JP4490123B2 - Floating structure - Google Patents

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JP4490123B2
JP4490123B2 JP2004014104A JP2004014104A JP4490123B2 JP 4490123 B2 JP4490123 B2 JP 4490123B2 JP 2004014104 A JP2004014104 A JP 2004014104A JP 2004014104 A JP2004014104 A JP 2004014104A JP 4490123 B2 JP4490123 B2 JP 4490123B2
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floating body
natural period
horizontal axis
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JP2005206010A (en
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聡 上田
憲一 井上
日出雄 小林
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株式会社アイ・エイチ・アイ マリンユナイテッド
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Description

本発明は、海洋観測ブイ，気象観測ブイ又は浮体式石油生産装置等の海洋観測や海洋開発に用いられる浮体構造物に関する。   The present invention relates to a floating structure used for ocean observation and ocean development, such as an ocean observation buoy, a weather observation buoy, or a floating oil production apparatus.

海洋観測ブイや気象観測ブイ又は浮体式石油生産装置等の水面に浮遊設置される浮体構造物において、波浪によって励起される動揺を抑制する構成が種々提案されている。（特許文献１参照）
浮体構造物の揺れは、船舶では並進運動（上下揺れ，左右揺れ，前後揺れ）と回転運動（縦揺れ，横揺れ，船首揺れ）に分類されるが、定まった海域に設置される海洋観測ブイ，気象観測ブイ又は浮体式石油生産装置等では前後左右を特段区別する必要がないため、以下、左右揺れと前後揺れを総称して水平並進揺れ、縦揺れと横揺れを総称して水平軸回り回転揺れとして説明する。また、鉛直軸回りの回転である船首揺れは重要な問題とはならない。 Various structures have been proposed to suppress the vibrations excited by waves in floating structures such as ocean observation buoys, meteorological observation buoys, or floating oil production equipment. (See Patent Document 1)
Fluctuations of floating structures are classified into translational movements (vertical shaking, horizontal shaking, forward / backward shaking) and rotational movements (longitudinal shaking, roll shaking, bow shaking) on ships, but ocean observation buoys installed in a fixed sea area. , Because weather observation buoys or floating oil production equipment, etc., do not need to distinguish between front and rear and left and right, the horizontal translation and forward and backward shaking are collectively referred to as horizontal translational shaking, and vertical and lateral shaking are collectively referred to as the horizontal axis. This will be described as rotational shaking. In addition, the bow swing which is the rotation around the vertical axis is not an important problem.

一般的な浮体形状と動揺の関係は、図５（Ａ）に示すように単純形状の浮体１では、波浪に追従して上下揺れ，水平並進揺れ及び水平軸回り回転揺れを生ずる。   As shown in FIG. 5 (A), a general floating body 1 has a relationship between the shape of the floating body and the shaking, and the simple floating body 1 follows up and down the waves, causing vertical shaking, horizontal translation shaking, and rotational shaking around the horizontal axis.

また、図５（Ｂ）に示すように浮体２を上下方向に細長い形状とすれば、上下方向の波力を低減でき、上下揺れは小さくなるが、水平軸回り回転揺れは低減できない。石油生産設備は、波に比べて浮体寸法を十分に大きくすることでこの水平軸回り回転揺れを低減させることができるが、多大な構造重量が必要となって効率的ではない。   5B, if the floating body 2 has an elongated shape in the vertical direction, the wave force in the vertical direction can be reduced and the vertical swing can be reduced, but the rotational swing around the horizontal axis cannot be reduced. Oil production equipment can reduce this rotational sway around the horizontal axis by making the floating body size sufficiently larger than the wave, but it is not efficient because it requires a large structural weight.

更に、図５（Ｃ）に示すように、没水浮体構造体３Ａの上に吃水線が中間高さとなるコラム３Ｂを介して甲板構造部３Ｃを連結して成る半潜水型の浮体３では、上下揺れ及び水平軸回り回転揺れを同時にある程度は低減できるが、複数の要素浮体を組み合わせる必要があり、構造が複雑になって建設費用が高い。
特開平８−１２７３８７号公報 Furthermore, as shown in FIG. 5 (C), in the semi-submersible type floating body 3 formed by connecting the deck structure portion 3C to the submerged floating body structure 3A via the column 3B where the inundation line has an intermediate height, Although the vertical swing and the rotational swing around the horizontal axis can be reduced to some extent at the same time, it is necessary to combine a plurality of element floating bodies, and the structure becomes complicated and the construction cost is high.
JP-A-8-127387

ところで、海洋観測ブイや気象観測ブイ等の比較的小型の浮体構造物では、その上下揺れと水平軸回り回転揺れの固有周期が設置海域における波浪の周期に近く成り易く、共振によって大きく動揺する虞がある。敏感な機器を搭載する観測ブイでは、特に、上下揺れと水平軸回り回転揺れによる傾斜が問題となるため、これらの動揺を極力抑制する必要がある。   By the way, in relatively small floating structures such as ocean observation buoys and meteorological observation buoys, the natural period of the vertical oscillation and the rotation around the horizontal axis tends to be close to the period of waves in the installation sea area, and may be greatly shaken by resonance. There is. In observation buoys equipped with sensitive equipment, in particular, vertical and horizontal tilts are a problem, so it is necessary to suppress these fluctuations as much as possible.

ここで、上下揺れと水平軸回り回転揺れの固有周期は、浮体の形状や寸法によって変化するが、相互に関連するために各々を独立して任意の固有周期に設定することは極めて困難であった。つまり、何れか一方の固有周期を変化させるために形状に手を加えると、変化させる必要のない他方の固有周期も同時に変化しまい、その結果、両者を所望の固有周期に設定することができないという問題を有するものである。   Here, the natural period of vertical swing and rotational swing around the horizontal axis varies depending on the shape and dimensions of the floating body, but it is extremely difficult to set each independently to an arbitrary natural period because they are related to each other. It was. In other words, if the shape is changed to change one of the natural periods, the other natural period that does not need to be changed also changes at the same time, and as a result, both cannot be set to a desired natural period. Have a problem.

本発明は、上記問題に鑑みてなされたものであって、上下揺れと水平軸回り回転揺れの固有周期をそれぞれ独立して設定することを可能とし、波浪によって励起される動揺を抑制することのできる浮体構造物を提供することを目的とする。   The present invention has been made in view of the above-described problems, and allows the natural periods of vertical and horizontal rotations to be set independently, and suppresses fluctuations excited by waves. An object of the present invention is to provide a floating structure.

上記目的を達成する請求項１に係る浮体構造物は、浮体本体の下側の水中に、前記浮体本体より大きな平面投影外形を有して水平軸回り回転揺れの固有周期を規定する円盤状でその最大径が上記浮体本体の二倍以上の動揺抑制部材が、連結部材を介して所定の間隔で相対移動不能に連結されると共に、前記動揺抑制部材の略中央に上下揺れの固有周期を規定する開口部が前記浮体本体以上の大きさで開口形成されて構成されていることを特徴とする。
The floating structure according to claim 1, which achieves the above object, has a disk shape that defines a natural period of rotational oscillation about a horizontal axis in the water below the floating body, having a larger planar projection outline than the floating body. A vibration suppression member whose maximum diameter is twice or more than that of the floating body is connected so as to be relatively unmovable at a predetermined interval via a connecting member, and a natural period of vertical vibration is defined at the approximate center of the vibration suppression member. The opening to be formed is formed with an opening larger than the size of the floating body .

この構成では、上下揺れの固有周期は動揺抑制部材の面積を大きな要因とし、水平軸回り回転揺れの固有周期は動揺抑制部材の外形を大きな要因として決まるため、開口部の大きさを変えて動揺抑制部材全体の面積を変えることで上下揺れの固有周期を水平軸回り回転揺れの固有周期に大きな影響を与えること無く設定できる。つまり、動揺抑制部材の円盤状の外形によって水平軸回り回転揺れの固有周期を設定できると共に、開口部の大きさによって上下揺れの固有周期を設定することができ、水平軸回り回転揺れと上下揺れの固有周期をそれぞれ独立して設定できるものである。
また、動揺抑制部材は単純な形状で、その開口部の大きさの設定によって動揺抑制部材全体の面積を設定することができ、水平軸回り回転揺れの固有周期を任意に設定できる。
さらに、上記動揺抑制部材はその円盤状の最大径が上記浮体本体の二倍以上であり、上記開口部は前記浮体本体以上であることにより、上下揺れの固有周期と水平軸回り回転揺れの固有周期とを分離独立させて浮体本体の固有周期から長周期側に大きく変位させることができる。 Upset this configuration, the natural period of heave is a major factor the area of fluctuation suppression member, because the natural period of the horizontal axis rotary shaking determined the profile of fluctuation suppression member, largely due to change the size of the opening By changing the area of the entire restraining member, the natural period of the vertical swing can be set without greatly affecting the natural period of the rotational swing around the horizontal axis. In other words, the natural period of rotational swing around the horizontal axis can be set by the disk-shaped outer shape of the vibration suppression member, and the natural period of vertical swing can be set by the size of the opening, so that the rotational swing and vertical swing around the horizontal axis can be set. Can be set independently of each other.
In addition, the vibration suppressing member has a simple shape, and the area of the entire vibration suppressing member can be set by setting the size of the opening, and the natural period of rotational fluctuation about the horizontal axis can be arbitrarily set.
Further, the vibration suppressing member has a disc-shaped maximum diameter that is at least twice that of the floating body, and the opening is larger than the floating body. The period can be separated and independent from the natural period of the floating body to the large period side.

請求項１に係る浮体構造物によれば、上下揺れの固有周期は動揺抑制部材の面積を大きな要因とし、水平軸回り回転揺れの固有周期は動揺抑制部材の外形を大きな要因として決まるため、動揺抑制部材の円盤状の外形を変えることで水平軸回り回転揺れの固有周期を変化させることができると共に、開口部の大きさを変えることで水平軸回り回転揺れの固有周期を殆ど変化させることなく上下揺れの固有周期を変化させることができる。これにより、設置海域において卓越する波浪の周期に応じて上下揺れと水平軸回り回転揺れの固有周期をそれぞれ独立して任意に設定し、波浪によって励起される動揺を抑制することができる。従って、動揺し難く安定した浮体構造物を構成することができるものである。
また、動揺抑制部材が平板状で、開口部はその略中央に開口形成されたものであることにより、動揺抑制部材は単純な形状で、その開口部の大きさによって動揺抑制部材全体の面積を設定することで、水平軸回り回転揺れの固有周期を容易に設定することができる。これにより、上下揺れと水平軸回り回転揺れの固有周期をそれぞれ独立して任意に設定して動揺し難く安定した浮体構造物を構成することができるものである。
さらに、動揺抑制部材はその円盤状の最大径が浮体本体の二倍以上であると共に開口部は浮体本体以上であることにより、上下揺れの固有周期と水平軸回り回転揺れの固有周期とを分離独立させて浮体本体の固有周期から長周期側に大きく変位させることができ、動揺し難く安定した浮体構造物を構成することができるものである。 According to the floating structure according to claim 1, the natural period of the vertical swing is determined by the area of the vibration suppressing member as a large factor, and the natural period of the rotational swing around the horizontal axis is determined by the outer shape of the vibration suppressing member as a large factor. By changing the disk-shaped outer shape of the restraining member, the natural period of rotation fluctuation around the horizontal axis can be changed, and by changing the size of the opening , the natural period of rotation fluctuation around the horizontal axis is hardly changed. It is possible to change the natural period of vertical shaking. This makes it possible to independently set the natural period of the vertical oscillation and the rotational oscillation around the horizontal axis independently according to the wave period prevailing in the installation sea area, and to suppress the vibration excited by the wave. Accordingly, it is possible to construct a floating structure that is difficult to shake and stable.
In addition, since the vibration suppression member has a flat plate shape and the opening is formed at the approximate center thereof, the vibration suppression member has a simple shape, and the area of the entire vibration suppression member can be increased depending on the size of the opening. By setting, the natural period of rotational swing around the horizontal axis can be easily set. As a result, it is possible to configure a stable floating structure that is difficult to shake by arbitrarily setting the natural periods of vertical and horizontal rotations independently and independently.
In addition, the vibration suppression member has a disc-shaped maximum diameter that is more than twice that of the floating body and the opening is larger than the floating body, thereby separating the natural period of vertical shaking and the natural period of rotational shaking around the horizontal axis. It can be made independent and can be greatly displaced from the natural period of the floating body to the long period side, and a stable floating structure that is not easily shaken can be configured.

以下、添付図面を参照して本発明を実施するための最良の形態について説明する。
図１は、本願発明を適用した浮体構造物の一構成例の概念図である。
図示浮体構造物１０は、海洋観測や気象観測のためのブイであり、浮体本体としての上部浮体１１の下側に、動揺抑制部材としての下部浮体１２が、連結部材としての連結構造材１３によって連結一体化して構成されている。 The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a conceptual diagram of a configuration example of a floating structure to which the present invention is applied.
The illustrated floating structure 10 is a buoy for ocean observation and meteorological observation, and a lower floating body 12 as a rocking suppression member is provided on a lower side of an upper floating body 11 as a floating body by a connecting structural member 13 as a connecting member. Concatenated and integrated.

上部浮体１１は、その内部に観測機器等が収容される当該浮体構造物１０の本体部であり、所定容積の円盤状を呈している。   The upper floating body 11 is a main body of the floating structure 10 in which an observation device or the like is accommodated, and has a disk shape with a predetermined volume.

下部浮体１２は、図４に平面形状を示すようにその外形が上部浮体より大きな円盤状で、中央に開放部としての円形の開口部１２Ａが形成されている。また、その厚さは剛性を保つ範囲で極力薄く形成されている。 The lower floating body 12 has a disk shape whose outer shape is larger than that of the upper floating body as shown in a plan view in FIG. 4, and a circular opening 12A as an open portion is formed at the center. Moreover, the thickness is formed as thin as possible within a range that maintains rigidity.

連結構造材１３は、上部浮体１１と下部浮体１２の中央を連結する連結バー１３Ａと、周辺部を連結する補強ワイヤ１３Ｂとから成り、連結バー１３Ａが上部浮体１１と下部浮体１２の間隔を規定すると共に、補強ワイヤ１３Ｂが両者を結合している。連結バー１３Ａは分岐した下端先端で下部浮体１２の開口部１２Ａの縁に固定され、補強ワイヤ１３Ｂは上部浮体１１と下部浮体１２の外周部を結んで張設され、これによって水の抵抗が少ない極めて細い（小さい水平方向の投影面積の）部材によって上部浮体１１と下部浮体１２を所定の上下間隔で相対移動不能に結合しているものである。尚、連結バー１３Ａはパイプ状の部材であっても良く、補強ワイヤ１３Ｂもワイヤに限らず他の部材であっても良い。   The connecting structural member 13 includes a connecting bar 13A that connects the centers of the upper floating body 11 and the lower floating body 12, and a reinforcing wire 13B that connects the peripheral portions. The connecting bar 13A defines the distance between the upper floating body 11 and the lower floating body 12. In addition, the reinforcing wire 13B couples both. The connecting bar 13A is fixed to the edge of the opening 12A of the lower floating body 12 at the tip of the branched lower end, and the reinforcing wire 13B is stretched by connecting the outer periphery of the upper floating body 11 and the lower floating body 12, thereby reducing water resistance. The upper floating body 11 and the lower floating body 12 are coupled so as not to be relatively movable at a predetermined vertical interval by an extremely thin member (having a small horizontal projection area). Note that the connecting bar 13A may be a pipe-like member, and the reinforcing wire 13B is not limited to a wire but may be another member.

そして、係留索１４を介して海底のアンカー１５に係留されて所定の海域に設置されるものである。   And it is moored by the anchor 15 of the seabed via the mooring line 14, and is installed in a predetermined sea area.

上記のごとき構成の浮体構造物１０では、波浪による動揺（上下揺れ及び水平軸回り回転揺れ）の固有周期は下部浮体１２に作用する付加質量又は付加慣性モーメントと相関関係にある。   In the floating structure 10 having the above-described configuration, the natural period of the vibration caused by the waves (vertical swing and rotational swing around the horizontal axis) is correlated with the additional mass or additional moment of inertia acting on the lower floating body 12.

即ち、浮体の上下揺れの固有周期は、一般に下記数式で表される。   That is, the natural period of the vertical swing of the floating body is generally expressed by the following formula.

Figure 0004490123
Figure 0004490123

また、浮体の水平軸回り回転揺れの固有周期は、一般に下記数式で表される。   Further, the natural period of the rotational swing around the horizontal axis of the floating body is generally expressed by the following mathematical formula.

Figure 0004490123
Figure 0004490123

これらの式から解るように、付加質量（ｍ）又は付加慣性モーメント（ｉ）が大きくなると、それぞれの固有周期（ＴＨＮ又はＴＲＮ）は大きく（長周期に）なり、従って、付加質量及び付加慣性モーメントを大きく設定することで、固有周期を長周期側にずらすことができる。   As can be seen from these equations, when the added mass (m) or the added moment of inertia (i) is increased, the respective natural period (THN or TRN) is increased (long period). By setting a large value, the natural period can be shifted to the long period side.

上下揺れの付加質量：ｍを決定する大きな要因はその全体の面積であり、一方、水平軸回り回転揺れの付加慣性モーメント：ｉを決定する大きな要因はその周辺面積（つまり外径の大小）である。しかし、全体の面積を大きくして付加質量：ｍを大きくすると、必然的に周辺面積も大きくなって付加慣性モーメント：ｉも増加する（その逆も同様）ために両者は不可分の関係にあり、上下揺れと水平軸回り回転揺れの固有周期が連動することから個別に任意に設定することはできない。   The major factor that determines the additional mass of vertical shaking: m is the overall area, while the additional moment of inertia of the rotational oscillation about the horizontal axis: the major factor that determines i is its peripheral area (that is, the outer diameter). is there. However, when the total area is increased and the added mass: m is increased, the peripheral area is necessarily increased, and the added moment of inertia: i is increased (and vice versa). Since the natural period of vertical swing and rotational swing around the horizontal axis is linked, it cannot be arbitrarily set individually.

本構成では、下部浮体１２の開口部１２Ａの大きさを適宜設定することで、水平軸回り回転揺れの付加慣性モーメント：ｉに大きな影響を与えること無く上下揺れの付加質量：ｍを任意に設定できる。   In this configuration, by appropriately setting the size of the opening 12A of the lower floating body 12, the additional moment of inertia of the vertical swing: m is arbitrarily set without significantly affecting the additional moment of inertia of the rotational swing about the horizontal axis: i. it can.

即ち、下部浮体１２の外径を水平軸回り回転揺れの固有周期が設置海域の波浪周期から長周期側に十分離れた任意の周期となる（付加慣性モーメント：ｉとなる）よう設定すると共に、その外径は変えずに開口部１２Ａの大きさ（面積）を適宜設定することで下部浮体１２の全体面積を上下揺れの固有周期が設置海域の波浪周期から十分離れた任意の周期となる（付加質量：ｍとなる）ように設定することができ、これによって水平軸回り回転揺れ及び上下揺れのそれぞれの固有周期：ＴＲＮ及びＴＨＮを設置海域の波浪周期から十分離間させてそれぞれ独立して設定することができるものである。   That is, the outer diameter of the lower floating body 12 is set so that the natural period of the rotational swing around the horizontal axis is an arbitrary period sufficiently separated from the wave period of the installation sea area to the long period side (additional moment of inertia: i), By appropriately setting the size (area) of the opening 12A without changing the outer diameter, the natural area of the vertical swing of the entire area of the lower floating body 12 becomes an arbitrary period sufficiently separated from the wave period of the installation sea area ( (Additional mass: m), so that each natural period of rotation and vertical oscillation around the horizontal axis: TRN and THN are set independently from each other by sufficiently separating them from the wave period of the sea area. Is something that can be done.

図２（Ａ），（Ｂ）に、周期が５−１６秒の波が卓越する海域を想定し、水平軸回り回転揺れの固有周期：ＴＲＮと上下揺れの固有周期：ＴＨＮをそれぞれ独立に設定して動揺を抑制した構成例における、入力波に対する動揺応答特性のグラフを、比較例と重ねて示す。   2 (A) and 2 (B), assuming a sea area where a wave with a period of 5 to 16 seconds is dominant, set the natural period of rotation around the horizontal axis: TRN and the natural period of vertical movement: THN independently. Then, the graph of the oscillation response characteristic with respect to the input wave in the configuration example in which the oscillation is suppressed is shown overlapping the comparative example.

これは、図２（Ｃ）に示すように上部浮体１１の外径：Ｄ，下部浮体１２の外径：Ｄ２，開口部１２Ａの径：Ｄ３，上部浮体１１の厚さ：ｈ，総高さ：Ｌとし、これら各部の寸法を図２（Ｄ）に示す数値に設定して入力波に対する動揺応答を計算した結果のグラフであり、図２（Ａ）は水平軸回り回転揺れ，図２（Ｂ）は上下揺れを示す。何れのグラフも横軸が周期，縦軸が入力波に対する動揺量の比率（角度の比又は長さの比）となっている。縦軸が大きい程入力波に対する応答が大きく、グラフのピークが共振する固有周期である。   As shown in FIG. 2 (C), the outer diameter of the upper floating body 11 is D, the outer diameter of the lower floating body 12 is D2, the diameter of the opening 12A is D3, the thickness of the upper floating body 11 is h, and the total height. : L, and the dimensions of these parts are set to the numerical values shown in FIG. 2D, and the vibration response to the input wave is calculated. FIG. B) shows vertical shaking. In each graph, the horizontal axis represents the period, and the vertical axis represents the ratio of the fluctuation amount to the input wave (angle ratio or length ratio). The larger the vertical axis is, the larger the response to the input wave is, and the natural period in which the peak of the graph resonates.

比較例１は下部浮体１２に開口部がなく上下揺れの固有周期が波浪周期から長周期側に十分離れる（２０秒）ようにその面積（付加質量：ｍ）を理想的に設定したもの、比較例２は下部浮体１２に開口部がなく水平軸回り回転揺れの固有周期が波浪周期から長周期側に十分離れる（２８秒）ようにその外径（付加慣性モーメント：ｉ）を理想的に設定したものである。   In Comparative Example 1, the lower floating body 12 has no opening, and the area (additional mass: m) is ideally set so that the natural period of vertical shaking is sufficiently separated from the wave period to the long period side (20 seconds). In Example 2, the outer diameter (additional moment of inertia: i) is ideally set so that there is no opening in the lower floating body 12 and the natural period of rotational fluctuation about the horizontal axis is sufficiently separated from the wave period to the long period side (28 seconds). It is a thing.

これらのグラフから解るように、比較例１では、上下揺れは問題ないが、水平軸回り回転揺れの固有周期が設定海域の波浪周期に重なってしまう。一方、比較例２では、水平軸回り回転揺れは問題ないが、上下揺れの固有周期が長周期側に大きく変位し、これに伴ってそれより短周期側に生ずる設定海域の波浪周期と重なる動揺の二次ピーク（図中Ｘで示す）が増大してしまう。つまり、上下揺れは固有周期が長周期側に変位し過ぎても揺れの増大を招来することとなり、上下揺れと水平軸回り回転揺れの両方を満足させる設定ができない。   As can be seen from these graphs, in Comparative Example 1, there is no problem with vertical shaking, but the natural period of rotational shaking around the horizontal axis overlaps with the wave period of the set sea area. On the other hand, in Comparative Example 2, there is no problem with rotational swing around the horizontal axis, but the natural period of the vertical swing is greatly displaced toward the long period side, and accordingly, the fluctuation overlaps with the wave period of the set sea area that occurs on the short period side. Secondary peaks (indicated by X in the figure) will increase. In other words, the vertical shaking causes an increase in the shaking even if the natural period is displaced too much to the long cycle side, and cannot be set to satisfy both the vertical shaking and the rotational shaking around the horizontal axis.

そこで、本願構成では、下部浮体１２を、比較例２と等しい外形で、且つ開口部１２Ａによって全体面積が比較例１とほぼ等しくなるように設定したものである。これにより、上下揺れは比較例１と殆ど同じ動揺応答特性を示して動揺の二次ピークも小さく、水平軸回り回転揺れは若干短周期側に変位して固有周期が２４秒程度となるが設定海域の波浪周期とは十分離れた設定とすることができる。   Therefore, in the configuration of the present application, the lower floating body 12 is set to have the same outer shape as that of the comparative example 2 and the entire area is substantially equal to that of the comparative example 1 by the opening 12A. As a result, the vertical shake shows almost the same oscillation response characteristics as in Comparative Example 1, the secondary peak of the oscillation is small, and the rotational oscillation around the horizontal axis is slightly displaced to the short period side, so that the natural period becomes about 24 seconds. It can be set sufficiently away from the ocean wave cycle.

このように、下部浮体１２に開口部１２Ａを設けてその大きさを適宜設定することにより、上下揺れの動揺応答特性に大きな影響を与えること無く水平軸回り回転揺れの動揺応答特性を変化させることができ、上下揺れと水平軸回り回転揺れの両方の動揺を抑制した設定が可能となるものである。   In this way, by providing the opening 12A in the lower floating body 12 and appropriately setting the size thereof, the vibration response characteristic of the rotational swing around the horizontal axis can be changed without greatly affecting the vibration response characteristic of the vertical swing. Therefore, it is possible to make settings that suppress both up-and-down shaking and rotation around the horizontal axis.

特に、海洋観測ブイや気象観測ブイ等の比較的小型の浮体構造物においては、下部浮体１２の大きさは上部浮体１１の二倍以上、開口部１２Ａの大きさは上部浮体１１の大きさ以上とすることで、上下揺れの固有周期と水平軸回り回転揺れの固有周期とを分離独立させて上部浮体１１の固有周期から長周期側に大きく変位させることができ、動揺抑制効果が大きくより好ましい。   In particular, in a relatively small floating structure such as an ocean observation buoy or a weather observation buoy, the size of the lower floating body 12 is more than twice that of the upper floating body 11, and the size of the opening 12A is larger than the size of the upper floating body 11. By doing so, the natural period of the vertical swing and the natural period of the rotational swing around the horizontal axis can be separated and independently displaced from the natural period of the upper floating body 11 to the long period side, and the vibration suppressing effect is large and more preferable. .

尚、本願発明は上記構成例に限るものではなく、適宜変更可能なものである。例えば、浮体構造物の全体構成は、図３に示す浮体構造物１０′のように、上部浮体１１と下部浮体１２を連結する連結部材としての連結構造材１６を、パイプ部材による斜材１６Ａと、当該斜材１６Ａの間に架設された連結材１６Ｂとで構成し、連結材１６Ｂに係留索１４を結合しても良い。また、下部浮体１２は、上記構成例のように円形外径に円形の開口部１２Ａが形成された図４（Ａ）に示すごときドーナツ状に限らず多角形であっても良く、更に、図４（Ｂ）に示す下部浮体１２′のように平板１２Ｂを組み合わせる等して中央を開放させて（開放部１２Ａ′）構成しても良いものである。   Note that the present invention is not limited to the above configuration example, and can be changed as appropriate. For example, the entire structure of the floating structure is composed of a connecting structural member 16 as a connecting member for connecting the upper floating body 11 and the lower floating body 12 as shown in FIG. The mooring line 14 may be coupled to the connecting member 16B by connecting the connecting member 16B to the connecting member 16B. Further, the lower floating body 12 is not limited to a donut shape as shown in FIG. 4A in which a circular opening 12A is formed in a circular outer diameter as in the above configuration example, and may be a polygonal shape. As in the lower floating body 12 ′ shown in FIG. 4 (B), the center may be opened (opened portion 12A ′) by combining the flat plates 12B.

本願発明を適用した浮体構造物の一構成例の概念図である。It is a conceptual diagram of the example of 1 structure of the floating body structure to which this invention is applied. （Ａ），（Ｂ）は入力波に対する動揺応答特性のグラフである。(A), (B) is a graph of the fluctuation response characteristic with respect to an input wave. （Ｃ），（Ｄ）は図２−１の設定条件の図表である。(C), (D) is a chart of the setting conditions of FIG. 浮体構造物の他の構成例の概念図である。It is a conceptual diagram of the other structural example of a floating body structure. 下部浮体の平面図である。It is a top view of a lower floating body. 従来例の浮体の説明図である。It is explanatory drawing of the floating body of a prior art example.

符号の説明Explanation of symbols

１０ 浮体構造物
１１ 上部浮体（浮体本体）
１２ 下部浮体（動揺抑制部材）
１２Ａ 開口部（開放部）
１３，１６ 連結構造材（連結部材）

10 Floating structure 11 Upper floating body (floating body)
12 Lower floating body (sway suppression member)
12A opening (opening)
13, 16 Connection structural material (connection member)

Claims (1)

浮体本体の下側の水中に、前記浮体本体より大きな平面投影外形を有して水平軸回り回転揺れの固有周期を規定する円盤状でその最大径が上記浮体本体の二倍以上の動揺抑制部材が、連結部材を介して所定の間隔で相対移動不能に連結されると共に、前記動揺抑制部材の略中央に上下揺れの固有周期を規定する開口部が前記浮体本体以上の大きさで開口形成されて構成されていることを特徴とする浮体構造物。
A vibration suppressing member having a planar projection outer shape larger than that of the floating body and defining a natural period of rotational swing around the horizontal axis in the water below the floating body and having a maximum diameter twice or more that of the floating body. Are connected through a connecting member so as not to move relative to each other at a predetermined interval, and an opening for defining a natural period of vertical shaking is formed at an approximate size in the center of the vibration suppressing member so as to be larger than the floating body. floating structure, characterized by being composed Te.
JP2004014104A 2004-01-22 2004-01-22 Floating structure Expired - Lifetime JP4490123B2 (en)

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JP4798573B2 (en) * 2004-10-04 2011-10-19 株式会社アイ・エイチ・アイ マリンユナイテッド Fluctuation reduction device for floating structure
JP4766394B2 (en) * 2007-02-14 2011-09-07 独立行政法人海上技術安全研究所 Estimation method of vibration response characteristics of multiple adjacent floating models in waves
JP6180385B2 (en) * 2014-08-12 2017-08-16 公立大学法人大阪府立大学 Spur buoy with posture stabilizer and design method thereof

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4958292U (en) * 1972-08-30 1974-05-22
JPS5181091U (en) * 1974-12-20 1976-06-28
JPS62241792A (en) * 1986-04-11 1987-10-22 Zeniraito V:Kk Disk type light buoy
JPS646199U (en) * 1987-06-29 1989-01-13
JPH0499191U (en) * 1991-01-25 1992-08-27
JPH08127387A (en) * 1993-12-14 1996-05-21 Zeniraito V:Kk Buoy
JPH09240578A (en) * 1996-03-12 1997-09-16 Zeniraito V:Kk Floating light

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4958292U (en) * 1972-08-30 1974-05-22
JPS5181091U (en) * 1974-12-20 1976-06-28
JPS62241792A (en) * 1986-04-11 1987-10-22 Zeniraito V:Kk Disk type light buoy
JPS646199U (en) * 1987-06-29 1989-01-13
JPH0499191U (en) * 1991-01-25 1992-08-27
JPH08127387A (en) * 1993-12-14 1996-05-21 Zeniraito V:Kk Buoy
JPH09240578A (en) * 1996-03-12 1997-09-16 Zeniraito V:Kk Floating light

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