JP2002340741A - System for predicting damage to storage tank using optical fiber - Google Patents
System for predicting damage to storage tank using optical fiberInfo
- Publication number
- JP2002340741A JP2002340741A JP2001144144A JP2001144144A JP2002340741A JP 2002340741 A JP2002340741 A JP 2002340741A JP 2001144144 A JP2001144144 A JP 2001144144A JP 2001144144 A JP2001144144 A JP 2001144144A JP 2002340741 A JP2002340741 A JP 2002340741A
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- Japan
- Prior art keywords
- side plate
- bottom end
- strain
- end plate
- optical fiber
- 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.)
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- Optical Transform (AREA)
- Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、例えば地震等によ
り石油タンク等の貯蔵タンクが損傷を受けた場合、損傷
の程度及びその発生位置を検知し、重大損傷を予知でき
る光ファイバを用いた貯蔵タンクの損傷予知システムに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage system using an optical fiber capable of detecting the degree of damage and its location when a storage tank such as an oil tank is damaged due to, for example, an earthquake, and foreseeing serious damage. The present invention relates to a tank damage prediction system.
【０００２】[0002]
【従来の技術】従来、石油タンク等貯蔵タンクの保守点
検や地震その他による損傷の有無は外観検査により行わ
れている。また、本出願人による特願平１１−２３５３
３２には石油タンク側板の下部近傍全周に光ファイバを
軸方向に折り返しつつ連続して布設する方法が開示され
ている。2. Description of the Related Art Conventionally, maintenance inspections of storage tanks such as oil tanks and the presence or absence of damage due to earthquakes or the like have been carried out by visual inspection. Also, Japanese Patent Application No. 11-2353 filed by the present applicant.
No. 32 discloses a method of continuously laying the optical fiber around the entire periphery of the lower portion of the oil tank side plate while folding the optical fiber in the axial direction.
【０００３】[0003]
【発明が解決しようとする課題】石油タンク等貯蔵タン
クの外観検査では、目にみえるほどの異常がないと検知
できず、貯蔵タンクがどのように傾き、どのような歪が
発生しているかは検知できないのが実情であった。つま
り、貯蔵タンクが目に見える程の損傷を受けてはいなく
ても、構造物としてなんらかの変化を受けているかも知
れず、その内容、程度を検知することは不可能であっ
た。損傷が予想される箇所に歪ゲージを貼付して歪を計
測することは可能ではあるが、測定箇所は膨大とならざ
るを得ず、多大な労力と費用を要し、貯蔵タンク毎にそ
のような測定装置を配設することは現実的には不可能で
あった。In the appearance inspection of a storage tank such as an oil tank, it cannot be detected that there is no noticeable abnormality, and how the storage tank is tilted and what kind of distortion is generated. The fact was that it could not be detected. In other words, even though the storage tank was not visibly damaged, it may have undergone some change as a structure, and it was impossible to detect the contents and extent of the change. It is possible to measure strain by attaching a strain gauge to the location where damage is expected, but the measurement location must be enormous, requiring a lot of labor and cost, and such a storage tank It was not practically possible to provide a suitable measuring device.
【０００４】また、上記開示の光ファイバ布設方法は光
ファイバを側板の軸方向に折り返しつつ布設して側板の
軸方向の歪を測定するものであり、光ファイバを側板外
周に沿って波状に布設する作業はやや複雑である。本発
明は、上記問題点に鑑み、最近の光ファイバセンシング
技術の著しい進歩によって可能となった長距離に亘る歪
分布の測定方法を用い、石油タンク等貯蔵タンクの周囲
に沿って光ファイバをリング状に布設して周方向歪を測
定し、測定した歪によって貯蔵タンクの状態を監視し、
重大損傷に至る前に予知できるシステムを提供すること
を目的とする。Further, the optical fiber laying method disclosed above is to lay the optical fiber while folding it in the axial direction of the side plate and measure the axial strain of the side plate, and lay the optical fiber in a wavy shape along the outer periphery of the side plate. The task is somewhat complicated. In view of the above problems, the present invention uses a method of measuring strain distribution over a long distance made possible by a remarkable advance in recent optical fiber sensing technology, and rings an optical fiber around a storage tank such as an oil tank. Laid in the shape of a circle, measure the circumferential strain, monitor the state of the storage tank by the measured strain,
It is an object of the present invention to provide a system capable of predicting before serious damage occurs.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、貯蔵タンクの底端板に接合された側板の該接合部近
傍の全周囲および前記底端板から適宜高さ位置の全周に
亘って光ファイバをリング状に布設し、該光ファイバを
介して前記側板の周方向歪を全周に亘って測定する歪計
測装置と該歪計測装置により測定されたデータを処理す
る歪データ処理装置を具備し、前記接合部近傍の側板の
周方向歪測定値から前記接合部における側板の前記底端
板に対する傾斜角を推定し、前記底端板から適宜高さ位
置に置ける側板の周方向歪測定値、座屈により発生する
塑性歪値と併せて、前記接合部に発生する局部的塑性歪
値、亀裂の発生、前記底端板下基礎の陥没等を推定し監
視することを特徴とする光ファイバを用いた貯蔵タンク
の損傷予知システムを提案する。In order to achieve the above object, the side plate joined to the bottom end plate of the storage tank is provided at the entire periphery near the joint and at the appropriate height from the bottom end plate. A strain measuring device for laying an optical fiber in a ring shape over the entire circumference and measuring the circumferential strain of the side plate over the entire circumference via the optical fiber, and a strain data processing for processing data measured by the strain measuring device Equipped with a device, the inclination angle of the side plate at the joint portion with respect to the bottom end plate is estimated from the measured circumferential strain of the side plate near the joint portion, and the circumferential direction of the side plate can be appropriately positioned at a height from the bottom end plate. The strain measurement value, together with the plastic strain value generated by buckling, the local plastic strain value generated in the joint, the occurrence of cracks, the estimation and monitoring of the collapse of the foundation under the bottom end plate and the like, characterized in that Prediction system for storage tanks using rotating optical fiber Suggest.
【０００６】外部条件の変化、例えば石油の液面高さ、
底端板基礎の陥没や沈下によって貯蔵タンクの側板に発
生する周方向歪は、底端板と側板の接合部極近傍よりも
底端板からある程度離れた高さ位置におけるほうが外部
条件の変化に対する歪の変化が大きいことが、後述する
ように有限要素法による解析の結果明らかになった。し
たがって、外部条件の変化による歪変化が大きい高さ位
置の歪変化を測定、監視することによって、外部条件の
変化をより容易、正確に検知することができる。底端板
から適宜高さ位置とはこの外部条件の変化による歪変化
が大きい高さ位置のことをいう。Changes in external conditions, such as the level of oil
Circumferential strain generated on the side plate of the storage tank due to the sinking or subsidence of the bottom end plate foundation is more sensitive to changes in external conditions at a height position somewhat away from the bottom end plate than near the junction of the bottom end plate and the side plate As will be described later, the result of analysis by the finite element method revealed that the change in strain was large. Therefore, by measuring and monitoring the strain change at the height position where the strain change due to the change of the external condition is large, the change of the external condition can be more easily and accurately detected. An appropriate height position from the bottom end plate means a height position where a change in distortion due to a change in the external condition is large.
【０００７】貯蔵タンクの底端板と側板の接合部の亀裂
は、該亀裂がタンク内部に発生する場合、外側からの目
視観察では発見できない。貯蔵タンク側板の底端板に対
する傾き角と隅肉溶接接合部の側板周方向歪の関係を有
限要素方法によって解析した結果では、側板の傾き角変
化に対する側板周方向の歪の変化は前記接合部において
大きいので、該接合部近傍の側板周方向歪の測定値によ
り底端板に対する側板の傾き角を推定するのがよい。該
傾き角の初期状態からの変化量と亀裂発生の関係を実験
により求めておき、前記推定傾き角より局部的塑性歪
値、亀裂発生及びその発生位置と範囲を推定することが
できる。[0007] A crack at the joint between the bottom end plate and the side plate of the storage tank cannot be found by visual observation from the outside when the crack occurs inside the tank. The analysis of the relationship between the inclination angle of the storage tank side plate with respect to the bottom end plate and the side plate circumferential direction distortion of the fillet welded joint by the finite element method shows that the change in the side plate circumferential direction change with respect to the change in the side plate tilt angle is the same as that of the joint. Therefore, it is preferable to estimate the inclination angle of the side plate with respect to the bottom end plate from the measured value of the side plate circumferential strain near the joint. The relationship between the amount of change in the tilt angle from the initial state and the occurrence of cracks is obtained by an experiment, and the local plastic strain value, the occurrence of cracks, and the position and range of occurrence of cracks can be estimated from the estimated tilt angle.
【０００８】したがって、外部条件の変化による側板周
方向の歪変化が大きい底端板から或る高さ位置の側板の
全周に亘って光ファイバをリング状に布設するととも
に、前記接合部近傍の側板の全周に亘って光ファイバを
リング状に布設することによって、タンク内の液面高
さ、底端板下基礎の陥没位置と陥没幅、側板の座屈を検
知してその変化を監視し、また、底端板に対する側板の
傾き角を推定して、前記接合部に発生する局部的塑性歪
値、亀裂の発生を推定することができる。なお、光ファ
イバは側板の全周にわたってリング状に布設されている
ので、周上の周方向歪が測定され、その位置も同定され
る。Therefore, an optical fiber is laid in a ring shape from the bottom end plate where the change in distortion in the circumferential direction of the side plate due to a change in external conditions is large to the entire circumference of the side plate at a certain height. By laying the optical fiber in a ring shape over the entire circumference of the side plate, the height of the liquid level in the tank, the depression position and the depression width of the foundation under the bottom end plate, the buckling of the side plate are detected, and changes are monitored. In addition, by estimating the inclination angle of the side plate with respect to the bottom end plate, it is possible to estimate a local plastic strain value and a crack generated at the joint. Since the optical fiber is laid in a ring shape over the entire circumference of the side plate, circumferential strain on the circumference is measured, and its position is also identified.
【０００９】また、例えば「１０万ＫＬ貯油クラスの通
常の石油タンク」の場合、前記接合部近傍の位置は歪発
生レベルが大きい底端板から０．１ｍ未満、例えば底端
板から０．０５ｍに、するのが適当である。外部条件変
化に対する側板周方向の歪が大きい位置としては底端板
から５ｍ未満、例えば１．６ｍにするのが適当である。In the case of, for example, a "normal oil tank of the 100,000 KL oil storage class", the position near the joint is less than 0.1 m from the bottom end plate where the strain generation level is large, for example, 0.05 m from the bottom end plate. It is appropriate to do so. It is appropriate that the position where the distortion in the circumferential direction of the side plate with respect to the change in the external condition is large is less than 5 m from the bottom end plate, for example, 1.6 m.
【００１０】[0010]
【発明の実施の形態】以下、本発明を図に示した実施例
を用いて詳細に説明する。但し、この実施例に記載され
る寸法、材質、形状、その相対位置などは特に特定的な
記載がない限り、この発明の範囲をそれのみに限定する
趣旨ではなく単なる説明例に過ぎない。図１は本発明の
実施例に係わる光ファイバを用いた貯蔵タンクの損傷予
知システムの構成を示す。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. However, dimensions, materials, shapes, relative positions, and the like described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. FIG. 1 shows a configuration of a damage prediction system for a storage tank using an optical fiber according to an embodiment of the present invention.
【００１１】図１において、１は貯蔵タンクの底端板、
２は側板であり、側板２は円筒形である。該側板２は前
記底端板１に隅肉溶接接合３されいる。前記側板２の外
周には前記底端板１から高さＨの位置に光ファイバ４が
リング状に布設され、該光ファイバは延長されて前記底
端板と側板の接合部近傍の側板外周にリング状に布設さ
れた光ファイバ５となっている。光ファイバはタンク側
板の膨張・収縮を計測できるように若干の初期張力を与
えて側板外周に接着剤で固定される。接着剤はシリコン
系、エポキシ系等により、屋外の環境下において十分な
接着力を長期間に亘って保持できるようにすると共に太
陽光及び雨等から光ファイバを保護するため接着剤のシ
リコンシーラントで光ファイバのタンク布設部を均一に
覆う。６は側板２から歪計測装置７に接続される部分の
光ファイバである。なお、請求項２は側板周囲に光ファ
イバ５のみを布設する場合であり、請求項３は側板周囲
に光ファイバ４のみを布設する場合である。In FIG. 1, 1 is a bottom end plate of a storage tank,
2 is a side plate, and the side plate 2 is cylindrical. The side plate 2 is welded to the bottom end plate 1 by fillet welding. An optical fiber 4 is laid in a ring shape on the outer periphery of the side plate 2 at a height H from the bottom end plate 1, and the optical fiber is extended so as to extend around the outer periphery of the side plate near the joint between the bottom end plate and the side plate. The optical fiber 5 is laid in a ring shape. The optical fiber is fixed to the outer periphery of the side plate by applying an initial tension so that the expansion and contraction of the tank side plate can be measured. The adhesive is silicone-based or epoxy-based, and it is a silicone sealant that can maintain sufficient adhesive strength in outdoor environments for a long period of time and protects optical fibers from sunlight and rain. Cover the optical fiber tank installation part uniformly. Reference numeral 6 denotes an optical fiber connected from the side plate 2 to the strain measuring device 7. In addition, claim 2 is a case where only the optical fiber 5 is laid around the side plate, and claim 3 is a case where only the optical fiber 4 is laid around the side plate.
【００１２】前記歪計測装置７は歪分布測定機（ＢＯＴ
ＤＲ：Brillouin Optical Time Domain Reflectomete
r）で、光ファイバの一端からレーザー光パルスを入射
し、それによって光ファイバ内で発生した自然ブリルア
ン後方散乱光を同一端で観察して散乱した部位の歪を測
定するものである。光ファイバに光を入射すると入射光
は光ファイバを構成する例えば石英ガラス等の分子等に
衝突して散乱され、その一部が後方散乱光として入射端
にもどってくる。The strain measuring device 7 has a strain distribution measuring device (BOT).
DR: Brillouin Optical Time Domain Reflectomete
In r), a laser beam pulse is incident from one end of the optical fiber, and natural Brillouin backscattered light generated in the optical fiber is observed at the same end to measure the distortion of the scattered portion. When light is incident on the optical fiber, the incident light collides with molecules of the optical fiber, such as silica glass, and is scattered, and a part of the light returns to the incident end as backscattered light.
【００１３】その後方散乱光の一つであるブリルアン散
乱光のパワースペクトルの周波数が光ファイバに生じて
いる歪に依存して変化することを利用するもので、この
ブリルアン周波数シフトを測定して歪を測定する。ブリ
ルアン後方散乱光が入射端にもどってくるまでの時間に
よって散乱された位置が分り、次々ともどってくる散乱
光を分析することにより光ファイバの各位置における歪
を知ることができる。８は歪データ処理装置で、光ファ
イバの入射端からの距離に対応する歪を表示した状態表
示９をアウトプットする。前記入射端からの距離から前
記側板外周上の位置を同定することができる。This method utilizes the fact that the frequency of the power spectrum of the Brillouin scattered light, which is one of the backscattered lights, changes depending on the distortion occurring in the optical fiber. Is measured. The position at which the Brillouin backscattered light is scattered is determined by the time required to return to the incident end, and the distortion at each position of the optical fiber can be known by analyzing the scattered light that returns one after another. Reference numeral 8 denotes a distortion data processing device, which outputs a state display 9 displaying distortion corresponding to the distance from the incident end of the optical fiber. The position on the outer periphery of the side plate can be identified from the distance from the incident end.
【００１４】図２は側板外径８２ｍの貯蔵タンクについ
て、石油液面高さと側板外周の周方向歪の関係を有限要
素法によって計算した結果を示し、（Ａ）は液面高さ３
種類について底端板からの側板外周の高さ位置と該位置
における周方向歪を、（Ｂ）は底端板から０．０５ｍ及
び１．６ｍの高さ位置における側板外周の周方向歪と液
面高さとの関係を示したものである。なお、有限要素法
による解析結果は実測結果とよく一致することが確かめ
られている。FIG. 2 shows the result of calculating the relationship between the oil level and the circumferential strain of the outer periphery of the side plate by a finite element method for a storage tank having a side plate outer diameter of 82 m, and FIG.
For each type, the height of the outer periphery of the side plate from the bottom end plate and the circumferential strain at that position, and (B) shows the circumferential strain of the outer periphery of the side plate at the height of 0.05 m and 1.6 m from the bottom end plate and the liquid. It shows the relationship with the surface height. It has been confirmed that the analysis result by the finite element method agrees well with the actual measurement result.
【００１５】図２（Ａ）において、各液面高さについ
て、高さ位置の増大に伴って周方向歪は増大するが、あ
る高さで最大となり、それ以上の高さ位置では歪は減少
し、液面高さの高さ位置で歪は零となる。液面高さ２
０．５ｍの場合、高さ位置１３ｍを越えたところで歪が
急激に低下している箇所が見られるのは、補強リングの
位置と一致しており、補強リングによる拘束効果を示す
ものである。歪が最大となる高さ位置は液面高さによっ
て異なるが、高さ位置を１．６ｍに選ぶと各液面高さに
ついて比較的大きな歪が発生することが分る。In FIG. 2 (A), for each liquid level, the circumferential strain increases as the height position increases, but reaches a maximum at a certain height, and decreases at higher height positions. However, the strain becomes zero at the height position of the liquid level. Liquid level 2
In the case of 0.5 m, the point where the strain is sharply reduced beyond the height position of 13 m is coincident with the position of the reinforcing ring, indicating the restraining effect of the reinforcing ring. Although the height position where the distortion is maximum differs depending on the liquid level, it can be seen that when the height position is selected to be 1.6 m, a relatively large distortion is generated for each liquid level.
【００１６】図２（Ｂ）において、底端板からの高さ位
置が０．０５ｍと１．６ｍの両位置とも周方向歪は液面
高さに対して直線的に増大している。ただし、底端板か
ら０．０５ｍの高さ位置では液面高さが２０．５ｍの場
合で歪は０．００７％であり、歪の計測精度が０．０２
％歪であることから実際の計測は困難と考えられる。し
かし、底端板から１．６ｍの高さ位置での周方向歪は液
面高さ５ｍの場合で０．０１５％であり、以後１ｍ当り
０．００４２％の歪が変化しているので、１．６ｍの高
さ位置における側板の周方向歪を測定することにより、
液面高さ５ｍからの液面監視が可能である。In FIG. 2B, the circumferential strain increases linearly with respect to the liquid level at both the 0.05 m and 1.6 m height positions from the bottom end plate. However, at a height of 0.05 m from the bottom end plate, the strain was 0.007% when the liquid level was 20.5 m, and the strain measurement accuracy was 0.02%.
It is considered that the actual measurement is difficult because of the% distortion. However, the circumferential strain at a height of 1.6 m from the bottom end plate is 0.015% when the liquid level is 5 m, and the strain changes by 0.0042% per meter thereafter. By measuring the circumferential strain of the side plate at a height of 1.6 m,
Liquid level monitoring from a liquid level height of 5 m is possible.
【００１７】石油満載時である液面高さ２０．５ｍの場
合、側板の周方向歪は底端板から３．５ｍの高さ位置で
最大値０．１１３％であり、側板外径８２ｍであるか
ら、これは半径で４５ｍｍの変形に相当する。目視でこ
の程度の膨らみを確認することは可能であるが、それ以
下になってくると難しいと言われている。したがって、
本システムの本実施形態によって、目視では確認できな
い側板の膨らみを検出することができ、上記したよう
に、液面高さ５ｍからの液面監視が可能である。When the liquid level is 20.5 m when oil is fully loaded, the circumferential strain of the side plate has a maximum value of 0.113% at a height of 3.5 m from the bottom end plate. As such, this corresponds to a deformation of 45 mm in radius. It is possible to visually confirm such a degree of swelling, but it is said that it becomes difficult if the swelling becomes smaller. Therefore,
According to this embodiment of the present system, it is possible to detect the bulge of the side plate that cannot be visually confirmed, and as described above, it is possible to monitor the liquid level from the liquid level height of 5 m.
【００１８】図３は、側板外径８２ｍの石油満載の貯蔵
タンクについて、側板から内側に０．５ｍ、１．０ｍ、
１．７５ｍ、２．０ｍの幅で全周に亘って基礎が陥没
（基礎抜け）した場合及び基礎抜けがない正常時につい
て有限要素法により解析した結果を示すもので、（Ａ）
は各基礎抜け幅について底端板からの側板外周の高さ位
置と該位置における周方向歪を、（Ｂ）は底端板から
０．０５ｍ及び１．６ｍの側板外周高さ位置における周
方向歪と基礎抜け幅との関係を示したものである。FIG. 3 shows a storage tank filled with petroleum having an outer diameter of 82 m on the side plate, 0.5 m, 1.0 m,
(A) shows the results of analysis by the finite element method when the foundation collapses (foundation missing) over the entire circumference with a width of 1.75 m and 2.0 m and when there is no foundation missing in normal condition.
Indicates the height position of the outer periphery of the side plate from the bottom end plate and the circumferential strain at that position for each base removal width, and (B) indicates the circumferential direction at the outer periphery height position of 0.05 m and 1.6 m from the bottom end plate. It shows the relationship between the distortion and the basic missing width.
【００１９】図３（Ａ）から、基礎抜け幅により周方向
歪が異なるのは底端板から７ｍ程度の高さ位置までであ
り、それ以上の高さ位置では周方向歪は基礎抜け幅には
無関係であることが分る。そして基礎抜け幅によって周
方向歪が大きく変化するのは底端板からの高さ位置が１
〜２ｍ付近であることが分る。From FIG. 3 (A), the circumferential strain differs depending on the base missing width up to a height of about 7 m from the bottom end plate. At a height higher than that, the circumferential strain is reduced to the basic missing width. Is irrelevant. The large change in the circumferential strain due to the width of the base dropout occurs when the height from the bottom end plate is 1
It can be seen that the distance is about 2 m.
【００２０】図３（Ｂ）は、底端板からの高さ位置０．
０５ｍ及び１．６ｍについて基礎抜け幅と周方向歪の関
係を示すが、基礎陥没幅の広がり（基礎抜け幅の増大）
とともに周方向歪は増大している。ただし、底端板から
０．０５ｍの高さ位置では基礎抜け幅２ｍの時、歪は
０．０２２％であり、基礎抜けがない時の歪が０．００
７％であるから、基礎抜けがない時からの歪の変化量は
０．０１５％である。したがって、計測精度０．０２％
歪を考えると、０．０５ｍ高さ位置における歪測定で陥
没状況を予知するのは困難と考えられる。FIG. 3B shows a case where the height position from the bottom end plate is 0.
The relationship between the basic void width and the circumferential strain is shown for 05m and 1.6m.
Along with this, the circumferential strain increases. However, at a height position of 0.05 m from the bottom end plate, the strain is 0.022% when the base removal width is 2 m, and the distortion is 0.00 when there is no foundation removal.
Since it is 7%, the amount of change in strain from when there is no missing base is 0.015%. Therefore, the measurement accuracy is 0.02%
Considering distortion, it is considered difficult to predict the state of depression by measuring distortion at a height of 0.05 m.
【００２１】一方、底端板から１．６ｍの高さ位置での
歪は、基礎抜け幅２ｍ時で０．１３５％であり、基礎抜
けがない時の歪が０．０８８％であるから、基礎抜けが
ない時からの歪の変化量は０．０４７％歪である。した
がって、１ｍ以上の基礎抜け幅であれば、底端板から
１．６ｍ高さ位置における周方向歪を測定することによ
って基礎陥没の監視が可能である。なお、上記の有限要
素法による解析は、基礎抜けは全周に亘るとした場合の
解析結果であるが、陥没の長さが陥没幅（基礎抜け幅）
の４倍以上では陥没長さの中央での歪は全周陥没とした
上記解析結果に一致するので、光ファイバで全周に亘っ
ての歪変化を検出することにより陥没位置の同定も可能
である。On the other hand, the strain at a height of 1.6 m from the bottom end plate is 0.135% when the base slip width is 2 m, and the strain when no base slip is 0.088%. The amount of change in strain from the time when there is no missing base is 0.047% strain. Therefore, if the foundation slippage width is 1 m or more, it is possible to monitor the depression of the foundation by measuring the circumferential strain at a height of 1.6 m from the bottom end plate. Note that the analysis by the finite element method described above is an analysis result in the case where the foundation removal is performed over the entire circumference, and the length of the depression is the depression width (the foundation removal width).
In the case of four times or more, the strain at the center of the depressed length matches the above-described analysis result that the depressed portion is all around. Therefore, it is possible to identify the depressed position by detecting the change in the distortion over the entire circumference with an optical fiber. is there.
【００２２】貯蔵タンクの損傷として、底端板と側板の
隅肉溶接接合部の亀裂が懸念されるが、タンク内部の亀
裂は外観の目視観察では発見不可能である。底端板に対
する側板の傾き角を変えて側板上の高さ位置と該位置に
おける周方向歪との関係を、側板外径８２ｍの石油満載
の貯蔵タンクについて有限要素方法により解析した結
果、図示しないが、側板の傾き角によって周方向歪が異
なるのは側板上の高さ位置７ｍまでであり、それ以上の
高さ位置では周方向歪は側板上の高さ位置には無関係で
あった。そして側板の傾き角によって周方向歪が大きく
変化するのは底端板からの高さ位置が１〜２ｍ付近であ
った。As a damage to the storage tank, a crack in the fillet weld joint between the bottom end plate and the side plate is concerned, but a crack inside the tank cannot be found by visual observation of the appearance. The relationship between the height position on the side plate and the circumferential strain at that position by changing the inclination angle of the side plate with respect to the bottom end plate was analyzed by a finite element method on a petroleum-loaded storage tank with a side plate outer diameter of 82 m, which is not shown. However, the circumferential distortion differs depending on the inclination angle of the side plate up to a height position of 7 m on the side plate, and at a height higher than that, the circumferential distortion was irrelevant to the height position on the side plate. The circumferential strain greatly changed depending on the inclination angle of the side plate when the height position from the bottom end plate was around 1 to 2 m.
【００２３】図４は、側板外径８２ｍの石油満載の貯蔵
タンクについて、有限要素法で解析した、底端板に対す
る側板の傾き角と周方向歪との関係を、側板上の高さ位
置０．０５ｍ及び１．６ｍについて示す。図で側板の傾
きθは、底端板と側板が直角の時が零で、＋が外側への
傾きを示し、−は内側への傾きを示す。底端板から１．
６ｍの高さ位置における周方向歪の側板傾きに対する変
化は０．０５ｍの位置におけるそれよりも緩やかであ
る。なお、石油満載によって側板は外側に約１゜傾いて
いる。FIG. 4 shows the relationship between the inclination angle of the side plate with respect to the bottom end plate and the circumferential strain, which was analyzed by the finite element method, for a storage tank filled with oil having a side plate outer diameter of 82 m. It shows about 0.05m and 1.6m. In the drawing, the inclination θ of the side plate is zero when the bottom end plate and the side plate are at a right angle, + indicates an outward inclination, and-indicates an inward inclination. From the bottom end plate 1.
The change in the circumferential strain at the height position of 6 m with respect to the inclination of the side plate is gentler than that at the position of 0.05 m. The side plate is inclined about 1 ° outward due to the full loading of oil.
【００２４】側板の傾き角に対する歪の変化が急である
０．０５ｍ位置について見ると、傾き角２２゜の時に歪
は０．２１％であり、また、側板の内面側傾き角度では
傾き角度−１９°で歪は−０．０９％である。傾き角度
２２°から傾き角度−１９°までの歪の変化量は０．３
％であるため、３°当り歪変化量は０．０２２％歪変化
である。したがって、本システムの計測精度が０．０２
％歪であることを考慮すると、底端板より０．０５ｍ位
置での周方向歪を測定することにより隅肉溶接部の局部
的塑性歪値を２°以上で監視が可能である。実験結果に
よれば、側板が無負荷状態から約１３゜傾くと溶接部に
ミクロ亀裂が発生し、約２３゜傾くとマクロ亀裂が発生
することが確認されているので、地震等により傾き角が
大きく変化した場合、傾き角によって局部的塑性歪値、
亀裂の発生やその発生位置と範囲を推定することができ
る。Looking at the 0.05 m position where the change of the strain with respect to the inclination angle of the side plate is sharp, the distortion is 0.21% at the inclination angle of 22 °, and the inclination angle− At 19 ° the strain is -0.09%. The change amount of the distortion from the inclination angle of 22 ° to the inclination angle of −19 ° is 0.3.
%, The amount of strain change per 3 ° is 0.022% strain change. Therefore, the measurement accuracy of this system is 0.02
Considering the% strain, it is possible to monitor the local plastic strain value of the fillet weld at 2 ° or more by measuring the circumferential strain at a position 0.05 m from the bottom end plate. According to the experimental results, it has been confirmed that when the side plate is tilted by about 13 ° from the no-load state, a micro crack is generated in the welded portion, and when the side plate is tilted by about 23 °, a macro crack is generated. If it changes greatly, the local plastic strain value depends on the tilt angle,
It is possible to estimate the occurrence of cracks and their locations and ranges.
【００２５】以上詳述したように、貯蔵タンクの内の液
面高さ及び基礎陥没に対して側板の周方向歪の変化が大
きい位置（側板外径８２ｍの場合１．６ｍ前後）の側板
周囲に光ファイバをリング状に布設して周方向歪を全周
に亘って測定すれば、半径方向変形が８．２ｍｍ（半径
４１ｍ×計測精度０．０２%）以上の監視が可能であ
り、また、タンク底端板下基礎の陥没については、陥没
幅１ｍ以上で陥没をその位置とともに検知できる。As described in detail above, the periphery of the side plate at a position where the change in the circumferential strain of the side plate is large with respect to the liquid level in the storage tank and the collapse of the foundation (approximately 1.6 m when the outer diameter of the side plate is 82 m). If an optical fiber is laid in a ring shape and the circumferential strain is measured over the entire circumference, the radial deformation can be monitored at 8.2 mm (radius 41 m × measurement accuracy 0.02%) or more, and As for the depression of the foundation under the tank bottom end plate, the depression can be detected together with its position at a depression width of 1 m or more.
【００２６】さらに、底端板と側板の接合部近傍の側板
周囲に光ファイバをリング状に布設して周方向歪を全周
に亘って測定すれば、底端板に対する側板の傾きについ
て、傾き角度変化２゜以上で検知することができ、前記
接合部に発生する局部的塑性歪値、亀裂の発生及びその
発生位置と範囲の監視が可能である。Further, when an optical fiber is laid in a ring shape around the side plate near the joint between the bottom end plate and the side plate, and the circumferential strain is measured over the entire circumference, the inclination of the side plate with respect to the bottom end plate is determined. An angle change of 2 ° or more can be detected, and the local plastic strain value, crack generation, and the position and range of generation of the crack at the joint can be monitored.
【００２７】[0027]
【発明の効果】以上説明したように、本発明によれば、
石油備蓄タンク等貯蔵タンクの底端板と側板の接合部近
傍及び底端板から適宜高さ位置の側板外周に光ファイバ
をリング状に布設して側板に発生する周方向歪を全周に
亘って測定することによって、つぎのような効果が得ら
れ、As described above, according to the present invention,
An optical fiber is laid in a ring shape around the joint between the bottom end plate and the side plate of the storage tank such as an oil storage tank and at the height of the side plate at an appropriate height from the bottom end plate. The following effects can be obtained by measuring
【００２８】（１）貯蔵タンクの内の液面高さ及び基礎
陥没に対して側板の周方向歪の変化が大きい位置の側板
全周に光ファイバをリング状に布設して周方向歪を全周
に亘って測定することにより、タンク底端板下基礎の陥
没を陥没幅１ｍ以上で陥没位置とともに検知でき、ま
た、タンクの座屈等による側板の膨張、収縮について半
径方向変形が８．２ｍｍ以上の監視が可能である。 （２）底端板と側板の接合部近傍の側板全周に光ファイ
バをリング状に布設して周方向歪を測定することによ
り、底端板に対する側板の傾きについて、傾き角度変化
２゜以上で検知することができ、前記接合部に発生する
局部的塑性歪値、亀裂の発生及びその発生位置と範囲の
監視が可能である。 （３）したがって、常時監視により貯蔵タンクの損傷の
程度とその位置を把握することができるので、重大損傷
に至る前に損傷を予知することができ、的確な対応処置
をとることが可能となる。(1) An optical fiber is laid in a ring shape around the side plate at a position where the change in the circumferential strain of the side plate is large with respect to the liquid level in the storage tank and the collapse of the foundation, and the entire circumferential strain is reduced. By measuring over the circumference, the depression of the foundation under the bottom plate of the tank bottom can be detected together with the depression position with a depression width of 1 m or more, and the expansion and contraction of the side plate due to buckling of the tank and the like can be reduced by 8.2 mm in the radial direction. The above monitoring is possible. (2) By laying an optical fiber in a ring shape around the entire side plate near the joint between the bottom end plate and the side plate and measuring the circumferential strain, the inclination angle change of the side plate with respect to the bottom end plate by 2 ° or more And the local plastic strain value, crack generation, and the generation position and range of the crack at the joint can be monitored. (3) Therefore, the degree of damage and the position of the storage tank can be ascertained by constant monitoring, so that damage can be predicted before serious damage occurs, and appropriate countermeasures can be taken. .
【図１】 本発明の実施例に係わる光ファイバを用いた
貯蔵タンクの損傷予知システムの構成図である。FIG. 1 is a configuration diagram of a damage prediction system for a storage tank using an optical fiber according to an embodiment of the present invention.
【図２】 貯蔵タンク内の石油液面高さ、側板外周の高
さ位置及び周方向歪の関係を有限要素法によって計算し
た結果を示すグラフである。FIG. 2 is a graph showing a result of calculating a relationship between a petroleum liquid level in a storage tank, a height position of a side plate outer periphery, and a circumferential strain by a finite element method.
【図３】 貯蔵タンクの底端板下基礎陥没幅、側板外周
の高さ位置及び周方向歪の関係を有限要素法によって計
算した結果を示すグラフである。FIG. 3 is a graph showing a result of calculating a relationship between a base depression width below a bottom end plate of a storage tank, a height position of an outer periphery of a side plate, and a circumferential strain by a finite element method.
【図４】貯蔵タンクの底端板に対する側板の傾き角と側
板外周の周方向歪との関係を有限要素法によって計算し
た結果を示すグラフである。FIG. 4 is a graph showing the result of calculating the relationship between the inclination angle of the side plate with respect to the bottom end plate of the storage tank and the circumferential strain of the outer periphery of the side plate by the finite element method.
１ 底端板 ２ 側板 ３ 底端板と側板の接合部 ４ 光ファイバ ５ 光ファイバ ６ 光ファイバ ７ 歪計測装置 ８ 歪データ処理装置 ９ 状態表示 REFERENCE SIGNS LIST 1 bottom end plate 2 side plate 3 joint between bottom end plate and side plate 4 optical fiber 5 optical fiber 6 optical fiber 7 strain measuring device 8 strain data processing device 9 status display
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｇ０８Ｃ 15/06 Ｇ０８Ｃ 15/06 Ｋ (72)発明者 井上 好章 長崎市深堀町五丁目717番１号 三菱重工 業株式会社長崎研究所内 (72)発明者 井上 克明 長崎市深堀町五丁目717番１号 三菱重工 業株式会社長崎研究所内 (72)発明者 越後 武彦 東京都新宿区西新宿五丁目１番14号 北海 道石油共同備蓄株式会社内 (72)発明者 南 義彦 東京都新宿区西新宿五丁目１番14号 北海 道石油共同備蓄株式会社内 Ｆターム(参考） 2F065 AA01 AA49 AA65 BB08 CC06 CC14 FF41 GG04 GG08 LL67 PP01 2F073 AA22 AB07 BB06 BC04 CC02 CD24 DD04 GG01 GG09 2F103 BA19 CA06 CA07 EB02 EC09 GA15 2G024 AD38 BA21 CA30 FA06 2G086 DD05 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) G08C 15/06 G08C 15/06 K (72) Inventor Yoshiaki Inoue 5-7-17-1 Fukahoricho, Nagasaki-shi Inside the Nagasaki Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Katsuaki Inoue 5-717-1, Fukaboricho, Nagasaki City Inside the Nagasaki Research Laboratory, Mitsubishi Heavy Industries, Ltd. No. 14 Inside the Hokkaido Petroleum Joint Stockpiling Co., Ltd. (72) Yoshihiko Minami 5-1-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo GG04 GG08 LL67 PP01 2F073 AA22 AB07 BB06 BC04 CC02 CD24 DD04 GG01 GG09 2F103 BA19 CA06 CA07 EB02 EC09 GA15 2G024 AD38 BA21 CA30 FA06 2G086 DD05
Claims (4)
該接合部近傍及び前記底端板から適宜高さ位置の全周に
亘って光ファイバをリング状に布設し、該光ファイバを
介して前記側板の周方向歪を全周に亘って測定する歪計
測装置と該歪計測装置により測定されたデータを処理す
る歪データ処理装置を具備し、前記接合部近傍の側板の
周方向歪測定値から前記接合部における側板の前記底端
板に対する傾斜角を推定し、前記底端板から適宜高さ位
置における側板の周方向歪測定値、座屈により発生する
塑性歪値と併せて、前記接合部に発生する局部的塑性歪
値、亀裂の発生、前記底端板下基礎の陥没等を監視する
ことを特徴とする光ファイバを用いた貯蔵タンクの損傷
予知システム。1. An optical fiber is laid in a ring shape around the joint of a side plate joined to a bottom end plate of a storage tank and the entire circumference at an appropriate height from the bottom end plate. A strain measuring device for measuring the circumferential strain of the side plate over the entire circumference thereof and a strain data processing device for processing data measured by the strain measuring device, wherein a circumferential strain of the side plate near the joint is provided. Estimate the inclination angle of the side plate at the joint with respect to the bottom end plate from the measured values, along with the circumferential strain measurement value of the side plate at an appropriate height from the bottom end plate, together with the plastic strain value generated by buckling, A damage prediction system for a storage tank using an optical fiber, wherein a local plastic strain value, a crack, and a collapse of the foundation under the bottom end plate are monitored at the joint.
該接合部近傍の全周に亘って光ファイバをリング状に布
設し、該光ファイバを介して前記側板の周方向歪を全周
に亘って測定する歪計測装置と該歪計測装置により測定
されたデータを処理する歪データ処理装置を具備し、前
記接合部近傍の側板の周方向歪測定値から前記接合部に
おける側板の前記底端板に対する傾斜角を推定して前記
接合部に発生する局部的塑性歪値、亀裂の発生等を監視
することを特徴とする光ファイバを用いた貯蔵タンクの
損傷予知システム。2. An optical fiber is laid in a ring shape around the entire periphery of the side plate joined to the bottom end plate of the storage tank in the vicinity of the joint, and the circumferential distortion of the side plate is completely reduced via the optical fiber. It comprises a strain measurement device that measures over the circumference and a strain data processing device that processes data measured by the strain measurement device, and the side plate at the joint portion from the circumferential strain measurement value of the side plate near the joint portion. A damage prediction system for a storage tank using an optical fiber, wherein an inclination angle with respect to a bottom end plate is estimated to monitor a local plastic strain value, a crack, and the like generated at the joint.
前記底端板から適宜高さ位置の全周に亘って光ファイバ
をリング状に布設し、該光ファイバを介して前記側板の
周方向歪を全周に亘って測定する歪計測装置と該歪計測
装置により測定されたデータを処理する歪データ処理装
置を具備し、前記適宜高さ位置における側板の周方向歪
測定値を介して前記底端板下基礎の陥没位置及び陥没幅
を間接的に検知することを特徴とする光ファイバを用い
た貯蔵タンクの損傷予知システム。3. An optical fiber is laid in a ring shape over the entire circumference at an appropriate height from the bottom end plate of the side plate joined to the bottom end plate of the storage tank, and the side plate is connected via the optical fiber. A strain measurement device that measures circumferential strain over the entire circumference and a strain data processing device that processes data measured by the strain measurement device are provided, and through a circumferential strain measurement value of the side plate at the appropriate height position. A damage prediction system for a storage tank using an optical fiber, wherein the position and width of the depression of the foundation under the bottom end plate are indirectly detected.
板の前記底端板より適宜高さ位置を該底端板より５ｍ未
満の高さ位置とすることを特徴とする請求項１或は３に
記載の光ファイバを用いた貯蔵タンクの損傷予知システ
ム。4. The side plate joined to the bottom end plate of the storage tank, the height position of the side plate being appropriately lower than the bottom end plate is set to a height position less than 5 m from the bottom end plate. 4. A damage prediction system for a storage tank using the optical fiber described in 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001144144A JP2002340741A (en) | 2001-05-15 | 2001-05-15 | System for predicting damage to storage tank using optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001144144A JP2002340741A (en) | 2001-05-15 | 2001-05-15 | System for predicting damage to storage tank using optical fiber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002340741A true JP2002340741A (en) | 2002-11-27 |
Family
ID=18990139
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001144144A Withdrawn JP2002340741A (en) | 2001-05-15 | 2001-05-15 | System for predicting damage to storage tank using optical fiber |
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| Country | Link |
|---|---|
| JP (1) | JP2002340741A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005003689A1 (en) * | 2003-07-02 | 2005-01-13 | Neubrex Co., Ltd. | Structure monitor system |
| WO2009037914A1 (en) * | 2007-09-21 | 2009-03-26 | National Institute Of Advanced Industrial Science And Technology | Method and system for detecting defect of structure |
| JP2009092644A (en) * | 2007-09-21 | 2009-04-30 | National Institute Of Advanced Industrial & Technology | Method and system for detecting defect of structure |
| WO2009095655A1 (en) * | 2008-01-28 | 2009-08-06 | Schlumberger Holdings Limited | Fatigue and damage monitoring of pipes |
| CN104634268A (en) * | 2015-01-23 | 2015-05-20 | 苏州市职业大学 | High-precision measurement mechanism for small tangential strains of materials with different rigidities |
| CN105674947A (en) * | 2016-03-31 | 2016-06-15 | 西南石油大学 | Large-sized oil storage tank deformation monitoring and deviation correcting device and method |
| CN111504214A (en) * | 2020-03-27 | 2020-08-07 | 中国特种设备检测研究院 | Large crude oil storage tank body deformation optical fiber monitoring device, system and method |
-
2001
- 2001-05-15 JP JP2001144144A patent/JP2002340741A/en not_active Withdrawn
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005003689A1 (en) * | 2003-07-02 | 2005-01-13 | Neubrex Co., Ltd. | Structure monitor system |
| JPWO2005003689A1 (en) * | 2003-07-02 | 2006-08-17 | ニューブレクス株式会社 | Structure monitoring system |
| CN100458371C (en) * | 2003-07-02 | 2009-02-04 | 光纳株式会社 | Structure monitoring system |
| US7542856B2 (en) | 2003-07-02 | 2009-06-02 | Neubrex Co., Ltd. | Structure monitor system |
| JP4495672B2 (en) * | 2003-07-02 | 2010-07-07 | ニューブレクス株式会社 | Structure monitoring system |
| WO2009037914A1 (en) * | 2007-09-21 | 2009-03-26 | National Institute Of Advanced Industrial Science And Technology | Method and system for detecting defect of structure |
| JP2009092644A (en) * | 2007-09-21 | 2009-04-30 | National Institute Of Advanced Industrial & Technology | Method and system for detecting defect of structure |
| WO2009095655A1 (en) * | 2008-01-28 | 2009-08-06 | Schlumberger Holdings Limited | Fatigue and damage monitoring of pipes |
| CN104634268A (en) * | 2015-01-23 | 2015-05-20 | 苏州市职业大学 | High-precision measurement mechanism for small tangential strains of materials with different rigidities |
| CN105674947A (en) * | 2016-03-31 | 2016-06-15 | 西南石油大学 | Large-sized oil storage tank deformation monitoring and deviation correcting device and method |
| CN111504214A (en) * | 2020-03-27 | 2020-08-07 | 中国特种设备检测研究院 | Large crude oil storage tank body deformation optical fiber monitoring device, system and method |
| CN111504214B (en) * | 2020-03-27 | 2021-06-08 | 中国特种设备检测研究院 | Optical fiber monitoring method for deformation of large crude oil storage tank body |
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| Date | Code | Title | Description |
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| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20080805 |