JP2007152938A

JP2007152938A - Member made from frp

Info

Publication number: JP2007152938A
Application number: JP2006290761A
Authority: JP
Inventors: Takuya Karaki; 琢也唐木; Akihiko Kitano; 彰彦北野; Kenichi Yoshioka; 健一吉岡
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2005-11-11
Filing date: 2006-10-26
Publication date: 2007-06-21

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member made from FRP (Fiber Reinforced Plastic) having the high notch strength. <P>SOLUTION: The member made from a fiber reinforced composite material (FRP) has at least one or more notches, and comprises two or more sorts of reinforcement fibers having different tensile rupture elongations, wherein the volume ratio VA1 of a reinforcement fiber A oriented in the elastic main axis direction occupying all reinforcement fiber volume oriented in an elastic main axis direction in the stress concentration domain is higher than the volume ratio VA2 of a reinforcement fiber A oriented in the elastic main axis direction occupying all reinforcement fiber volume oriented in an elastic main axis direction in the outside of the stress concentration domain, and VA2 is 0.1 or less. The reinforcement fiber A is a reinforcement fiber having the highest tensile rupture elongation in the reinforcement fibers included in the member made from FRP. The stress concentration domain is a domain within the distance d (mm) from the notch end to where defined by formula 1 in the orthogonal direction with the elastic main axis. The V0 is the volume ratio of the reinforcement fiber oriented in the elastic main axis direction occupying all the reinforcement fiber volume in the member made from FRP. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、軽量、高剛性であり、かつ、切り欠きを有しながらも高い強度を保持し、輸送機器のフレームや建築物の支柱補強材として好適に使用することができる繊維強化プラスチック製部材（以下、ＦＲＰ製部材と略することもある）に関するものである。 The present invention is a fiber-reinforced plastic member that is lightweight, highly rigid, has high strength while having a notch, and can be suitably used as a frame for transportation equipment or a strut reinforcement for buildings. (Hereinafter, it may be abbreviated as a member made of FRP).

ＦＲＰ製部材は比強度、比剛性、耐熱性、耐環境性に優れるため、スポーツ分野、航空機分野を始め、幅広く普及している。特に補強繊維に炭素繊維を用いた炭素繊維強化プラスチック（以下ＣＦＲＰと略することもある）は比強度、比剛性に優れ、さらに近年では、高伸度タイプと呼ばれる炭素繊維が開発され、この高伸度タイプの炭素繊維を用いたＣＦＲＰは特に比強度に優れるため、すでに航空機分野を始め多方面で活用されている。 Since FRP members are excellent in specific strength, specific rigidity, heat resistance, and environmental resistance, they are widely used in the sports and aircraft fields. In particular, carbon fiber reinforced plastic using carbon fiber as a reinforcing fiber (hereinafter sometimes abbreviated as CFRP) is excellent in specific strength and specific rigidity. In recent years, a carbon fiber called a high elongation type has been developed. CFRP using an elongation-type carbon fiber is particularly excellent in specific strength, and has already been used in various fields including the aircraft field.

しかしながらＦＲＰはボルト孔などに代表される切り欠きを有する場合は引張強度が大きく低下することが知られている（以下、切り欠きを有するＦＲＰの引張強度を切り欠き強度と略することもある）。例えば非特許文献１に代表されるように、スチールやアルミニウムに代表される金属類は、切り欠きを有していても強度の低下率は切り欠きの大きさにほぼ比例した低下率であるのに対し（例えば幅７６ｍｍのアルミニウム板の中心に２２ｍｍの円孔が存在しているときは、その板の引張強度の低下率は１７％にしかならない）、ＦＲＰでは小規模の切り欠きが存在しているだけで大幅に強度が低下することが確認されている（例えば幅７６ｍｍのＦＲＰ板の中心に２２ｍｍの円孔が存在しているときは、その板の引張強度は半減してしまう）。このメカニズムについては非特許文献２に示されているとおり、切り欠き端部にかかる応力集中が関係している。すなわち、円孔などに代表される切り欠きを有する部材に一定の引張荷重をかけたときは、切り欠き端部に応力が集中し、この部分の応力が他の領域の応力に比べて数倍に増幅される。例えば円孔を有する金属板に引張荷重をかけたときは、円孔の端部付近には、円孔から十分離れた領域にかかる応力と比べて、約３倍の応力がかかることが確認されている。しかしながら金属材料の場合は、切り欠き端部付近の材料が塑性変形を起こすことで応力を緩和するため、切り欠き端部の応力集中が引き起こす強度低下は重大な問題として顕在化する事はなかった。 However, it is known that when FRP has a notch typified by a bolt hole or the like, the tensile strength is greatly reduced (hereinafter, the tensile strength of FRP having a notch may be abbreviated as notch strength). . For example, as represented by Non-Patent Document 1, metals such as steel and aluminum have a notch, but the rate of decrease in strength is a rate of decrease approximately proportional to the size of the notch. On the other hand (for example, when a 22 mm circular hole exists in the center of an aluminum plate having a width of 76 mm, the rate of decrease in the tensile strength of the plate is only 17%), FRP has a small notch. It has been confirmed that the strength is significantly reduced by simply holding the plate (for example, when a 22 mm circular hole is present at the center of a 76 mm wide FRP plate, the tensile strength of the plate is halved). As shown in Non-Patent Document 2, this mechanism is related to the stress concentration applied to the notch end. In other words, when a constant tensile load is applied to a member having a notch typified by a circular hole, the stress concentrates at the notch end, and the stress at this part is several times greater than the stress in other areas. Is amplified. For example, when a tensile load is applied to a metal plate having a circular hole, it is confirmed that about three times as much stress is applied near the end of the circular hole as compared to the stress applied to a region sufficiently away from the circular hole. ing. However, in the case of a metal material, the stress in the vicinity of the notch end is plastically deformed to relieve stress, so the strength reduction caused by the stress concentration at the notch end has not become a significant problem. .

しかしながらＦＲＰの場合は、補強繊維の塑性変形能力は金属材料と比較して小さい場合が多く、特に炭素繊維は、塑性変形をせずに脆性破壊を起こすため、切り欠き端部付近の応力集中により切り欠き端部付近の繊維が破断し、その破断が部材全体の破壊を引き起こすため、切り欠き強度が大幅に低下してしまうのである。この傾向は特に切り欠きにボルトなど他の部材をはめあわせたＦｉｌｌｅｄＨｏｌｅと呼ばれる形状において特に顕在化し、この理由については諸説あるが、例えばボルトをはめあわせた場合、ボルトと切り欠き面との接触面積が大きく、この領域全てで応力が集中する。前述したように塑性変形する金属材料であれば、この領域でも応力が緩和されるため大きな強度低下は引き起こされないが、ＦＲＰではこの応力が集中する領域全てで脆性破壊してしまうため、より強度の低下が激しくなると考えられている。 However, in the case of FRP, the plastic deformation capacity of the reinforcing fiber is often smaller than that of the metal material. In particular, the carbon fiber causes brittle fracture without plastic deformation, and therefore, due to stress concentration near the notch end. The fiber near the notch end breaks, and the breakage causes the entire member to be broken, so that the notch strength is greatly reduced. This tendency is particularly apparent in a shape called Filled Hole in which other members such as bolts are fitted into the notch, and there are various theories about this reason. For example, when the bolt is fitted, the contact between the bolt and the notched surface The area is large, and the stress is concentrated in this whole area. As described above, if the metal material is plastically deformed, the stress is relaxed even in this region, so that a large strength reduction is not caused. However, in FRP, since the entire region where the stress is concentrated is brittle, the strength is further increased. It is thought that the decline of will become severe.

このような問題を解決するため特許文献１では穴周りを肉厚化し、強度の低下幅を断面積の増加によって補う方法が公開されている。しかしながらこの方法では、切り欠きによる強度の低下は補えるものの、部材が肉厚化し、結果重量増となって、軽量高強度というＦＲＰ本来の特長を損なってしまうという問題を抱えていた。また部分的に肉厚化する方法では、他部品との取り合いの関係からも設計上の制約が大きく、現実的に不可能であるケースが多々あるのである。 In order to solve such a problem, Patent Document 1 discloses a method in which the periphery of a hole is thickened and the decrease in strength is compensated by increasing the cross-sectional area. However, although this method can compensate for the decrease in strength due to the notch, the member becomes thicker, resulting in an increase in weight, resulting in a problem that the original characteristics of the FRP such as light weight and high strength are impaired. In addition, in the method of partially thickening, there are many cases that are practically impossible because there are large design restrictions due to the relationship with other parts.

このように、切り欠きを有しながら、厚肉化などの重量増を引き起こさずに、かつＦＲＰ本来が持つ高い強度と剛性を維持するＦＲＰ製部材が望まれて久しいのである。
特開平６−１９３２８１号公報ベイカー（Ｂａｋｅｒ，Ａ．Ａ．），メタルフォーラム（ＭｅｔａｌｓＦｏｒｕｍ），１９８３年，６巻，２号，ｐ．８１ゲイ・ダニエル（Ｇａｙ，Ｄａｎｉｅｌ．），ハオ・ソン（Ｈｏａ，Ｓｕｏｎｇ．），ツァイ・ステファン（Ｔｓａｉ，Ｓｔｅｐｈｅｎ．），「コンポジットマテリアル（ＣｏｍｐｏｓｉｔｅＭａｔｅｒｉａｌｓ）」、シーアールシー・プレス（ＣＲＣＰＲＥＳＳ），２００３年，ｐ．１１６ Thus, it has long been desired to have a member made of FRP that has a notch but does not cause an increase in weight such as thickening and maintains the high strength and rigidity inherent in FRP.
JP-A-6-193281 Baker, A.A., Metals Forum, 1983, Vol. 6, No. 2, p. 81 Gay Daniel, Hoa, Suong, Tsai, Stephen, “Composite Materials”, CRC PRESS, 2003 , P. 116

本発明の目的は、かかる従来技術の持つ課題を解決し、高い切り欠き強度を有するＦＲＰ製部材を提供することにある。 An object of the present invention is to solve the problems of the prior art and to provide an FRP member having high notch strength.

本発明は、かかる課題を解決するために、次のような手段を採用するものである。すなわち、少なくとも一つ以上の切り欠きを有する繊維強化複合材料（ＦＲＰ）製部材であって、引張破断伸度が異なる２種以上の補強繊維を含み、応力集中領域において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ１が、応力集中領域外において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ２よりも高く、かつ、ＶＡ２が０．１以下であるＦＲＰ製部材である。 The present invention employs the following means in order to solve such problems. That is, a fiber reinforced composite material (FRP) member having at least one notch, including two or more types of reinforcing fibers having different tensile elongation at break, and oriented in the elastic principal axis direction in the stress concentration region. The elastic main axis direction in which the volume ratio VA1 of the reinforcing fibers A oriented in the elastic main axis direction in the total reinforcing fiber volume is occupied in the total reinforcing fiber volume oriented in the elastic main axis direction outside the stress concentration region It is a member made of FRP which is higher than the volume ratio VA2 of the reinforcing fibers A oriented to VA2 and VA2 is 0.1 or less.

補強繊維Ａ：ＦＲＰ製部材に含まれる補強繊維の中で最も引張破断伸度の高い補強繊維
応力集中領域：切り欠き端部より弾性主軸と直行する方向に（式１）で定義される距離ｄ（ｍｍ）以内の領域 Reinforcing fiber A: Reinforcing fiber having the highest tensile breaking elongation among reinforcing fibers contained in the FRP member Stress concentration region: Distance d defined by (Equation 1) in a direction perpendicular to the elastic main axis from the notch end Area within (mm)

Ｖ０：ＦＲＰ製部材中の全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維の体積割合 V0: Volume ratio of reinforcing fibers oriented in the elastic principal axis direction in the total reinforcing fiber volume in the FRP member

本発明によれば、以下に説明するとおり、切り欠きの存在にもかかわらず高い強度を有するＦＲＰ製部材を提供することができる。 According to the present invention, as described below, it is possible to provide an FRP member having high strength despite the presence of a notch.

以下、本発明の実施の形態を図１を用いて詳細に説明する。本発明のＦＲＰ製部材は２種類以上の補強繊維と、マトリクス樹脂とからなり、かつ、少なくとも一つ以上の切り欠き３を有している。そして、本発明のＦＲＰ製部材は、切り欠きの端部より、弾性主軸４と直行する方向に下記（式１）で定義される距離ｄ（ｍｍ）内の領域１（以下応力集中領域と呼称することもある）とそれ以外の領域２（以下応力集中領域外の領域と呼称することもある）に分けられる。 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. The FRP member of the present invention is composed of two or more types of reinforcing fibers and a matrix resin, and has at least one notch 3. The FRP member of the present invention is a region 1 (hereinafter referred to as a stress concentration region) within a distance d (mm) defined by the following (Equation 1) in a direction perpendicular to the elastic main shaft 4 from the end of the notch. And other regions 2 (hereinafter also referred to as regions outside the stress concentration region).

補強繊維の中で最も引張破断伸度の高い補強繊維（以下この補強繊維を補強繊維Ａと呼称することもある）は応力集中領域に主として配され、補強繊維Ａ以外の繊維（ここでは、説明のため補強繊維を２種類と限定し、補強繊維Ａ以外の補強繊維を補強繊維Ｂと呼称することもある）は主として応力集中領域外の領域に配される。応力集中領域において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ１は、応力集中領域外において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ２よりも高く、かつ、ＶＡ２は０．１以下である必要がある。 Among the reinforcing fibers, the reinforcing fiber having the highest tensile elongation at break (hereinafter, this reinforcing fiber may be referred to as the reinforcing fiber A) is mainly arranged in the stress concentration region, and fibers other than the reinforcing fiber A (here, explanation) Therefore, the reinforcing fibers are limited to two types, and reinforcing fibers other than the reinforcing fibers A may be referred to as reinforcing fibers B) are mainly arranged in a region outside the stress concentration region. In the stress concentration region, the volume ratio VA1 of the reinforcing fibers A oriented in the elastic principal axis direction in the total reinforcing fiber volume oriented in the elastic principal axis direction is oriented in the elastic principal axis direction outside the stress concentration region. It is higher than the volume ratio VA2 of the reinforcing fibers A oriented in the elastic principal axis direction in the total reinforcing fiber volume, and VA2 needs to be 0.1 or less.

補強繊維Ａは主として切り欠きの端部から距離ｄ（ｍｍ）の領域に配せられ、特に応力が集中し、高い応力がかかる部分の応力集中を緩和させるために他の補強繊維Ｂより高伸度である必要がある。この条件さえ満たせば補強繊維Ａの材料は特に限定されるものではないが、高伸度タイプの炭素繊維やガラス繊維などの無機繊維、そして、ポリアミド繊維、ポリエステル繊維、ポリビニルアルコール繊維、ポリアクリロニトリル繊維、ポリウレタン繊維などの有機繊維を用いることができる。特にガラス繊維や高伸度タイプの炭素繊維は高い引張破断伸度を有しながら、適当な弾性率を有しており好ましい。引張破断伸度３％以上６％以下のガラス繊維は特にこのバランスに優れてさらに好ましい。引張破断伸度が３％未満であると応力集中を緩和させるのに十分ではなく、６％を超えるガラス繊維は存在しない。ここで補強繊維Ａの引張破断伸度とはＪＩＳＲ７６０１（１９８６）で測定される値をいう。 The reinforcing fiber A is mainly disposed in a region at a distance d (mm) from the end of the notch. Particularly, the stress is concentrated, and in order to alleviate the stress concentration in a portion where high stress is applied, the reinforcing fiber A is stretched higher than other reinforcing fibers B. Must be degrees. The material of the reinforcing fiber A is not particularly limited as long as this condition is satisfied, but inorganic fibers such as high elongation type carbon fiber and glass fiber, and polyamide fiber, polyester fiber, polyvinyl alcohol fiber, and polyacrylonitrile fiber. Organic fibers such as polyurethane fibers can be used. In particular, glass fibers and high elongation type carbon fibers are preferable because they have an appropriate elastic modulus while having high tensile elongation at break. Glass fibers having a tensile elongation at break of 3% or more and 6% or less are particularly preferable because of excellent balance. If the tensile elongation at break is less than 3%, it is not sufficient to relieve stress concentration, and there is no glass fiber exceeding 6%. Here, the tensile elongation at break of the reinforcing fiber A refers to a value measured according to JIS R 7601 (1986).

補強繊維Ｂは特に限定されるものではないが、切り欠き端部以外の部分、すなわち部材の大半の部分に配せられているので、部材の強度のみならず剛性を保持する視点からも高い弾性率を持つ物が好ましい。この観点から言うと炭素繊維は軽量ながら高い弾性率を有しており特に好ましい。弾性率３００ＧＰａ以上１２００ＧＰａ以下の炭素繊維は特に高い剛性を付与することができさらに好ましい。弾性率が３００ＧＰａ未満であると、ＦＲＰ製部材に十分な剛性を付与することができないことがあり、また、１２００ＧＰａを超える炭素繊維は存在しない。ここで補強繊維Ｂの弾性率とはＪＩＳＲ７６０１（１９８６）で測定される値をいう。 Although the reinforcing fiber B is not particularly limited, it is arranged in a portion other than the notched end portion, that is, most of the member, so that it has high elasticity not only from the strength of the member but also from the viewpoint of maintaining rigidity. Those with a rate are preferred. From this point of view, the carbon fiber is particularly preferable because it is lightweight and has a high elastic modulus. Carbon fibers having an elastic modulus of 300 GPa or more and 1200 GPa or less are more preferable because they can impart particularly high rigidity. When the elastic modulus is less than 300 GPa, it may not be possible to impart sufficient rigidity to the FRP member, and there is no carbon fiber exceeding 1200 GPa. Here, the elastic modulus of the reinforcing fiber B refers to a value measured according to JIS R 7601 (1986).

補強繊維Ａと補強繊維Ｂは同方向に引き揃えられている必要があるが、製造上の制約などから引き揃え方向が必ずしも完全に一致している必要はない。ただし、両者の方向の差は２度以内であることが好ましい。そして、補強繊維Ａと補強繊維Ｂの引き揃え方向は、弾性主軸と平行である必要がある。弾性主軸とはＦＲＰ製部材が最も高い剛性を持つ方向のことを指し、ＦＲＰ製部材においては最も補強繊維が配向されている方向に等しいことが多い。また、多用される擬似等方構成では、弾性主軸は実質的に２方向以上存在するが、この場合は、主たる荷重がかかる方向を弾性主軸と定義する。 The reinforcing fiber A and the reinforcing fiber B need to be aligned in the same direction, but the alignment direction is not necessarily completely coincident due to manufacturing restrictions. However, the difference between the two directions is preferably within 2 degrees. And the alignment direction of the reinforcing fiber A and the reinforcing fiber B needs to be parallel to the elastic main axis. The elastic main shaft refers to the direction in which the FRP member has the highest rigidity, and in the FRP member, it is often equal to the direction in which the reinforcing fibers are oriented most. In the quasi-isotropic configuration that is frequently used, there are substantially two or more elastic main axes. In this case, the direction in which the main load is applied is defined as the elastic main axis.

本発明における切り欠きとは、厚さ方向に全ての補強繊維が不連続となっている部分を意味し、例えば、ボルト孔や勘合用の受け孔などである。切り欠きの形状は円形、楕円形、矩形、菱形など部材が要求する設計によって決定されるものであり特に限定されるものではないが、実質的に円形であると、ボルトなどで他の部材と結合したときに局部的に異常に高い応力がかかることが無いため好ましい。ここで実質的に円形とは、切り欠きの端部と端部を任意に選び、両者の距離が最も大きい組み合わせを長軸、最も小さい組み合わせを短軸としたときに長軸／短軸比が１．３以下であることをいう。この長軸／短軸比が１．３を超えると、他の部材と結合したときに局部的に高い応力がかかってしまい、部材の切り欠き強度が著しく低下してしまうことがある。また、部材の厚さ方向の断面形状は、他の部材とのはめあいにより決定されるものであり、特に限定はされないが、ストレート孔と呼ばれるように一様断面であると、一般に使用されているボルトが不具合なく使用できて好ましい。また、図２のように部材の厚さ方向にテーパーがついている、いわゆる皿孔形状を有していると、皿ねじと呼ばれる形状のボルトを隙間無くはめあわせることができ特に好ましい。ここで、皿孔の深さ７は、部材の厚さ８に対して２／３以下であると、実質的に荷重を支えるストレート孔の部分が相対的に大きくなり特に好ましい。切り欠きの作製方法は、公知の手段を用いることができ特に限定されるものではないが、例えばダイヤモンドドリルで下孔を空け、リーマーで仕上げる方法などは、切り欠きの表面品位を劣化させることなく好ましい。また、ダイヤモンドドリルとリーマーが一体となったドリルを用いて作製する方法も、簡便でかつ切り欠きの表面品位を劣化させることなく好ましい。本発明のＦＲＰ製部材は二つ以上の切り欠きを有することもあり、切り欠き同士の間隔もＦＲＰ製部材の設計要件によって決定されるものであるため特に限定されることはないが、切り欠きの幅をφとすると、切り欠き同士の間隔は３φ以上であると、例えば片方の切り欠きの端部に生じた欠陥が他方の切り欠き周辺の強度に影響を与えることなく好ましい。ここで切り欠きの幅φとは、切り欠きの端部と端部を任意に選び両者の距離が最も大きい組み合わせを幅φと規定する。 The notch in the present invention means a portion in which all the reinforcing fibers are discontinuous in the thickness direction, such as a bolt hole and a receiving hole for fitting. The shape of the notch is determined by the design required by the member, such as a circle, an ellipse, a rectangle, and a diamond, and is not particularly limited. Since it does not apply an abnormally high stress locally when bonded, it is preferable. Here, the term “substantially circular” means that the notch end and the end are arbitrarily selected, and the long axis / short axis ratio is the long axis with the longest combination and the shortest with the shortest combination. It means 1.3 or less. When the major axis / minor axis ratio exceeds 1.3, a high stress is locally applied when coupled to another member, and the notch strength of the member may be significantly reduced. In addition, the cross-sectional shape in the thickness direction of the member is determined by fitting with other members, and is not particularly limited, but is generally used as a uniform cross-section called a straight hole. Bolts are preferred because they can be used without problems. Further, it is particularly preferable to have a so-called countersunk hole shape having a taper in the thickness direction of the member as shown in FIG. 2 so that bolts having a shape called a countersunk screw can be fitted without a gap. Here, it is particularly preferable that the depth 7 of the countersunk hole is 2/3 or less of the thickness 8 of the member because the portion of the straight hole that substantially supports the load becomes relatively large. The manufacturing method of the notch is not particularly limited since known means can be used. For example, a method of drilling a pilot hole with a diamond drill and finishing with a reamer does not deteriorate the surface quality of the notch. preferable. A method of manufacturing using a drill in which a diamond drill and a reamer are integrated is also preferable because it is simple and does not deteriorate the surface quality of the notch. The FRP member of the present invention may have two or more notches, and the interval between the notches is determined by the design requirements of the FRP member, but is not particularly limited. If the width of the notch is φ, the interval between the notches is preferably 3φ or more, for example, a defect generated at the end of one notch does not affect the strength around the other notch. Here, the notch width φ is defined as a width φ in which the notch end and end are arbitrarily selected and the distance between them is the largest.

上述したように、弾性主軸とはＦＲＰ製部材が最も高い剛性を持つ方向のことを指し、ＦＲＰ製部材においては最も補強繊維が配向されている方向に等しいことが多い。そして、弾性主軸方向に引張荷重がかけられたときは、切り欠きの端部には応力集中により他の部分より高い応力がかかる。発明者らはこの応力集中がかかる領域を簡便に予測できる式を検討の結果生み出すことに成功した。すなわち応力集中がかかる領域は切り欠き端部より弾性主軸と直交する方向に距離ｄ（ｍｍ）以内の領域である。 As described above, the elastic main shaft refers to the direction in which the FRP member has the highest rigidity, and in the FRP member, it is often equal to the direction in which the reinforcing fibers are oriented most. When a tensile load is applied in the direction of the elastic principal axis, a higher stress is applied to the end portion of the notch due to stress concentration than other portions. The inventors have succeeded in producing an equation that can easily predict the region where the stress concentration is applied. That is, the region where the stress is concentrated is a region within a distance d (mm) in the direction perpendicular to the elastic main axis from the notch end.

ここで距離ｄ（ｍｍ）とは下記（式１）で定義される値であり、Ｖ０とは、ＦＲＰ製部材中の全補強繊維のなかで、弾性主軸方向に配向されている補強繊維の体積割合を意味し、具体的には、弾性主軸方向に配向されている補強繊維の体積／ＦＲＰ製部材中の全補強繊維体積で表される。 Here, the distance d (mm) is a value defined by the following (Equation 1), and V0 is the volume of the reinforcing fiber oriented in the elastic principal axis direction among all the reinforcing fibers in the FRP member. It means a ratio, and is specifically represented by the volume of reinforcing fibers oriented in the elastic main axis direction / the total volume of reinforcing fibers in the FRP member.

たとえば一方向積層板の場合Ｖ０は１となり、擬似等方材と呼ばれる[４５／９０／−４５／０]ｓ（ｓは厚さ方向に鏡面対称に積層することを示す）構成では０．２５である。この応力集中領域内に引張破断伸度の高い補強繊維Ａを主として配することにより、応力集中による強度の低下をふせぎ、応力集中のかからない他の領域には弾性率の高い補強繊維Ｂを配することにより、優れた切り欠き強度を保持したまま高い剛性を有するＦＲＰ製部材を提供することが可能となる。具体的には、応力集中領域において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ１は、応力集中領域外において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ２よりも大きく、かつ、ＶＡ２は０．１以下である必要がある。ＶＡ２が０．１を超えると、一般的に引張破断伸度が高い補強繊維（この場合は補強繊維Ａ）は、塑性域が大きく塑性変形による応力緩和には優れるものの、最終破断強度は決して高くないため、ＦＲＰ製部材の強度は結果的に低下してしまう。また、引張破断伸度が高い補強繊維は一般的に弾性率が低めであるため、弾性率の高い補強繊維Ｂが十分量配されないことになり、ＦＲＰ製部材に十分な剛性を付与することが難しくなる。また、ＶＡ１がＶＡ２より低い場合は、応力集中領域に十分な補強繊維Ａが配されていないことになり、ＦＲＰ製部材の切り欠き強度が著しく低下してしまう。ＶＡ１は０．１以上であると、補強繊維Ａが応力集中領域の応力を十分緩和でき好ましい。０．７以上であると、応力集中領域のほぼ全域をカバーできることになりさらに好ましい。なおＶＡ１は１．０を超えることはない。ＶＡ２は０．１以下であればＦＲＰ製部材に十分な剛性を付与できることができ、より好ましくは０である。なぜなら応力集中領域外の領域にかかる応力は、応力集中領域にかかる応力に比べて著しく低く、切欠き強度向上という観点からは補強繊維Ａを配する利点がないからである。なお、引張破断伸度が高く、かつ、引張弾性率も高い補強繊維を用いるのが効果的ではあるが、繊維の引張破断伸度と引張弾性率は一般的にトレードオフの関係にある。なおＶＡ１とＶＡ２は以下に示す方法によって測定することができる。すなわち、応力集中領域と応力集中領域外の領域をそれぞれダイヤモンドカッターなどで切り取り、弾性主軸に直行する断面を研磨した後、光学顕微鏡で観察する。その観察結果を、例えばＡｄｏｂｅ社製Ｐｈｏｔｏｓｈｏｐ（登録商標）などの画像処理ソフトで取り込み、繊維断面の大きさや形状から補強繊維の選別行う。選別後に、補強繊維Ａと推定される補強繊維と、全ての補強繊維の断面積の総和をそれぞれ画像処理ソフトの面積測定機能などで測定した後、それぞれの領域において、弾性主軸方向に配向されている補強繊維Ａの体積／弾性主軸方向に配向されている全補強繊維体積を算出することによって、ＶＡ１、ＶＡ２が算出できる。 For example, in the case of a unidirectional laminated board, V0 is 1, and in a configuration called [quasi-isotropic material] [45/90 / −45 / 0] s (s indicates that the layers are laminated symmetrically in the thickness direction), it is 0.25. It is. By mainly disposing the reinforcing fiber A having a high tensile breaking elongation in the stress concentration region, the strength reduction due to the stress concentration is prevented, and the reinforcing fiber B having a high elastic modulus is disposed in other regions where the stress concentration is not applied. Thus, it becomes possible to provide an FRP member having high rigidity while maintaining excellent notch strength. Specifically, in the stress concentration region, the volume ratio VA1 of the reinforcing fibers A oriented in the elastic principal axis direction in the total reinforcing fiber volume oriented in the elastic principal axis direction is the elastic principal axis outside the stress concentration region. The volume ratio VA2 of the reinforcing fibers A oriented in the elastic principal axis direction in the total reinforcing fiber volume oriented in the direction is larger than VA2, and VA2 needs to be 0.1 or less. When VA2 exceeds 0.1, a reinforcing fiber (in this case, reinforcing fiber A) generally having a high tensile elongation at break has a large plastic region and is excellent in stress relaxation due to plastic deformation, but the final breaking strength is never high. Therefore, the strength of the FRP member is reduced as a result. Further, since the reinforcing fiber having a high tensile breaking elongation generally has a low elastic modulus, a sufficient amount of the reinforcing fiber B having a high elastic modulus is not distributed, and sufficient rigidity can be imparted to the FRP member. It becomes difficult. Moreover, when VA1 is lower than VA2, sufficient reinforcing fibers A are not arranged in the stress concentration region, and the notch strength of the FRP member is significantly reduced. It is preferable that VA1 is 0.1 or more because the reinforcing fiber A can sufficiently relax the stress in the stress concentration region. When it is 0.7 or more, almost the entire stress concentration region can be covered, which is further preferable. Note that VA1 does not exceed 1.0. If VA2 is 0.1 or less, sufficient rigidity can be imparted to the FRP member, and more preferably 0. This is because the stress applied to the region outside the stress concentration region is significantly lower than the stress applied to the stress concentration region, and there is no advantage of providing the reinforcing fiber A from the viewpoint of improving the notch strength. Although it is effective to use a reinforcing fiber having a high tensile breaking elongation and a high tensile elastic modulus, the tensile breaking elongation of the fiber and the tensile elastic modulus are generally in a trade-off relationship. VA1 and VA2 can be measured by the following method. That is, the stress concentration region and the region outside the stress concentration region are each cut out by a diamond cutter or the like, and a cross section perpendicular to the elastic main axis is polished and then observed with an optical microscope. The observation result is captured by image processing software such as Photoshop (registered trademark) manufactured by Adobe, and the reinforcing fibers are selected based on the size and shape of the fiber cross section. After the selection, the total of the cross-sectional areas of the reinforcing fibers estimated to be the reinforcing fibers A and all the reinforcing fibers are measured by the area measurement function of the image processing software, respectively, and then oriented in the elastic main axis direction in each region. VA1 and VA2 can be calculated by calculating the volume of reinforcing fibers A being present / the total volume of reinforcing fibers oriented in the elastic principal axis direction.

ここまでは説明のため、２種類の補強繊維に限定して説明してきたが、補強繊維Ａと補強繊維Ｂの他に、本発明の効果を損なわない範囲で、第３の繊維を含んでいても良い。全ての繊維を含めた繊維体積含有率（Ｖｆ）は、部材の力学特性と製造の安定性とのバランスをはかる上で、好ましくは４０〜８０％の範囲内がよく、さらに好ましくは５０〜７０％の範囲内にあるのが良い。ここでＶｆは、含まれる種々の補強繊維の比重が実質的に同一と見なせる場合は（例えば炭素繊維の場合は１．７５から１．８５の範囲におさまる）、その中で任意の補強繊維の比重を用い、残りの方法はＪＩＳＫ７０７５（１９９１）に従って測定することができる。また、例えばガラス繊維（比重約２．５）と炭素繊維（比重約１．８）のように比重が大きく異なる補強繊維が使われている場合は、それぞれの補強繊維が主に配されている領域を任意に選定し、（本発明においては、例えばこの場合は、ガラス繊維は応力集中領域に、炭素繊維は応力集中領域外に主に配されているため、測定個所の選定は容易である）ＪＩＳＫ７０７５（１９９１）に従ってそれぞれの箇所のＶｆを測定し、それらのうちどれか一つが上述した範囲内に入っていればよい。 Up to this point, the description has been limited to two types of reinforcing fibers. However, in addition to the reinforcing fiber A and the reinforcing fiber B, the third fiber is included in a range that does not impair the effects of the present invention. Also good. The fiber volume content (Vf) including all the fibers is preferably in the range of 40 to 80%, more preferably 50 to 70, in order to balance the mechanical properties of the member and the stability of production. It should be in the range of%. Here, when the specific gravity of the various reinforcing fibers included can be regarded as substantially the same (for example, in the case of carbon fiber, it falls within the range of 1.75 to 1.85), Vf of any reinforcing fiber Using the specific gravity, the remaining method can be measured according to JIS K 7075 (1991). In addition, when reinforcing fibers having greatly different specific gravity such as glass fiber (specific gravity of about 2.5) and carbon fiber (specific gravity of about 1.8) are used, the respective reinforcing fibers are mainly arranged. (In the present invention, for example, in this case, the glass fiber is mainly disposed in the stress concentration region, and the carbon fiber is mainly disposed outside the stress concentration region. Therefore, the measurement location can be easily selected. ) Vf of each part is measured according to JIS K 7075 (1991), and any one of them may be within the above-mentioned range.

マトリックス樹脂は特に限定されないが、エポキシ樹脂、ポリエステル樹脂、ビニルエステル樹脂、フェノール樹脂等の熱硬化樹脂が成形性に優れていて好ましく、ナイロンやポリプロピレン、ポリエチレン、アクリル樹脂等の熱可塑樹脂も力学特性に優れていて好ましい。特にエポキシ樹脂は成形性と力学特性のバランスに優れていて特に好ましい。またマトリクス樹脂中には、様々な性能や機能を付加するために、本発明の効果を損なわない範囲で粒子や繊維状等の物質が含まれていてもよい。 The matrix resin is not particularly limited, but a thermosetting resin such as an epoxy resin, a polyester resin, a vinyl ester resin, and a phenol resin is preferable because of its excellent moldability, and a thermoplastic resin such as nylon, polypropylene, polyethylene, and an acrylic resin is also a mechanical property. It is excellent and preferable. In particular, an epoxy resin is particularly preferable because of its excellent balance between moldability and mechanical properties. In addition, in order to add various performances and functions, the matrix resin may contain particles, fibrous substances, and the like as long as the effects of the present invention are not impaired.

本発明のＦＲＰ製部材は、プリプレグを用いて成形することができる。かかる本発明のプリプレグは、得られるＦＲＰ製部材のＶＡ１、ＶＡ２が前記特定範囲になるように単位面積あたりの繊維量を調整して、補強繊維Ａと補強繊維Ｂとを同方向に引き揃えてシート状にし、これに硬化前のマトリックス樹脂を含浸する方法で得ることができる。具体的には、マトリックス樹脂をメチルエチルケトン、メタノールなどの溶媒に溶解して低粘土化し、含浸させるウェット法と、加熱により低粘度化し含浸させるホットメルト法などの方法により製造するのが簡便で好ましい。また別の本発明のプリプレグの例としては、補強繊維Ａを含むプリプレグの表面に補強繊維Ｂを貼付する、或いは補強繊維Ａを含むプリプレグの表面に補強繊維Ｂを含むプリプレグを貼付するなどの方法でも得ることができる。この補強繊維Ａを含むプリプレグとしては公知のものを用いることもできる。 The FRP member of the present invention can be molded using a prepreg. In the prepreg of the present invention, the amount of fibers per unit area is adjusted so that the VA1 and VA2 of the obtained FRP member are in the specific range, and the reinforcing fibers A and the reinforcing fibers B are aligned in the same direction. It can be obtained by forming a sheet and impregnating it with a matrix resin before curing. Specifically, it is convenient and preferable to produce the matrix resin by a method such as a wet method in which a matrix resin is dissolved in a solvent such as methyl ethyl ketone and methanol to lower the clay and impregnated, and a hot melt method in which the viscosity is lowered by heating and impregnated. As another example of the prepreg of the present invention, a method of sticking the reinforcing fiber B on the surface of the prepreg containing the reinforcing fiber A, or sticking a prepreg containing the reinforcing fiber B to the surface of the prepreg containing the reinforcing fiber A, etc. But you can get it. As the prepreg containing the reinforcing fiber A, a known prepreg can be used.

本発明のプリプレグとしては、補強繊維Ａ’が配せられた幅が７ｍｍ以上１３ｍｍ以下であることが好ましい。補強繊維Ａ’とは、プリプレグに含まれる補強繊維の中で最も引張破断伸度が高い補強繊維をさす。この範囲内であると、ＦＲＰ製部材の成形・加工時に、切り欠きが補強繊維Ａが配せられた幅の中心に位置するように設計することで、補強繊維Ａが切り欠き端部から距離ｄ（ｍｍ）以内の領域に配せられることが多いからである。より好ましくは、補強繊維Ａが配せられた幅が９ｍｍ以上１２ｍｍ以下であると、さらに補強繊維Ａが最適に配せられることが多くより好ましい。 In the prepreg of the present invention, the width in which the reinforcing fibers A ′ are arranged is preferably 7 mm or more and 13 mm or less. The reinforcing fiber A 'refers to a reinforcing fiber having the highest tensile breaking elongation among the reinforcing fibers contained in the prepreg. Within this range, when the FRP member is molded and processed, the notch is designed to be positioned at the center of the width where the reinforcing fiber A is arranged, so that the reinforcing fiber A is a distance from the notch end. This is because it is often arranged in an area within d (mm). More preferably, when the width of the reinforcing fibers A is 9 mm or more and 12 mm or less, it is more preferable that the reinforcing fibers A are further optimally arranged.

また、補強繊維Ａが引き揃え方向の直角方向に実質的に等間隔で配されていると、切り欠きが複数個あるＦＲＰ製部材を成形する際にも便利であることがあり好ましい。そして、このプリプレグには、別のプリプレグを貼り付けるなどして用いることもでき、貼り付けるプリプレグの繊維には強度や弾性率の異なる種類の物を用いてもよい。 Further, it is preferable that the reinforcing fibers A are arranged at substantially equal intervals in the direction perpendicular to the aligning direction because it is convenient when molding an FRP member having a plurality of notches. Further, this prepreg can be used by attaching another prepreg or the like, and the fibers of the prepreg to be attached may be of different types having different strengths and elastic moduli.

また本発明のプリプレグにおいては、良好な品質を得るためには補強繊維の単位面積あたりの重量を５〜５００ｇ／ｍ^２の範囲とするのが良い。５ｇ／ｍ^２未満であると補強繊維を均一に拡幅する事が困難になることがある。５００ｇ／ｍ^２を超えるとプリプレグの厚みが増大しすぎ、軽量化の効果や使用上の利便性が損なわれることがある。そして、マトリクス樹脂の単位面積あたりの重量は１〜３００ｇ／ｍ^２の範囲とするのがよい。１ｇ／ｍ^２未満であるとマトリックス樹脂量が足りず、補強繊維にマトリックス樹脂を十分に含浸させることが難しくなることがある。また、３００ｇ／ｍ^２以上であるとマトリックス樹脂量が多すぎて、プリプレグを製造する過程で過剰なマトリックス樹脂がはみ出すなど生産性が損なわれるおそれがある。そして、プリプレグ状態での補強繊維の含有量（Ｖｆ）は、最終的にこのプリプレグを成形して得られるＦＲＰ製部材の力学特性と製造の安定性とのバランスをはかる上で、好ましくは４０〜８０％の範囲内がよく、さらに好ましくは５０〜７０％の範囲内にあるのが良い。特に補強繊維Ａに関しては、応力集中領域では単位面積あたりの重量はやはり５〜５００ｇ／ｍ^２の範囲とすると上述と同じ理由で好ましく、体積含有量もやはり４０〜８０％、さらに好ましくは５０〜７０％の範囲内にあるのが良い。本発明のＦＲＰ製部材は、同方向に引き揃えられた補強繊維Ａと補強繊維Ｂに樹脂を含浸させたプリプレグを用いて成形することにより、従来の複合材料部材とほとんど変わらないプロセスで製造することができ、例えば、プリプレグを積層後、積層物に圧力を付与しながら樹脂を加熱し硬化させて成形する方法として、プレス成形法、オートクレーブ成形法、バッギング成形法、ラッピングテープ法、内圧成形法などがあり、用途によって適時成形方法を選択することができる。従って製造コストは従来とほとんど変わらない。そして、本発明のＦＲＰ製部材は、切り欠きを有する種々のＦＲＰ製部材に適用でき、例えば航空機や自動車のパネルやフレームなどの輸送機器用途や、建築柱の補強材などの一般産業用途に適用できる。 In the prepreg of the present invention, the weight per unit area of the reinforcing fiber is preferably in the range of 5 to 500 g / m ² in order to obtain good quality. If it is less than 5 g / m ² , it may be difficult to uniformly widen the reinforcing fibers. If it exceeds 500 g / m ² , the thickness of the prepreg increases excessively, and the effect of weight reduction and convenience in use may be impaired. And the weight per unit area of a matrix resin is good to set it as the range of 1-300 g / m < ² >. If it is less than 1 g / m ² , the amount of the matrix resin is insufficient, and it may be difficult to sufficiently impregnate the reinforcing fibers with the matrix resin. On the other hand, if it is 300 g / m ² or more, the amount of the matrix resin is too large, and the productivity may be impaired, for example, excessive matrix resin may protrude in the process of producing the prepreg. And the content (Vf) of the reinforcing fiber in the prepreg state is preferably 40 to in order to balance the mechanical properties of the FRP member finally obtained by molding this prepreg and the production stability. It is preferable to be in the range of 80%, more preferably in the range of 50 to 70%. Especially for reinforcing fibers A, preferably a weight per unit area also in the range of 5 to 500 g / ^{m 2} for the same reason as described above in the stress concentration area, volume content also still 40% to 80%, more preferably 50 to It should be in the range of 70%. The FRP member of the present invention is manufactured by a process that is almost the same as a conventional composite material member by molding using a prepreg in which a reinforcing fiber A and a reinforcing fiber B that are aligned in the same direction are impregnated with a resin. For example, after a prepreg is laminated, the resin is heated and cured while applying pressure to the laminate, and as a method of molding, press molding method, autoclave molding method, bagging molding method, wrapping tape method, internal pressure molding method The timely molding method can be selected depending on the application. Therefore, the manufacturing cost is almost the same as the conventional one. The FRP member of the present invention can be applied to various FRP members having cutouts, for example, transportation equipment uses such as aircraft and automobile panels and frames, and general industrial uses such as building column reinforcements. it can.

以下実施例により本発明を詳細に説明する。
（実施例１）
（１）プリプレグの作製
ＰＡＮ系炭素繊維束（補強繊維”トレカ（登録商標）”Ｔ７００Ｓ（東レ（株）社製、伸度２．１％、引張弾性率２３０ＧＰａ））を引き揃え、単位面積あたりの炭素繊維重量が
１２５ｇ／ｍ^２となるようにシート状に広げた。この状態のＰＡＮ系炭素繊維束で繊維直行方向を幅方向と規定し、この幅方向で中心から両側に５．５ｍｍの領域に配せられた補強繊維Ｔ７００Ｓを取り除き、代わりに、ガラス繊維（日東紡（株）社製グラスファイバーロービング（ＲＳ１１０ＱＬ−５２０、引張破断伸度４．８％、引張弾性率７０ＧＰａ）、表１ではＧＦと表示）を単位面積あたり１７４ｇ／ｍ^２配した。 Hereinafter, the present invention will be described in detail by way of examples.
Example 1
(1) Preparation of prepreg PAN-based carbon fiber bundles (reinforcing fibers "Treka (registered trademark)" T700S (manufactured by Toray Industries, Inc., elongation 2.1%, tensile elastic modulus 230 GPa)) are aligned per unit area Of carbon fiber weight
The sheet was spread to 125 g / m ² . With the PAN-based carbon fiber bundle in this state, the direction perpendicular to the fiber is defined as the width direction, and the reinforcing fiber T700S disposed in the region of 5.5 mm on both sides from the center in this width direction is removed. Glass fiber roving (RS 110 QL-520, tensile elongation at break 4.8%, tensile elastic modulus 70 GPa), indicated as GF in Table 1), manufactured by Bobo Co., Ltd., was distributed at 174 g / m ² per unit area.

この補強繊維束に下記の組成のBステージのエポキシ樹脂を単位面積あたりの重量が４２ｇ／ｍ^２となるように含浸させ、このプリプレグをプリプレグＡとした（補強繊維Ａ＝ガラス繊維、補強繊維Ｂ＝Ｔ７００Ｓ）。 This reinforcing fiber bundle was impregnated with a B-stage epoxy resin having the following composition so that the weight per unit area was 42 g / m ^2, and this prepreg was designated as prepreg A (reinforcing fiber A = glass fiber, reinforcing fiber B). = T700S).

一方で、炭素繊維のみを引き揃え、単位面積あたりの炭素繊維重量が１２５ｇ／ｍ^２となるようにシート状に広げ、プリプレグＡを作製するのに使用したのと同じＢステージのエポキシ樹脂を単位面積あたりの重量が４２ｇ／ｍ^２となるように含浸させたプリプレグを作製し、これをプリプレグＢとした。 On the other hand, only the carbon fibers are aligned, and the carbon fiber weight per unit area is expanded into a sheet shape so that the weight is 125 g / m ^2. A prepreg impregnated so as to have a weight per area of 42 g / m ² was prepared, and this was designated as prepreg B.

エポキシ樹脂の組成物
・“エピコート（登録商標）”８２８（ジャパンエポキシレジン（株）製、ビスフェノールＡ型液状エポキシ樹脂）５０重量部
・“スミ−エポキシ（登録商標）”ＥＬＭ４３４（住友化学工業（株）製、テトラグリシジルジアミノジフェニルメタン、液状）５０重量部
・“スミキュア（登録商標）”Ｓ（住友化学工業（株）、４，４’−ジアミノジフェニルスルフォン）３０重量部
（２）ＦＲＰ製部材（平板）の作製
上記のプリプレグを、擬似等方構成［４５／９０／−４５／０］ｓ（記号ｓは、鏡面対称を示す。）の構成で積層（ただし０方向にはプリプレグＡ、他の方向にはプリプレグＢ）し、オートクレーブ中で温度１７７℃、圧力０．６ＭＰａで２時間加熱硬化し、ＦＲＰ製平板を得た。得られたＦＲＰ製平板は、同目付のプリプレグ８層のうち、２層が０度方向に配せられているので、Ｖ０は０．２５となった。そして、(式１)で定義される距離ｄの計算値は２．６０となった。また、得られたＦＲＰ製平板のＶｆを、応力集中領域と応力集中領域外で共にＪＩＳＫ７０７５（１９９１）に従って測定したところ、共に６６％であった。
（３）ＦＲＰ製平板の物性測定
得られたＦＲＰ製平板からＡＳＴＭＤ５７６６−９５に従って試験片を切り出し、中心にはボール盤を使用して直径６．３５ｍｍの円孔（切欠き）を空けて有孔試験片を作製した。結果、弾性主軸方向に平行な補強繊維の中でガラス繊維が配向されているのは孔端部から（１１−６．３５）／２≒２．３３ｍｍ以内の領域となった。この有孔試験片を、ＡＳＴＭＤ５７６６−９５に従って、引張破断荷重（切り欠き強度）を測定した。結果を表１に示す。
（４）体積割合の求め方
引張試験に使用しなかった有効試験片から、図１に示すように、円孔中心を中心として
弾性主軸方向に幅２ｍｍ、長さを円孔端部から距離ｄまでとする矩形領域５を切り出した。また、円孔端部から距離ｄ以上離れた任意の場所から１ｃｍ角の矩形領域６を切り出した。そして、切り出した矩形物のうち、弾性主軸に直行する断面５ａと断面６ａをそれぞれ研磨したのち光学顕微鏡で観察した。観察結果をＡｄｏｂｅ社製Ｐｈｏｔｏｓｈｏｐ（登録商標）で取り込み、繊維断面の色や大きさや形状から、弾性主軸方向に配されているガラス繊維（＝補強繊維Ａ）と炭素繊維（＝補強繊維Ｂ）の選別を行った。選別後に、弾性主軸方向に配されているガラス繊維の断面積の総和と炭素繊維の断面積の総和をそれぞれ面積測定機能で測定したところ、断面５ａではガラス繊維の断面積の総和は０．６４ｍｍ^２、炭素繊維の断面積の総和は０．０７ｍｍ^２であった。また、断面６ａではガラス繊維は存在せず炭素繊維のみであった。これらの結果から、ガラス繊維（補強繊維Ａ）の体積割合を算出したところ、矩形領域５に含まれているガラス繊維の体積割合（ＶＡ１）は０．９０であった。同様にして算出したところ、矩形領域６に含まれているガラス繊維の体積割合（ＶＡ２）は０であった。
（実施例２〜４、比較例１〜４）
補強繊維Ａ、補強繊維Ｂの種類および補強繊維Ａを配した領域、そして積層構成を表１に示す通り変更した以外は、実施例１に従い、ＦＲＰ製部材を作製し、得られたＦＲＰ製部材の物性を測定した。なお、炭素繊維”トレカ（登録商標）”Ｍ４０Ｊとは東レ（株）社製、伸度１．２％、引張弾性率３７７ＧＰａの炭素繊維である。そして、表中の積層構成で擬似等方とは［４５／９０／−４５／０］ｓ、６０ＵＤとは［４５／９０／−４５／（０）_４／４５／（０）_４／−４５／（０）_４／−４５／９０／４５］、ＵＤとは［０］_８の積層構成をそれぞれ示す。
（実施例５）
有孔試験片の寸法をＡＳＴＭＤ５９６１（２００５）のＦｉｇ．５に記載のＳｉｎｇｌｅ−ＳｈｅａｒＴｅｓｔＳｐｅｃｉｍｅｎＤｒａｗｉｎｇに従って変更し、孔形状を皿孔にし、皿孔（Ｆｉｇ．５ではＣｏｕｎｔｅｒｓｉｎｋと記載されている）の径を１２．１ｍｍ、皿孔の深さを２．４５ｍｍ、積層構成を［４５／９０／−４５／０］３ｓ、部材厚さｈを３．６ｍｍにした以外は、実施例1と同様にして有孔試験片を作製した。この試験片をやはりＡＳＴＭＤ５９６１（２００５）に従って面圧強さを測定した。
（比較例５）
有孔試験片寸法をＡＳＴＭＤ５９６１（２００５）のＦｉｇ．５に記載のＳｉｎｇｌｅ−ＳｈｅａｒＴｅｓｔＳｐｅｃｉｍｅｎＤｒａｗｉｎｇに従って変更し、孔形状を皿孔にし、皿孔（Ｆｉｇ．５ではＣｏｕｎｔｅｒｓｉｎｋと記載されている）の径を１２．１ｍｍ、皿孔の深さを２．４５ｍｍ、積層構成を［４５／９０／−４５／０］３ｓ、部材厚さｈを３．６ｍｍにした以外は、比較例1と同様にして有孔試験片を作製した。この試験片をやはりＡＳＴＭＤ５９６１（２００５）に従って面圧強さを測定した。 Composition of epoxy resin “Epicoat (registered trademark)” 828 (manufactured by Japan Epoxy Resin Co., Ltd., bisphenol A type liquid epoxy resin) 50 parts by weight • “Sumi-Epoxy (registered trademark)” ELM434 (Sumitomo Chemical Co., Ltd.) ), Tetraglycidyldiaminodiphenylmethane, liquid) 50 parts by weight-"SumiCure (registered trademark)" S (Sumitomo Chemical Co., Ltd., 4,4'-diaminodiphenylsulfone) 30 parts by weight (2) FRP member (flat plate) The above prepreg is laminated in a quasi-isotropic configuration [45/90 / −45 / 0] s (the symbol s indicates mirror symmetry) (provided that the prepreg A is in the 0 direction and the other direction). Prepreg B), and heat-cured in an autoclave at a temperature of 177 ° C. and a pressure of 0.6 MPa for 2 hours to obtain a flat plate made of FRP. The obtained FRP flat plate had 8 layers of prepregs with the same weight, and 2 layers were arranged in the 0 degree direction, so V0 was 0.25. And the calculated value of the distance d defined by (Formula 1) was 2.60. Further, Vf of the obtained FRP flat plate was measured according to JIS K 7075 (1991) both in the stress concentration region and outside the stress concentration region, and both were 66%.
(3) Measurement of physical properties of FRP flat plate A test piece was cut out from the obtained FRP flat plate according to ASTM D5766-95, and a 6.35 mm diameter circular hole (notch) was drilled at the center using a drilling machine. A test piece was prepared. As a result, among the reinforcing fibers parallel to the elastic principal axis direction, the glass fiber was oriented in a region within (11−6.35) /2≈2.33 mm from the hole end. The perforated test piece was measured for tensile breaking load (notch strength) according to ASTM D5766-95. The results are shown in Table 1.
(4) Determining the volume ratio From an effective test piece not used in the tensile test, as shown in FIG. 1, the width d is 2 mm in the elastic main axis direction around the center of the circular hole, and the distance is d from the end of the circular hole. A rectangular area 5 was cut out. Further, a rectangular area 6 of 1 cm square was cut out from an arbitrary place away from the end of the circular hole by a distance d or more. And among the cut-out rectangular objects, the cross section 5a and the cross section 6a perpendicular to the elastic main axis were each polished and then observed with an optical microscope. The observation result is taken in by Photoshop (registered trademark) manufactured by Adobe, and from the color, size and shape of the fiber cross section, the glass fiber (= reinforcing fiber A) and the carbon fiber (= reinforcing fiber B) arranged in the elastic main axis direction. Sorting was performed. After selection, when the total cross-sectional area of the glass fibers and the total cross-sectional area of the carbon fibers arranged in the elastic principal axis direction were measured by the area measurement function, the total cross-sectional area of the glass fibers was 0.64 mm in the cross-section 5a. ² and the total cross-sectional area of the carbon fiber was 0.07 mm ² . Moreover, in the cross section 6a, there was no glass fiber and it was only carbon fiber. From these results, when the volume ratio of the glass fiber (reinforcing fiber A) was calculated, the volume ratio (VA1) of the glass fiber contained in the rectangular region 5 was 0.90. When calculated in the same manner, the volume ratio (VA2) of the glass fibers contained in the rectangular region 6 was 0.
(Examples 2-4, Comparative Examples 1-4)
The FRP member was prepared according to Example 1 except that the reinforcing fiber A, the type of the reinforcing fiber B, the region where the reinforcing fiber A was arranged, and the laminated configuration were changed as shown in Table 1. The physical properties of were measured. The carbon fiber “Torayca (registered trademark)” M40J is a carbon fiber manufactured by Toray Industries, Inc., having an elongation of 1.2% and a tensile elastic modulus of 377 GPa. Then, [45/90 / -45 / 0] s, the _{60UD [45/90 / -45 /} (0) 4/45 / (0) is the pseudo-isotropic in a stacked configuration in Table 4 / -45 / (0) ₄ / −45 / 90/45] and UD each indicate a stacked configuration of [0] ₈ .
(Example 5)
The size of the perforated test piece was measured according to ASTM D5961 (2005), FIG. The hole shape is changed to a countersink, the diameter of the countersunk hole (described as Countersink in FIG. 5) is 12.1 mm, and the depth of the countersink is 2. A perforated test piece was prepared in the same manner as in Example 1 except that the thickness was 45 mm, the laminated configuration was [45/90 / −45 / 0] 3 s, and the member thickness h was 3.6 mm. The surface pressure strength of this test piece was also measured according to ASTM D5961 (2005).
(Comparative Example 5)
Perforated specimen dimensions were measured according to ASTM D5961 (2005), FIG. The hole shape is changed to a countersink, the diameter of the countersunk hole (described as Countersink in FIG. 5) is 12.1 mm, and the depth of the countersink is 2. A perforated test piece was produced in the same manner as in Comparative Example 1 except that the thickness was 45 mm, the laminated configuration was [45/90 / −45 / 0] 3 s, and the member thickness h was 3.6 mm. The surface pressure strength of this test piece was also measured according to ASTM D5961 (2005).

結果を、表１に纏めて示す。なお、比較例１、比較例３、比較例４では一種類の補強繊維しか使用していないので、その補強繊維を補強繊維Ａとし、補強繊維Ｂの欄は空欄とした。 The results are summarized in Table 1. In Comparative Example 1, Comparative Example 3, and Comparative Example 4, only one type of reinforcing fiber was used, so that the reinforcing fiber was the reinforcing fiber A and the reinforcing fiber B column was blank.

実施例１〜４のように、補強繊維Ａの引張破断伸度が補強繊維Ｂの引張破断伸度よりも高く、かつ、補強繊維Ａが本発明で生み出した応力集中領域以内に配せられている場合は高い切り欠き強度を維持したままであった。 As in Examples 1 to 4, the tensile break elongation of the reinforcing fiber A is higher than the tensile break elongation of the reinforcing fiber B, and the reinforcing fiber A is disposed within the stress concentration region generated in the present invention. When it was, the high notch strength was maintained.

例えば実施例１と比較例１を比較すると、ガラス繊維に比べて引張破断伸度の低いＴ７００Ｓを一様に配した比較例１の切り欠き強度は、孔周りに引張破断伸度の高いガラス繊維を配した実施例１に比べて大幅な切り欠き強度の低下が見られる。 For example, when Example 1 and Comparative Example 1 are compared, the notch strength of Comparative Example 1 in which T700S, which has a lower tensile breaking elongation than glass fiber, is uniformly arranged, has a high tensile breaking elongation around the hole. As compared with Example 1 in which the thickness is arranged, the notch strength is greatly reduced.

一方で同じようにガラス繊維を孔周りに配しても、本発明で生み出した応力集中領域以上にガラス繊維を配した（すなわちＶＡ２が０．１以上）比較例２では、やはり大幅な切り欠き強度の低下が見られる。 On the other hand, even if the glass fiber is arranged around the hole in the same manner, in the comparative example 2 in which the glass fiber is arranged more than the stress concentration region produced in the present invention (that is, VA2 is 0.1 or more), the notch is still greatly cut out. A decrease in strength is observed.

また、実施例３と比較例４とを比較すると、炭素繊維のみを使用しても、一様にＭ４０Ｊを使用した比較例４では、孔周りにＭ４０Ｊと比較して引張破断伸度の高いＴ７００Ｓを使用した実施例３と比べて、やはり切り欠き強度の低下がみられる。このことから補強繊維の種類によらず、補強繊維Ａと補強繊維Ｂとの引張破断伸度の優劣が、切り欠きを有するＦＲＰ部材の引張強度に大きく影響していることが分かる。また、比較例３のように引張破断伸度の高いガラス繊維のみを使用した場合では、実施例４のようにガラス繊維と弾性率の高い炭素繊維とを組み合わせた場合に比べてやはり引張強度が低いことがわかる。さらに実施例５と比較例５とを比較すると、本発明の構成を使用することで面圧強さが飛躍的に向上することが分かる。 Moreover, when Example 3 and Comparative Example 4 are compared, even if only carbon fiber is used, in Comparative Example 4 in which M40J is uniformly used, T700S, which has a higher tensile fracture elongation than M40J, around the hole. Compared with Example 3 using No. 3, the notch strength is still reduced. From this, it can be seen that regardless of the type of reinforcing fiber, the superiority or inferiority of the tensile breaking elongation between the reinforcing fiber A and the reinforcing fiber B greatly affects the tensile strength of the FRP member having a notch. Further, when only glass fibers having a high tensile breaking elongation are used as in Comparative Example 3, the tensile strength is still higher than when combining glass fibers and carbon fibers having a high elastic modulus as in Example 4. It turns out that it is low. Furthermore, when Example 5 and Comparative Example 5 are compared, it can be seen that the surface pressure strength is dramatically improved by using the configuration of the present invention.

本発明は、軽量、高強度であり、かつ、優れた切り欠き強度を有し、航空機や自動車などの輸送機器や建築物の支柱補強材などの一般産業用途として好適に使用することができる。 INDUSTRIAL APPLICABILITY The present invention is lightweight, high-strength, has excellent notch strength, and can be suitably used for general industrial applications such as transportation equipment such as aircraft and automobiles, and strut reinforcements for buildings.

本発明を説明するための概略図である。It is the schematic for demonstrating this invention. 皿孔形状の切り欠きを説明するための部材の断面図である。It is sectional drawing of the member for demonstrating a notch of a countersink shape.

符号の説明Explanation of symbols

１応力集中領域
２応力集中領域外の領域
３切り欠き
４弾性主軸
５ＶＡ１を測定するための矩形領域
５ａ矩形領域５の中で弾性主軸に直交する観察面
６ＶＡ２を測定するための矩形領域
６ａ矩形領域６の中で弾性主軸に直交する観察面
７皿孔の深さ
８部材の厚さ DESCRIPTION OF SYMBOLS 1 Stress concentration area | region 2 Area | region outside stress concentration area | region 3 Notch 4 Elastic main axis | shaft 5 Rectangular area | region 5a for measuring VA1 Observation surface orthogonal to an elastic main axis | shaft in the rectangular area | region 6 6 Rectangular area | region 6A for measuring VA2 Observation surface perpendicular to the elastic main axis in the rectangular region 6 7 Countersink depth 8 Member thickness

Claims

少なくとも一つ以上の切り欠きを有する繊維強化複合材料（ＦＲＰ）製部材であって、引張破断伸度が異なる２種以上の補強繊維を含み、応力集中領域において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ１が、応力集中領域外において、弾性主軸方向に配向されている全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維Ａの体積割合ＶＡ２よりも高く、かつ、ＶＡ２が０．１以下であるＦＲＰ製部材。
補強繊維Ａ：ＦＲＰ製部材に含まれる補強繊維の中で最も引張破断伸度の高い補強繊維
応力集中領域：切り欠き端部より弾性主軸と直行する方向に（式１）で定義される距離ｄ（ｍｍ）以内の領域

Ｖ０：ＦＲＰ製部材中の全補強繊維体積に占める、弾性主軸方向に配向されている補強繊維の体積割合 A fiber reinforced composite material (FRP) member having at least one notch, including two or more types of reinforcing fibers having different tensile elongation at break, and oriented in the elastic principal axis direction in a stress concentration region The volume fraction VA1 of the reinforcing fibers A oriented in the elastic principal axis direction in the total reinforcing fiber volume is oriented in the elastic principal axis direction in the total reinforcing fiber volume oriented in the elastic principal axis outside the stress concentration region. A member made of FRP which is higher than the volume ratio VA2 of the reinforcing fibers A and VA2 is 0.1 or less.
Reinforcing fiber A: Reinforcing fiber having the highest tensile breaking elongation among reinforcing fibers contained in the FRP member Stress concentration region: Distance d defined by (Equation 1) in a direction perpendicular to the elastic main axis from the notch end Area within (mm)

V0: Volume ratio of reinforcing fibers oriented in the elastic principal axis direction in the total reinforcing fiber volume in the FRP member

補強繊維Ａの引張破断伸度が３％以上６％以下である請求項１に記載のＦＲＰ製部材。 The FRP member according to claim 1, wherein the tensile breaking elongation of the reinforcing fiber A is 3% or more and 6% or less.

補強繊維Ａ以外の補強繊維の引張弾性率が３００ＧＰａ以上１２００ＧＰａ以下である請求項１または２に記載のＦＲＰ製部材。 The FRP member according to claim 1 or 2, wherein the tensile elastic modulus of reinforcing fibers other than the reinforcing fiber A is 300 GPa or more and 1200 GPa or less.

補強繊維Ａと補強繊維Ａ以外の補強繊維が同方向に引き揃えられている請求項１〜３のいずれかに記載のＦＲＰ製部材。 The FRP member according to any one of claims 1 to 3, wherein reinforcing fibers other than the reinforcing fibers A and the reinforcing fibers A are aligned in the same direction.

補強繊維Ａと補強繊維Ａ以外の補強繊維の引き揃え方向が、弾性主軸と平行である請求項１〜４のいずれかに記載のＦＲＰ製部材。 The FRP member according to any one of claims 1 to 4, wherein an alignment direction of the reinforcing fibers other than the reinforcing fibers A and the reinforcing fibers A is parallel to the elastic main axis.

切り欠きが実質的に円形である請求項１〜５のいずれかに記載のＦＲＰ製部材。 The FRP member according to any one of claims 1 to 5, wherein the notch is substantially circular.

切り欠きが実質的に皿孔形状を有する請求項１〜６のいずれかに記載のＦＲＰ製部材。 The FRP member according to any one of claims 1 to 6, wherein the notch has a substantially countersink shape.

切り欠きの幅をφとし、切り欠き同士の間隔が３φ以上である請求項１〜７のいずれかに記載のＦＲＰ製部材。 The FRP member according to any one of claims 1 to 7, wherein a width of the notch is φ, and an interval between the notches is 3φ or more.

補強繊維を樹脂で含浸したプリプレグであって、引張破断伸度が異なる２種以上の補強繊維を含み、補強繊維Ａ’が配せられた幅が７ｍｍ以上１３ｍｍ以下であるプリプレグ。
補強繊維Ａ’：プリプレグに含まれる補強繊維中で最も引張破断伸度の高い補強繊維 A prepreg in which reinforcing fibers are impregnated with a resin, the prepreg including two or more types of reinforcing fibers having different tensile elongation at break, and a width in which the reinforcing fibers A ′ are arranged is 7 mm or more and 13 mm or less.
Reinforcing fiber A ′: Reinforcing fiber having the highest tensile breaking elongation among the reinforcing fibers contained in the prepreg

補強繊維Ａ’が繊維軸に直角方向に実質的に等間隔で配されている請求項８に記載のプリプレグ。 The prepreg according to claim 8, wherein the reinforcing fibers A ′ are arranged at substantially equal intervals in a direction perpendicular to the fiber axis.