JP4909237B2 - Reinforced structure excellent in stopping brittle crack propagation - Google Patents
Reinforced structure excellent in stopping brittle crack propagation Download PDFInfo
- Publication number
- JP4909237B2 JP4909237B2 JP2007285295A JP2007285295A JP4909237B2 JP 4909237 B2 JP4909237 B2 JP 4909237B2 JP 2007285295 A JP2007285295 A JP 2007285295A JP 2007285295 A JP2007285295 A JP 2007285295A JP 4909237 B2 JP4909237 B2 JP 4909237B2
- Authority
- JP
- Japan
- Prior art keywords
- brittle crack
- base material
- reinforcing
- reinforcing plate
- stopping
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
本発明は、コンテナ船、タンカーなどの船舶分野、ＬＮＧ貯蔵タンクなどの圧力容器分野において、溶接継手部を持つ溶接鋼構造体に発生した脆性亀裂の伝播を停止させるための補強構造に関するものである。 The present invention relates to a reinforcing structure for stopping the propagation of a brittle crack generated in a welded steel structure having a welded joint in a vessel field such as a container ship and a tanker and a pressure vessel field such as an LNG storage tank. .
大型コンテナ船や大型貯蔵タンクなどの溶接構造体は、突合せ溶接により接合された多数の鋼板で構成されている。この様な構造体においては、溶接欠陥から発生した脆性亀裂が急速に伝播して、構造体に重大な損傷を与えることが懸念される。通常、鋼構造では脆性破壊を発生させないことが安全上最も重要な要件であり、材料選定から検査に至るまで細心の注意が払われている。更に、溶接欠陥から発生した脆性亀裂が、母材側に逸れて伝播する場合には、鋼板の脆性亀裂伝播停止特性が十分高ければその停止が期待できる。 Welding structures such as large container ships and large storage tanks are composed of a number of steel plates joined by butt welding. In such a structure, there is a concern that brittle cracks generated from weld defects propagate rapidly and cause serious damage to the structure. Usually, the most important requirement for safety is not to cause brittle fracture in steel structures, and great care is taken from material selection to inspection. Furthermore, when a brittle crack generated from a weld defect is propagated to the base metal side, it can be expected to stop if the brittle crack propagation stop characteristic of the steel sheet is sufficiently high.
しかし、脆性亀裂停止伝播特性が母材よりも劣る溶接線に沿って脆性亀裂が伝播する場合には、母材の性能によらずに脆性亀裂が停止しないことが懸念される。そこで、例えば船殻構造体においては、鋼板の溶接線が一列に並ばないようにして、万一溶接線に沿って脆性亀裂が伝播しても、短い距離で母材に脆性亀裂を突入させるように施工している。しかしながら、このような施工を全ての懸念部位に適用できるとは限らないので、溶接線に沿った脆性亀裂を確実に停止させる構造形式（クラックアレスター）が必要である。 However, when a brittle crack propagates along a weld line whose brittle crack stop propagation characteristic is inferior to that of the base material, there is a concern that the brittle crack will not stop regardless of the performance of the base material. Therefore, for example, in a hull structure, the weld lines of the steel plates should not be arranged in a line, and even if a brittle crack propagates along the weld line, the brittle crack should enter the base material at a short distance. We are constructing. However, since such construction cannot be applied to all parts of concern, a structural form (crack arrester) that reliably stops brittle cracks along the weld line is required.
そこで先ず、溶接線に沿った脆性亀裂のアレスターに関する従来技術について、添付図１２，１３を参照しながら体系的に説明する。図１２は従来技術１に係る溶接鋼構造物及びその製造方法の一実施例を示す図、図１３は従来技術３に係る溶接構造体の溶接方法及び溶接構造体を示す図である。 First, the prior art related to the arrester of brittle cracks along the weld line will be systematically described with reference to FIGS. FIG. 12 is a view showing an embodiment of a welded steel structure and a manufacturing method thereof according to the prior art 1, and FIG. 13 is a view showing a welding method and a welded structure of the welded structure according to the prior art 3.
（１）圧縮予ひずみ付与による方法（従来技術１）
図１２に示す如く、圧縮予ひずみ部２２を溶接線２３の両側のほぼ線対称位置に一対以上配設することにより、鋼板２１の溶接部の一部に圧縮残留応力を与えて脆性亀裂２４の伝播を阻止することと、同時に溶接部から離れた位置に引張応力を発生させることで、脆性亀裂２４を脆性亀裂伝播特性の高い母材に導き、前記脆性亀裂２４の進展を停止させる方法である（特許文献１参照）。
(1) Method by applying compression prestrain (prior art 1)
As shown in FIG. 12, a pair of compression pre-strained portions 22 are disposed at substantially line symmetrical positions on both sides of the weld line 23, thereby applying compressive residual stress to a part of the welded portion of the steel plate 21 and causing the brittle crack 24. It is a method of stopping the progress of the brittle crack 24 by guiding the brittle crack 24 to a base material having a high brittle crack propagation characteristic by preventing the propagation and simultaneously generating a tensile stress at a position away from the welded portion. (See Patent Document 1).
（２）補修溶接による方法（従来技術２）
例えば、特許文献２によれば、突合せ溶接部、または垂直部材と水平部材の溶接継手が交差する部分において、当該領域の一部をガウジング、あるいは機械加工により除去した後、破壊靭性に優れた溶接材料で補修溶接するか、ないしは補修領域の形状を特殊なものにする方法である（特許文献２〜４参照）。
(2) Repair welding method (prior art 2)
For example, according to Patent Document 2, in a butt weld or a portion where a welded joint between a vertical member and a horizontal member intersects, a part of the region is removed by gouging or machining, and then welding with excellent fracture toughness is performed. It is a method of repair welding with a material or making the shape of the repair region special (see Patent Documents 2 to 4).
（３）アレスター材の挿入による方法（従来技術３）
図１３に示す如く、垂直部材の溶接継手で脆性亀裂を停止させたい領域において、当該領域の垂直部材２６と溶接継手２５をくり抜いた後、当該部分に脆性亀裂が停止可能なアレスター材２７を挿入する方法である（特許文献５参照）。
(3) Method by inserting arrester material (prior art 3)
As shown in FIG. 13, in a region where a brittle crack is to be stopped by a welded joint of a vertical member, after the vertical member 26 and the welded joint 25 in the region are cut out, an arrester material 27 capable of stopping the brittle crack is inserted into the portion. (See Patent Document 5).
（４）溶接金属の破壊靭性を向上する方法（従来技術４）
溶接金属の機械的強度や成分の組合せを工夫して、破壊靭性を向上することにより脆性亀裂伝播を妨げる方法である（特許文献６〜９参照）。
(4) Method for improving fracture toughness of weld metal (prior art 4)
This is a method for preventing brittle crack propagation by improving the fracture toughness by devising a combination of mechanical strength and components of the weld metal (see Patent Documents 6 to 9).
（５）鋼製橋脚の補強施工工法（従来技術５）
一方、脆性破壊のアレスターに関する発明ではないが、橋脚部材と補強部材との間に温度差を与えて連結し、温度差の低減により前記補強部材にプレストレスを与える鋼製橋脚の補強施工方法が開示されている（特許文献１０）。
(5) Steel bridge pier reinforcement construction method (prior art 5)
On the other hand, although it is not an invention related to the arrester of brittle fracture, there is a method for reinforcing steel piers that gives a prestress to the reinforcing member by connecting the pier member and the reinforcing member with a temperature difference and reducing the temperature difference. It is disclosed (Patent Document 10).
上記従来技術に係るクラックアレスターは、溶接材料や母材の材質を改良する方法、および溶接線を遮断するように孔を明けるかまたはアレスター材を挿入する方法に大別される。
本発明者らは、補強板を介して溶接部に機械的に圧縮応力を付与することによって、脆性亀裂の進展が母材に突入するのを防止できる知見を得て本発明に至ったものである。即ち、本発明の目的は、溶接線に沿って伝播する脆性亀裂を停止させることであり、具体的には、例えば大型コンテナ船の溶接欠陥から発生した脆性亀裂が溶接線に沿って伝播し、溶接構造体の母材を配設した領域に接近または突入した場合に、前記脆性亀裂の進展を停止させる優れた補強構造を提供することにある。 The present inventors have obtained the knowledge that can prevent the progress of brittle cracks from entering the base material by mechanically applying a compressive stress to the welded portion via the reinforcing plate, and have reached the present invention. is there. That is, the object of the present invention is to stop a brittle crack that propagates along the weld line, specifically, for example, a brittle crack generated from a welding defect of a large container ship propagates along the weld line, An object of the present invention is to provide an excellent reinforcing structure that stops the progress of the brittle crack when approaching or entering a region where a base material of a welded structure is disposed.
前記目的を達成するために、本発明の請求項１に係る脆性亀裂伝播停止に優れた補強構造が採用した手段は、溶接構造体に発生した脆性亀裂の伝播を停止させるための補強構造において、前記脆性亀裂を跨ぐ補強板とこの補強板を母材に結合する結合手段とによって、前記脆性亀裂によって離反された母材同士が結合されると共に、前記補強板に予め引張予ひずみが付与されてなることを特徴とするものである。 In order to achieve the above object, the means adopted by the reinforcing structure excellent in stopping brittle crack propagation according to claim 1 of the present invention is a reinforcing structure for stopping the propagation of brittle cracks generated in the welded structure. The reinforcing plates straddling the brittle cracks and the connecting means for connecting the reinforcing plates to the base material couple the base materials separated by the brittle cracks, and the tensile pre-strain is applied to the reinforcing plate in advance. It is characterized by.
本発明の請求項２に係る脆性亀裂伝播停止に優れた補強構造が採用した手段は、請求項１に記載の脆性亀裂伝播停止に優れた補強構造において、前記補強板が、溶接線を跨いで母材に結合されてなることを特徴とするものである。 The means adopted by the reinforcing structure excellent in stopping brittle crack propagation according to claim 2 of the present invention is the reinforcing structure excellent in stopping brittle crack propagation according to claim 1, wherein the reinforcing plate straddles the weld line. It is characterized by being bonded to a base material.
本発明の請求項３に係る脆性亀裂伝播停止に優れた補強構造が採用した手段は、請求項１または２に記載の脆性亀裂伝播停止に優れた補強構造において、前記結合手段が、締結部材または溶接であることを特徴とするものである。 The means employed by the reinforcing structure excellent in stopping brittle crack propagation according to claim 3 of the present invention is the reinforcing structure excellent in stopping brittle crack propagation according to claim 1 or 2, wherein the coupling means is a fastening member or It is characterized by welding.
本発明の請求項４に係る脆性亀裂伝播停止に優れた補強構造が採用した手段は、前請求項１乃至３のうちの何れか一つの項に記載の脆性亀裂伝播停止に優れた補強構造において、前記引張予ひずみが、加熱または機械的な引張力によって付与されてなることを特徴とするものである。 The means adopted by the reinforcing structure excellent in stopping brittle crack propagation according to claim 4 of the present invention is the reinforcing structure excellent in stopping brittle crack propagation according to any one of claims 1 to 3. The tensile pre-strain is applied by heating or mechanical tensile force.
本発明の請求項５に係る脆性亀裂伝播停止に優れた補強構造が採用した手段は、請求項１または２に記載の脆性亀裂伝播停止に優れた補強構造において、前記結合手段が、脆性亀裂によって離反された母材に対向する様に接合された一対の取付金具と、前記補強板の両端に前記取付金具との間に隙間を有して設けられた開孔板と、前記取付金具と開孔板に貫通された締結部材とからなり、この締結部材の締結により前記補強板に引張予ひずみを付与して母材同士が結合されてなることを特徴とするものである。 The means adopted by the reinforcing structure excellent in stopping brittle crack propagation according to claim 5 of the present invention is the reinforcing structure excellent in stopping brittle crack propagation according to claim 1 or 2, wherein the joining means is formed by brittle cracks. A pair of mounting brackets joined so as to face the separated base material, an aperture plate provided with a gap between the mounting brackets at both ends of the reinforcing plate, and the mounting bracket and the opening It consists of a fastening member that is penetrated by a hole plate, and a tensile pre-strain is applied to the reinforcing plate by fastening of the fastening member, and the base materials are combined.
本発明の請求項１に係る脆性亀裂伝播停止に優れた補強構造によれば、溶接構造体に発生した脆性亀裂の伝播を停止させるための補強構造において、前記脆性亀裂を跨ぐ補強板とこの補強板を母材に結合する結合手段とによって、前記脆性亀裂によって離反された母材同士が結合されると共に、前記補強板に予め引張予ひずみが付与されてなるものであるから、簡単な構造によって脆性亀裂の伝播を確実に停止する優れた補強構造を提供し得る。 According to the reinforcing structure excellent in stopping brittle crack propagation according to claim 1 of the present invention, in the reinforcing structure for stopping the propagation of the brittle crack generated in the welded structure, the reinforcing plate straddling the brittle crack and the reinforcement Since the base materials separated by the brittle cracks are joined to each other by the joining means for joining the plates to the base material, and the tensile pre-strain is preliminarily applied to the reinforcing plate, An excellent reinforcing structure that reliably stops the propagation of brittle cracks can be provided.
また、本発明の請求項２に係る脆性亀裂伝播停止に優れた補強構造によれば、前記補強板が溶接線を跨いで母材に結合されてなるので、簡単な構造によって、溶接線に沿う脆性亀裂の伝播を確実に停止する優れた補強構造を提供し得る。 Further, according to the reinforcing structure excellent in stopping brittle crack propagation according to claim 2 of the present invention, the reinforcing plate is joined to the base material across the weld line. An excellent reinforcing structure that reliably stops the propagation of brittle cracks can be provided.
更に、本発明の請求項３に係る脆性亀裂伝播停止に優れた補強構造によれば、前記結合手段が、締結部材または溶接であることを特徴とするので、前記補強材を確実に母材に結合して脆性亀裂の伝播を停止できる。 Furthermore, according to the reinforcing structure excellent in stopping brittle crack propagation according to claim 3 of the present invention, the connecting means is a fastening member or welding, so that the reinforcing material can be reliably used as a base material. Bonding can stop the propagation of brittle cracks.
また更に、本発明の請求項４に係る脆性亀裂伝播停止に優れた補強構造によれば、前記引張予ひずみが、加熱または機械的な引張力によって付与されてなるので、引張ひずみの付与が施工現場においても比較的簡単に実施可能である。 Furthermore, according to the reinforcing structure excellent in stopping brittle crack propagation according to claim 4 of the present invention, the tensile prestrain is applied by heating or mechanical tensile force. It can be implemented relatively easily on site.
一方、本発明の請求項５に係る脆性亀裂伝播停止に優れた補強構造によれば、前記結合手段が、脆性亀裂によって離反された母材に対向する様に接合された一対の取付金具と、前記補強板の両端に前記取付金具との間に隙間を有して設けられた開孔板と、前記取付金具と開孔板に貫通された締結部材とからなり、この締結部材の締結により前記補強板に引張予ひずみを付与して母材同士が結合されてなるので、引張ひずみの付与が施工現場においても更に簡単に実施可能である。 On the other hand, according to the reinforcing structure excellent in stopping brittle crack propagation according to claim 5 of the present invention, a pair of mounting brackets joined so that the coupling means faces the base material separated by the brittle crack, It comprises an aperture plate provided with a gap between the mounting plate and both ends of the reinforcing plate, and a fastening member penetrating the mounting bracket and the aperture plate. Since the pre-strain is applied to the reinforcing plate and the base materials are bonded to each other, it is possible to more easily apply the tensile strain even at the construction site.
先ず、本発明の実施の形態１に係る溶脆性亀裂伝播停止に優れた補強構造につき、図１〜６を参照しながら説明する。図１は本発明の実施の形態１に係る脆性亀裂伝播停止に優れた補強構造を示す斜視図、図２は図１の断面Ｓ（溶接継手部に平行して高力ボルトを通り鋼板に垂直な断面）において矢視Ａ−Ａを示す断面図である。また、図３は本発明の実施の形態１に係り、予め引張予ひずみの付与された補強板により補強された溶脆性亀裂伝播停止に優れた補強構造の作用を説明するための図、図４は本発明の実施の形態１に係り、補強板が母材の片面にのみ結合された態様例を示す断面図、図５は本発明の実施の形態１に係り、リベット接合の態様例を示す断面図、図６は本発明の実施の形態１に係り、溶接接合の態様例を示す斜視図である。 First, a reinforcing structure excellent in stopping brittle crack propagation according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a reinforcing structure excellent in stopping brittle crack propagation according to Embodiment 1 of the present invention, and FIG. 2 is a cross-section S of FIG. It is sectional drawing which shows arrow AA in a simple cross section. FIG. 3 relates to the first embodiment of the present invention, and is a diagram for explaining the action of the reinforcing structure excellent in stopping the brittle crack propagation reinforced by the reinforcing plate to which the tensile prestrain is applied in advance. FIG. 5 is a sectional view showing an example of a mode in which a reinforcing plate is bonded to only one side of a base material according to the first embodiment of the present invention, and FIG. 5 is an example of a rivet joining mode according to the first embodiment of the present invention. Sectional drawing and FIG. 6 are related to Embodiment 1 of this invention, and are perspective views which show the example of a mode of welding joining.
本発明の実施の形態１に係る脆性亀裂伝播停止に優れた補強構造は、図１，２に示す通り、鋼板（母材１）を突合せ溶接された溶接構造体の溶接継手部２に沿って発生した脆性亀裂８の表裏面を挟む様に２枚の補強板３を対向して配設され、これら２枚の補強板２が、前記脆性亀裂８を跨いで結合手段である高力ボルト４及びナット５によって、溶接構造体の母材１に結合される。そして同時に、前記補強板３は、母材１に結合する前に予め引張予ひずみ６を付与されるのが好ましい。この様に、前記脆性亀裂８が溶接継手部２に沿って発生した場合は、図１に示す如く、溶接継手部２の溶接線も跨ぐ様に、前記結合手段によって溶接構造体の母材１に結合されるのが好ましい。 As shown in FIGS. 1 and 2, the reinforcing structure excellent in stopping brittle crack propagation according to Embodiment 1 of the present invention is along a welded joint portion 2 of a welded structure in which a steel plate (base material 1) is butt welded. Two reinforcing plates 3 are arranged to face each other so that the front and back surfaces of the generated brittle crack 8 are sandwiched, and these two reinforcing plates 2 straddle the brittle crack 8 and are high-strength bolts 4 serving as coupling means. And the nut 5 are coupled to the base material 1 of the welded structure. At the same time, the reinforcing plate 3 is preferably preliminarily given a tensile pre-strain 6 before being bonded to the base material 1. In this way, when the brittle crack 8 occurs along the welded joint portion 2, as shown in FIG. 1, the base material 1 of the welded structure is formed by the coupling means so as to straddle the weld line of the welded joint portion 2. It is preferable that it is couple | bonded.
次いで、引張予ひずみ６が付与された補強板３を用いる本発明に係る補強構造の作用について、図３を参照しながら説明する。図３において、図（ａ）は図１の正面図、図（ｂ）〜（ｅ）は図（ａ）の溶接部断面Ｂ−Ｂの板厚中心線に作用する溶接線直交方向応力の分布を示し、図（ｂ）は溶接残留応力、図（ｃ）は外力により発生する応力、図（ｄ）は補強板への引張予ひずみ付与により発生する応力、図（ｅ）は全応力を示す図である。 Next, the operation of the reinforcing structure according to the present invention using the reinforcing plate 3 to which the tensile prestrain 6 is applied will be described with reference to FIG. 3, (a) is a front view of FIG. 1, and (b) to (e) are distributions of stress in a direction perpendicular to the weld line acting on the thickness center line of the weld cross section BB in FIG. Fig. (B) shows welding residual stress, Fig. (C) shows stress generated by external force, Fig. (D) shows stress generated by applying tensile prestrain to the reinforcing plate, and Fig. (E) shows total stress. FIG.
補強板３と母材１を結合した後に、補強板３には溶接継手部２の溶接線に対して略直交方向に引張応力７が発生し、その反作用として母材１及び溶接継手部２には、補強板３の近傍で溶接線に対して略直交方向に圧縮応力が作用する（図（ｃ）参照）。この圧縮応力によって、補強板３下部および近傍の溶接継手部２に残存する溶接時の熱収縮に起因する残留引張応力６が緩和され、前記溶接継手部２の応力が圧縮側に移行する（図（ｄ）参照）。更に、母材１に溶接線に対して略直交方向の引張外力７が作用して付加応力が発生した場合には、前記溶接継手部２に発生する付加応力は、補強板の剛性付与効果によって、補強板の影響の無い一般部の付加応力に比べて小さくなる。 After the reinforcing plate 3 and the base material 1 are joined, a tensile stress 7 is generated in the reinforcing plate 3 in a direction substantially orthogonal to the weld line of the welded joint portion 2, and as a reaction to the base material 1 and the welded joint portion 2. In the vicinity of the reinforcing plate 3, compressive stress acts in a direction substantially orthogonal to the weld line (see FIG. 3C). Due to this compressive stress, the residual tensile stress 6 caused by thermal shrinkage during welding remaining in the lower portion of the reinforcing plate 3 and in the adjacent welded joint portion 2 is relieved, and the stress of the welded joint portion 2 shifts to the compression side (see FIG. (See (d)). Further, when a tensile external force 7 in a direction substantially orthogonal to the weld line acts on the base material 1 to generate an additional stress, the additional stress generated in the welded joint portion 2 is caused by the rigidity imparting effect of the reinforcing plate. This is smaller than the applied stress of the general part without the influence of the reinforcing plate.
即ち、補強板３への引張予ひずみ６付与の効果によって、溶接継手部２の引張残留応力が低減されるとともに、補強板３の剛性付与効果によって、外力が作用した場合にも応力の増加は一般部に比べて小さくなる（図（ｅ）参照）。この結果、溶接継手部２に沿って伝播してきた脆性亀裂８が前記溶接継手部２に突入した場合、脆性亀裂８の先端近傍の応力が圧縮側に移行して、後述の式［数１］の左辺で定義される応力拡大係数（Ｋ値）が大幅に低減するか乃至はゼロになり、前記脆性亀裂８は溶接継手部２において進展を停止する。 That is, the tensile residual stress of the welded joint portion 2 is reduced due to the effect of applying the tensile prestrain 6 to the reinforcing plate 3, and the stress is increased even when an external force is applied due to the rigidity applying effect of the reinforcing plate 3. It becomes smaller than the general part (see FIG. (E)). As a result, when the brittle crack 8 that has propagated along the welded joint portion 2 enters the welded joint portion 2, the stress in the vicinity of the tip of the brittle crack 8 shifts to the compression side, and the following formula [Equation 1] The stress intensity factor (K value) defined on the left side of is greatly reduced to zero, and the brittle crack 8 stops progressing in the welded joint portion 2.
補強板３に引張予ひずみ６を与える方法としては、結合前に補強板３を予めバーナなどにより加熱して、温度を母材よりも所望の温度だけ上昇させておき、この温度差を維持したままで高力ボルト４とナット５等の締結手段により補強板３と母材１とを結合する。そして、全体が一様の温度になるまで放置しておけば、自然に補強板３に引張予ひずみ６を発生させることが出来る。尚、施工において補強板３の温度管理が困難な場合には、補強板３の変位を測定して所望の伸び量が得られた時点で結合を実施すれば、簡単に精度良く所望の予ひずみ６を与えることが可能である。また、結合前の補強板３を機械的に溶接線直交方向に引張り、その引張力を維持した状態で結合手段により結合しても良い。 As a method of giving the tensile prestrain 6 to the reinforcing plate 3, the reinforcing plate 3 is heated in advance with a burner or the like before joining, and the temperature is raised by a desired temperature from the base material, and this temperature difference is maintained. The reinforcing plate 3 and the base material 1 are joined together by fastening means such as the high-strength bolt 4 and the nut 5. And if it is allowed to stand until the whole reaches a uniform temperature, the tensile prestrain 6 can be naturally generated in the reinforcing plate 3. In addition, when it is difficult to control the temperature of the reinforcing plate 3 during construction, the desired pre-strain can be easily and accurately performed by measuring the displacement of the reinforcing plate 3 and performing the coupling when the desired elongation is obtained. 6 can be given. Alternatively, the reinforcing plate 3 before joining may be mechanically pulled in the direction perpendicular to the weld line and joined by the joining means while maintaining the tensile force.
そして、本発明に係る脆性亀裂伝播停止に優れた補強構造は、前記引張予ひずみが次式［数１］を満足するように付与されてなるのが好ましい。ここで、次式［数１］の左辺は応力拡大係数（Ｋ値）を示す。即ち、前記補強構造が、次式［数１］を満足する様に構成されることによって、母材の脆性破壊伝播停止靱性が応力拡大係数より大きくなるので、脆性亀裂の進展が阻止されるのである。
And it is preferable that the reinforcement structure excellent in the brittle crack propagation stop which concerns on this invention is provided so that the said tension | pulling pre-strain may satisfy | fill following Formula [Formula 1]. Here, the left side of the following equation [Equation 1] indicates a stress intensity factor (K value). That is, when the reinforcing structure is configured so as to satisfy the following formula [Equation 1], the brittle fracture propagation stop toughness of the base material becomes larger than the stress intensity factor, so that the progress of brittle cracks is prevented. is there.
前記補強板３は、図２に示した様に、母材１の脆性亀裂８や溶接線２の表裏に対向して配設することが、母材１の面外曲げを防止するためと、圧縮力を母材１の板厚方向に一様に付与するために望ましいが、この様な構成が困難な場合には、図４に示す様に母材１の片面のみに補強板３を配置して、高力ボルト４及びナット５により締結しても良い。片面配置の場合には、引張予ひずみ６を適切に制御することによって、表裏面配置と同様の脆性亀裂停止効果が得られる。また、補強板３と母材１とを結合する結合手段には、高力ボルト・ナットによる締結部材以外に、図５に示すリベット９や図６に示す溶接１０を用いても良い。 As shown in FIG. 2, the reinforcing plate 3 is disposed to face the front and back of the brittle crack 8 of the base material 1 and the weld line 2 in order to prevent the base material 1 from being bent out of plane. Although it is desirable to apply a compressive force uniformly in the thickness direction of the base material 1, when such a configuration is difficult, the reinforcing plate 3 is disposed only on one side of the base material 1 as shown in FIG. And you may fasten with the high strength volt | bolt 4 and the nut 5. FIG. In the case of the single-sided arrangement, the brittle crack stopping effect similar to that of the front-and-back side arrangement can be obtained by appropriately controlling the tensile prestrain 6. Further, as a connecting means for connecting the reinforcing plate 3 and the base material 1, a rivet 9 shown in FIG. 5 or a weld 10 shown in FIG.
以上、本発明の実施の形態１に係る溶接構造体によれば、脆性亀裂８を跨ぐ補強板３とこの補強板３を母材１に結合する結合手段、即ち、高力ボルト４とナット５、リベット９または溶接１０によって、前記脆性亀裂８によって離反された母材１同士が結合されると共に、前記補強板３に予め引張予ひずみ６が付与されてなるものであるから、簡単な構造によって溶脆性亀裂８の伝播を確実に停止する優れた補強構造を提供し得る。 As described above, according to the welded structure according to Embodiment 1 of the present invention, the reinforcing plate 3 straddling the brittle crack 8 and the coupling means for connecting the reinforcing plate 3 to the base material 1, that is, the high strength bolt 4 and the nut 5. The base material 1 separated by the brittle crack 8 is bonded to each other by the rivet 9 or the weld 10, and the tensile prestrain 6 is applied to the reinforcing plate 3 in advance. An excellent reinforcing structure that reliably stops propagation of the brittle crack 8 can be provided.
＜実施例＞
次に、突合せ溶接された母材に、前記溶接線を跨って補強板を結合した本発明に係る脆性亀裂伝播停止に優れた補強構造の実施例について、以下添付図７〜９を参照しながら説明する。図７は本発明に係る本実施例の外観を示す斜視図、図８は本発明の実施例に係る解析結果であり、母材全面の応力分布を示す図、図９は本発明の実施例に係る解析結果であり、図８のｙ座標（溶接中心）における母材の溶接線直交方向の無次元化応力分布を示す図である。
<Example>
Next, an example of a reinforcing structure excellent in stopping brittle crack propagation according to the present invention in which a reinforcing plate is joined to a base material that has been butt welded across the weld line will be described below with reference to FIGS. explain. FIG. 7 is a perspective view showing an appearance of the present embodiment according to the present invention, FIG. 8 is an analysis result according to the embodiment of the present invention, and shows a stress distribution on the entire surface of the base material, and FIG. 9 is an embodiment of the present invention. FIG. 9 is a diagram showing a non-dimensional stress distribution in a direction orthogonal to the weld line of the base material at the y coordinate (welding center) in FIG. 8.
母材１は図７に示す如く、幅（縦方向寸法）１０００ｍｍ、長さ（横方向寸法）８００ｍｍ、板厚６０ｍｍの鋼材であり、補強板３は幅２００ｍｍ、長さ８００ｍｍ、板厚３０ｍｍの鋼板である。そして、母材１と補強板３は、温度差による引張予ひずみを付与された状態で、図示しない高力ボルトとナットにより強固に摩擦接合されている。この結果、母材１に開孔されたボルト孔周辺での応力集中が緩和されるとともに、補強板３による剛性付与効果によって、全体としての強度低下は無い。 As shown in FIG. 7, the base material 1 is a steel material having a width (longitudinal dimension) of 1000 mm, a length (lateral dimension) of 800 mm, and a plate thickness of 60 mm, and the reinforcing plate 3 has a width of 200 mm, a length of 800 mm, and a plate thickness of 30 mm. It is a steel plate. The base material 1 and the reinforcing plate 3 are firmly joined by high-strength bolts and nuts (not shown) in a state where a tensile pre-strain due to a temperature difference is applied. As a result, the stress concentration around the bolt hole opened in the base material 1 is alleviated, and the rigidity is not increased due to the rigidity imparting effect by the reinforcing plate 3.
図８において、母材1の補強板３が接合された領域は、補強板３に付与された引張予ひずみの反力として圧縮応力が広く分布している。一方、母材１のその他の領域においては、突合せ溶接による収縮ひずみから引張応力が作用している。そして、図９から分かる様に、母材１の補強板中心（ｘ軸）から４００ｍｍ離れた位置まで、補強板３に付与された引張予ひずみの反力として圧縮側に移行している。この圧縮応力によって溶接による引張残留応力が緩和されるとともに、補強板の剛性付与効果によって外力による引張応力増加も小さくなり、脆性亀裂を停止させることが可能となる。 In FIG. 8, in the region where the reinforcing plate 3 of the base material 1 is joined, compressive stress is widely distributed as a reaction force of the tensile prestrain applied to the reinforcing plate 3. On the other hand, in other regions of the base material 1, tensile stress acts from shrinkage strain caused by butt welding. As can be seen from FIG. 9, the reaction force of the tensile prestrain applied to the reinforcing plate 3 is shifted to the compression side up to a position 400 mm away from the center (x axis) of the reinforcing plate of the base material 1. This compressive stress alleviates the tensile residual stress due to welding, and the increase in tensile stress due to external force is also reduced by the rigidity imparting effect of the reinforcing plate, making it possible to stop brittle cracks.
因みに、本実施例において補強板３と母材１の温度差が１００℃の場合には、母材１の中心まで脆性亀裂が進展したとき（亀裂長さ５００ｍｍ）の亀裂先端の応力拡大係数（Ｋ値）は６３００Mpa・mm1/2となる。一方、補強板３が無い場合においては、同条件での応力拡大係数は１２０００Mpa・mm1/2なので、本発明によって応力拡大係数は５３％に低減することになり、脆性亀裂の停止性能が格段に向上することが分かる。 Incidentally, in the present embodiment, when the temperature difference between the reinforcing plate 3 and the base material 1 is 100 ° C., the stress intensity factor at the tip of the crack when the brittle crack progresses to the center of the base material 1 (crack length 500 mm) ( (K value) is 6300 Mpa · mm 1/2 . On the other hand, when the reinforcing plate 3 is not provided, the stress intensity factor under the same conditions is 12000 Mpa · mm 1/2, so the stress intensity factor is reduced to 53% according to the present invention, and the stopping performance of brittle cracks is remarkably increased. It can be seen that
次に、本発明の実施の形態２に係る脆性亀裂伝播停止に優れた補強構造を、添付図１０，１１を参照しながら説明する。図１０は本発明の実施の形態２に係り、結合手段が異なる他の態様例を示す斜視図、図１１は図１０の態様例において、補強板に引張予ひずみを付与する方法を説明するための断面図である。但し、本発明の実施の形態２が上記実施の形態１と相違するところは、補強板を母材に結合する結合手段の構成に相違があり、これ以外は上記実施の形態１と全く同構成であるから、上記実施の形態１と同一のものに同一符号を付して、以下その相違する点について説明する。 Next, a reinforcing structure excellent in stopping brittle crack propagation according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 10 is a perspective view showing another embodiment example in which the coupling means is different according to the second embodiment of the present invention, and FIG. 11 is a view for explaining a method of applying tensile prestrain to the reinforcing plate in the embodiment example of FIG. FIG. However, the second embodiment of the present invention differs from the first embodiment in the configuration of the coupling means for coupling the reinforcing plate to the base material, and the other configuration is exactly the same as in the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be described below.
即ち、上記実施の形態１に係る脆性亀裂伝播停止に優れた補強構造の結合手段が、締結部材または溶接接合からなるのに対し、本実施の形態２に係る脆性亀裂伝播停止に優れた補強構造の結合手段は、脆性亀裂８によって離反された母材１に対向する様に接合接合１３された一対の取付金具１１と、前記補強板３の両端に前記取付金具１１との間に隙間１２を有して溶接接合１３された開孔板３ａと、前記取付金具１１及び補強板３の開孔板３ａに貫通された締結部材である高力ボルト４、ナット５とからなる。 That is, the reinforcing structure coupling means excellent in stopping brittle crack propagation according to the first embodiment is composed of a fastening member or welded joint, whereas the reinforcing structure excellent in stopping brittle crack propagation according to the second embodiment. The coupling means includes a pair of mounting brackets 11 joined and bonded so as to face the base material 1 separated by the brittle cracks 8, and a gap 12 between the mounting brackets 11 at both ends of the reinforcing plate 3. It comprises an aperture plate 3a that is welded and joined, and a high-strength bolt 4 and a nut 5 that are fastening members penetrated through the mounting bracket 11 and the aperture plate 3a of the reinforcing plate 3.
そして、この高力ボルト４、ナット５の締結により前記隙間１２を閉じることによって、前記補強板３に引張予ひずみ６を付与して母材同士が結合されるのが好ましい。即ち、図１１に示す如く、高力ボルト４、ナット５が締結される前の補強板３及び開孔板３ａの端部は、二点鎖線で示す様に、前記取付金具１１との間に隙間１２を有して設けられている。そして、この高力ボルト４、ナット５の締結により前記隙間１２を閉じることによって、前記補強板３に引張予ひずみ６を付与するのである。 Then, by closing the gap 12 by fastening the high-strength bolt 4 and the nut 5, it is preferable that a tensile pre-strain 6 is applied to the reinforcing plate 3 so that the base materials are joined to each other. That is, as shown in FIG. 11, the ends of the reinforcing plate 3 and the aperture plate 3a before the high-strength bolt 4 and nut 5 are fastened are between the mounting bracket 11 as shown by the two-dot chain line. A gap 12 is provided. Then, by closing the gap 12 by fastening the high-strength bolt 4 and the nut 5, the tensile prestrain 6 is applied to the reinforcing plate 3.
前記締結部材としては高力ボルト４、ナット５の外、リベットを用いることが出来る。尚、図１０，１１においては、前記開孔板３ａはアングル状の短板を補強板３に溶接接合１３した例を示したが、本発明はこれに限るものではなく、補強板３自体を折り曲げたり、削り出したりして前記開孔板３ａに相当する部分を形成した構造であっても良い。 As the fastening member, a rivet can be used in addition to the high strength bolt 4 and the nut 5. 10 and 11 show an example in which the aperture plate 3a is formed by welding an angle-shaped short plate to the reinforcing plate 3 by welding, but the present invention is not limited to this, and the reinforcing plate 3 itself is used. A structure in which a portion corresponding to the aperture plate 3a is formed by bending or cutting may be used.
以上の様に、本発明に係る脆性亀裂伝播停止に優れた補強構造によれば、前記脆性亀裂、更には溶接線を跨ぐ補強板とこの補強板を母材に結合する結合手段とによって、前記脆性亀裂によって離反された母材同士が結合されると共に、前記補強板に予め引張予ひずみが付与されてなるものであるから、簡単な構造によって溶脆性亀裂の伝播を確実に停止する優れた補強構造を提供し得る。 As described above, according to the reinforcing structure excellent in stopping brittle crack propagation according to the present invention, the brittle crack, and further, the reinforcing plate straddling the weld line and the coupling means for coupling the reinforcing plate to the base material, Since the base materials separated by the brittle cracks are bonded to each other and a tensile pre-strain is applied to the reinforcing plate in advance, excellent reinforcement that reliably stops the propagation of the brittle cracks with a simple structure A structure can be provided.
また、本発明に係る脆性亀裂伝播停止に優れた補強構造によれば、前記結合手段が、脆性亀裂によって離反された母材に対向する様に接合された一対の取付金具と、前記補強板の両端に前記取付金具との間に隙間を有して設けられた開孔板と、前記取付金具と開孔板に貫通された締結部材とからなり、この締結部材の締結により前記補強板に引張予ひずみを付与して母材同士が結合されてなるので、引張ひずみの付与が施工現場においても更に簡単に実施可能である。 Further, according to the reinforcing structure excellent in stopping brittle crack propagation according to the present invention, the coupling means is a pair of mounting brackets joined so as to face the base material separated by the brittle crack, and the reinforcing plate It consists of an aperture plate provided with a gap between the mounting bracket at both ends and a fastening member that penetrates the mounting bracket and the aperture plate. Since the pre-strain is applied and the base materials are bonded to each other, the tensile strain can be easily applied even at the construction site.
Ｓ：溶接継手部に平行して高力ボルトを通り鋼板に垂直な断面，
Ｗ：母材の幅，
ａ：母材の上端と補強板中心との距離，
１：母材（鋼板）， ２：溶接継手部，
３：補強板， ３ａ：開孔板，
４：高力ボルト， ５：ナット， ６：引張予ひずみ， ７：引張外力，
８：脆性亀裂， ９：リベット， １０：溶接， １１：取付金具，
１２：隙間， １３：溶接接合
S: A cross section perpendicular to the steel sheet passing through the high-strength bolt parallel to the weld joint,
W : width of base material,
a : Distance between the upper end of the base material and the center of the reinforcing plate,
1: Base material (steel plate), 2: Welded joint,
3: Reinforcing plate, 3a: Opening plate,
4: High-strength bolt, 5: Nut, 6: Tensile pre-strain, 7: External tensile force,
8: Brittle crack, 9: Rivet, 10: Welding, 11: Mounting bracket,
12: gap, 13: welded joint
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007285295A JP4909237B2 (en) | 2007-11-01 | 2007-11-01 | Reinforced structure excellent in stopping brittle crack propagation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007285295A JP4909237B2 (en) | 2007-11-01 | 2007-11-01 | Reinforced structure excellent in stopping brittle crack propagation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2009113046A JP2009113046A (en) | 2009-05-28 |
| JP4909237B2 true JP4909237B2 (en) | 2012-04-04 |
Family
ID=40780772
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007285295A Expired - Fee Related JP4909237B2 (en) | 2007-11-01 | 2007-11-01 | Reinforced structure excellent in stopping brittle crack propagation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4909237B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101187972B1 (en) * | 2010-07-22 | 2012-10-04 | 주식회사 포스코 | Weld Structure and Method for Manufacturing The Same |
| KR101284868B1 (en) | 2011-12-22 | 2013-07-09 | 삼성중공업 주식회사 | Welding joint of steel structure and fablcating method thereof |
| JP5939542B2 (en) * | 2012-11-02 | 2016-06-22 | トヨタ車体株式会社 | Crack growth prevention structure |
| JP6459030B2 (en) * | 2014-09-18 | 2019-01-30 | 株式会社Ihi | Crack growth prevention apparatus and method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6049890A (en) * | 1983-08-30 | 1985-03-19 | Mitsubishi Heavy Ind Ltd | Welded structure |
| JPS61144293A (en) * | 1984-12-17 | 1986-07-01 | Kobe Steel Ltd | Mending method of crack caused on pressure container shell |
| JP3381595B2 (en) * | 1997-12-25 | 2003-03-04 | 京橋工業株式会社 | Bridge reinforcement method |
| JP3476129B2 (en) * | 1999-03-19 | 2003-12-10 | 京橋工業株式会社 | Bridge reinforcement method |
| JP2003080392A (en) * | 2001-09-07 | 2003-03-18 | Mitsubishi Heavy Ind Ltd | Welding repair structure and welding repair method of pipe |
| JP4505368B2 (en) * | 2004-04-21 | 2010-07-21 | 新日本製鐵株式会社 | Welded steel structure excellent in brittle crack propagation stopping characteristics and method for producing the same |
-
2007
- 2007-11-01 JP JP2007285295A patent/JP4909237B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2009113046A (en) | 2009-05-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2018929B1 (en) | Welded structure excellent in brittle-cracking propagation stopping characteristics | |
| JP4505368B2 (en) | Welded steel structure excellent in brittle crack propagation stopping characteristics and method for producing the same | |
| KR102001923B1 (en) | Welded structure | |
| JP5629895B2 (en) | Welded structure | |
| JP5441114B2 (en) | Fatigue crack repair structure and repair method for steel structures | |
| JP4909237B2 (en) | Reinforced structure excellent in stopping brittle crack propagation | |
| JP6304074B2 (en) | Method and structure for welding and joining steel members | |
| BR112014025358B1 (en) | welded structure | |
| JP4733955B2 (en) | Welding method of welded structure with excellent brittle crack propagation resistance | |
| KR102258423B1 (en) | Welded structure having excellent brittle crack arrestability | |
| EP1731824A2 (en) | Method of Impeding Crack Propagation | |
| JP5052918B2 (en) | Welded joint, welded structure excellent in crack initiation propagation characteristics, and method for improving crack initiation propagation characteristics | |
| JP5657873B2 (en) | Welded structure with excellent fracture prevention characteristics after brittle crack arrest | |
| JP6693205B2 (en) | Welding method and ship manufacturing method | |
| JP6562189B1 (en) | Welded structure | |
| JPWO2012008056A1 (en) | Welded structure with brittle crack propagation resistance | |
| JP5935395B2 (en) | Welding assembly groove part for square welding of four-sided box section | |
| JP3811479B2 (en) | Weld metal for welded structure having excellent brittle fracture propagation resistance, its construction method, and welded structure | |
| JP5953744B2 (en) | Groove for corner welding of welded four-sided box-shaped cross-section members | |
| KR20120111436A (en) | Weld structure and method for manufacturing the same | |
| JP6562190B1 (en) | Welded structure | |
| Oh et al. | Cyclic performance of existing moment connections in steel retrofitted with a reduced beam section and bottom flange reinforcements | |
| WO2019220681A1 (en) | Welded structure | |
| JP3854415B2 (en) | Building structure using steel with excellent arrestability | |
| KR20190014068A (en) | Welded structure excellent in brittle crack propagation stopping property |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20100125 |
|
| RD02 | Notification of acceptance of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7422 Effective date: 20110408 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20110411 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110706 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110816 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20111011 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20120110 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120113 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150120 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |