JP2003288382A - Collision analytic device for ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collision analytic device for ball capable of dealing with a structure having an uniform thickness, and superior to an analysis using 4-node solid element in analytic precision. <P>SOLUTION: This collision analytic device for ball 1 is a collision analytic device for ball used for the collision analysis of a striking sporting good for striking a ball by use of the finite element method. This device is provided with a storage device 2, a display device 3, a computer (arithmetic part) 4, and an input device 5. In the arithmetic part 4, a collision analysis is performed by use of a ball model consisting of 8-node solid elements. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball collision analysis apparatus for use in the collision analysis of hitting sports equipment such as golf clubs and baseball bats using the finite element method. The present invention relates to a ball collision analysis device that performs a collision analysis using a collision analysis ball model.

[0002]

2. Description of the Related Art In order to generate a spherical element such as a ball by using finite element generating software (preprocessor), a spherical element can be formed by a 4-node solid element using an automatic element generating function.

[0003]

When a ball is hit with a sports equipment, the ball and the sports equipment collide with each other at an angle perpendicular to or close to the normal direction of each element constituting the ball, so that the shock wave is not propagated. Very important. However, if the ball model is composed of four-node solid elements, the shock wave does not propagate accurately, so the analysis accuracy is significantly reduced, and the result deviates from the experimental value. Therefore, there is a problem in terms of analysis accuracy when using a ball model created using four-node solid elements for collision analysis.

Balls used for hitting sports equipment such as golf clubs and baseball bats often have a multi-layered structure. Although each layer of the ball model has a uniform thickness, it is not desirable to model the uniform thickness with a 4-node solid element.

When modeling the uniform wall thickness using a 4-node solid element, if the thickness of each layer is very thin, such as a golf ball, the maximum value of the internal angle of the triangular face forming the 4-node solid element is obtained. Is close to 180 degrees. If the angle exceeds 140 degrees, the analysis accuracy deteriorates. Therefore, in order to avoid this, the size of the four-node solid element is reduced to reduce the angle of the interior angle.

Normally, only one 8-node solid element is required to form a hexahedral shape such as a dice, but at least six 4-node solid elements are required. That is, it is better to model a layer having a uniform thickness with 8-node solid elements.
The number of elements that make up the model is smaller than when using solid nodes. Since the increase in the number of elements depends on the increase in analysis time, the number of elements should be as small as possible.

Therefore, the present invention is to provide a ball collision analysis device which can cope with a structure having a uniform wall thickness and can exceed the precision in the case of using a four-node solid element. To aim.

[0008]

A ball collision analysis apparatus according to the present invention is a collision analysis apparatus for use in a collision analysis of a sports equipment for hitting a ball, which uses a finite element method, and is an 8-node solid element. A collision analysis device for a ball, comprising: a calculation unit that performs a collision analysis using a ball model configured by. The arithmetic unit is preferably
It has a function of creating a ball model including a core layer located on the center side and a coating layer coating the core layer.

In this way, the ball model for collision analysis is
By constructing with nodal solid elements, modeling of uniform wall thickness is possible. Further, by performing the collision analysis in the calculation unit using the ball model as described above, the shock wave can be accurately propagated as compared with the case where the ball model including the four-node solid element is created.

It is preferable that the ratio (aspect ratio) of the maximum length and the minimum length of the edges along the quadrangular face constituting the 8-node solid element is 1 or more and 5 or less. If it deviates from this range, the analysis accuracy will deteriorate.

Further, it is preferable that the internal angle of the quadrangular face constituting the 8-node solid element is 40 degrees or more and 140 degrees or less. Even if it deviates from this range, the analysis accuracy will deteriorate. If the interior angle is 180 degrees or more, the stiffness matrix becomes negative and calculation cannot be performed.

Further, when the quadrangular face forming the 8-node solid element is divided into two triangles, it is preferable that the angle formed by the normal lines of the triangles is 0 degree or more and 10 degrees or less. Even if it deviates from this range, the analysis accuracy will deteriorate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A ball collision analysis apparatus according to the present invention is an analysis apparatus which uses the finite element method and is used for collision analysis of a hitting sports equipment such as a golf club or a baseball bat. , An input device, a storage device, a display device, and a calculation unit.

The input device inputs the conditions necessary for the collision analysis to the arithmetic unit. The storage device stores data necessary for collision analysis. The display device displays the collision analysis result. The calculation unit creates a ball model described later, executes a collision analysis based on various conditions and data using the ball model, and outputs the analysis result.

An important feature of the present invention is to perform a collision analysis using a ball model composed of 8-node solid elements.

The 8-node solid element is a solid element having 8 nodes. FIG. 7 shows an example of the 8-node solid element 11. In the example shown in this figure, the 8-node solid element 11 is composed of a hexahedral element having a shape close to a rectangular parallelepiped, but is not limited to this.

To generate a ball model such as a golf ball or a baseball using the 8-node solid element,
For example, the core layer, which is the core of the ball model, may be formed from 8-node solid elements, and the 8-layer solid elements may be radially generated from the core layer to form the coating layer. For example, the cover layer may be formed on the outside of the core layer as a two-layer structure of a mid layer and a cover layer, or may be a laminated structure of three or more layers. By constructing a ball model with 8-node solid elements in this way, it is possible to make a model with a uniform wall thickness with a smaller number of elements and better analysis accuracy than in the case of using 4-node solid elements.

The ratio (aspect ratio) between the maximum length and the minimum length of the edges along the quadrangular face which constitutes the 8-node solid element is 1 or more and 5 or less. Preferably,
The aspect ratio is 1. For example, in the example shown in FIG. 7, the maximum length L1 of the edge along the square face 13 is
And the minimum length L2 correspond to the aspect ratio.
By setting the aspect ratio within the above range, accurate results can be obtained.

Further, it is preferable that the inside angle (angle θ in the example shown in FIG. 7) of the quadrangular face forming the 8-node solid element is 40 degrees or more and 140 degrees or less. More preferably, the interior angle of the square face is 90 degrees. Also in this case, an accurate result can be obtained.

Further, when the quadrangular face forming the 8-node solid element is divided into two triangles, it is preferable that the angle formed by the normal lines of the triangles is 0 ° or more and 10 ° or less. More preferably, the angle is 0 degrees. Also in this case, an accurate result can be obtained. The above-mentioned "normal line" is defined as a normal line passing through the centroid of each triangle when the quadrangular face is divided into two triangles.

[0021]

EXAMPLES Examples of the present invention will be described below with reference to FIGS. FIG. 1 shows a collision analysis device 1 of the present invention.
3 is a block diagram showing a schematic configuration of FIG.

As shown in FIG. 1, the collision analysis device 1 of the present invention comprises a storage device 2, a display device 3, a computer (arithmetic unit) 4, and an input device 5.

The input device 5 is connected to the arithmetic unit 4 and inputs conditions required for collision analysis to the arithmetic unit 4. Storage device 2
Is connected to the calculation unit 4 and stores data required for collision analysis. The display device 3 displays the collision analysis result calculated by the calculation unit 4. As shown in FIG. 2, the calculation unit 4 creates a ball model, a sports equipment model, assembles a ball model and a sports equipment model, and inputs various conditions from the input device 5 and the storage device 2 to the assembly. Is input, collision analysis is executed based on a predetermined program, and the analysis result is output.

In the collision analysis device 1 of the present invention, first, the ball model is created in the calculation section 4 according to the input condition from the input device 5. At this time, a ball model composed of 8-node solid elements is created.

FIG. 3 shows a front view of the ball model 6 used in the collision analysis apparatus 1 of the present invention, and FIG. 4 shows the ball model 6.
The figure which looked at from the isometric direction is shown. As shown in FIGS. 3 and 4, the ball model 6 is created by combining 8-node solid elements having a predetermined shape and is divided into meshes.

FIG. 5 shows a sectional view of the ball model 6 used in the present invention. As shown in FIG. 5, the ball model 6 is
It has a core layer 7 located on the center side, a mid layer 8 formed on the outer periphery of the core layer 7, and a cover layer 9 formed on the outer periphery of the mid layer 8. The core layer 7 has a core 10 having the shape shown in FIG. This kernel 10 is also created by combining 8-node solid elements.

To create the ball model 6 shown in FIG.
As shown in, the dimensions of each layer of the ball model 6 are determined,
After determining the mesh size and creating the core 10 by combining the 8-node solid elements, the core is created by arranging the 8-node solid elements (hexahedral elements) of a predetermined shape at equal intervals radially from the center of the core 10. A finite element of the layer 7 is created, a plurality of layers of solid elements are arranged on the surface layer of the core layer 7, finite elements of the mid layer 8 and the cover layer 9 are sequentially created, and the quality check of the finite element is performed. Enter the material properties of. HyperMesh (Altair Engi
neering), MSC.PATRAN (MSC, USA) are used.

After the ball model 6 is created, as shown in FIG. 2, the CAD model is read, the mesh size is determined, the finite element of the sports equipment model is created, the finite element quality is checked, and the material of each layer is Enter physical properties. As software, ThinkDesign (I Think3
Company), I-DEAS (Unigraphic Solutions Company, USA), P
Uses RO / ENGINEER (Parametric Technology Inc., USA).

Next, the ball model 6 and the sports equipment model are respectively read and their positions are aligned.
After that, various boundary conditions are input by the input device 5. Specifically, the contact conditions are set by inputting the conditions regarding the ball model 6 and the sports equipment model such as the position, velocity, and acceleration. As software, GENERIS (France ESI)
To use.

Next, a collision analysis is performed in the arithmetic unit 4.
For collision analysis, explicit software PAMCRASH (France ESI
Company) is used. In this embodiment, as shown in FIG. 8, the ball model 6 is collided with the rigid wall 12 and the time history of the impact force at the time of collision is obtained. Specifically, the SH rod made of steel with a length of 2 m is regarded as a rigid body and collided with the ball model 6 of the superelastic element, and the impact response analysis is performed with the above PAMCRASH, and the time history of the impact force at the time of collision is obtained. It was The collision speed at this time was 36 m / s.

After the above collision analysis, the analysis result is displayed on the display device 3.
Output to. Specifically, the position (speed, acceleration), strain (stress), etc. of the ball model 6 and the sports equipment model are output.

As a model of the ball model 6, NE
WING (R) (Bridgestone Co., Ltd.) is used and the material type is treated as a super elastic material. Mooney Rivli at PAMCRASH
Adopt n. The Mooney Rivlin coefficient (A, B) is calculated from the elastic modulus (E) and Poisson's ratio (ν). Specifically, it is calculated by the following formula (1).

E = 4 (1 + ν) (A + B) (1) Further, the mesh size of the ball model 6 is based on 4 mm. However, the wall thicknesses of the mid layer 8 and the cover layer 9 are 1.7 mm and 2.0 mm, respectively. Since the mid layer 8 and the cover layer 9 are divided into two layers, the mesh thickness of each layer in the wall thickness direction is respectively. It becomes 0.85 mm and 1.0 mm.
The mesh thickness of the core layer in the thickness direction is 0.9 mm.

Next, the collision analysis result using the collision analysis apparatus 1 of the present invention will be described with reference to FIGS. 9 to 14.
FIG. 9: is a figure which shows the approximate curve of the Example of this invention, the comparative examples 1 and 2, and this Example. 10 is an analysis result and an approximate curve of the present embodiment, FIG. 11 is an analysis result and an approximate curve of the ball model 6 (Comparative Example 1) shown in FIG. 12, and FIG. 13 is a ball model 6 (Comparative Example 2) shown in FIG. FIG. 7 is a diagram showing an analysis result and an approximated curve of FIG.

The ball model 6 (Comparative Examples 1 and 2) shown in FIGS. 12 and 14 is a model created using four-node solid elements, and the ball model 6 shown in FIG.
(Comparative Example 1) is a model including a triangular element (four-node solid element) in the core, and the ball model 6 shown in FIG.
(Comparative Example 2) is a model having no nucleus in the center.

As shown in FIG. 10, in the case of the present embodiment, the analysis result data and the approximate curve are in good agreement, and it can be seen that the variation in the data is small. On the other hand, FIG.
In the comparative example shown in FIG. 13 and FIG. 13, the analysis result data and the approximate curve often do not match, and it can be seen that there is a large variation in the data.

Further, as shown in FIG. 9, it can be seen that the example of the present invention is closer to the experimental value than the comparative examples 1 and 2. Therefore, by performing the collision analysis using the ball model of the present invention, data close to the experimental value can be obtained and the analysis accuracy can be improved.

Although the embodiments of the present invention have been described above, it should be considered that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown by the claims, and includes meanings equivalent to the claims and all modifications within the scope.

[0039]

According to the present invention, since the ball model for collision analysis is made up of 8-node solid elements, not only can a uniform thickness be modeled, but also a shock wave can be accurately propagated. Therefore, analysis accuracy can also be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a collision analysis device of the present invention.

FIG. 2 is a flowchart for explaining a process in the collision analysis device of the present invention.

FIG. 3 is a front view of a ball model used in the collision analysis device of the present invention.

FIG. 4 is a view seen from an isometric direction of a ball model used in the collision analysis device of the present invention.

FIG. 5 is a sectional view of a ball model used in the collision analysis device of the present invention.

FIG. 6 is a cross-sectional view showing a structural example of a core of a ball model used in the collision analysis device of the present invention.

FIG. 7 is a perspective view of an example of an 8-node solid element.

FIG. 8 is a perspective view showing an example of a collision analysis using the ball model of the present invention.

FIG. 9 is a diagram showing a result of collision analysis.

FIG. 10 is a diagram showing an analysis result and an approximate curve of an example of the present invention.

11 is a diagram showing an analysis result and an approximate curve of the ball model (Comparative Example 1) shown in FIG.

12 is a cross-sectional view showing a ball model of Comparative Example 1. FIG.

13 is a diagram showing an analysis result and an approximate curve of the ball model (Comparative Example 2) shown in FIG.

FIG. 14 is a cross-sectional view showing a ball model of Comparative Example 2.

[Explanation of symbols]

1 collision analysis device, 2 storage device, 3 display device, 4
Computer (arithmetic unit), 5 input device, 6 ball model, 7 core layer, 8 mid layer, 9 cover layer, 10
Core, 11 8-node solid elements, 12 rigid walls, 13
Square face.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takao Oda             12-35 South Kohoku, Suminoe-ku, Osaka City, Osaka Prefecture             Issue Mitsuno Co., Ltd. F-term (reference) 5B046 AA00 JA07

Claims (5)

[Claims] 1. A collision analysis device for a ball, which is used for collision analysis of a sports equipment for hitting a ball, using the finite element method, wherein collision analysis is performed using a ball model composed of 8-node solid elements. A ball collision analysis device comprising a calculation unit. 2. The ball collision analysis device according to claim 1, wherein the arithmetic unit has a function of creating a ball model including a core layer located on the center side and a coating layer coating the core layer. . 3. The ball collision analysis according to claim 1, wherein the ratio of the maximum length to the minimum length of the edges along the quadrangular face constituting the 8-node solid element is 1 or more and 5 or less. apparatus. 4. The ball collision analysis device according to claim 1, wherein an inner angle of a quadrangular face constituting the 8-node solid element is 40 degrees or more and 140 degrees or less. 5. The angle formed by the normal line of each triangle when the quadrangular face forming the 8-node solid element is divided into two triangles is 0 degree or more and 10 degrees or less.
5. The ball collision analysis device according to claim 4.