JPH0552385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a spar structure consisting of flanges and webs. In particular, the invention relates to girder structures made of composite materials. As is well known in the art, composite materials are made by impregnating reinforcing fibers with resin,
It is a hardened material, and the reinforcing fibers used include glass fibers, carbon fibers, organic fibers such as aramid fibers, and the impregnated resin includes epoxy resin. The present invention can be applied to a wide range of girder structures, such as girders for aircraft, which require light weight and high strength, as well as girders for bridges and buildings.

BACKGROUND OF THE INVENTION In general, a girder structure is composed of a flange that mainly bears axial force and a web that mainly bears shear force, and the flanges are connected to edges on both sides of the web. Made by impregnating reinforcing fibers with resin and hardening them.
In girder structures made of so-called composite materials,
The flange has a thick plate-like structure with fibers arranged mainly in the longitudinal direction of the girder, and the web has a structure in which fibers are arranged in the longitudinal direction of the girder.
It has a thin structure with fibers arranged at 45 degrees. When the web is flat, it is necessary to arrange reinforcing members extending in the width direction of the girder at intervals in the longitudinal direction of the girder. This structure has been conventionally employed in metal girders, and has the advantage of being simple in structure. In particular, in the case of a metal girder, it is possible to design it to allow shear buckling of the web, which has the advantage of being lightweight. However, girder structures made of composite materials have a problem in that buckling of the webs cannot be tolerated, resulting in increased weight. moreover,
The reinforcing members must be attached manually one by one, which takes time and increases manufacturing costs.

In girder structures made of composite materials, it has also been proposed to use a honeycomb sandwich structure for the web, but although this structure has the advantages of being lightweight and resistant to buckling, it has the fatal disadvantage of high manufacturing costs. Furthermore, the skin and core tend to peel off even with a light impact, and when separation occurs, a high level of skill is required to repair it.

It is also known to increase buckling strength by forming the web into a waveform that repeats in the longitudinal direction of the girder.
With this structure, there is a problem in joining the web and the flange. In other words, when joining a web to a flange, the fibers of the web are bent along the flange surface at the edge of the web and joined to the flange, but since the web is corrugated, the directions of the folded fibers are not aligned. This results in uneven distribution of fibers on the flange surface, making the flange surface uneven.
When folding the fibers of the web, care should be taken to avoid uneven distribution of the fibers, but this will complicate the work and increase manufacturing costs.

As a technical equivalent to a corrugated web, it is also conceivable to form beads extending in the width direction of the web at intervals or continuously in the longitudinal direction of the spar. In this case, the bead is formed so that both ends do not reach the edge of the web and disappear inside the edge of the web, so the edge of the web becomes straight and the distribution of fibers changes as described above when joining with the flange. There is no need to worry about the occurrence of density problems. However, in order to form a bead on a web, it is necessary to draw the end of the bead to form a hemispherical or similar shape, and during this drawing process, the fibers at the end of the web are stretched. This will cause twitching in the web.

Problems to be Solved by the Invention The present invention solves the problem that when manufacturing a composite material girder structure in which a bead is formed on the web to increase buckling strength, the web This aims to solve the problem of twitching and other deformations at the edges.

That is, the present invention provides a method in which beads are formed on the web to increase buckling strength, there is no fear that the fibers of the web will become coarse or dense when joining the web and the flange, and furthermore, forming can be performed mechanically and easily. The purpose is to provide a composite material girder structure that can.

Means for Solving the Problems In the present invention, the following measures are taken to solve the above problems. That is, a connecting member with a T-shaped cross section is used to connect the flange and the web, the top of the T-shaped cross section of this connecting member is joined to the flange by adhesive, and the leg part of the T-shaped cross section is joined to the web by adhesive. . The connecting member may be formed by bonding a pair of L-shaped cross-sectional members to each other. A plurality of beads extending in the width direction of the web are formed on the web, and constricted portions are formed at both ends of each bead near the edges on both sides of the web. The constriction begins at a location corresponding approximately to the edge of the leg of the T-shaped cross-section of the connecting member and ends at a location corresponding to near the edge of the web. The legs of the T-shaped cross section of the connecting member are also formed with a constriction portion having a shape corresponding to the constriction portion at the bead end of the web.

As described above, the girder structure made of a composite material according to the present invention includes a flange made of a composite material made by impregnating reinforcing fibers with resin, and a connecting member made of a composite material made by impregnating reinforcing fibers with resin. and a web made of a composite material made of reinforcing fibers impregnated with resin, and the connecting member is joined by attaching one leg of each of a pair of L-shaped cross-sectional members to each other. The connecting member has a T-shaped cross-section formed, the top of the T-shaped cross-section of the connecting member being adhesively joined to the flange, the legs of the T-shaped cross-section being adhesively joined to the edges of the web, the web having A bead is formed extending in the width direction thereof, the bead having a constriction at each end, the constriction beginning near the edge of the web at a location approximately corresponding to the edge of the leg of the T-shaped cross-section of the connecting member. , is formed so as to end near the edge of the web, and is characterized in that the leg portion of the T-shaped cross section of the connecting member is also formed with a constricted portion having a shape corresponding to the constricted portion of the bead. Here, the bead is
The ridges may be formed in a wave shape in which concave and convex portions are alternately continuous in the longitudinal direction of the spar, or may be formed at intervals in the longitudinal direction of the spar.

Effects In the composite material girder structure of the present invention, since the top of the T-shaped cross section of the connecting member is joined to the flange, there is no fear that the fibers will become coarse or dense during joining. Since the constricted portion of the web is located close to the edge of the web, the restriction of the fibers is relatively weak, and there is no risk of defects such as twitching occurring at the edge of the web. Further, since the constricted portion of the leg portion of the connecting member is also formed near the edge of the leg portion, defects such as twitching will not occur in the leg portion of the connecting member.

Embodiment 1 Embodiment 1 Referring to FIGS. 1 and 2, the illustrated composite material girder structure has an upper flange 2a and a lower flange 2b, and these flanges 2a, 2b are
It has a substantially flat structure in which the fibers are arranged mainly in the longitudinal direction of the girder. The web 4 is formed by combining two thin plates 4a and 4b, and has a structure in which the fibers are oriented at 45° with respect to the longitudinal direction of the girder.

Connecting members 6 are provided for joining the flanges 2a, 2b to the opposite edges of the web 4. The connecting member 6 has a structure in which a pair of L-shaped cross-sectional members 6a and 6b are bonded together and formed into a T-shaped cross-section,
The top of the T-shaped cross section is glued to form flanges 2a and 2b.
are connected to each other. Thin plate 4 of web 4
a, 4b are placed one on top of the other on both sides of the leg of the T-shaped cross section of the connecting member, and are joined to this leg by adhesive. In this embodiment, each of the above-mentioned adhesion is achieved by the adhesive force of the resin impregnated into the fibers. As shown in FIG. 1, beads 8 extending in the width direction of the web 4 are formed at intervals in the longitudinal direction of the beam. Hemispherical constricted portions 8a and 8b are formed at both ends of each bead 8.
As shown in FIG. 2, a constriction is also formed on the leg of the T-shaped cross section of the connecting member 6, and the constricted portion of the bead 8 of the web 4 is formed on the edge 7 of the leg of the T-shaped cross section of the connecting member 6. They begin at approximately corresponding positions and end near the edge 5 of the web. The edge 5 of the web is therefore formed substantially straight. The constricted portion formed in the leg portion of the connecting member 6 has a shape corresponding to the constricted portion at the bead end portion of the web 4. FIG. 3 shows the position of the constricted portion 8a of the bead 8.

FIG. 4 shows an example of a method for manufacturing the above-mentioned girder structure, and the flanges are formed using a known automatic laminating machine as shown in FIG. 4a. The connecting member is formed by passing two sheets formed into a flat plate shape using an automatic laminating machine into an L-shaped cross section by passing them through a roll forming machine. This process is shown in Figure 4b. The thin plates 4a and 4b of the web 4 are also formed into flat plate shapes by an automatic laminating machine. The parts formed in this way are assembled as shown in FIG. 4c, and the legs of the web 4 and the connecting member 6 are sandwiched between the lower die 10 and the upper die 12 for bead forming, and press-molded. Then, in this state, the resin is cured. This process is shown in Figure 4d.

Second Embodiment This embodiment has almost the same configuration as the previous embodiment, but the beads 8 formed on the web 4 are not arranged at intervals in the longitudinal direction of the girders, but are formed continuously in a wave shape. This embodiment differs from the previous embodiment in that In other respects, this embodiment is the same as the previous embodiment, so corresponding parts are given the same reference numerals and detailed explanations will be omitted.

Effects As described above, in the present invention, since beads are formed on the web, the buckling strength of the web is increased, and the web can be made into a thin wall structure without attaching a reinforcing member to the web. .
In addition, the bead has a constricted portion at the end that is connected to the T of the connecting member.
Since it is configured to start at a position approximately corresponding to the leg of the shaped cross section and end near the edge of the web, there is no risk of defects such as twitching occurring at the edge of the web when forming the drawn portion.

[Brief explanation of drawings]

FIG. 1 shows a girder structure according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the parts slightly separated from each other; FIG. 2 is a cross-sectional view taken along the - line in FIG. 1; FIG.
b, c, and d are perspective views showing the manufacturing method of the girder structure shown in FIGS. 1 to 3; FIG. 5 is a perspective view similar to FIG. 1 showing another embodiment of the present invention; 6 is a sectional view taken along the - line in FIG. 5, and FIG. 7 is a sectional view taken along the - line in FIG. 2a, 2b...flange, 4...web, 6...
... Connection member, 8... Bead.

Claims (1)

[Claims] 1. A flange made of a composite material made by impregnating reinforcing fibers with resin, a connecting member made of a composite material made by impregnating reinforcing fibers with resin, and a composite material made by impregnating reinforcing fibers with resin. The connecting member has a T-shaped cross-section formed by bonding one leg of each of a pair of L-shaped cross-sectional members to each other, and the connecting member has a web made of a material. The top of the T-shaped section is joined to the flange by adhesive, the legs of the T-shaped section are joined to the edge of the web by adhesive, the web is formed with a bead extending in the width direction thereof, and the bead has a constriction at each end, the constriction beginning near the edge of the web at a position approximately corresponding to the edge of the leg of the T-shaped cross section of the connecting member;
A girder made of composite material, which is formed to end near the edge of the web, and has a constricted portion having a shape corresponding to the constricted portion of the bead also formed in the leg portion of the T-shaped cross section of the connecting member. structure.