JP2004050670A

JP2004050670A - Connecting structure of fiber reinforced plastic and method of connecting the same

Info

Publication number: JP2004050670A
Application number: JP2002212265A
Authority: JP
Inventors: Goichi Hen; 邉　　　吾　一
Original assignee: Nihon University
Current assignee: Nihon University
Priority date: 2002-07-22
Filing date: 2002-07-22
Publication date: 2004-02-19
Anticipated expiration: 2022-07-22
Also published as: JP4079313B2

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a connecting structure of a fiber reinforced plastic which facilitates the designing of the connecting part of a pipe material or a bar material, improves the assembling and repairing workability at a job site with simplicity and which has a large breaking load and stress, a large joint efficiency, excellent specific strength and specific rigidity, and to provide a method of connecting the same. <P>SOLUTION: The method of connecting fiber reinforced plastic includes the steps of exposing reinforced fibers 5 of the end part 1a of a pipe or a bar material 1 made of a fiber reinforced plastic, winding the exposed fiber 6 along the outer peripheral direction of other pipe or bar material 2, or broadening the fiber 6 in the axial central direction of the other pipe or bar material, impregnating the fiber 6 with a synthetic resin, curing the resin, and connecting the fiber 6 to the other pipe or bar material 2. The exposed fiber 6 is wound on the other pipe or bar material 2 with a reinforcing fiber 7, a carbon cloth 8 made of a patch-like reinforcing fiber or a tape-like woven fabric 9 and is reinforced. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、繊維強化プラスチックの接合構造及び接合方法に関し、更に詳細に説明すると、繊維強化プラスチックからなるパイプまたは棒材の端部が他のパイプまたは棒材に接合された繊維強化プラスチックの接合構造、及び繊維強化プラスチックからなるパイプまたは棒材の端部を他のパイプまたは棒材に接合する繊維強化プラスチックの接合方法に関する。
【０００２】
【従来の技術】
従来より、比強度、比剛性に大変優れた繊維強化プラスチック（以後ＦＲＰと称する。）は広く構造材料として用いられている。これらの特徴を活かしたＦＲＰの接合部の設計が難しいのもまたよく知られている。現在ＦＲＰの主構造材における接合法として広く用いられる手法は金属製のフランジやソケットタイプのジョイントを用いた方法である。
【０００３】
前記金属製のフランジやソケットタイプのジョイントを用いた方法ではジョイント自体の重量や異材料との組み合わせであるため、破壊モードが複雑となるといった問題が生じ、更にボルトによる締結ではボルト穴によりＦＲＰの繊維が破断される欠点を有するものであった。このため、本発明者は先に、特開２００１−２５２９８５号により「複合材料接合継手および接合と補修方法」を提案している。これらの手法は、複合材料接合継手の継手部から破壊することのない継手部を得ることを目的とするものである。
【０００４】
【発明が解決しようとする課題】
然し乍ら、従来の複合材料接合継手の継手部は複合材料として平板を用いたものであり、応用範囲が狭く、簡便で且つ現場での組み立て補修作業性に適さず、また破壊荷重及び破壊応力が小さく、更に継手効率が小さいものであった。
【０００５】
本発明の目的は、パイプまたは棒材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、破壊荷重及び破壊応力が大きく、継手効率が大きく、比強度、比剛性に大変優れたＦＲＰの接合構造及び接合方法を提供するものである。
【０００６】
【課題を解決するための手段】
本発明の請求項１に係る繊維強化プラスチックの接合構造は、繊維強化プラスチックからなるパイプまたは棒材の端部が他のパイプまたは棒材に接合された繊維強化プラスチックの接合構造において、
前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維が他方のパイプまたは棒材の外周方向に沿って巻き付けられ、該巻き付けられた露出繊維に合成樹脂材を含浸硬化させて他方のパイプまたは棒材と接合されていることを特徴とする。
【０００７】
また、本発明の請求項２に係る繊維強化プラスチックの接合構造は、繊維強化プラスチックからなるパイプまたは棒材の端部が他のパイプまたは棒材に接合された繊維強化プラスチックの接合構造において、
前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維が他方のパイプまたは棒材の軸心方向に広げられ、該他方のパイプまたは棒材の軸心方向に広げられた露出繊維に合成樹脂材を含浸硬化させて他方のパイプまたは棒材と接合されていることを特徴とする。
【０００８】
更に、本発明の請求項３に係る繊維強化プラスチックの接合構造は、前記露出繊維をパッチ状の強化繊維からなる布地またはテープ状の織物で他方のパイプまたは棒材に巻き付けて補強していることを特徴とする。
【０００９】
本発明の請求項４に係る繊維強化プラスチックの接合方法は、繊維強化プラスチックからなるパイプまたは棒材の端部を他のパイプまたは棒材に接合する繊維強化プラスチックの接合方法において、
前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維を他方のパイプまたは棒材の外周方向に沿って巻き付け、該巻き付けられた露出繊維に合成樹脂材を含浸させ、硬化させて他方のパイプまたは棒材に接合することを特徴とする。
【００１０】
また、本発明の請求項５に係る繊維強化プラスチックの接合方法は、繊維強化プラスチックからなるパイプまたは棒材の端部を他のパイプまたは棒材に接合する繊維強化プラスチックの接合方法において、
前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維を他方のパイプまたは棒材の軸心方向に広げ、該他方のパイプまたは棒材の軸心方向に広げられた露出繊維に合成樹脂材を含浸させ、硬化させて他方のパイプまたは棒材に接合することを特徴とする。
【００１１】
更に、本発明の請求項６に係る繊維強化プラスチックの接合方法は、前記露出繊維をパッチ状の強化繊維からなる布地またはテープ状の織物で他方のパイプまたは棒材に巻き付けて補強することを特徴とする。
【００１２】
また、本発明の請求項７に係る繊維強化プラスチックの接合方法は、繊維強化プラスチックからなるパイプまたは棒材の端部を他のパイプまたは棒材に接合する繊維強化プラスチックの接合方法において、
前記接合する少なくも２本の前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を夫々露出させて夫々露出繊維を形成し、該露出繊維同士を対向させて絡め、該絡めた露出繊維に合成樹脂材を含浸させ、硬化させて少なくも２本の前記繊維強化プラスチックからなるパイプまたは棒材を軸方向に接合することを特徴とする。
【００１３】
【発明の実施の形態】
以下、本発明に係わる繊維強化プラスチックの接合構造及び接合方法の実施の形態を図面を参照して説明する。
図１（ａ），（ｂ）乃至図６は本発明に係わる繊維強化プラスチックの接合構造及び接合方法を夫々示すもので、図１（ａ），（ｂ）は繊維強化プラスチック（ＦＲＰ）からなるパイプまたは棒材の斜視図、図２は繊維強化プラスチックからなるパイプまたは棒材の端部の合成樹脂材を燃焼させている状態の斜視図、図３（ａ），（ｂ）はタイプＡの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図、図４はタイプＢの繊維強化プラスチックからなるパイプまたは棒材の接合構造を示す斜視図、図５（ａ），（ｂ）はタイプＣの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図、図６はタイプＤの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図である。また、図７はタイプＡ〜タイプＤの繊維強化プラスチックの荷重変位線図、図８は本発明の異なる実施の形態を示す概略断面図である。
【００１４】
先ず、図１（ａ）に示す繊維強化プラスチック（ＦＲＰ）からなるパイプまたは棒材１を形成する。このパイプまたは棒材１は熱可塑性樹脂または熱硬化性樹脂等の高分子を母材とする炭素繊維強化プラスチック，ガラス繊維強化プラスチック，アラミド繊維強化プラスチック等から形成されている。パイプまたは棒材１は母材としての高分子のプラスチック３に炭素繊維，ガラス繊維またはアラミド繊維等の長繊維の強化繊維５を混入して形成されている。尚、本実施の形態では炭素繊維強化プラスチックからなる円筒状のパイプ１を用いたが、中実の棒体であってもよい。この中実の棒体は四角形状，丸，楕円形状等の種々の形状とすることができる。
【００１５】
前記繊維強化プラスチックからなるパイプまたは棒材１の端部１ａが、図３（ａ），（ｂ）〜図６に示す如く、他のパイプまたは棒材２に接合される。尚、本実施の形態ではＴ字型接合につき説明するが、パイプまたは棒材を長手方向に接合するＩ字型接合（バット接合）であってもよい。更に十字接合あるいは多方向接合とすることもできる。図１（ｂ）に示す如く、前記繊維強化プラスチックからなるパイプまたは棒材１の端部１ａの炭素繊維，ガラス繊維またはアラミド繊維等からなる強化繊維５を露出させ、露出繊維６を形成する。
【００１６】
前記パイプまたは棒材１の端部１ａの強化繊維５を露出させる手段としては、図２に示す如く、接合部の樹脂である母材としての高分子のプラスチック３をガスバーナー１１を用いて発火点以上に加熱して燃焼させて除去することにより強化繊維５を露出させ、露出繊維６を得ることができる。尚、本実施の形態ではガスバーナー１１を用いたが、図示のものに限定されるものではなく、他の加熱手段を用いることができるものである。
【００１７】
また、パイプまたは棒材１の端部１ａを融点以上発火点以下に加熱して母材としての高分子のプラスチック３を溶解させて除去することで強化繊維５を露出させることもでき、その他機械的手段や繊維強化プラスチックの成形時に、例えば引き抜き成形時に強化繊維５を樹脂槽に通さずに、加熱成形金型に直接入れれば、この部分の強化繊維５はプラスチック３が存在しない露出した露出繊維６を得ることができる。またフィラメントワイディング成形（ＦＷ成形）の場合でも軸方向の端部に強化繊維５がくるときに、強化繊維５を樹脂槽を通さずに、マンドレルに巻き付けることにより強化繊維５を端部で露出させ、露出繊維６を得ることが可能である。また薬品を用いて樹脂を溶かす化学的な手法により露出繊維６を得るものであってもよい。
【００１８】
図２に示すように、完全に樹脂を取り除くために、燃焼の熱源として、本実施の形態では温度約１２００℃のガスバーナー１１を用いた。また燃焼部と非燃焼部の境界をいかに保護するかも大切である。試行錯誤の実験から、非燃焼部の保護に濡れたウエス１３を用いる方法が最も容易で確実性のあることが判明した。更に水気が直接燃焼されている炭素繊維からなる強化繊維５に触れると、強化繊維５に対する影響に加え、燃焼中の強化繊維５を通しての毛細管現象により完全な燃焼ができなくなる。
【００１９】
そこで、浸水防止対策として、アルミテープ１５をウエス１３が触れるパイプ１に直接巻く。その後、燃焼により露出させた露出繊維６をアセトンで超音波洗浄を３０分程度行い、接合部となる露出繊維６に付着しているすす等を取り除く。すすの除去が十分でない場合は、特に接合部に後で塗布する新しい合成樹脂が十分に含浸せず強度低下をまねく虞れを有する。尚、すす等を取り除く洗浄は超音波洗浄に限定されるものではない。
【００２０】
前記パイプまたは棒材１の端部１ａの強化繊維５を露出させた後、露出繊維６を他方のパイプまたは棒材２の外周方向に沿って巻き付ける。この際露出繊維６の繊維方向を入念に揃えておく。次いで、巻き付けられた露出繊維６に常温で硬化する、例えばビニールエステルまたは不飽和ポリエステル等の新たな合成樹脂材を含浸させ、成形硬化させて他方のパイプまたは棒材２と接合する。これらの工程により製作された接合部は従来の金属製のボルトやソケットを介した接合部に比べ軽量である。またパイプまたは棒材１とパイプまたは棒材２の双方が同一の材料からなる場合には、材料間でのヤング率，強度の違いや線膨張率の違いによる複雑な破壊様相を考慮する心配が少ないという効果を有する。
【００２１】
前記パイプ１は炭素繊維を本実施の形態ではフィラメントワインディング装置でヘリカル巻きにより製作したがこれに限定されるものではない。試験片の形状は繊維配向角３０度、内径１０ｍｍ、４プライ（外径約１４ｍｍ）、各繊維強化プラスチックからなるパイプまたは棒材１の長さを１７０ｍｍとした。前記パイプ１及びパイプまたは棒材２は同一の材質からなり、このパイプ１及びパイプまたは棒材２を用いてタイプＡ〜タイプＤまで計４種類の試験片を作成した。
【００２２】
即ち、図３（ａ），（ｂ）に示す如く、タイプＡの試験片を作成し、図４に示す如く、タイプＢの試験片を作成し、図５（ａ），（ｂ）に示す如く、タイプＣの試験片を作成し、図６に示す如く、タイプＤの試験片を作成した。また、タイプＡ〜タイプＤまで計４種類の試験片の製作に用いた材料を表１に示す。
【００２３】
【表１】

【００２４】
図３（ａ），（ｂ）に示す如く、前記タイプＡの試験片はパイプまたは棒材１の端部１ａの露出繊維６を入念に繊維方向を揃えた状態で他方のパイプまたは棒材２の外周方向に沿って、パイプまたは棒材２を握るように巻き付け、最後にロービング繊維により補強されている。この巻き付けられた露出繊維６に新たな合成樹脂材を含浸硬化させて他方のパイプまたは棒材２と接合されている。
【００２５】
図４に示す如く、前記タイプＢの試験片はパイプまたは棒材１の端部１ａに露出繊維６を他方のパイプまたは棒材２の軸心方向に繊維方向を揃えた状態で左右方向に広げ、補強繊維７を巻き付ける。この他方のパイプまたは棒材２の軸心方向に広げられた露出繊維６に常温で硬化する新たな合成樹脂材を含浸硬化させて他方のパイプまたは棒材２と接合されている。このタイプＢの試験片は前記タイプＡの試験片に比較して一方のパイプまたは棒材に対する応力集中や接合部面内強度向上を考慮した接合構造である。尚、新たな合成樹脂材の材質は適宜変更することができる。
【００２６】
また、図５（ａ），（ｂ）に示す如く、前記タイプＣの試験片はカーボンクロス８をパッチ状にして使用したもので、露出繊維６の配置は、図５（ａ）に示す如く、タイプＢの試験片と同様である。前記タイプＡの試験片やタイプＢの試験片は熟練した作業技術を必要とするために接合部強度のバラツキが懸念されるが、タイプＣの試験片はパッチ状のカーボンクロス８を用いることにより作業の単純化を狙っているので接合部強度のバラツキを減少させることができる。
【００２７】
更に、図６に示す如く、タイプＤの試験片は、前記タイプＡの試験片における接合と露出繊維６の配置は同様である。前記タイプＡの試験片は熟練した作業技術を必要とするために接合部強度のバラツキが懸念されるが、タイプＤの試験片はバラツキを防止するために、もう一枚補助的なテープ状の織物９使用して接合部に巻き付け、強度の安定化を図っている。
【００２８】
前記タイプＡ〜タイプＤまで計４種類の試験片を用いて静的引張試験をストローク制御（０．５ｍｍ／ｓｅｃ）、常温で行った。Ｔ字接合の引張試験治具を作製し、接合される側のパイプ２には接合部の大変形を抑制するスチール製の丸棒材を挿入した。また油圧チャックで握り潰されないようにガラスロービングの周巻きでタブ部を作製し、スチール製の中子を入れた。
【００２９】
以上の試験条件で本発明の接合構造を用いたタイプＡ〜タイプＤの引張試験結果を表２に示す。更にその荷重変位線図を図７に示す。尚、表２中の継手効率は同じ材料で製作した同形状ＦＷパイプの引張試験結果（破壊強度２２．０ｋＮ，破壊応力１５９．２ＭＰａ）と比較している。
【００３０】
【表２】

【００３１】
前記タイプＡは本発明の接合法の中で最も軽量な接合法である。しかし引張強度は従来の継手効率に若干劣る。応力集中緩和と曲げ強度向上を目指したタイプＢは接合部自体の重量が若干大きくなるが、その分タイプＡに比べ強度が２割り以上向上するため、荷重／重量はタイプＡと同様の値となった。
【００３２】
前記タイプＣにおいては作業を従来よりも単純化し強度安定化を目指したが、パッチ状のカーボンクロス８が浮かないように押さえ付ける必要があった。このため作業上の都合から合成樹脂材を多めに使う必要が有り、重量が増大してしまった。また接合部では露出繊維のみを局所的に抑えてしまったため、破壊様相が繊維を折るように破壊していた。また繊維配置をタイプＢと同様にしたにもかかわらず、結果として強度試験結果が不安定で、その上荷重も低下してしまった。
【００３３】
一方、前記タイプＤでは破壊荷重が２０ｋＮ近くまで達した。前記タイプＡ〜タイプＣでは接合部の破壊がほとんどであったのに対して、タイプＤでは接合部での破壊が巨視的にはみられず、パイプ１自体が接合部以外の場所、試験片タブ付近で破壊していた。このことから、つかみ治具の形状を見直せば更に強度が上昇する可能性も十分にある。またこの試験片の接合は非常に簡単で試験片を１つ製作するのに３分程度、従って結果のバラツキも現在のところほとんど見られない。
【００３４】
図８には、本発明の異なる実施の形態が示されており、この実施の形態では、軸方向にパイプを接合するＩ字型接合に本発明を適用したもので、図１（ｂ）に示すと同様に、前記繊維強化プラスチックからなるパイプ１，２の端部１ａ，２ａの強化繊維５を露出させ、軽くて樹脂に影響を与えない程度の高温で溶けるウレタン製等の中子１７をパイプ１，２の端部１ａ，２ａに入れて、その上で両側の露出繊維６同士を絡め、その上から補強繊維７を用い、樹脂を塗布する方法で軸方向に接合することができる。またこの場合に接合部の外側からパイプ材の断面形状の雌型の治具で締めつければ、接合部も非接合部と同じ形状を有し、更に熱を加えれば、中子１７は溶けてＩ字型接合となる。
【００３５】
更に棒材１，２を軸方向に接合する場合には、両側の強化繊維５を露出させた後、オーバーラップさせて圧縮空気を用いて両方の露出繊維６同士を絡め、補強繊維７と樹脂で接合するが、接合する際に棒材１，２の断面形状の雌型を有する金型で締めつければ、接合部も非接合部と同じ形状となる。
【００３６】
【発明の効果】
以上説明したように、本発明の請求項１に係る繊維強化プラスチックの接合構造によれば、繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維が他方のパイプまたは棒材の外周方向に沿って巻き付けられ、該巻き付けられた露出繊維に合成樹脂材を含浸硬化させて他方のパイプまたは棒材と接合されているので、軽量でパイプまたは棒材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、継手効率が大きく、比強度、比剛性に優れたＦＲＰの接合構造を得ることができる。
【００３７】
また、本発明の請求項２に係る繊維強化プラスチックの接合構造によれば、繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維が他方のパイプまたは棒材の軸心方向に広げられ、該他方のパイプまたは棒材の軸心方向に広げられた露出繊維に合成樹脂材を含浸硬化させて他方のパイプまたは棒材と接合されているので、接合部の強度を向上させることができ、パイプまたは棒材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、破壊荷重及び破壊応力が大きく、継手効率が大きく、比強度、比剛性に優れたＦＲＰの接合構造を得ることができる。
【００３８】
更に、本発明の請求項３に係る繊維強化プラスチックの接合構造によれば、前記露出繊維をパッチ状の強化繊維からなる布地またはテープ状の織物で他方のパイプまたは棒材に巻き付けて補強しているので接合部の強度を更に向上させることができるＦＲＰの接合構造を得ることができる。
【００３９】
また、本発明の請求項４に係る繊維強化プラスチックの接合方法によれば、繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維を他方のパイプまたは棒材の外周方向に沿って巻き付け、該巻き付けられた露出繊維に合成樹脂材を含浸させ、硬化させて他方のパイプまたは棒材に接合するので、軽量でパイプまたは棒材材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、継手効率が大きく、比強度、比剛性に優れたＦＲＰの接合方法を得ることができる。
【００４０】
また、本発明の請求項５に係る繊維強化プラスチックの接合方法によれば、繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を露出させて露出繊維を形成し、該露出繊維を他方のパイプまたは棒材の軸心方向に広げ、該他方のパイプまたは棒材の軸心方向に広げられた露出繊維に合成樹脂材を含浸させ、硬化させて他方のパイプまたは棒材に接合するので、接合部の強度を向上させることができ、パイプまたは棒材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、破壊荷重及び破壊応力が大きく、継手効率が大きく、比強度、比剛性に優れたＦＲＰの接合方法を得ることができる。
【００４１】
更に、本発明の請求項６に係る繊維強化プラスチックの接合方法によれば、露出繊維をパッチ状の強化繊維からなる布地またはテープ状の織物で他方のパイプまたは棒材に巻き付けて補強するので接合部の強度を更に向上させることができるＦＲＰの接合方法を得ることができる。
【００４２】
また、本発明の請求項７に係る繊維強化プラスチックの接合方法によれば、接合する少なくも２本の前記繊維強化プラスチックからなるパイプまたは棒材の端部の強化繊維を夫々露出させて夫々露出繊維を形成し、該露出繊維同士を対向させて絡め、該絡めた露出繊維に合成樹脂材を含浸させ、硬化させて少なくも２本の前記繊維強化プラスチックからなるパイプまたは棒材を軸方向に接合するので、接合部の強度を向上させることができ、パイプまたは棒材の接合部の設計が容易であり、簡便で且つ現場での組み立て補修作業性に適し、破壊荷重及び破壊応力が大きく、継手効率が大きく、比強度、比剛性に優れたＦＲＰの接合方法を得ることができる。
【図面の簡単な説明】
【図１】本発明に係わる繊維強化プラスチックの接合構造及び接合方法に用いられる繊維強化プラスチックからなるパイプまたは棒材を夫々示すもので、（ａ）は斜視図、（ｂ）はパイプまたは棒材の一端の強化繊維を露出させた状態の斜視図。
【図２】本発明に係わる繊維強化プラスチックの接合方法を示すもので、繊維強化プラスチックからなるパイプまたは棒材の端部の合成樹脂材を燃焼させている状態の斜視図。
【図３】本発明に係わる繊維強化プラスチックの接合方法を示すもので、（ａ），（ｂ）はタイプＡの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図。
【図４】本発明に係わる繊維強化プラスチックの接合構造を示すもので、タイプＢの繊維強化プラスチックからなるパイプまたは棒材の接合構造を示す斜視図。
【図５】本発明に係わる繊維強化プラスチックの接合方法を示すもので、（ａ），（ｂ）はタイプＣの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図。
【図６】本発明に係わる繊維強化プラスチックの接合方法を示すもので、タイプＤの繊維強化プラスチックからなるパイプまたは棒材の接合方法を示す斜視図。
【図７】本発明に係わる繊維強化プラスチックの接合構造のタイプＡ〜タイプＤの繊維強化プラスチックの荷重変位線図である。
【図８】本発明に係わる繊維強化プラスチックの接合方法の異なる実施の形態を示す概略断面図である。
【符号の説明】
１　　パイプまたは棒材
１ａ　端部
２　　パイプまたは棒材
２ａ　端部
３　　プラスチック
５　　強化繊維
６　　露出繊維
７　　補強繊維
８　　カーボンクロス
９　　テープ状の織物
１１　　ガスバーナー
１３　　ウエス
１５　　アルミテープ
１７　　中子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a joining structure and a joining method of a fiber-reinforced plastic, and more particularly, to a joining structure of a fiber-reinforced plastic in which an end of a pipe or a rod made of a fiber-reinforced plastic is joined to another pipe or a rod. And a method of joining a fiber reinforced plastic to join an end of a pipe or a rod made of fiber reinforced plastic to another pipe or a rod.
[0002]
[Prior art]
BACKGROUND ART Conventionally, fiber reinforced plastics (hereinafter, referred to as FRP) having extremely excellent specific strength and specific rigidity have been widely used as structural materials. It is also well known that it is difficult to design an FRP joint utilizing these characteristics. At present, a method widely used as a joining method for a main structural material of FRP is a method using a metal flange or socket type joint.
[0003]
In the method using the metal flange or the socket type joint, since the joint is a combination of the weight of the joint itself and a different material, a problem that a failure mode becomes complicated occurs. It had the disadvantage that the fibers were broken. For this reason, the present inventor has previously proposed "composite material joint and joining and repairing method" in Japanese Patent Application Laid-Open No. 2001-252985. These techniques aim at obtaining a joint that does not break from the joint of the composite material joint.
[0004]
[Problems to be solved by the invention]
However, the joint portion of the conventional composite material joint uses a flat plate as a composite material, has a narrow application range, is simple and is not suitable for on-site assembly and repair workability, and has a small breaking load and a small breaking stress. And the joint efficiency was small.
[0005]
It is an object of the present invention to easily design a joint of a pipe or a rod, to be simple and suitable for on-site assembly and repair workability, to have a large breaking load and a large breaking stress, a large joint efficiency, a large specific strength, An object of the present invention is to provide a joining structure and a joining method of FRP having very excellent rigidity.
[0006]
[Means for Solving the Problems]
The joint structure of the fiber-reinforced plastic according to claim 1 of the present invention is a joint structure of a fiber-reinforced plastic in which an end of a pipe or a rod made of a fiber-reinforced plastic is joined to another pipe or a rod.
The reinforcing fibers at the ends of the pipe or rod made of the fiber reinforced plastic are exposed to form exposed fibers, and the exposed fibers are wound along the outer circumferential direction of the other pipe or rod, and the wound exposed The fiber is impregnated and cured with a synthetic resin material and is joined to the other pipe or rod.
[0007]
Further, the joint structure of the fiber-reinforced plastic according to claim 2 of the present invention is a joint structure of a fiber-reinforced plastic in which an end of a pipe or a bar made of a fiber-reinforced plastic is joined to another pipe or a bar.
The reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic is exposed to form an exposed fiber, and the exposed fiber is spread in the axial direction of the other pipe or rod, and the other pipe or rod is formed. It is characterized in that the exposed fibers spread in the axial direction of the material are impregnated and cured with a synthetic resin material and joined to the other pipe or rod material.
[0008]
Further, in the joint structure of a fiber-reinforced plastic according to claim 3 of the present invention, the exposed fiber is reinforced by winding it around the other pipe or bar with a cloth or a tape-like woven fabric composed of patch-like reinforcing fibers. It is characterized by.
[0009]
The method for joining fiber-reinforced plastic according to claim 4 of the present invention is a method for joining fiber-reinforced plastic to join an end of a pipe or bar made of fiber-reinforced plastic to another pipe or bar.
Exposing the reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic to form an exposed fiber, winding the exposed fiber along the outer circumferential direction of the other pipe or rod, and winding the exposed fiber; Is impregnated with a synthetic resin material, cured, and joined to the other pipe or rod material.
[0010]
Further, the method of joining a fiber reinforced plastic according to claim 5 of the present invention is a method of joining a fiber reinforced plastic in which an end of a pipe or a rod made of a fiber reinforced plastic is joined to another pipe or a rod.
Exposing the reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic to form an exposed fiber, spreading the exposed fiber in the axial direction of the other pipe or rod, and exposing the other pipe or rod Is characterized by impregnating the exposed fibers spread in the axial direction with a synthetic resin material, curing the fibers, and bonding the fibers to the other pipe or rod.
[0011]
Further, in the method of bonding a fiber-reinforced plastic according to claim 6 of the present invention, the exposed fiber is reinforced by winding it around the other pipe or bar with a cloth or a tape-like woven fabric composed of patch-like reinforcing fibers. And
[0012]
Further, the method for joining fiber-reinforced plastic according to claim 7 of the present invention is a method for joining fiber-reinforced plastic for joining an end of a pipe or rod made of fiber-reinforced plastic to another pipe or rod.
The reinforcing fibers at the ends of at least two of the pipes or rods made of the fiber-reinforced plastic to be joined are respectively exposed to form exposed fibers, and the exposed fibers are entangled by facing each other, and the entangled exposure is performed. The fiber is impregnated with a synthetic resin material and cured to join at least two pipes or rods made of the fiber reinforced plastic in the axial direction.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a bonding structure and a bonding method of a fiber reinforced plastic according to the present invention will be described with reference to the drawings.
1 (a) and 1 (b) to 6 show a joining structure and a joining method of a fiber reinforced plastic according to the present invention, respectively. FIGS. 1 (a) and 1 (b) are made of fiber reinforced plastic (FRP). FIG. 2 is a perspective view of a pipe or rod material, FIG. 2 is a perspective view of a state in which a synthetic resin material at the end of the pipe or rod material made of fiber reinforced plastic is burned, and FIGS. FIG. 4 is a perspective view showing a joining method of a pipe or a rod made of fiber reinforced plastic, FIG. 4 is a perspective view showing a joining structure of a pipe or a rod made of type B fiber reinforced plastic, and FIGS. FIG. 6 is a perspective view showing a method of joining a pipe or a rod made of a type C fiber reinforced plastic, and FIG. 6 is a perspective view showing a method of joining a pipe or a rod made of a type D fiber reinforced plastic. FIG. 7 is a load displacement diagram of type A to type D fiber reinforced plastic, and FIG. 8 is a schematic sectional view showing another embodiment of the present invention.
[0014]
First, a pipe or bar 1 made of fiber reinforced plastic (FRP) shown in FIG. 1A is formed. The pipe or rod 1 is made of carbon fiber reinforced plastic, glass fiber reinforced plastic, aramid fiber reinforced plastic, or the like, whose base material is a polymer such as a thermoplastic resin or a thermosetting resin. The pipe or rod 1 is formed by mixing a high-molecular plastic 3 as a base material with a long fiber reinforcing fiber 5 such as carbon fiber, glass fiber or aramid fiber. In the present embodiment, the cylindrical pipe 1 made of carbon fiber reinforced plastic is used, but a solid rod may be used. This solid rod can have various shapes such as a square shape, a round shape, and an elliptical shape.
[0015]
The end 1a of the pipe or rod 1 made of the fiber reinforced plastic is joined to another pipe or rod 2 as shown in FIGS. 3 (a) and 3 (b) to FIG. In this embodiment, a T-shaped joint will be described, but an I-shaped joint (butt joint) in which pipes or rods are joined in the longitudinal direction may be used. Furthermore, a cross joint or a multi-directional joint can be used. As shown in FIG. 1 (b), the reinforcing fiber 5 made of carbon fiber, glass fiber, aramid fiber or the like at the end 1a of the pipe or rod 1 made of the fiber reinforced plastic is exposed to form an exposed fiber 6.
[0016]
As means for exposing the reinforcing fibers 5 at the end 1a of the pipe or rod 1, as shown in FIG. 2, a polymer plastic 3 as a base material, which is a resin at a joint portion, is ignited using a gas burner 11. By heating and burning above the point to remove the fibers, the reinforcing fibers 5 are exposed, and the exposed fibers 6 can be obtained. In this embodiment, the gas burner 11 is used. However, the present invention is not limited to the illustrated one, and other heating means can be used.
[0017]
In addition, the reinforcing fiber 5 can be exposed by heating the end 1a of the pipe or rod 1 to a temperature higher than the melting point and lower than the ignition point to dissolve and remove the high-molecular plastic 3 as a base material. If the reinforcing fiber 5 is directly put into a heat-molding mold without passing through a resin tank at the time of forming a fiber means or a fiber reinforced plastic, for example, at the time of drawing, the reinforcing fiber 5 in this portion becomes an exposed exposed fiber where the plastic 3 does not exist. 6 can be obtained. Also, in the case of filament winding molding (FW molding), when the reinforcing fiber 5 comes to the end in the axial direction, the reinforcing fiber 5 is exposed at the end by winding the reinforcing fiber 5 around the mandrel without passing through the resin tank. Then, the exposed fiber 6 can be obtained. Alternatively, the exposed fibers 6 may be obtained by a chemical method of dissolving the resin using a chemical.
[0018]
As shown in FIG. 2, in order to completely remove the resin, in this embodiment, a gas burner 11 having a temperature of about 1200 ° C. was used as a heat source for combustion. It is also important how to protect the boundary between the burning part and the non-burning part. From trial and error experiments, it was found that the method using the wet rag 13 for protection of the non-combustion portion was the easiest and most reliable. Further, when the water comes into contact with the reinforcing fibers 5 made of carbon fibers directly burned, in addition to the effect on the reinforcing fibers 5, complete combustion cannot be performed due to the capillary phenomenon through the reinforcing fibers 5 during burning.
[0019]
Therefore, as a countermeasure against inundation, the aluminum tape 15 is directly wound around the pipe 1 touched by the waste 13. Thereafter, the exposed fibers 6 exposed by combustion are subjected to ultrasonic cleaning with acetone for about 30 minutes to remove soot and the like adhering to the exposed fibers 6 to be joined. If the removal of soot is not sufficient, there is a possibility that a new synthetic resin to be applied later particularly to the joint portion may not be sufficiently impregnated, leading to a decrease in strength. Cleaning for removing soot and the like is not limited to ultrasonic cleaning.
[0020]
After exposing the reinforcing fiber 5 at the end 1a of the pipe or rod 1, the exposed fiber 6 is wound along the outer circumference of the other pipe or rod 2. At this time, the fiber directions of the exposed fibers 6 are carefully aligned. Next, the wound exposed fiber 6 is impregnated with a new synthetic resin material, such as vinyl ester or unsaturated polyester, which cures at room temperature, is molded and cured, and is joined to the other pipe or rod material 2. The joints produced by these steps are lighter than conventional joints via metal bolts and sockets. Further, when both the pipe or the bar 1 and the pipe or the bar 2 are made of the same material, there is a concern that a complicated failure mode due to a difference in Young's modulus and strength between the materials and a difference in linear expansion coefficient is considered. It has the effect of being small.
[0021]
In the present embodiment, the pipe 1 is manufactured by winding a carbon fiber by helical winding with a filament winding device, but the present invention is not limited to this. The test piece had a fiber orientation angle of 30 degrees, an inner diameter of 10 mm, 4 plies (outer diameter of about 14 mm), and a pipe or rod 1 made of each fiber-reinforced plastic having a length of 170 mm. The pipe 1 and the pipe or the bar 2 were made of the same material, and a total of four types of test specimens of type A to type D were prepared using the pipe 1 and the pipe or the bar 2.
[0022]
That is, as shown in FIGS. 3 (a) and 3 (b), a type A test piece was prepared, and as shown in FIG. 4, a type B test piece was prepared, and as shown in FIGS. 5 (a) and 5 (b). A test piece of type C was prepared as described above, and a test piece of type D was prepared as shown in FIG. In addition, Table 1 shows the materials used for manufacturing the four types of test pieces from Type A to Type D.
[0023]
[Table 1]

[0024]
As shown in FIGS. 3 (a) and 3 (b), the test piece of the type A has the exposed fiber 6 at the end 1a of the pipe or rod 1 carefully aligned with the other pipe or rod 2 with the fiber direction aligned. Is wound around the pipe or bar 2 so as to be gripped, and finally reinforced by roving fibers. The wound exposed fiber 6 is impregnated with a new synthetic resin material and cured to be joined to the other pipe or rod material 2.
[0025]
As shown in FIG. 4, the test piece of the type B is formed by spreading the exposed fiber 6 on the end 1a of the pipe or bar 1 in the left-right direction with the fiber direction aligned with the axial direction of the other pipe or bar 2. Then, the reinforcing fiber 7 is wound. The exposed fiber 6 expanded in the axial direction of the other pipe or rod 2 is impregnated and cured with a new synthetic resin material that cures at room temperature and joined to the other pipe or rod 2. The type B test piece has a joint structure in which stress concentration on one of the pipes or the bar and an improvement in the in-plane strength of the joint portion are considered in comparison with the type A test piece. In addition, the material of the new synthetic resin material can be appropriately changed.
[0026]
Further, as shown in FIGS. 5A and 5B, the test piece of the type C uses a carbon cloth 8 in a patch shape, and the arrangement of the exposed fibers 6 is as shown in FIG. 5A. , Type B test piece. Since the type A test piece and the type B test piece require skillful working techniques, there is a concern about variation in joint strength. However, the type C test piece uses a patch-like carbon cloth 8. Since the aim is to simplify the operation, it is possible to reduce the variation in the strength of the joint.
[0027]
Further, as shown in FIG. 6, the type D test piece has the same bonding and the arrangement of the exposed fibers 6 in the type A test piece. The type A test piece requires skillful working techniques, so there is a concern about the variation in joint strength. However, the type D test piece has another auxiliary tape-shaped material to prevent the variation. The woven fabric 9 is used to wrap around the joint to stabilize the strength.
[0028]
A static tensile test was performed at room temperature at a stroke control (0.5 mm / sec) using a total of four types of test specimens from type A to type D. A T-joint tensile test jig was prepared, and a steel round bar material for suppressing large deformation of the joint was inserted into the pipe 2 on the side to be joined. Further, a tab portion was formed around the periphery of the glass roving so as not to be crushed by the hydraulic chuck, and a steel core was put therein.
[0029]
Table 2 shows the results of the tensile tests of type A to type D using the joint structure of the present invention under the above test conditions. FIG. 7 shows the load displacement diagram. Note that the joint efficiency in Table 2 is compared with the tensile test results (breaking strength 22.0 kN, breaking stress 159.2 MPa) of FW pipes of the same shape manufactured from the same material.
[0030]
[Table 2]

[0031]
Type A is the lightest joining method among the joining methods of the present invention. However, the tensile strength is slightly inferior to the conventional joint efficiency. Type B, which aims to alleviate stress concentration and improve bending strength, slightly increases the weight of the joint itself, but the strength is improved by more than 20% compared to type A, so the load / weight is the same value as type A. became.
[0032]
In the type C, the work was simplified and the strength was stabilized as compared with the conventional type, but it was necessary to press down the patch-like carbon cloth 8 so as not to float. For this reason, it is necessary to use a large amount of synthetic resin material for the convenience of work, and the weight has increased. In addition, since only the exposed fiber was locally suppressed at the joint, the fracture mode was broken like breaking the fiber. In addition, despite the fact that the fiber arrangement was the same as that of Type B, the result of the strength test was unstable, and the load was reduced.
[0033]
On the other hand, in the case of the type D, the breaking load reached nearly 20 kN. In the type A to type C, the joint was almost destroyed, whereas in the type D, the fracture at the joint was not macroscopically observed. Destroyed near the tab. For this reason, if the shape of the gripping jig is reconsidered, there is a possibility that the strength is further increased. Also, the joining of the test pieces is very simple, and it takes about 3 minutes to manufacture one test piece, so that there is almost no variation in the results at present.
[0034]
FIG. 8 shows a different embodiment of the present invention. In this embodiment, the present invention is applied to an I-shaped joint for joining pipes in the axial direction. Similarly, the reinforcing fibers 5 at the ends 1a and 2a of the

pipes

1 and 2 made of the fiber-reinforced plastic are exposed, and a core 17 made of urethane or the like that is light and melts at a high temperature that does not affect the resin is used. The

pipes

1 and 2 can be inserted into the ends 1a and 2a, and the exposed fibers 6 on both sides can be entangled on the pipes 1 and 2a. Also, in this case, if the joint is tightened from the outside of the joint with a female jig having a cross-sectional shape of the pipe material, the joint has the same shape as the non-joined part, and if further heat is applied, the core 17 melts. It becomes an I-shaped joint.
[0035]
Further, when the

rods

1 and 2 are joined in the axial direction, after exposing the reinforcing fibers 5 on both sides, both exposed fibers 6 are overlapped and entangled with each other using compressed air, and the reinforcing fibers 7 and the resin However, if a metal mold having a female die having the cross-sectional shape of the

rods

1 and 2 is used for joining, the joined portion has the same shape as the non-joined portion.
[0036]
【The invention's effect】
As described above, according to the joint structure of the fiber-reinforced plastic according to claim 1 of the present invention, the exposed fiber is formed by exposing the reinforcing fiber at the end of the pipe or the rod made of the fiber-reinforced plastic. Since the exposed fiber is wound along the outer peripheral direction of the other pipe or rod, and the wound exposed fiber is impregnated with a synthetic resin material and cured to be joined to the other pipe or rod, the pipe or rod is light in weight. It is possible to obtain an FRP joint structure in which the design of the joint portion of the bar is easy, simple and suitable for on-site assembling and repair workability, large joint efficiency, and excellent specific strength and specific rigidity.
[0037]
According to the joint structure of fiber-reinforced plastic according to claim 2 of the present invention, the exposed fiber is formed by exposing the reinforcing fiber at the end of the pipe or rod made of fiber-reinforced plastic. The exposed fiber expanded in the axial direction of the other pipe or bar is impregnated with a synthetic resin material and cured by being joined to the other pipe or rod. Therefore, it is possible to improve the strength of the joint, it is easy to design the joint of the pipe or bar, it is simple and suitable for on-site assembling and repair work, large breaking load and breaking stress, joint efficiency And an FRP joint structure excellent in specific strength and specific rigidity can be obtained.
[0038]
Further, according to the joint structure of the fiber-reinforced plastic according to the third aspect of the present invention, the exposed fiber is reinforced by being wound around the other pipe or bar with a cloth or a tape-like woven fabric composed of patch-like reinforcing fibers. Therefore, it is possible to obtain a joint structure of FRP that can further improve the strength of the joint.
[0039]
Further, according to the fiber-reinforced plastic bonding method of the present invention, the reinforcing fiber at the end of the pipe or rod made of fiber-reinforced plastic is exposed to form an exposed fiber, and the exposed fiber is connected to the other end. Wrapped along the outer circumference of the pipe or bar, impregnated with a synthetic resin material on the wrapped exposed fiber, cured, and then bonded to the other pipe or bar, so that the pipe or bar is lightweight and lightweight. It is possible to obtain an FRP joining method that is easy to design, is simple and suitable for on-site assembly and repair workability, has high joint efficiency, and is excellent in specific strength and specific rigidity.
[0040]
Further, according to the fiber reinforced plastic bonding method according to claim 5 of the present invention, exposed fibers are formed by exposing the reinforcing fibers at the ends of a pipe or a rod made of fiber reinforced plastic, and the exposed fibers are connected to the other end. Since the exposed fiber expanded in the axial direction of the other pipe or rod material is impregnated with a synthetic resin material, cured and joined to the other pipe or rod material, It can improve the strength of the joint, it is easy to design the joint of the pipe or bar, it is simple and suitable for on-site assembling and repair work, large breaking load and breaking stress, and high joint efficiency. It is possible to obtain an FRP joining method that is large and has excellent specific strength and specific rigidity.
[0041]
Furthermore, according to the fiber reinforced plastic bonding method of the sixth aspect of the present invention, the exposed fiber is wrapped around the other pipe or bar with a cloth or a tape-shaped woven fabric made of patch-shaped reinforcing fiber, so that the exposed fiber is reinforced. A method of joining FRP that can further improve the strength of the portion can be obtained.
[0042]
Further, according to the fiber reinforced plastic bonding method according to claim 7 of the present invention, at least two ends of the pipe or rod made of the fiber reinforced plastic to be bonded are respectively exposed to expose the reinforcing fibers. Fibers are formed, the exposed fibers are tangled with each other so as to face each other, the entangled exposed fibers are impregnated with a synthetic resin material, and cured to at least two pipes or rods made of the fiber-reinforced plastic in the axial direction. Since joining, the strength of the joint can be improved, the design of the joint of the pipe or bar is easy, and it is simple and suitable for on-site assembling and repair workability, the breaking load and the breaking stress are large, It is possible to obtain an FRP joining method that has high joint efficiency and excellent specific strength and specific rigidity.
[Brief description of the drawings]
FIG. 1 shows a pipe or a rod made of fiber reinforced plastic used for a joining structure and a joining method of a fiber reinforced plastic according to the present invention, wherein (a) is a perspective view and (b) is a pipe or a rod. FIG. 3 is a perspective view showing a state in which a reinforcing fiber at one end of the base material is exposed.
FIG. 2 is a perspective view showing a joining method of a fiber reinforced plastic according to the present invention, in which a synthetic resin material at an end of a pipe or a rod made of the fiber reinforced plastic is burned.
3 (a) and 3 (b) are perspective views showing a method for joining a pipe or a rod made of type A fiber reinforced plastic, showing a method for joining fiber reinforced plastics according to the present invention.
FIG. 4 is a perspective view showing a joining structure of a fiber-reinforced plastic according to the present invention, and showing a joining structure of a pipe or a rod made of a type B fiber-reinforced plastic.
5 (a) and 5 (b) are perspective views showing a joining method of a pipe or a rod made of a type C fiber reinforced plastic, showing a joining method of a fiber reinforced plastic according to the present invention.
FIG. 6 is a perspective view showing a joining method of a fiber reinforced plastic according to the present invention, and showing a joining method of a pipe or a rod made of a type D fiber reinforced plastic.
FIG. 7 is a load displacement diagram of fiber reinforced plastics of the type A to type D of the joint structure of the fiber reinforced plastic according to the present invention.
FIG. 8 is a schematic sectional view showing a different embodiment of the method of joining fiber-reinforced plastics according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pipe or bar 1a End 2 Pipe or bar 2a End 3 Plastic 5 Reinforcement fiber 6 Exposed fiber 7 Reinforcement fiber 8 Carbon cloth 9 Tape-shaped fabric 11 Gas burner 13 Waste 15 Aluminum tape 17 Core

Claims

In a joint structure of a fiber-reinforced plastic in which an end of a pipe or a rod made of a fiber-reinforced plastic is joined to another pipe or a rod,
The reinforcing fibers at the ends of the pipe or rod made of the fiber reinforced plastic are exposed to form exposed fibers, and the exposed fibers are wound along the outer circumferential direction of the other pipe or rod, and the wound exposed A fiber-reinforced plastic joining structure, wherein a fiber is impregnated and cured with a synthetic resin material and joined to the other pipe or rod.

In a joint structure of a fiber-reinforced plastic in which an end of a pipe or a rod made of a fiber-reinforced plastic is joined to another pipe or a rod,
The reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic is exposed to form an exposed fiber, and the exposed fiber is spread in the axial direction of the other pipe or rod, and the other pipe or rod is formed. A joint structure of a fiber-reinforced plastic, wherein an exposed fiber expanded in the axial direction of the material is impregnated with a synthetic resin material and cured to be joined to the other pipe or rod material.

The fiber-reinforced plastic according to claim 1 or 2, wherein the exposed fiber is reinforced with a cloth or a tape-like woven fabric made of patch-like reinforcing fibers wound around the other pipe or bar. Joint structure.

In a joining method of a fiber-reinforced plastic for joining an end of a pipe or a rod made of fiber-reinforced plastic to another pipe or a rod,
Exposing the reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic to form an exposed fiber, winding the exposed fiber along the outer circumferential direction of the other pipe or rod, and winding the exposed fiber; A method of joining fiber-reinforced plastics, comprising impregnating a synthetic resin material, curing the material, and joining the material to the other pipe or rod.

In a joining method of a fiber-reinforced plastic for joining an end of a pipe or a rod made of fiber-reinforced plastic to another pipe or a rod,
Exposing the reinforcing fiber at the end of the pipe or rod made of the fiber reinforced plastic to form an exposed fiber, spreading the exposed fiber in the axial direction of the other pipe or rod, and exposing the other pipe or rod A method of joining fiber-reinforced plastics, comprising impregnating an exposed fiber spread in the axial direction with a synthetic resin material, curing the resin, and joining the cured material to the other pipe or rod.

The method for joining fiber-reinforced plastics according to claim 4 or 5, wherein the exposed fibers are reinforced by winding them around the other pipe or bar with a cloth or a tape-like woven fabric made of patch-like reinforcing fibers. .

In a joining method of a fiber-reinforced plastic for joining an end of a pipe or a rod made of fiber-reinforced plastic to another pipe or a rod,
The reinforcing fibers at the ends of at least two of the pipes or rods made of the fiber-reinforced plastic to be joined are respectively exposed to form exposed fibers, and the exposed fibers are entangled by facing each other, and the entangled exposure is performed. A method for joining fiber-reinforced plastics, wherein a fiber is impregnated with a synthetic resin material and cured to join at least two pipes or rods made of the fiber-reinforced plastic in the axial direction.