JPH0736193B2 - CAD system for layout analysis of linear objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention analyzes a mechanical effect when a linear object such as a brake hose is attached to a structure to analyze the linear object. A CAD system for layout analysis of linear objects that analyzes the layout of objects.

(Prior Art) For example, various kinds of linear objects such as brake hoses are used in vehicles. These linear objects cause a problem of interference with each part of the vehicle in layout design.
Above all, the brake hose exhibits complicated behavior due to wheel bound, rebound, steer, etc., so it is necessary to seek an appropriate layout for safety.

As a conventional layout study CAD system for obtaining such a layout, the positions (coordinates) of the surrounding parts, which are the structures to which the linear objects are attached, are input as CAD data and displayed on a CAD terminal. Layout designer is CAD
Consider the mounting position of the linear object based on the layout drawing displayed on the terminal. This is to check the positional relationship between the surrounding parts in the space where the linear object is attached with the CAD terminal from the layout screen, measure and select the size of the space where the surrounding parts and the linear object do not interfere, and determine the attachment position. .
This decision depends on the experience of the designer. In addition, whether or not interference between the linear object and the surrounding parts will occur at the determined mounting position will be examined by mounting the linear object on the actual structure and measuring the dimensions.

(Problems to be Solved by the Invention) In the above-described conventional CAD system for layout examination, since it is not possible to analyze the mechanical effect of the linear object when the linear object is attached to examine the layout, The shape when actually attached is not the shape expected in the design due to the influence of twisting, bending, etc., and if a linear object is attached at the attachment position decided by the designer, it may interfere with surrounding parts. However, there is a problem that the mounting position must be repeatedly reviewed.

The present invention has been made in view of the above, and an object thereof is to analyze a mechanical influence when a linear object is mounted to obtain a mounting shape, and to accurately determine the layout of the linear object and the structure. It is to provide a CAD system for layout analysis of linear objects that can be studied efficiently and efficiently.

[Structure of Invention]

(Means for Solving the Problem) In order to achieve the above-mentioned object, the layout analysis CAD system for linear objects of the present invention, as shown in FIG. 1, is a mechanical system when linear objects are attached to a structure. Layout analysis CA of linear objects that analyzes the influence to analyze the layout of linear objects
In the D system, the structure storage means 1 that stores information including the shape of the structure to which the linear object is attached, and the information including the length, outer diameter, inner diameter, and material of the linear object are stored. The linear object storage means 3, the input means 5 for inputting the position and the direction to attach the linear object, the displacement path dividing means 7 for dividing the displacement path of the linear object, and the divided displacement course. Therefore, the increasing means 9 for gradually increasing the amount of the mounting condition, the calculating means 11 for calculating the shape of the linear object according to the information of the linear object according to the amount of the given condition, and the target amount of the mounting condition. The gist is to have a display means 13 for displaying the calculated shape in addition to the information of the structure.

(Operation) In the layout analysis CAD system of the linear object of the present invention,
By inputting the information of the linear object and the mounting position and attaching the linear object to the structure, the mechanical effect on the linear object is analyzed, the mounting shape is calculated, and the coordinates are converted to match the coordinates of the structure, The position of the structure is combined with the input CAD data and displayed as a layout drawing.

(Examples) Examples of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a layout analysis CAD system for linear objects according to an embodiment of the present invention. The layout analysis CAD system shown in the figure includes, for example, a CAD data memory 21 that stores CAD data that is positions (coordinates) of surrounding parts that are structures to which linear objects such as brake hoses are attached, and a linear object Input device 23 for inputting physical conditions such as length, outer diameter, inner diameter, material, and mounting position and direction, and mounting shape of linear object and shape of linear object accompanying movement of structure to which linear object is mounted An analyzer 25 for analyzing changes, a coordinate conversion of the analysis result of this analyzer 25, a synthesizing device 27 for synthesizing with CAD data from the CAD data memory 21, and a mounting shape of a linear object analyzed and obtained by the analyzer 25. And input the position of the rotating parts
The display device 29 is configured to display a result obtained by combining the CAD data from the CD data memory 21 as a layout drawing.

The analyzer 25, a mechanical influence that is a factor that changes the mounting shape of the linear object such as an external force applied to the linear object at the time of mounting, an external force applied by the operation of the rotating parts mounted after mounting the linear object. It is provided for analysis. As the numerical analysis method, a method of reproducing the mechanical influence applied to the linear object by using the finite element method and analyzing the mounting shape is used. Note that the analyzer
As 25, there is also a method to obtain the state in which strain energy is most stable by convergence calculation from the value added in addition to directly calculating the mechanical effect on the linear object to obtain the shape. .

Further, in order to display the analysis result of the mounting shape of the linear object output from the analyzer 25 together with the rotating parts on the display device 29 as a layout drawing, the mounting shape data of the linear object and the CAD data of the rotating parts are coordinated. Convert and synthesize. There are infinite combinations of types of external force applied to find the mounting shape of a linear object. Therefore, it is necessary to find some kind of law to find the mounting shape.

In analyzing the mounting shape of the linear object with the analyzer 25, it is examined whether the mounting shape depends on the deformation path. The calculation is performed by changing several kinds of deformation paths, and the relationship between the deformation path and the mounting shape is examined. In addition,
The attachment shape is the shape when it was finally attached, and the deformation path is when one end of the linear object is fixed and then the other end is moved (that is, calculated) to bring it to the final attachment shape. Is the route. And, no matter what kind of deformation path is followed, the attachment shape is determined by tension or the like.

The displacements applied to linear objects such as brake hoses during installation work are parallel movements such as tension and compression and rotations such as bending and twisting. Bending deformation is expressed by compression and torsional deformation. Therefore, we will compare the mounting shapes when changing the amount and the method of applying torsional displacement by parallel movement and rotation by linear movement to a linear object.

FIG. 3 shows an analysis in which a mounting position and a direction of a linear object such as a brake hose are fixed, a displacement is given, and a size thereof is changed. The path A is obtained by determining the mounting shape while applying a twist due to rotation, and does not apply a compressive or tensile displacement to the linear object. The route B applies tensile and compression displacements due to parallel movement to the linear object, and then imparts torsional displacements due to rotation. The amount of torsional displacement is different from the paths A and C. Route C
Applies a tensile displacement to a linear object by parallel movement, and then applies parallel movement and rotation simultaneously to apply torsional displacement while applying compression. The amount of torsional displacement is equal to that of the route A, but the amount of torsional displacement applied by rotation is equal to that of the route B.

The mounting shapes are the same for the paths A and C and the paths B and D with the same amount of torsional displacement. In addition, the paths B and D are different in how to apply tension, compression, and torsional displacement, but the mounting shapes are the same.

Therefore, if the amount of torsional displacement when the linear object is routed is the same, it can be said that the mounting shape does not depend on how to give tension, compression, or torsional displacement, that is, the deformation path.
The analyzer 25 takes this knowledge into consideration to determine the mounting shape of the linear object.

Next, the processing of the CAD system for examining the layout of linear objects will be described with reference to the flowchart of FIG. In addition,
FIG. 5 shows an example of a CAD screen on which the layout of the brake hose is examined by the layout analysis CAD system. In this description, however, the brake hose 31 is used as an example of the linear object. A tube 33 and the like are shown as a structure for the brake hose 31.

First, the shapes of the surrounding parts, which are the structures to which the linear object is attached, are displayed on the display device 29, and the coordinates of the attachment position of the linear object and the attachment direction are input (step 11).
0). This input method may be designated by a pick with a light pen from the screen of the display device 29, or the coordinates and the mounting direction (angle or the like) may be directly input. Since the connection of the brake hose is devised so as to be positioned and connected, the twist amount can be calculated by determining the coordinates and the mounting direction of the linear object as in step 110. However, if the fuel hose or the like is not positioned, the twist amount at the time of connection needs to be set in step 110.

Then, the length of the linear object, the outer diameter, the inner diameter, the number of element divisions,
For example, a physical property condition such as a material constant of rubber or iron is given as input data and used for calculation of a mounting shape to create a finite element method model of a linear object (step 120). In addition,
FIG. 6 shows an example of object conditions such as length, outer diameter, inner diameter, number of element divisions, material constants, etc. of such a linear object.

The model created with the above input data connects a set of nodes having coordinates defined from the number of input element divisions,
The linear object itself may be modeled in three dimensions, or a beam model may be used by connecting a set of nodes having coordinates on the neutral axis of the linear object. When the beam element is used, the area of the beam, the moment of inertia of area, and the torsion moment are calculated from the input data, and the characteristics of the linear object are expressed.

Next, in order to reproduce the mounting shape of the linear object at the mounting position from the values input in steps 110 and 120, one end of the linear object is fixed and a displacement amount is added to the other end, and FIG.
The displacement path in the three-dimensional space shown in (1) is routed and the displacement path is calculated (step 130). Note that FIG. 8 shows an example of the displacement path.

Since the analysis of the mounting shape of the linear object is a non-linear analysis, the displacement amount is given separately. The form of the displacement amount is movement and rotation (torsion) in the translational direction as shown in FIG. 7 (b). Therefore, as mentioned above, if the mounting shape of the linear object has the same torsional displacement, the same mounting shape is used, and it is equal to the amount of twist applied when actually mounting the linear object to the structure. Control the amount of twist given.

This control is shown by steps 210 to 280 in FIG. In this analysis, the displacement increment method was used as shown in FIG. 9, and the Newton-Raphson method was used for the convergence calculation of the unbalance amount. In the nonlinear analysis, how much the unbalance amount is allowed affects the analysis time and the convergence speed of accuracy. Here, this value was set to 0.1% of the load generated by the brake hose. In addition, when convergence cannot be obtained with the given incremental displacement, the incremental calculation is controlled so that the incremental displacement is reduced to 1/4 and continues.

In the work of installing the brake hose, the hose may be greatly deformed at one time depending on the deformation path. In order to analyze this, it is necessary to reduce the incremental displacement of the incremental calculation, but there is a possibility that the solution cannot be obtained from the increase of calculation time and the accumulation of rounding error. However, if the amount of torsional deformation when the hose is routed is the same, the mounting shape does not depend on how to give tension, compression, or torsional deformation, so the state of torsional deformation due to the rotation given to the final mounting position. Is parallel to the actual phenomenon and is given by dividing the parallel movement and rotation so as not to give a large primary deformation. The amount of twist given to the hose can be specified at the design stage. Also,
This analysis was performed by incorporating a program that controls the deformation applied to the hose into the finite element method program.

The displacement path calculated in step 130 is applied to the model created in step 120 to perform the finite element method calculation (step 140).

Then, the deformed shape of the linear object is obtained, and the obtained value is the amount of movement on the three-dimensional coordinates of the node from the initial shape of the linear object to the attached shape. Therefore, this value is added to the coordinates of the nodes of the initial shape of the linear object, the shape of the attached state is expressed in the coordinate system of the linear object, and the linear object of the obtained linear object is expressed in the coordinate system. The mounting shape is converted into the coordinates of the mounting space (step 150).

Then, from the coordinates of the linear object obtained by the conversion, the linear object and the shapes of the surrounding parts are combined and displayed on the display device 29, and the layout is evaluated by this (step 16).
0).

In addition, in order to calculate the mounting shape of the brake hose in various states of the vehicle, for example, in step 110, the coordinates of the surrounding parts in a state in which the vehicle is stopped (the wheels are straight ahead) are input, or Consider the installation of the brake hose in various situations by changing the conditions such as inputting the coordinates of the rotating parts in the bound state or inputting the coordinates of the rotating parts in the state where the steering is turned off.

As a result of the above processing, a CAD screen example in which the layout of the brake hose is examined is shown in FIG. The accuracy verification result in this case is shown in FIG.
In Fig. 10, the abscissa is the analysis value, and the ordinate is the actual vehicle measurement value, and the experimental value and the analysis value are compared for the distance between the brake hose and the main parts of the vehicle at full bound and steer. This is the result. In this analysis, considering that the mounting shape does not depend on the deformation path as long as the amount of twist added is the same, the analysis was performed with consideration given to making the amount of torsional displacement applied to the brake hose match during mounting work. As can be seen from the figure, the analytical value corresponds to the experimental value with a practically sufficient accuracy that satisfies the design allowable range, and a practically sufficient accuracy can be obtained.

〔The invention's effect〕

As described above, according to the present invention, when the linear object is attached to the structure by inputting the information of the linear object and the mounting position, the mechanical influence on the linear object is analyzed, and the attachment shape is obtained, The coordinates are converted to match the coordinates of the structure, and the position of the structure is combined with the input CAD data and displayed as a layout drawing, so the layout of the linear objects and the structure can be calculated from the displayed layout drawing. It is possible to perform accurate and accurate examinations, reduce the number of man-hours to be examined in experiments using conventional equipment, and improve efficiency and economy. Further, when the finite element method is used as an analyzer for analysis, it is possible to analyze the layout with high accuracy even if an accessory such as a cover is attached to the linear object.

[Brief description of drawings]

1 is a block diagram showing the configuration of a linear object layout analysis CAD system of the present invention, and FIG. 3 is a diagram showing the relationship between the mounting shape of a brake hose and a deformation path. FIG. 4 is a flowchart showing the operation of the CAD system for layout analysis of linear objects according to the present invention,
FIG. 5 is a diagram showing an example of a CAD screen in which the layout of the brake hose is examined by the layout analysis CAD system of FIG. 2, and FIG. 6 is the length, outer diameter, inner diameter, number of element divisions, material constants of the linear object. Fig. 7 (a), (b), (c) is a flow chart showing displacement path processing, Fig. 8 is a flow chart showing the displacement amount form and the layout of the displacement path, and Fig. 8 is an example. Fig. 9 is a diagram showing an example of the displacement path, Fig. 9 is a graph showing the relationship between the load and the displacement and the unbalance amount and the displacement in the incremental calculation, and Fig. 10 is the analysis value and the experimental value concerning the distance between the brake hose and each part of the vehicle. It is a graph which shows the comparison of. 21 ... CAD data memory, 23 ... input device, 25 ... analyzer, 27 ... synthesis device, 29 ... display device.

Claims (1)

[Claims] 1. A linear object layout analysis CAD system for analyzing the layout of a linear object by analyzing the mechanical influence when the linear object is attached to a structure, wherein the structure is a structure to which the linear object is attached. The structure storage means for storing information including the shape of the linear object, the linear object storage means for storing information including the length, outer diameter, inner diameter, and material of the linear object, and the linear object Input means for inputting a mounting position and direction,
Displacement path dividing means for dividing the displacement path of the linear object, increasing means for gradually increasing the amount of mounting conditions along the divided displacement course, and the linear object according to the amount of given conditions Layout analysis of a linear object, characterized by having a computing means for computing the shape of the linear object based on the information it has, and a display means for displaying the shape calculated up to the target amount of mounting conditions in addition to the information of the structure. CAD system.