JP2009034985A - Advanced grid structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an advanced grid structure having a high strength and a low thermal expansion characteristic. <P>SOLUTION: The advanced grid structure comprises, a first grid side group which extends in the same direction as that of a first tape prepreg group and constitutes one side of a grid group, a second grid side group which extends in the same direction with that of a second tape prepreg group and constitutes one side of a grip group, and a third grid side group which extends in the same direction as that of a third tape prepreg group and constitutes one side of a grid group, wherein a structure ratio obtained by dividing a grid side width by an interval between the central point of a region crossed at the second grid side group and the third grid side group and the central point of the region obtained by crossing the second grid side group nearest the region thus crossed with the central point of the region crossed at the third grid side group and the third grid side group is larger than 0 and 0.107 or less, and the tensile elastic modulus of the carbon fiber is 280 GPa or more and 330 GPa or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an advanced grid structure having high strength and low thermal expansion characteristics using carbon fiber reinforced plastic which is a material for aerospace which is lighter than metal and has a low thermal expansion coefficient.

  In recent years, with the increasing demand for high-resolution images on the earth, there are plans to deploy a large number of small satellites equipped with optical equipment in low-orbit earth orbit, and the development of small satellites equipped with optical equipment is important. Is being viewed. Such a satellite is required to have a satellite structure having thermal dimensional stability in order not to deteriorate the observation accuracy of the optical equipment. In addition, small satellite structures are required to have high strength, unlike medium and large satellite structures that are required to have high rigidity.

  As a satellite structure having thermal dimensional stability, a low thermal expansion structure having a composite square lattice has been proposed. The low thermal expansion structure of a composite quadrangular lattice is configured by combining a square tube and a rod provided with a slot. The square tube utilizes the property that the coefficient of thermal expansion differs between the direction in which the carbon fiber of the carbon fiber reinforced plastic runs and the direction perpendicular to the direction in which the carbon fiber runs, so that the carbon fiber has a coefficient of thermal expansion close to zero. It is formed by adjusting the orientation angle. Further, the rod includes a first rod made of carbon fiber reinforced plastic and a second rod made of carbon fiber reinforced plastic, and slits are provided at positions where they are fitted. The low thermal expansion structure is configured such that the first rod and the second rod are arranged so as to be orthogonal to each other and assembled by fitting with a slit, and a rectangular tube is fitted into the inner side surrounded by the side surface of the rod. Yes. In this way, a structure having a value close to zero with respect to the thermal expansion coefficient of the entire structure is realized (for example, see Non-Patent Document 1).

K. J. et al. Yoon, 3 others, "COMPOSITE GRID STRUCTURE WITH NEAR-ZERO THERMAL INDUCED 2000, DEFECT DEFECTION, 41st AIAA / ASME / ASCE / AHS / AHS / Astr Structure, 41st AIAA / ASME / ASCE / AHS / Astr Structure. -1476, pp. 971-976

However, in the above-described low thermal expansion structure, the thermal expansion coefficient can be in the range of -1.0 ppm / K to 1.0 ppm / K. However, since the rod is fitted and bonded by the slit, There is a problem that the strength is limited due to the low tensile strength of about 40 MPa at the bonded portion and is lowered.
Therefore, if a conventional pseudo-isotropic laminated structure is configured using carbon fibers having a tensile modulus of 280 GPa or more and 330 GPa or less, a high-strength structure having a tensile strength of 4600 MPa or more can be realized. A thermal expansion coefficient will be 1.1 ppm / K or more.

In general, carbon fiber has a negative coefficient of thermal expansion and resin has a positive coefficient of thermal expansion. Therefore, carbon fiber reinforced plastic, which is a unidirectional laminated structure of carbon fiber, has a negative coefficient of thermal expansion in the direction of carbon fiber. However, the pseudo-isotropic laminated structure has a positive thermal expansion coefficient.
In addition, there is an inversely proportional relationship between the elastic modulus and the thermal expansion coefficient of carbon fiber, and there is also an inversely proportional relationship between the elastic modulus and strength, resulting in the strength and thermal expansion coefficient of carbon fiber. Is a proportional relationship, and the pseudo-isotropic laminated structure using high-strength carbon fibers cannot have a coefficient of thermal expansion close to zero. For this reason, this structure also has a problem that it is not suitable as a satellite structure on which optical equipment is mounted from the viewpoint of thermal dimensional stability.
Also, since the earth observation satellites so far were medium and large, a satellite structure having high rigidity and low thermal expansion characteristics was required. Therefore, a problem of developing a satellite structure having high strength and low thermal expansion characteristics was required. There was a situation that was not conceived.

  An object of the present invention is to provide an advanced grid structure having high strength and low thermal expansion characteristics.

  The advanced grid structure according to the present invention is a first tape prepreg group in which carbon fibers arranged at equal intervals in the first direction are oriented in the longitudinal direction, and counterclockwise with respect to the first direction. A second tape prepreg group in which carbon fibers arranged at equal intervals in a second direction inclined by 60 degrees are oriented in the longitudinal direction, and a third inclined by 60 degrees clockwise with respect to the first direction. The third tape prepreg group in which the carbon fibers arranged at equal intervals in the direction of are oriented in the longitudinal direction are repeatedly laminated in order so that the two tape prepreg groups overlap each other, and heated under pressure. In the advanced grid structure formed by the first tape prepreg group, the first grid side group that is in the same direction as the first tape prepreg group and constitutes one side of the grid group, the second tape prepreg group, and The second grid side group that is a direction and constitutes one side of the grid group, and the third grid side group that is the same direction as the third tape prepreg group and constitutes one side of the grid group, The second grid side group and the third grid side group that are closest to the center point of the area where the second grid side group and the third grid side group intersect and the intersecting area intersect. The structural ratio obtained by dividing the grid side width by the distance from the center point of the region is greater than 0 and 0.107 or less, and the tensile modulus of the carbon fiber is 280 GPa or more and 330 GPa or less.

  The advanced grid structure according to the present invention has three side groups in which grid sides on which carbon fibers are oriented in one direction are arranged at equal intervals, and remains based on the first side group of the three side groups. Since the second side group and the third side group intersect with each other at an angle of 60 degrees in the clockwise direction and the counterclockwise direction, the unidirectionally laminated portion of the carbon fiber which is the portion where the grid side does not intersect, and the grid side group The grid area structure has a structure in which the cross area part of the grid side group has characteristics close to a quasi-isotropic stacked structure, and the proportion of equilateral triangle grid groups in the grid structure increases. Since this characteristic approaches that of the pseudo-isotropic laminated structure, there is an effect of having high strength and low thermal expansion characteristics.

Embodiment 1 FIG.
FIG. 1 is a front view of an example of an advanced grid structure according to Embodiment 1 of the present invention. FIG. 2 is a front view of another example of the advanced grid structure according to Embodiment 1 of the present invention.
The advanced grid structure according to Embodiment 1 of the present invention uses a prepreg made by impregnating a resin into carbon fibers and then semi-curing the fibers, and orienting the carbon fibers so as to face in the longitudinal direction. This is a truss structure formed by laminating strip-shaped tape prepregs made of reinforced epoxy resin prepregs and heating them under pressure. As the carbon fiber, TORAYCA (registered trademark) yarn T800HB manufactured by Toray Industries, Inc., which is a high-strength system and has a tensile elastic modulus of 280 GPa or more and 330 GPa or less, is used.

The vocabulary used in the following description will be described.
“Grid side” means what constitutes the sides of an equilateral triangular grid and a hexagonal grid included in the advanced grid structure, which will be described in detail later.
The “tape prepreg” is a semi-cured tape-like product produced by impregnating a resin into a plurality of collected carbon fibers.

  In the advanced grid structure according to Embodiment 1 of the present invention, in the drawings of FIG. 1 and FIG. 2, the length direction is in the vertical direction of the drawing, and is parallel to the first direction perpendicular to the length direction at equal intervals. A plurality of grid sides (hereinafter referred to as “0-degree direction grid sides”) 1 and 0-degree direction grid sides 1 intersect with each other at an angle of 60 degrees counterclockwise and are arranged in parallel at equal intervals. A plurality of grid sides (hereinafter referred to as “+60 degree direction grid side”) 2, a plurality of grids that are inclined at 60 degrees clockwise with respect to the 0 degree direction grid side 1 and arranged in parallel at equal intervals A side (hereinafter referred to as “−60 degree direction grid side”) 3 is provided. The plurality of 0 degree direction grid sides 1 are the first grid side group, the plurality of +60 degree direction grid sides 2 are the second grid side group, and the plurality of −60 degree direction grid sides 3 are the third grid side group. Called.

In the advanced grid structure according to the first embodiment of the present invention, the equilateral triangular grid 4 and the hexagonal grid 5 are formed by the 0 degree direction grid side 1, the +60 degree direction grid side 2, and the −60 degree direction grid side 3. Is formed.
FIG. 3 is an enlarged view including one node of the advanced grid structure according to Embodiment 1 of the present invention. The enlarged view shown in FIG. 3A is a diagram in the case where the distance between the intersecting regions of the grid side group is zero as in the advanced grid structure of FIG. The enlarged view shown in FIG. 3B is a diagram in the case where the distance between the intersecting regions of the grid side group is not zero as in the advanced grid structure of FIG.
As shown in FIG. 3, the 0 degree direction grid side 1 intersects with the +60 degree direction grid side 2 and the −60 degree direction grid side 3 in the first intersection area 6 and the second intersection area 7, respectively. The +60 degree direction grid side 2 intersects with the −60 degree direction grid side 3 in the third intersection region 8. It has been discovered that the presence of these intersecting regions 6, 7, and 8 in the vicinity of each other has a characteristic close to a quasi-isotropic laminated structure. The third intersecting region 8 is a rhombus, and a center point where two diagonal lines of the rhombus intersect is referred to as a node 9.
Further, the grid structure is formed into a quasi-isotropic stacked structure by increasing the ratio of equilateral triangle grid groups included in the grid structure by separating the intersection areas 6, 7, and 8 by a distance 10 so as not to contact each other. I found it to have similar characteristics. However, at this time, the maximum value of the distance 10 between the intersecting regions 6 and 7 is a half value of the distance between the nodes 9.

Next, a method for manufacturing the advanced grid structure according to Embodiment 1 of the present invention will be described. FIG. 4 is a plan view of a tape prepreg for manufacturing the advanced grid structure according to Embodiment 1 of the present invention.
Using Torayca (registered trademark) yarn T800HB manufactured by Toray Industries, Inc., which has a tensile modulus of elasticity of 280 GPa or more and 330 GPa or less, and an epoxy resin raw material, An oriented strip-shaped tape prepreg is prepared. A carbon fiber tape prepreg 12 in which the carbon fibers as shown in FIG. 4A are oriented parallel to the reference side 11, and the carbon fibers as shown in FIG. +60 degree direction carbon fiber tape prepreg 13 oriented so as to incline 60 degrees in the direction, carbon fiber as shown in FIG. 4C was oriented so as to incline 60 degrees clockwise relative to the reference side 11. The advanced grid structure according to the first embodiment of the present invention shown in FIG. 1 or FIG. 2 is manufactured by laminating the -60 degree carbon fiber tape prepreg 14 in order several times and heating under pressure.

  A plurality of 0-degree direction carbon fiber tape prepregs 12 arranged in the first tape prepreg group, and a plurality of +60 degree direction carbon fiber tape prepregs 13 arranged in the second tape prepreg group, −60 degree direction. A structure in which a plurality of carbon fiber tape prepregs 14 are arranged is referred to as a third tape prepreg group.

At this time, a first grid side group that is in the same direction as the first tape prepreg group and constitutes one side of the grid group, and a second grid that is in the same direction as the second tape prepreg group and constitutes one side of the grid group Among the grid side groups, and the third grid side group that is in the same direction as the third tape prepreg group and constitutes one side of the grid group, the first grid side group, the second grid side group, and It was discovered that the regions where the third grid side groups intersect each other exist in the vicinity of each other, so that the regions have characteristics close to a quasi-isotropic stacked structure.
In addition, in a grid structure including an equilateral triangle grid group and a hexagonal grid group, the distance between the areas where the grid side groups intersect is increased so that the ratio of the equilateral triangle grid group included in the grid structure is increased. By increasing the number, it was discovered that the grid structure has characteristics close to a quasi-isotropic laminated structure.

FIG. 5 is an enlarged view including a regular triangular grid 4 and a hexagonal grid 5 of the advanced grid structure according to the first embodiment of the present invention.
Here, two factors representing the structure of the advanced grid structure having the equilateral triangular grid 4 and the hexagonal grid 5 are introduced, and the relationship between the factor and the thermal expansion coefficient of the advanced grid structure is obtained.
One factor to be introduced is a quotient obtained by dividing the width W of the grid side by the distance L between the nodes 9 and is referred to as a structure ratio. Another factor to be introduced is the distance a between the intersecting regions where the grid sides intersect. However, at this time, the distance a is 0 or more and L / 2 or less.

Next, measurement of the thermal expansion coefficient of the advanced grid structure will be described.
In the measurement of the thermal expansion coefficient of the advanced grid structure, first, the advanced grid structure that is the measurement sample 15 is placed on the sample support 16 and fixed in the thermostatic chamber 17. Next, while controlling the temperature in the thermostatic chamber 17 and changing the temperature of the measurement sample 15, the laser reflecting mirror 18 adhered to both ends of the measurement sample 15 is irradiated with laser from the laser focus displacement meter 19, and reflected light is reflected. Is received, the amount of displacement of the measurement sample 15 due to heating is measured, and the thermal expansion coefficient is calculated.

Since the distance L between the nodes 9 of the advanced grid structure according to Embodiment 1 of the present invention is 105 mm and the width W of the grid side is 1.60 mm, the structure ratio is 1.60 / 105 = 0.015. It is. The distance a between the intersecting areas where the grid sides intersect is 0 mm.
At this time, the measured thermal expansion coefficient is −0.20 ppm / K.

Next, an advanced grid structure was manufactured by preparing a tape prepreg so that the distance at which the grid sides are arranged, that is, the distance L between the nodes 9 is different. The structural ratios at this time are 1.60 / 105 = 0.015, 1.60 / 52.5 = 0.030, 1.60 / 26.25 = 0.060, 1.60 / 14.953 = 0. 107. The distance a between the regions was 0 mm and 24 mm. The thermal expansion coefficient of this advanced grid structure was measured as shown in FIG.
FIG. 7 is a graph showing the thermal expansion coefficient with the structural ratio as the horizontal axis.

  Next, the advanced grid structure defines the range of carbon fibers considered to be high strength as a small satellite structure. In general, carbon fibers include high-strength carbon fibers and high-elasticity carbon fibers. However, when a conventional quasi-isotropic laminated structure is made using high-elasticity carbon fibers, the coefficient of thermal expansion is near zero. It is possible to This is because the carbon fiber reinforced plastic has a negative coefficient of thermal expansion in the direction of carbon fiber and a positive coefficient of thermal expansion in the direction orthogonal to the carbon fiber, so that the combination becomes near zero. However, when this becomes a high-strength carbon fiber, since the tensile strength and tensile modulus of carbon fiber generally show an inversely proportional relationship, the tensile modulus decreases and the thermal expansion coefficient of the carbon fiber itself approaches zero. In the pseudo isotropic laminated structure, the coefficient of thermal expansion cannot be close to zero. FIG. 8 is a graph showing the relationship between the tensile elastic modulus and the thermal expansion coefficient of the carbon fiber.

On the other hand, in advanced grid structures including a unidirectional laminate structure of carbon fibers and a structure close to a quasi-isotropic laminate structure, by adjusting the structure ratio and the distance between crossing areas of the grid side, Even if carbon fiber is used, the thermal expansion coefficient can be made zero.
For this reason, the conventional quasi-isotropic laminated structure cannot have a coefficient of thermal expansion close to zero, but if an advanced grid structure is used, carbon fiber that can have a coefficient of thermal expansion of zero is considered as one criterion. The tensile elastic modulus is specified to be 330 GPa or less.
Further, among the high-strength carbon fibers, there are carbon fibers whose tensile strength is lower than that of the carbon fiber based on the above-mentioned criteria, so that they need to be removed from the high-strength range. Since the carbon fiber has a tensile strength of about 4600 MPa, the tensile elastic modulus of the carbon fiber is defined as 280 GPa or more.
In summary, the carbon fiber having a high strength in the advanced grid structure is a carbon fiber having a tensile modulus of 280 GPa or more and 330 GPa or less.

  The advanced grid structure then defines the range of carbon fibers that are considered to have low thermal expansion as a small satellite structure. Here, a thermal expansion coefficient that cannot be obtained with a conventional pseudo-isotropic laminated structure using Toray Co., Ltd. TORAYCA (registered trademark) yarn T1000G, which is currently the strongest carbon fiber, is used as one criterion. At this time, since the thermal expansion coefficient of the quasi-isotropic laminated structure is 0.93 ppm / K, the range of the structure having low thermal expansion in the advanced grid structure has a thermal expansion coefficient of −0.9 ppm / K or more and 0. The structure is 9 ppm / K or less.

The advanced grid structure according to Embodiment 1 of the present invention has three grid side groups in which grid sides in which carbon fibers are oriented in one direction are arranged at equal intervals. Since the remaining second grid side group and the third grid side group intersect with each other with an inclination of 60 degrees clockwise and counterclockwise with respect to the first grid side group, the grid side groups do not intersect each other. A structure in which carbon fibers are laminated in only one direction and an intersecting region where grid side groups intersect is formed.
At this time, since the intersecting region portion of the grid side group has a structure having a characteristic close to a pseudo isotropic laminated structure, the ratio of the intersecting region portion and the unidirectional laminated portion included in the grid structure is adjusted by the structure ratio, Furthermore, as the ratio of equilateral triangles in the grid structure increases, the characteristics of the grid structure approach the characteristics of the quasi-isotropic laminated structure, so the ratio of equilateral triangles and hexagonal grids included in the grid structure By adjusting the distance with the distance between the intersecting regions, it has high strength and low thermal expansion characteristics.

FIG. 7 is a graph showing the dependence of the thermal expansion coefficient on the structure ratio with the distance between intersecting regions as a parameter.
As can be seen from FIG. 7, using carbon fibers having a tensile modulus of 280 GPa or more and 330 GPa or less, the width W of the grid side or between the nodes 9 is set so that the structural ratio is greater than 0 and 0.107 or less. When the distance L is adjusted, an advanced grid structure having a thermal expansion coefficient of −0.9 ppm / K or more and 0.9 ppm / K or less can be obtained.
In the advanced grid structure according to the first embodiment of the present invention, after impregnating an epoxy resin with carbon fiber of Toray Industries, Inc. trading card (registered trademark) yarn T800HB having a tensile modulus of elasticity of 280 GPa or more and 330 GPa or less. A prepreg made by semi-curing is used, but the resin is not limited to an epoxy resin, and any resin can be applied to the present invention as long as its thermal, mechanical and chemical characteristics can withstand the use environment. it can.

Embodiment 2. FIG.
The advanced grid structure according to the second embodiment of the present invention is different from the advanced grid structure according to the first embodiment of the present invention in carbon fiber, and as a result, has a different structural ratio, but is otherwise the same. Therefore, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.
The carbon fiber used for the advanced grid structure according to Embodiment 2 of the present invention has a tensile elastic modulus of 280 GPa or more and 330 GPa or less.

Next, an advanced grid structure was manufactured by preparing a tape prepreg so that the distance at which the grid sides are arranged, that is, the distance L between the nodes 9 is different. The structural ratios at this time were 0.015, 0.030, 0.060, and 0.107. The distance a between the intersecting regions was 0 mm and 24 mm. The thermal expansion coefficient of this advanced grid structure was measured as shown in FIG.
FIG. 9 is a graph showing the dependence of the thermal expansion coefficient on the structure ratio with the distance between intersecting regions as a parameter.

  The advanced grid structure then defines the range of carbon fibers that are considered to have very low thermal expansion. Here, the minimum coefficient of thermal expansion obtained when a conventional quasi-isotropic laminated structure is formed using existing carbon fibers is used as one criterion. When a pseudo isotropic laminated structure is made using Toray Industries, Inc. Torayca (registered trademark) yarn M60J, the thermal expansion coefficient can be -0.25 ppm / K. Therefore, the range of structures having extremely low thermal expansion in the advanced grid structure is structures having a thermal expansion coefficient of −0.25 ppm / K or more and 0.25 ppm / K or less.

  As can be seen from FIG. 9, thermal expansion is achieved by adjusting the width W of the grid side or the distance L between the nodes 9 and the distance a between the intersection regions so that the structural ratio is greater than 0 and less than or equal to 0.053. An advanced grid structure having a coefficient of −0.25 ppm / K or more and 0.25 ppm / K or less can be obtained.

  On the other hand, one of three carbon fiber prepreg sheets in which carbon fibers having a tensile modulus of elasticity of 280 GPa or more and 330 GPa or less are oriented in one direction is tilted 60 degrees counterclockwise, and the other one is clockwise. The epoxy resin is cured by laminating three sheets inclined at 60 degrees and heating under pressure. This laminate is quasi-isotropic, but the thermal expansion coefficient is 1.1 ppm / K or more.

As in the advanced grid structure according to the first embodiment, the advanced grid structure according to the second embodiment of the present invention is a unidirectional laminate in which the grid-side intersecting region and the grid side do not intersect in the advanced grid structure. The coefficient of thermal expansion of the advanced grid structure can be reduced by adjusting the ratio with the portion and the distance between the grid-side intersection regions.
In addition, carbon fiber having a tensile modulus of 280 GPa or more and 330 GPa or less is used, and the grid side width W or the distance L between nodes 9 and the distance between intersecting regions so that the structural ratio is greater than 0 and 0.053 or less. Since a is set, an advanced grid structure having a thermal expansion coefficient of −0.25 ppm / K or more and 0.25 ppm / K or less can be obtained.

Embodiment 3 FIG.
The advanced grid structure according to the third embodiment of the present invention is different from the advanced grid structure according to the first embodiment of the present invention in carbon fiber, and as a result, has a different structural ratio, but is otherwise the same. Therefore, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.
The carbon fiber used for the advanced grid structure according to Embodiment 3 of the present invention has a tensile elastic modulus of 280 GPa or more and 330 GPa or less.

Next, an advanced grid structure was manufactured by preparing a tape prepreg so that the distance at which the grid sides are arranged, that is, the distance L between the nodes 9 is different. The structural ratios at this time were 0.015, 0.030, 0.060, and 0.107. The distance a between the intersecting regions was 0 mm and 24 mm. The thermal expansion coefficient of this advanced grid structure was measured as shown in FIG.
FIG. 10 is a graph showing the dependence of the coefficient of thermal expansion on the structure ratio with the distance between intersecting regions as a parameter.

  The advanced grid structure then defines the range of carbon fibers that are considered to have zero low thermal expansion. Here, the case where the absolute value of the thermal expansion coefficient is 0.10 ppm / K or less is defined as zero thermal expansion. Therefore, the range of the structure having zero low thermal expansion in the advanced grid structure is a structure having a coefficient of thermal expansion of −0.10 ppm / K or more and 0.10 ppm / K or less.

  As can be seen from FIG. 10, heat is obtained by adjusting the width W of the grid side or the distance L between the nodes 9 and the distance a between the intersecting regions so that the structural ratio is greater than 0 and less than or equal to 0.040. An advanced grid structure having an expansion coefficient of −0.10 ppm / K or more and 0.10 ppm / K or less can be obtained.

  On the other hand, one of three carbon fiber prepreg sheets in which carbon fibers having a tensile modulus of elasticity of 280 GPa or more and 330 GPa or less are oriented in one direction is tilted 60 degrees counterclockwise, and the other one is clockwise. The epoxy resin is cured by laminating three sheets inclined at 60 degrees and heating under pressure. This laminate is quasi-isotropic, but the thermal expansion coefficient is 1.1 ppm / K or more.

As in the advanced grid structure according to the first embodiment, the advanced grid structure according to the third embodiment of the present invention is a unidirectional laminate in which the grid-side intersection region and the grid side do not intersect in the advanced grid structure. The coefficient of thermal expansion of the advanced grid structure can be reduced by adjusting the ratio with the portion and the distance between the grid-side intersection regions.
In addition, carbon fiber having a tensile modulus of 280 GPa or more and 330 GPa or less is used, and the grid side width W or the distance L between nodes 9 and the distance between intersecting regions so that the structural ratio is greater than 0 and 0.040 or less. Since a can be set, an advanced grid structure having a thermal expansion coefficient of −0.10 ppm / K or more and 0.10 ppm / K or less can be obtained.

Embodiment 4 FIG.
FIG. 11 is a front view of an advanced grid structure according to Embodiment 4 of the present invention.
As shown in FIG. 11, the advanced grid structure according to the fourth embodiment of the present invention is integrated with the quasi-isotropic carbon fiber reinforced epoxy resin plate 20 in the advanced grid structure according to the first embodiment of the present invention. It has become.
Next, the process of integrating the quasi-isotropic carbon fiber reinforced epoxy resin plate with the advanced grid structure according to Embodiment 1 of the present invention will be described.
FIG. 12 is a plan view of three types of unidirectional carbon fiber prepreg sheets for manufacturing an advanced grid structure according to Embodiment 4 of the present invention.
As shown in FIG. 12A, the three types of carbon fiber prepreg sheets in which carbon fibers and resin are selected so as to be equivalent to the thermal expansion coefficient of the grid group are such that the carbon fibers are parallel to the reference side 21. 0 degree direction carbon fiber prepreg sheet 22 oriented in the direction, as shown in FIG. 12B, carbon fiber is oriented in a direction inclined 60 degrees counterclockwise with respect to the reference side 21 +60 degree direction carbon A fiber prepreg sheet 23, as shown in FIG. 12C, is a -60 degree carbon fiber prepreg sheet 24 in which carbon fibers are oriented in a direction inclined 60 degrees clockwise with respect to the reference side 21.
The three types of carbon fiber prepreg sheets are laminated, and the advanced grid structure according to the first embodiment of the present invention is placed thereon, and heated under pressure, and according to the fourth embodiment of the present invention shown in FIG. Advanced grid structures are manufactured.

The advanced grid structure according to the fourth embodiment of the present invention does not intersect the grid side intersection region portion and the grid side that occupy the advanced grid structure, similarly to the advanced grid structure according to the first embodiment of the present invention. The coefficient of thermal expansion of the advanced grid structure can be reduced by adjusting the ratio with the portion and the distance between the grid-side intersection regions.
In addition, since the pseudo isotropic carbon fiber reinforced epoxy resin plate 20 is disposed on one surface of the advanced grid structure, the area as the advanced grid structure is increased, so that it is possible to combine with other components and mount equipment. It becomes easy.

  In the advanced grid structure according to Embodiments 1 to 4 described above, two types of carbon fibers are used. However, the carbon fibers are not limited to this, and carbon fibers that can satisfy a desired strength are used. An advanced grid structure having low thermal expansion characteristics can be obtained by adjusting the ratio of the portions having high and low thermal expansion coefficients.

It is a front view of an example of the advanced grid structure concerning Embodiment 1 of this invention. It is a front view of the other example of the advanced grid structure which concerns on Embodiment 1 of this invention. It is an enlarged view including one node of the advanced grid structure which concerns on Embodiment 1 of this invention. It is a top view of three types of carbon fiber tape prepregs for manufacturing the advanced grid structure concerning Embodiment 1 of this invention. It is an enlarged view containing the equilateral triangular grid and hexagonal grid of the advanced grid structure which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the measuring apparatus of the thermal expansion coefficient of the advanced grid structure which concerns on Embodiment 1 of this invention. It is the graph which showed the dependence of the thermal expansion coefficient with respect to a structure ratio as a parameter between the distance between crossing areas. It is the graph showing the dependence of the thermal expansion coefficient of carbon fiber with respect to the tensile elasticity modulus of carbon fiber. It is a graph showing the structural ratio dependence of the thermal expansion coefficient of the advanced grid structure which concerns on Embodiment 2 of this invention. It is a graph showing the structural ratio dependence of the thermal expansion coefficient of the advanced grid structure which concerns on Embodiment 3 of this invention. It is a front view of the advanced grid structure which concerns on Embodiment 4 of this invention. It is a top view of three types of carbon fiber prepreg sheets for manufacturing the advanced grid structure concerning Embodiment 4 of this invention.

Explanation of symbols

  10 degree grid side, 2 +60 degree direction grid side, 3-60 degree direction grid side, 4 equilateral triangle grid, 5 hexagonal grid, 6 first intersecting area, 7 second intersecting area, 8 third Crossing area, 9 nodes, 10 Distance between crossing areas, 11 reference side, 120 degree carbon fiber tape prepreg, 13 +60 degree carbon fiber tape prepreg, 14-60 degree carbon fiber tape prepreg, 15 measurement sample, 16 Sample support base, 17 thermostatic chamber, 18 laser reflector, 19 laser focus displacement meter, 20 carbon fiber reinforced epoxy resin plate, 21 reference side, 220 degree direction carbon fiber prepreg sheet, 23 +60 degree direction carbon fiber prepreg sheet, 24 -60 degree carbon fiber prepreg sheet.

Claims (4)

First tape prepreg group in which carbon fibers arranged at equal intervals in the first direction are oriented in the longitudinal direction, etc. in a second direction inclined 60 degrees counterclockwise with respect to the first direction, etc. Second tape prepreg group in which carbon fibers arranged at intervals are oriented in the longitudinal direction, and carbon arranged at equal intervals in a third direction inclined 60 degrees clockwise with respect to the first direction In the advanced grid structure in which the third tape prepreg group in which the fibers are oriented in the longitudinal direction is repeatedly laminated in order so that the two tape prepreg groups overlap each other and heated under pressure,
A first grid side group that is in the same direction as the first tape prepreg group and constitutes one side of the grid group, and a second grid that is in the same direction as the second tape prepreg group and constitutes one side of the grid group Among the grid side group and the third grid side group that is in the same direction as the third tape prepreg group and constitutes one side of the grid group, the second grid side group and the third grid side group The grid side width is divided by the distance between the center point of the region where the crossing and the center point of the region where the second grid side group closest to the crossing region intersects the third grid side group. The structural ratio obtained is greater than 0 and 0.107 or less, and the tensile modulus of the carbon fiber is 280 GPa or more and 330 GPa or less. Advanced grid structure to the butterflies.   The advanced grid structure according to claim 1, wherein the structural ratio is greater than 0 and equal to or less than 0.053.   The advanced grid structure according to claim 1, wherein the structural ratio is greater than 0 and 0.040 or less.   The advanced grid structure according to any one of claims 1 to 3, wherein a laminated plate in which carbon fibers are oriented and laminated so as to have low thermal expansion is disposed.

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