JP2003058584A - Method for simulating static physical property value of golf club shaft and golf club shaft design system using the simulation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of a design of a golf club shaft by predicting a static physical property value such as the bending and twisting quantity of a shaft with high accuracy without producing a prototype for a shaft. SOLUTION: A golf club shaft made of a fiber-reinforced resin composed of a laminated body of fiber-reinforced pre-preg is set as a model for an analysis object, a modeled shaft is divided in the circumferential direction of the shaft, a laminated state of the fiber-reinforced pre-preg being data of a shaft configuration is inputted in each divided area, simulation is performed with a finite element analysis to predict a static physical property value such as the bending and twisting quantity, etc., of the shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of simulating static physical property values of a golf club shaft and a golf club shaft design system using the simulation method. More specifically, the present invention relates to static physical property values such as the amount of bending and twisting of the shaft. Is accurately predicted to improve the efficiency of golf club shaft design.

[0002]

2. Description of the Related Art In order to evaluate the performance characteristics of a golf club shaft, not only the shaft behavior in the actual swing state but also static physical property values such as bending rigidity and torsional rigidity are evaluated. It can be a target.

For example, in evaluating the simple bending rigidity or torsional rigidity of a shaft formed by laminating a plurality of fiber reinforced prepregs, a theoretical formula in a beam model of material mechanics is used. Point bending (supporting two points and applying a load to another point), or
The efficiency of the design is being improved by calculating the torsion angle etc. when one end is fixed and the other end is given a torsion moment, and bending and torsional rigidity are predicted before trial manufacture and manufacturing.

[0004]

However, in recent years,
Golf club shafts having various laminated patterns have been proposed in order to obtain a rigidity value according to the player, and the laminated structure of the fiber reinforced prepreg has become complicated. For this reason, the bending and torsional rigidity as described above may not be calculated by a theoretical formula of material mechanics (area moment method, etc.), and it is difficult to predict the rigidity value before trial manufacture. Furthermore, in addition to the above-mentioned bending rigidity and torsional rigidity, it may be necessary to consider the torsion angle (hereinafter referred to as the bending torsion amount) that occurs when bending occurs. Is also difficult.

Therefore, in the shaft having the above-mentioned complicated structure, the bending twist amount can be confirmed only by the experiment after the trial production. Therefore, it is necessary to repeat the trial manufacture of the shaft in order to confirm the difference, degree, and tendency of the rigidity value and the like caused by the difference in the laminated state of the fiber-reinforced prepregs laminated in multiple layers. It took a lot of time and money to get the product to reach.

In particular, the anisotropic index shaft in which the shaft is twisted by the bending of the shaft generated during the swing by making the laminated structure of the fiber reinforced prepreg different in the circumferential direction of the shaft is a bending index which is the above-mentioned evaluation index. Not only the rigidity and the torsional rigidity, but also the twist angle (hereinafter referred to as the bending twist amount) generated when bending occurs greatly affects the design index. Therefore, it becomes more difficult to predict the bending twist amount by calculation using a theoretical formula.

The present invention has been made in view of the above problems, and accurately predicts static physical properties such as the amount of bending and twisting of the shaft without trial production of the shaft, and improves the efficiency of golf club shaft design. The challenge is to achieve this.

[0008]

In order to solve the above-mentioned problems, the present invention has been modeled by setting a golf club shaft made of a fiber-reinforced resin made of a laminate of fiber-reinforced prepregs as a model to be analyzed. By dividing the shaft in the circumferential direction of the shaft, inputting the laminated state of the fiber reinforced prepreg which is the data of the shaft configuration for each divided region, and performing simulation by the finite element method analysis to predict the static physical property value of the shaft. A method for simulating static physical property values of a characteristic golf club shaft is provided.

In addition to simple bending and twisting of the shaft, the inventor of the present invention evaluates the static physical property values such as the bending twist amount of the shaft (twist angle generated when bending occurs), etc. It causes bending and twisting,
It was found that the laminated structure (arrangement condition) of the fiber reinforced prepreg in the circumferential direction of the shaft is important. Therefore,
By modeling a shaft made of a laminated body of fiber reinforced prepreg, dividing the modeled shaft in the circumferential direction, and inputting the laminated structure for each divided region, the difference in the laminated structure in the circumferential direction of the shaft becomes the bending twist amount. It is possible to perform an analysis that considers the influence. Further, since the static physical property values such as the amount of bending and torsion are predicted by the simulation using the finite element method analysis, it is possible to obtain accurate prediction results without the need for trial production. Therefore, the efficiency of the design of the golf club shaft can be improved, and the golf club shaft having the desired performance can be obtained without repeating the trial manufacture.

Specifically, under the same conditions as in the actual test, the golf club shaft is divided into a large number of quadrangular shell-shaped elements and set as a model to be analyzed.
A simple bending test (forward / reverse flex (deflection)) of the shaft and an analysis assuming a bending / twisting test are performed by inputting the lamination condition for each divided region in the circumferential direction and performing a simulation by the finite element method. Therefore, the test result of the static physical property value can be predicted accurately.

The shaft is an anisotropic shaft in which the laminated structure of the fiber reinforced prepreg is different in the circumferential direction of the shaft, and the modeled shaft is equally divided into three or more equal parts in the circumferential direction of the shaft. It is preferable that the cross-sectional shape of the shaft is regarded as a regular polygonal shape having the apex at the boundary point of each region divided by the equal division, and the bending and twisting amount is analyzed as the static physical property value.

The anisotropic shaft is anisotropy (bends) by changing the laminated structure of the fiber reinforced prepreg (in particular, the bias layer in which the fiber angle is angled with respect to the shaft axis direction) in the circumferential direction of the shaft. And the property of twisting). As described above, at least a part in the longitudinal direction or the entire length may be different in the laminated structure. Further, the anisotropy as described above changes the value of the fiber angle or the tensile modulus of the reinforcing fiber of the fiber reinforced prepreg,
It can also be realized by setting the number of turns to a non-integer. In order to perform the analysis in consideration of such anisotropy, it is preferable to divide the shaft model into at least three equal parts in the circumferential direction so that the difference in the physical properties of the shaft in the circumferential direction can be reflected. As a result, it is possible to grasp the difference in physical properties of the shaft in the circumferential direction, and it is possible to accurately predict the bending and twisting amount.

Further, by analyzing the cross-sectional shape of the shaft, which is originally circular, as a regular polygonal shape having the apex at the boundary point of each region divided by the equal division,
The calculation can be facilitated, and accurate prediction results can be obtained while shortening the calculation time. If the number of divisions is equal to or more than three, the larger the number of divisions, the more accurate the simulation can be performed, and the number of divisions can be increased within the range permitted by the computer capacity.

The portion where the laminated structure of the fiber reinforced prepreg differs in the circumferential direction of the shaft is divided into
It is preferable that the shaft model is equally divided in the circumferential direction so as to be included in one divided region. There are 2 parts where the laminated structure of the fiber reinforced prepreg differs in the circumferential direction of the shaft.
When placed over two divided areas, an error may occur between the actual bending and twist amount and the simulation result. It is better to divide it to include.

Further, it is preferable that the end of the anisotropy portion in the circumferential direction coincides with the end of the divided area, and when the end portion extends over two areas, it is located in the middle portion of the anisotropy portion in the circumferential direction. It is good to be divided into two. The number of divisions can be set as appropriate according to the number of windings of the fiber reinforced prepreg.

It is preferable that the modeled shaft is equally divided into 4 equal parts or more and 12 equal parts or less, preferably 8 parts or more and 12 equal parts or less in the circumferential direction of the shaft. The optimum number of divisions is 12 equal parts. The number of divisions can be increased within the range of the computer's capability, but if it is too large, it takes time to perform the calculation and a high-performance computer is required. Thus, it is possible to accurately calculate static physical property values such as the amount of bending and torsion in a short period of time. Further, if the number of divisions is within the above range, it is possible to divide the circumferential direction to a certain degree, so it is not necessary to consider the position having anisotropy, the divided area is not adjusted to the stacking state, or the number of windings is not limited (a non-integer number). (Even if it is not rolled)
It is possible to accurately predict static physical property values such as the amount of bending and torsion.

In the finite element method, the shaft is modeled as a shell in its original shape into a shell and the lamination data is input to each shell element constituting the shaft model, or the shaft is modeled as a beam and each layer is modeled as a beam. Calculate the second moment of area of the part and
A method of inputting as a characteristic of m may be mentioned, but from the viewpoint of accuracy, it is preferable to analyze by a method modeled as a pipe as a shell.

Further, by using the finite element method, it is possible to easily and accurately perform a simulation. When the shaft of a golf club model is analyzed by the finite element method, since the shaft has a hollow shape, the element has a pipe-shaped surface with a thickness. At the time of analysis, it seems that there is no volume of the element visually, but since the thickness is input as described above, it is necessary to input the value of the material density in order to calculate the weight of the entire shaft in the calculation. However, since the bending deflection and three-point bending test simulations are static calculations, they can be calculated without the density value.

The modeled shaft can also be divided in the axial direction of the shaft. This allows
The accuracy can be further improved. The mesh may be divided at equal intervals in the axial direction of the shaft, and about 10 mm is optimal, but it may be further subdivided within the range allowed by the calculation capability. When the number of windings of the fiber reinforced prepreg decreases in the axial direction of the shaft and the thickness gradually changes, the thickness can be changed for each axially divided region for modeling.

The result of the simulation according to the present invention can be used as a design guide for designing a new golf club shaft. For example, from the results of the fiber angle of 45 ° and the fiber angle of 90 °, the fiber angle of both of 45 ° to
The results can be predicted with fiber angles between 90 °.

The material of the golf club shaft, such as the resin type and the fiber type, for performing this simulation is not particularly limited, and various conventionally used materials can be used. Further, the size and shape of the golf club shaft can be set appropriately. It can be applied to all types of golf club shafts such as drivers, irons and putters.

The present invention also provides a golf club shaft design system characterized by using the above-described method of simulating static physical property values of a golf club shaft.

As described above, by using the simulation method of the present invention, it is possible to design a shaft having an appropriate static physical property value such as an amount of bending and torsion. That is, by simulating a test for measuring static physical properties such as the amount of bending and twisting by the finite element method, it is possible to reduce the number of times of trial production and efficiently design and manufacture a golf club shaft.

The contents of the golf club shaft design system according to the present invention will be specifically described. First, the target bending twist amount, the amount of bending in forward / reverse 3-point bending, the shaft weight, etc. are determined. Next, a shaft such as an anisotropic shaft is designed (a laminated structure, a shaft diameter, a material, etc.) so as to satisfy the above target value. Then, the shaft with the completed design drawing is modeled as an analysis target by the finite element method, and a simulation such as a bending twist amount, a forward / reverse three-point bending test is performed by the simulation method of the present invention. It is determined from the calculation result of the above simulation whether the above target value is satisfied. Here, when the target is satisfied, the shaft is actually manufactured. If the target is not satisfied, the shaft is designed again (the laminated structure, the shaft diameter, the material, etc.) so as to satisfy the target value.

As described above, on the basis of a series of flows, performance prediction is performed on static physical property values such as bending and twisting amounts, which are difficult to calculate by theoretical formulas, to realize efficient golf club shaft design. There is.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method for simulating static physical properties of a golf club shaft according to the present invention and a golf club shaft design system using the simulation method will be described below with reference to the drawings.

In the golf club shaft design system of the present invention, first, the target bending twist amount, the amount of flexure (flex) in forward / reverse 3-point bending, and the shaft weight are determined. Next, design of an anisotropic shaft in which the laminated structure of fiber reinforced prepreg is varied in the circumferential direction of the shaft to satisfy the target value (laminated structure, shaft diameter, material, etc.).
It is carried out. FIG. 1 shows a cross section of a shaft in which a fiber-reinforced prepreg of the designed shaft is wound. Five fiber reinforced prepregs 11 to 15 are wound to have anisotropy. Then, the shaft with the finished design drawing is modeled as an analysis target by the finite element method, and by the simulation method of the present invention, the bending and torsion amount of the shaft and the value of the forward / backward deflection are predicted and calculated (analytical value). ) Is calculated. It is determined from the calculation result of the above simulation whether the above target value is satisfied.
Here, when the target is satisfied, the shaft is actually manufactured. If the target is not satisfied, the shaft is designed again (lamination structure, shaft diameter, material, etc.) in order to satisfy the above target value.

Further, the method of simulating the static physical property values of the golf club shaft of the present invention will be described in detail.
As shown in Fig. 2, a golf club shaft made of a fiber reinforced resin made of a laminate of fiber reinforced prepregs with the target bending twist amount and the forward / backward flexure amount determined was set as a model to be analyzed. , Divided into a number of quadrilateral shell-shaped elements. As shown in FIG. 2 (A), the shaft 1 is 110 mm apart at 10 mm intervals in the axial direction.
It is divided. Further, as shown in FIG. 2 (B), the shaft 1 is
The shaft 1 is divided into 12 equal parts (30 ° intervals).
Further, the cross-sectional shape of the shaft 1 is circular, but the cross-sectional shape of the shaft 1 is regarded as a regular dodecagonal shape with the boundary points of the respective divided regions (10A to 10L) divided into 12 equal parts as vertices and analyzed. is doing. Further, the winding start position of the fiber reinforced prepreg and the boundary point of the above region are aligned in the circumferential direction of the shaft 1. The grid lines in the figure are schematic lines showing the mesh.

The above modeled shaft is divided in the circumferential direction of the shaft, the laminated state of the fiber reinforced prepreg which is the data of the shaft configuration is input for each divided region, and the simulation is performed by the finite element method analysis. As shown in FIG. 4, the amount of bending and twisting of the shaft 1 and the amount of forward / backward deflection (flex) are predicted.

In this way, the shaft 1 is divided into 12 equal parts in the circumferential direction, the laminated state of the fiber reinforced prepreg is input as the shaft constitution data for each divided region, and the finite element method is used to analyze as described above. Therefore, it is possible to accurately predict the amount of bending and twisting even in an anisotropic shaft that exhibits complicated behaviors of bending and twisting. Therefore, the number of times of trial manufacture of the shaft is reduced, so that the shaft can be efficiently designed.

In the above embodiment, the shaft is set to 1 in the circumferential direction.
Although it is divided into two equal parts, the number of divisions is not particularly limited as long as it is equal to or more than three parts, and can be appropriately set according to the laminated structure of the shaft, the performance of the computer, and the like.

(Experiment 1) Hereinafter, Example 1 of the method for simulating the static physical properties of the golf club shaft of the present invention will be described.
3 will be described in detail. First, in Examples 1 to 3, three anisotropic shafts having different laminated configurations of fiber reinforced prepreg were actually prepared, and the configurations of the shafts were modeled and simulated.

(Example 1) Fiber-reinforced prepregs 21 to 31 shown in FIG. 5 were wound on a core metal (not shown) from the inner peripheral side and laminated. Carbon fiber was used for all the reinforcing fibers, and epoxy resin was used as the matrix resin. The fiber reinforced prepreg 21 was arranged on the head side, with the fiber angle of the reinforcing fibers with respect to the shaft axis being 0 °. The fiber reinforced prepregs 22, 23 and 24, 25 have a fiber angle of -25 ° and + 25 ° made by the reinforcing fibers with respect to the shaft axis line, respectively.
And the total shaft length (1170 mm) was set. The fiber reinforced prepregs 26 and 28 were set to have a full shaft length with a fiber angle of 90 ° made by the reinforcing fibers with respect to the shaft axis. The fiber reinforced prepregs 27 and 29 were set to the total length of the shaft with the fiber angles of the reinforcing fibers with respect to the shaft axis being 0 °. Fiber reinforced prepreg 30, 31
Is the fiber angle made by the reinforcing fibers with respect to the shaft axis.
And placed on the head side (155 mm). The large side of the fiber reinforced prepreg was designated as the grip side. In addition, below,
The angle shown in each figure is the fiber angle of each fiber reinforced prepreg, and the number of plies is described. Specifically, as shown in FIG. 6 (A), the fiber reinforced prepreg 22,
23 (27, 28) and fiber reinforced prepregs 24-26
Pasted together. Further, the fiber reinforced prepregs 21 to 31 were wound around the mandrel with the positions shown in FIG. 6B as starting points (in the shaft circumferential direction on the BUTT side) to form anisotropic shafts.

The fiber reinforced prepregs 21, 30, 31 are X
N-10 (Nippon Graphite Fiber, thickness 0.1
03 mm) was used. MR40 (Mitsubishi Rayon, 0.083 mm) was used for the fiber reinforced prepregs 22 to 25. The fiber reinforced prepregs 26 and 28 are T800H (30
(tonf / mm ² ) (Toray, 0.042 mm) was used. The fiber reinforced prepregs 27 and 29 were TR50S (manufactured by Mitsubishi Rayon, 0.104 mm). The golf club shaft (type 1) was modeled.

Example 2 The fiber-reinforced prepregs 27 and 29 of Example 1 were replaced with HR40 (Mitsubishi Rayon, 0.104).
mm). Others were the same as in Example 1, and the golf club shaft (type 2) was modeled.

(Example 3) The fiber-reinforced prepregs 27 and 29 of Example 1 were changed to YS-80 (manufactured by Nippon Graphite Fiber Co., Ltd., 0.104 mm). Others are Example 1
Similarly to the above, a golf club shaft (type 3) was modeled.

The golf club shafts of Examples 1 to 3 were simulated by the same method as in the first embodiment. The shaft was divided into 12 equal parts in the circumferential direction. In addition, the mesh division position is always set at the joint between prepregs made of different materials.
The computer used is R1000 (512MB), S
GI (Silicon Graphics), software used was structural analysis software MARC2000.

In the shafts of Examples 1 to 3 described above, the forward and reverse flexes (deflection) and bending and twisting amount were limited by restraining the supporting points or fixing by contacting a rigid body in the same manner as in the test method described later. Analysis was performed using the element method, and each analysis value (calculated value) was obtained. Moreover, the above-mentioned test was actually performed using an actual shaft to obtain each experimental value. The test results are shown in Table 1 below.

[0039]

[Table 1]

(Measurement Method for Forward and Reverse Flex (Flexure)) The measurement method for the forward flex (W45 ″ position) and reverse flex (W45 ″ position) is shown below. The forward flex is an index of hardness on the grip side (hand side) of the shaft, and as shown in FIG. 7 (A), a position 129 mm from the head side end 1a of the shaft 1 toward the grip side end 1b. Is set as a load point W, and a portion 824 mm from the load point W toward the grip side end 1b is set as a first fulcrum T1. From the first fulcrum T1 to the grip side end 1b.
The second fulcrum T2 was located at 140 mm toward. The shaft 1 is fixed from below at the first fulcrum T1 and from above at the second fulcrum T2 so that the axial direction is horizontal, and the load point W when a 2.7 kg weight is hung at the load point W. Was measured. What is reverse flex?
It is an index of the hardness of the shaft on the side where the head is attached.
As shown in (B), a portion of 152 mm from the head side end 1a of the shaft 1 toward the grip side end 1b is defined as a first fulcrum T1 ′, and 140 mm from the first fulcrum to the head side.
Was set as the second fulcrum T2 '. A point 776 mm from the first fulcrum to the grip side was set as a load point W ′. First fulcrum T
The shaft 1 is fixed from below at 1'and from above at the second fulcrum T2 'so that the axial direction is horizontal, and the load point W'when a 1.3 kg weight is suspended at the load point W'. The amount of flexure of '

(Bending Twist Test) The amount of bending twist (twist angle generated when the shaft is bent) is measured by the following method. As shown in FIGS. 8A and 8B, the grip side of the shaft 1 is 150 mm from the end thereof.
Within this range, the shaft 1 is gripped by the chucking device 70, and a marker rod 72 orthogonal to the central axis of the shaft 1 is attached symmetrically at a position 15 mm from the head side end of the shaft 1. The marker rod 72 is made horizontal before the weight 71 is attached. In this state, by attaching a weight 71 of 1.1 kg at a position 20 mm from the end on the head side, the shaft 1 bends downward. At the same time, the shaft 1 is twisted as indicated by the rotation angle θ. The rotation angle θ changes depending on the circumferential position of the shaft 1, but the maximum value of the rotation angle θ is the bending twist amount. In the figure, the dotted line shows the shaft 1 before the weight 71 is attached.

As shown in Table 1, in the forward / backward deflection, the ratio of the analytical (calculated) value to the experimental value is 85.3.
% To 97.4%, and the ratio of the analysis value to the experimental value is 117.1% to 148.7% even in the bending twist amount.
Therefore, it was confirmed by simulation that the prediction was possible with high accuracy.

Further, the relationship between the analytical values (calculated values) of the forward and reverse deflections of Examples 1 to 3 shown in Table 1 and the experimental values is shown in FIG.
Shown in. Moreover, the relationship between the analysis value (calculated value) and the experimental value of the bending and twisting amount of Examples 1 to 3 is shown in FIG. 9 and 10
As shown in, in the graph of analysis value and the graph of experimental value,
The slopes of the graphs are almost the same. Therefore, by performing a simulation analysis, it is possible to predict how the performance of the shaft itself (forward / backward deflection, bending / torsion amount) will change by changing the stacking structure of each shaft, and its tendency can be predicted. It was confirmed that there is.

(Experiment 2) Hereinafter, Example 4 of the method for simulating the static physical properties of the golf club shaft of the present invention will be described.
6 will be described in detail. In Experiment 1 described above, three anisotropic shafts (types 1 to 3) having different laminated configurations of the fiber reinforced prepreg were actually prepared, and the same shaft was simulated by changing the analysis conditions. The evaluation was performed only on the bending and twisting amount.

(Example 4) The experiment was conducted under the same conditions as in Examples 1 to 3 of Experiment 1. That is, the shaft was divided into 12 equal parts in the circumferential direction so that there were mesh divisions at the dividing points of the lamination of the fiber reinforced prepreg.

(Embodiment 5) As shown in FIG. 11, the shaft 1'is divided into 24 equal parts (15 ° intervals) in the circumferential direction in the cross section of the shaft 1 '.
There was a mesh division at the separation of the fiber reinforced prepreg. Analysis was performed by regarding the cross-sectional shape of the shaft 1 ′ as a regular 24-sided shape. That is, only the number of divisions was different from that in Example 4.

(Embodiment 6) The shaft was divided into 12 equal parts in the circumferential direction so that there was a difference of 15 ° (deg.) Between the division of the laminated fiber reinforced prepreg and the mesh division. That is, only the division position is different from that of the fourth embodiment.

Bending twist amount [d] for Examples 4 to 6
eg. The relationship between the analytical value of (°)] and the experimental value is shown in Table 2 below.

[0049]

[Table 2]

FIG. 12 shows the relationship between the analytical values and the experimental values of the bending and twisting amounts of Examples 4 to 6 shown in Table 2. As shown in Table 2 and FIG. 12, in Example 5, compared with Example 4, in all three types of shafts, the analysis value of the bending twist amount was close to the experimental value. Therefore, it was confirmed that the larger the number of divisions, the more accurately the bending and twisting amount can be predicted. In addition, in Example 4 and Example 6, the analysis value of the amount of bending and torsion was close to the experimental value in any of the three types of shafts in Example 4. Therefore, it has been confirmed that it is possible to more accurately predict the presence of the mesh division at the division of the lamination of the fiber reinforced prepreg. In addition, in Examples 4 to 6, although there are slight differences in each analysis result, all show the same tendency as the experimental value and the ratio (error) of the analytical value to the experimental value is small. It was confirmed that it is possible to accurately predict the bending and twisting amount of the shaft under any of the conditions of to.

[0051]

As is apparent from the above description, according to the simulation method of the present invention, the shaft is divided in the circumferential direction, and the laminated state of the fiber reinforced prepreg is input as the shaft configuration data for each divided region. As described above, the finite element method is used for analysis, so it is possible to accurately predict static physical properties such as the amount of bending and twisting even on shafts such as anisotropic shafts that exhibit complicated bending and twisting behavior. You can

Further, according to the golf club shaft design system using the simulation method of the present invention, the static physical property values such as the amount of bending and torsion can be accurately predicted at the design stage of the golf club shaft. The cost and time required for trial manufacture can be reduced, and the shaft can be efficiently designed and manufactured in a short period of time.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a shaft wound with a fiber reinforced prepreg.

FIG. 2A is a diagram showing a situation in which the modeled shaft is divided in the axial direction, and FIG. 2B is a diagram showing a situation in which the circumferential direction of the modeled shaft is divided into 12 equal parts.

3 (A) and 3 (B) are diagrams showing a situation in which a bending torsion amount of a modeled shaft is predicted by simulation.

FIG. 4A is a diagram showing a state in which a forward deflection of a modeled shaft and a reverse deflection of a modeled shaft are predicted by simulation.

5 is a diagram showing a laminated structure of the fiber reinforced prepreg of Example 1. FIG.

6 (A) and 6 (B) are views showing a winding state of the fiber-reinforced prepreg of Example 1. FIG.

FIG. 7 (A) is a normal flexure of a real shaft,
(B) is a figure which shows the measuring method of the reverse deflection of a real shaft.

8A and 8B are diagrams showing a method for measuring the bending and twisting amount of a real shaft.

FIG. 9 is a diagram showing a relationship between an analytical value (calculated value) of a forward / backward deflection and an experimental value.

FIG. 10 is a diagram showing the relationship between analytical values (calculated values) of bending and twisting amounts of Examples 1 to 3 and experimental values.

FIG. 11 is a diagram showing a situation where the modeled shaft is divided into 24 equal parts in the circumferential direction.

FIG. 12 is a diagram showing a relationship between analytical values (calculated values) of bending and twisting amounts of Examples 4 to 6 and experimental values.

[Explanation of symbols]

1 shaft 10A-10L division area 11-15 Fiber reinforced prepreg

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Claims (5)

[Claims] 1. A golf club shaft made of fiber reinforced resin comprising a laminate of fiber reinforced prepregs is set as a model to be analyzed, the modeled shaft is divided in the circumferential direction of the shaft, and the shaft is divided for each divided region. A method for simulating the static physical properties of a golf club shaft, which comprises predicting the static physical properties of the shaft by inputting the laminated state of the fiber reinforced prepreg, which is configuration data, and performing a simulation by the finite element method analysis. 2. The shaft is an anisotropic shaft in which the laminated structure of the fiber reinforced prepreg is different in the circumferential direction of the shaft, and the modeled shaft is divided into three or more equal parts in the circumferential direction of the shaft. The sectional shape of the shaft is divided and regarded as a regular polygonal shape whose vertex is a boundary point of each region divided by the equal division, and the bending and twisting amount is analyzed as the static physical property value. A method for simulating static physical properties of a golf club shaft as described. 3. The shaft model is equally divided in the circumferential direction so that a portion where the laminated structure of the fiber reinforced prepreg is different in the circumferential direction of the shaft is included in the divided one divided region. Alternatively, the method for simulating static physical properties of the golf club shaft according to claim 2. 4. The golf club shaft according to claim 1, wherein the modeled shaft is equally divided into four equal parts or more and 12 parts or less in the circumferential direction of the shaft. Simulation method for static physical properties. 5. A golf club shaft design system using the method for simulating static physical property values of a golf club shaft according to claim 1. Description: