vehicle model, the 3D shape data 56 of the concept vehicle model, and the target stiffness value data 58 of the concept vehicle model are stored.

  Next, the basic flow of the vehicle planning support system according to the present embodiment will be described with reference to FIG. In FIG. 3, S indicates each step. Further, when the basic flow of the planning support system is described with reference to FIG. 3, specific contents in each step will be described with reference to FIGS.

  In the vehicle planning support system of the present embodiment, before the basic flow of FIG. 3 is performed, “input program 24 for receiving vehicle specification values and ranges of the reference vehicle model” shown in FIG. "Reference vehicle model generation program (including reference vehicle model generation program for analysis) 28", "rigidity calculation program 30", "weight calculation program 32", "3D shape (three-dimensional shape) creation program 34", and It is assumed that a detailed analysis such as optimization of rigidity, weight, 3D shape, and thickness of the reference vehicle model has already been made using the “plate thickness suitability program 36”. Furthermore, as described above, it has been verified that the analysis result of the reference vehicle model matches the actual vehicle with high accuracy.

In FIG. 3, first, in S1, vehicle specification values of a reference vehicle model, which is a vehicle model that is a reference for planning support, according to the “reference vehicle model vehicle specification value, range input receiving program 24” shown in FIG. Enter the range, plate thickness, and stiffness target values.
Specifically, as shown in FIG. 4, the specification values of the reference vehicle model are the lengths indicating the wheelbase, the vehicle height, the vehicle width, the total length, etc., which are the main specifications of the body structure model to be verified. Dimension) and design values of other specifications, and these specification values are input on the screen of the computer 2.

The range is a change allowable range for the specification value of the reference vehicle model that can be adopted by the concept vehicle model to be described later. For example, as shown in FIG. 4, when the specification value of the wheel base of the reference vehicle model is 2630 mm 2600-2700 mm is input as the range. In this case, the selectable specification values of the wheel base of the concept vehicle model are 2600 to 2700 mm.
As the plate thickness, a design value (1.4 mm) of the reference vehicle model and a selectable plate thickness (0.9 mm, etc.) are input.
Furthermore, as the rigidity target values, the bending rigidity (+ 10% to -10%), torsional rigidity (+ 5% to -5%), dynamic rigidity (+ 10%), which are target values expressed as a ratio to the rigidity value of the reference vehicle model. ~ -10%) is entered.

Next, the process proceeds to S2, a plurality of vehicle specification values for the reference vehicle model are set by the “vehicle specification value generation program 26 of the conceptual vehicle model” shown in FIG. 2, and then the process proceeds to S3, where FIG. A plurality of concept vehicle models corresponding to the plurality of vehicle specification values are set by the “concept vehicle model generation program 38” shown.
Specifically, among the main specifications, candidates for the vehicle height, wheel base, and the like that are required from the vehicle grade, comfortability, design, etc. are listed to be a concept vehicle model. If the vehicle height specification values are four and the wheel base specification values are three, twelve concept vehicle models are set.
As shown in FIG. 7, the conceptual vehicle model 76 includes a vehicle body skeleton frame, which is a vehicle body inner panel 70, a vehicle body outer panel 72, a vehicle body platform 74, and the like, as shown in FIG.

Next, it progresses to S4 and the several concept vehicle model and the concept vehicle models 1-6 which calculate rigidity are selected.
The plurality of concept vehicle models are selected by the designer based on various data and experiences.
In addition, a plurality of concept vehicle models may be selected by an experimental design method. When using the experimental design method, first, list the candidate values for vehicle height, wheelbase, design, etc. for the vehicle height and wheelbase that are the main specifications. Decide the verification factors (vehicle height, wheel base) and level (various length of vehicle height, various length of wheel base), verify the tendency of rigidity with this orthogonal table, and finally Narrows down to the minimum number of concept vehicle models for which intensity estimation is possible. In this way, the number of conceptual vehicle models that need to be analyzed can be minimized.
FIG. 5 shows the concept vehicle models 1 to 6 and the reference vehicle model selected in this way.

  Next, the process proceeds to S5, and the analysis vehicle models of the plurality of concept vehicle models 1 to 6 selected in S4 by the "concept vehicle model generation program (including the analysis concept vehicle model generation program) 38" shown in FIG. Create FIG. 8 shows a vehicle model for analysis of the concept vehicle model. This vehicle model for analysis is a mesh model that performs rigidity analysis using a finite element method (FEM).

  Next, proceeding to S6, first, the stiffness value of the analysis vehicle model of the first conceptual vehicle model is calculated. The rigidity values calculated here are “flexural rigidity” and “torsional rigidity” which are static rigidity, and “dynamic rigidity in a low frequency region”, which are specifically described with reference to FIGS. 9 to 11. explain.

  The calculation method of “bending rigidity” will be described with reference to FIG. As shown in FIG. 9, in the vehicle model for analysis 78, one part of the front end part 80 and two parts of the rear end part 82 are constrained, and then directed vertically downward to the upper surfaces of the side sills 84 on both sides. The bending load F1 is applied, and restraining reaction forces R1 and R2 are generated on the lower surface near the front suspension mounting portion 86 and the lower surface near the rear suspension mounting portion 88. 2 is applied to the analysis vehicle model 78 by applying these restraint parts, the value and action part of the bending load F1, and the values and action parts of the restraint reaction forces R1 and R2, and the “stiffness calculation program 40” shown in FIG. The bending rigidity of the vehicle model for analysis 78 is calculated by calculating the amount of displacement at each measurement site.

  A method of calculating “torsional rigidity” will be described with reference to FIG. As shown in FIG. 10, in the vehicle model 78 for analysis, similarly, one place of the front end 80 and two places of the rear end 82 are constrained, and then the right lower surface in the vicinity of the mounting portion 86 of the front suspension. Applies a vertical upward torsional load F2, and applies a downward downward vertical torsional load F2 to the lower left surface (that is, to apply a torque load). By applying these restraint parts, the values of the torsional loads F2 and F2 and the action positions to the vehicle model 78 for analysis, and using the “rigidity calculation program 40” shown in FIG. To calculate the torsional rigidity of the vehicle model 78 for analysis.

With reference to FIG. 11, a method of calculating “dynamic stiffness in the low frequency region” will be described. When the vehicle travels, various inputs are applied to the vehicle body from the suspension mounting portion. Since the size and direction of this input change from moment to moment, it is difficult to manage the dynamic rigidity with these inputs. The vehicle body rigidity is calculated when the input to the mounting part is simplified by a single point and unit input instead of multipoint input as in traveling. That is, when a certain suspension mounting portion is subjected to unit excitation in a certain direction (amplitude Fi = 1 [N]) and a displacement amount Xi [mm] in the same point and the same direction is calculated, the horizontal axis represents the frequency [Hz] and the vertical axis represents the suspension. A compliance Xi / Fi of the mounting portion, that is, a frequency response curve in which a displacement amount per unit input is plotted is obtained. This compliance corresponds to the reciprocal of the stiffness, and the characteristic of the low frequency region below the predetermined frequency of this frequency response curve is defined as “dynamic stiffness in the low frequency region”.
Further, from this frequency response curve, the “dynamic stiffness in the low frequency region” may be determined by the compliance value of the specific frequency in the low frequency region. In particular, the compliance value of 0 Hz is estimated from the frequency response curve (broken line in FIG. 11). The estimated compliance value at 0 Hz (= displacement amount per unit excitation = reciprocal of stiffness) may be defined as “dynamic stiffness [N / mm] in a low frequency region”.

  In the vehicle planning support system of the present embodiment, as shown in FIG. 11, the vehicle body is vibrated in a low frequency region of 100 Hz or less, which is a predetermined frequency, to obtain the maximum displacement amount of each measurement site. The “dynamic stiffness in the low frequency range” is calculated. Here, the dynamic stiffness in the low frequency region of 100 Hz or less, which is a predetermined frequency, is calculated based on the dynamic stiffness of the low frequency region to verify the dynamic stiffness of the vehicle body skeleton frame member that has an influence on the vehicle stability. Because it can.

Next, in S7, the weight of the vehicle model for analysis is calculated by the “weight calculation program 42” shown in FIG.
Here, the stiffness calculation value calculated in S6 is stored in “stiffness calculation value data 52” shown in FIG. 2, and the weight calculation value calculated in S7 is similarly “weight calculation value data 54”. Stored in

Next, proceeding to S8, the target stiffness value (bending stiffness, torsional stiffness, low frequency region) input by the “target stiffness value input receiving program 48” shown in FIG. 2 and stored in the “target stiffness value data 58” is shown. ) And the stiffness values calculated in S6 (bending stiffness, torsional stiffness, dynamic stiffness in the low frequency region) are compared.
Here, FIG. 12 shows the “bending displacement amount of the reference vehicle model” and the “range of the target bending displacement amount obtained from the bending displacement amount of the reference vehicle model”, and FIG. “Angular displacement amount” and “A range of the target torsional angular displacement obtained from the torsional angular displacement of the reference vehicle model” are shown, and it is determined whether or not the calculated stiffness value is within these target ranges.
The target range shown in FIGS. 12 and 13 is constant over the entire range, but the target range varies depending on the position from the front end of the vehicle, for example, the range from 0 to 100 mm is 0 to + 3%, 100. ˜200 mm may be set as −2% to + 5%. Further, different target ranges may be set depending on the part, for example, the side sill portion may be set to 0 to + 3%, the front side frame portion may be set to -2% to + 5%, and the like.

  Next, it progresses to S9 and it is determined whether a rigidity value is larger than a target rigidity value. When the stiffness value is larger than the target stiffness value, the process proceeds to S10, and the plate thickness of the vehicle model for analysis is reduced by the “plate thickness optimization program 46” shown in FIG. Then, it returns to S6 and performs the same step.

  If the stiffness value is less than or equal to the target stiffness value, the process proceeds to S11, and it is determined whether or not the stiffness value is smaller than the target stiffness value. When the stiffness value is smaller than the target stiffness value, the process proceeds to S12, and the plate thickness of the vehicle model for analysis is increased by the “plate thickness optimization program 46” shown in FIG. Then, it returns to S6 and performs the same step.

  If it is determined in S11 that the rigidity value is the same as the target rigidity value, the process proceeds to S13, and whether or not the rigidity and plate thickness optimization have been completed for all the concept vehicle models selected in S4. Determine whether. In this case, since the rigidity and plate thickness optimization for the first concept vehicle model has only been completed, the process returns to S5 to optimize the rigidity and plate thickness of the second concept vehicle model. The rigidity and plate thickness of the first concept vehicle model are optimized, and S13 ends.

  Here, supplementary explanation will be given for S8 to S13. FIG. 14 is a perspective view of a vehicle model for analysis showing a plate thickness distribution, and a region where a thin plate can be formed and a region where a thick plate is necessary can be easily recognized based on the displayed density. As shown in FIG. 14, the plate thickness is displayed for each mesh, but the plate thickness is managed for each member such as a side sill and a front side frame, so that each member is partially thickened or thinned. I can't do it. For this reason, for example, if there is a mesh display on the side sill where it is necessary to increase the plate thickness, the entire side sill is changed from the current plate thickness to the next thicker plate thickness, and the stiffness calculation is performed to obtain the target stiffness. Repeat until you are satisfied. Furthermore, the thickness of not only one member but also many members is changed to achieve the target rigidity.

  In this manner, in S8 to S13, the plate thickness is optimized for each vehicle body skeleton frame constituting the vehicle model for analysis.

  Next, the process proceeds to S14, in which the specification values, rigidity values (bending rigidity, torsional rigidity, dynamic rigidity in the low frequency region), weight, and plate thickness of the vehicle models for analysis of the plurality of conceptual vehicle models are displayed on the display unit. 18 is displayed. At this time, an image of the conceptual vehicle model is displayed by the “3D shape creation program 44 (3D-CAD)” shown in FIG. The obtained 3D shape data of the concept vehicle model is stored in the 3D shape data 56 of the database server 4 shown in FIG.

Here, in S14, for example, an analysis result of static stiffness as shown in FIG. 15 is displayed. From FIG. 15, for example, by comparing the reference vehicle model and the concept vehicle models 1 and 2 with each other, the tendency of the rigidity against the change of the wheel base can be grasped, and the quality of the body frame structure can be determined. I can grasp it. Further, by comparing the concept vehicle models 1, 3, 5, and 6 relative to each other, it is possible to grasp the tendency of the rigidity with respect to the change in the vehicle height, and it is possible to grasp the quality of the body frame structure.
Furthermore, it is possible to grasp the change in weight with respect to the reference vehicle model due to the specification value change and the plate thickness optimization for each concept vehicle model.

  Next, the process proceeds to S15, and an optimal concept vehicle model is selected from the six concept vehicle models (concept vehicle models 1 to 6) for which plate thickness optimization has been completed based on the analysis results shown in FIG. select.

Next, the operational effects of the vehicle planning support system according to this embodiment described above will be described.
In the present embodiment, the vehicle specification value generation program 26 of the conceptual vehicle model creates a plurality of vehicle specification values within a range (change allowable range) with respect to the reference vehicle model, and the conceptual vehicle model creation program 38 12 conceptual vehicle models composed of a plurality of vehicle body skeleton frame members (vehicle body inner panel 70, vehicle body outer panel 72, platform 74, etc.) having the following vehicle specification values are created. A plurality of concept vehicle models 1 to 6 that perform strength analysis are selected from the 12 concept vehicle models, a vehicle model for analysis of the plurality of concept vehicle models is created, and a stiffness calculation program 40 is used for the analysis. Calculate vehicle body stiffness values of vehicle models 1-6 ("flexural rigidity" and "torsional rigidity" and "dynamic rigidity in the low frequency range"). The rigidity calculation value is compared with the target rigidity value stored in advance in the target rigidity value data 58, and any one of the plurality of concept vehicle models 1 to 6 is selected. Since the relative evaluation of the vehicle body stiffness performance by changing the specification value with respect to the reference vehicle model is possible, the effect of the vehicle specification value on the stiffness performance can be grasped in a short period of time. Useless work such as adding reinforcement at the end of development can be avoided.

  In order to confirm the accuracy of the conceptual vehicle model obtained by the vehicle planning support system according to the present embodiment, the present inventors first create a detailed vehicle model having the same vehicle specification value that matches the actual vehicle with high accuracy. After that, we compared the rigidity performance of the detailed vehicle model and the concept vehicle model.

  In addition, according to the vehicle planning support system according to the present embodiment, the vehicle body specification values considering the bending stiffness and torsional stiffness, which are the static stiffness of the vehicle body, and the dynamic stiffness in the low frequency region, which is closely related to the steering performance, are obtained. It can be used to study vehicle body packages, structural plans, etc.

  In addition, according to the vehicle planning support system according to the present embodiment, the tendency of the vehicle body rigidity performance with respect to main vehicle specification values (wheel base, vehicle height, vehicle width, total length, etc.) that greatly affect the vehicle design and comfort. And an appropriate vehicle specification value can be selected.

  Further, according to the vehicle planning support system according to the present embodiment, since the concept vehicle model for performing the strength analysis is selected by the experimental design method, the number of the concept vehicle models for performing the strength analysis is minimized, and the vehicle specification value is determined. The trend of vehicle body rigidity performance can be grasped.

  In addition, according to the vehicle planning support system according to the present embodiment, the weight of a plurality of vehicle models for analysis can be calculated, and further, the vehicle body rigidity value and the vehicle body weight can be displayed, and both can be compared relatively. These superiority and inferiority can be judged.

  Further, according to the vehicle planning support system according to the present embodiment, when calculating the bending rigidity, the front end portion and the rear end portion (first predetermined portion) of the vehicle are restrained, and the front and rear suspension mounting portions are constrained. Since the restraint reaction forces R1 and R2 are applied to the (second predetermined part) and the bending load F1 is input to the upper surfaces (third predetermined parts) of the side sills on both sides, the displacement amount at the measurement part is calculated. The degree of coincidence is high, and the calculation result of the bending rigidity can be obtained with high accuracy.

  Further, according to the vehicle planning support system according to the present embodiment, when calculating the torsional rigidity, the front end portion and the rear end portion (first predetermined portion) of the vehicle are constrained and the front suspension mounting portion (second Since the torsion angle amount at the measurement site when the torque load is input to the predetermined site is calculated, the degree of coincidence with the actual vehicle is high, and the calculation result of the torsional rigidity can be obtained with high accuracy.

  In addition, according to the vehicle planning support system of the present embodiment, when calculating the dynamic stiffness in the low frequency region, the maximum displacement amount of the predetermined part when the predetermined low frequency is input to the vehicle model for analysis is calculated. Therefore, it is possible to evaluate the steering performance with high accuracy by evaluating only the low frequency, which is closely related to the steering performance.

  Further, according to the vehicle planning support system of the present embodiment, the plate thickness optimization program 46 optimizes the plate thickness of the vehicle body skeleton frame member based on the increase in the weight of the vehicle model for analysis by changing the vehicle specification value. Therefore, the increase in the vehicle weight accompanying the change in the vehicle specification value can be reduced by reducing the plate thickness of the vehicle body skeleton frame member.

1 Vehicle Planning Support System 2 Computer 4 Database Server 8 CPU
10 ROM
12 RAM
14 storage unit 16 input unit 18 display unit 20 communication unit 22 planning support program 24 vehicle specification value and range input program of reference vehicle model 26 vehicle specification value generation program of concept vehicle model 28 reference vehicle model generation program 30 for rigidity calculation Program 32 Weight calculation program 34 3D shape (3D shape) creation program 36 Thickness suitability program 38 Concept vehicle model generation program 40 Stiffness calculation program 42 Weight calculation program 44 3D shape (3D shape) creation Program 46 Thickness suitability program 48 Target stiffness value input reception program 50 Vehicle specification value and range data 52 of the reference vehicle model 52 Stiffness calculation value data 54 Weight calculation value data 56 3D shape data 58 Target stiffness value data 70 Car body inner panel 72 Car body outer panel 7 4 Vehicle Platform 76 Conceptual Vehicle Model 78 Analytical Vehicle Model 80 Front End 82 Rear End 84 Side Sill 86 Front Suspension Attachment 88 Rear Suspension Attachment

Claims (8)

A vehicle planning support system that supports vehicle planning using a reference vehicle model having a predetermined vehicle specification value,
Vehicle specification value creating means for creating a plurality of vehicle specification values within a predetermined range with respect to the reference vehicle model;
A conceptual vehicle model creating means for creating a plurality of conceptual vehicle models composed of a plurality of vehicle body skeleton frame members having the vehicle specification values created by the vehicle specification value creating means;
Selecting a plurality of concept vehicle models for strength analysis from the plurality of concept vehicle models, and generating an analysis vehicle model creating means for creating a vehicle model for analysis of the plurality of concept vehicle models;
Vehicle body stiffness calculating means for calculating vehicle body stiffness values of the plurality of vehicle models for analysis;
A concept vehicle model selection means for comparing the rigidity calculated value with a target stiffness value stored in advance in a storage device and selecting one of a plurality of concept vehicle models;
I have a,
The vehicle body rigidity calculating means calculates bending rigidity and torsional rigidity, which are static rigidity, and dynamic rigidity in a low frequency region below a predetermined frequency,
When calculating the dynamic stiffness in the low-frequency region, the vehicle body stiffness calculating means is a displacement amount in the excitation direction of the one suspension mounting portion when a unit of the suspension mounting portion in the vehicle model for analysis is subjected to unit excitation. And calculating the dynamic stiffness based on a frequency response curve plotting the compliance value of the one suspension mounting portion with respect to the frequency of the unit excitation. A vehicle planning support system characterized by that. 2. The vehicle planning support system according to claim 1, wherein the vehicle body stiffness calculation means estimates a compliance value when the unit excitation frequency is 0 Hz from the frequency response curve, and calculates a dynamic stiffness from the compliance value. .   2. The vehicle planning support system according to claim 1, wherein the vehicle specification value is obtained by changing a vehicle specification value relating to a wheel base and a vehicle specification value relating to a vehicle height for each predetermined value.   The vehicle planning support system according to claim 1, wherein a plurality of conceptual vehicle models for performing the strength analysis are selected by an experimental design method.   The vehicle body weight calculating means for calculating the vehicle body weight of the plurality of analytical vehicle models, and a display device for displaying the calculated vehicle body rigidity value and the vehicle body weight of the plurality of analytical vehicle models. Vehicle planning support system described in 1.   When calculating the bending rigidity, the vehicle body rigidity calculating means restrains the first predetermined portion, and then the displacement amount at the measurement portion when a restraining reaction force is input to the second predetermined portion and a bending load is input to the third predetermined portion. The vehicle planning support system according to claim 2, wherein: The vehicle body rigidity calculation means when calculating the torsional rigidity, after restraining the first predetermined portion, according to claim 1 for calculating the torsion angle amount in the measurement site when inputting the torque load on the second predetermined portion Vehicle planning support system. 6. The vehicle planning support system according to claim 5, further comprising plate thickness optimization means for performing plate thickness optimization of the vehicle body skeleton frame member based on an increase in weight of the vehicle model for analysis by changing the specification value. .