著者

浜本 剛実

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1968, no.124, pp.1-7, 1968-12-20 (Released:2009-09-04)

参考文献数

6

被引用文献数

1

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In this paper, the approximate analysis of the low aspect ratio wing is carried out, getting a new integral equation of the lifting surface being oblique in the plane of free stream in order to estimate the lift distribution on the wing with low aspect ratio.The bound vortices are herein assumed to be distributed over the wing surface that is considered as the lifting surface and hence the induced free vortex filaments extend over the infinite down. stream having reasonable small angle to the wing surface.Applying this integral equation to the extreme case of the lifting surface, it is shown that Munk's Integral Equation is derived in case of the infinite span, and on the other hand, in case of the infinite chord wing the same result is given as that being obtained by Newton's momentum theory. The integral equation identical with that by Prandtl is further derived from the author's equation, putting aspect ratio high as the approximate treatment.

著者

川島 栄一 坂尾 稔 田崎 亮

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

造船協會論文集 (ISSN:18842062)

巻号頁・発行日

vol.1959, no.105, pp.93-107, 1959 (Released:2009-09-16)

参考文献数

6

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The nuclear power plant for ship must be able to endure sufficently to the severe ship motion in rough sea. Therefore, in the design of reactor, we must predict the magnitude of acceleration_ or inertia force acting on it. In this paper, we attempted to the statistical considerations on the vertical acceleration due to the pitching and heaving, and some consideration of rolling acceleration. They are as follows.1. From the response amplitude operator of vertical acceleration that is measured at model experiment in regular wave and Neumann's spectrum of sea wave, we calculated the statistical magnitude of vertical acceleration of small fine ship, high speed cargo liner, and large oil tanker for various ship speed and wind velocity.2. From the above data, under the following condition, we obtained the values shown in Table 4 which was regarded as the reasonable values of vertical acceleration to use in the design of reactor part of various nuclear ship.a) As the ship speed, we adopted the maximum mean speed obtained from the point of view of resistance increase only.b) As the sea condition, we adopted the fully developed sea for wind velocity U=20 m/s.c) As the statistical magnitude of acceleration, we adopted the maximum acceleration a0, which is the vertical acceleration that the probability which maximum vertical acceleration in 5, 000 continuous waves exceeds a0 is 10%.3. The rolling acceleration at resonant condition are expressed by Ts·√g/B only approximately such as Fig. 17.The magnitude of rolling acceleration is smaller than that of vertical acceleration by pitching and heaving, but it must be careful because of the difference of its direction.

著者

遠山 泰美 小野 志郎 西原 誠一郎

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1992, no.172, pp.383-391, 1992 (Released:2009-09-04)

参考文献数

4

被引用文献数

1 1

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The first commercial ACV service started with Vickers VA-3 in Britain in 1962. Since 1964 Mitsui (MES) has been making R and D efforts in ACV production and constructed 29 hovercraft of MV-PP series.Recent MV-PP10, a diesel powered 105 passenger hovercraft has achieved high performance and remarkable running cost efficiency. The weight penalty due to the adoption of diesel engines and welded aluminium structures resulted in water drag increase particularly in low speed region. In order to overcome the water scoop, model tests and FEM numerical analyses together with full scale sea trials have been conducted. Full scale measurements with conventional rear skirt systems revealed that the rear skirts would scoop the sea water at about 8 knots.Through the research and development works new rear skirts were conceived and designed for actual use considering geometric instability of the inflated membrane. There were great improvements in the reduction of the drag compared with the conventional systems.Two MV-PP10 hovercraft equipped with the improved rear skirts are now in commercial service for access to Oita airport by Oita Hoverferry Co, Ltd.

著者

吉野 亥三郎 森谷 周行 八木 光 山下 進

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1993, no.174, pp.365-375, 1993 (Released:2009-09-04)

参考文献数

16

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Focussing on the sea-going maneuverability of a 105-passenger hovercraft, the authors made investigations through series of model tests and computer simulations. The wind forces acting on a scale model, which represents superstructure and cushion form, were measured in a wind tunnel test. Oblique towing tests with self-lifting model were carried out for the hydrodynamic characteristics between cushion skirt and water plane. Regarding the characteristics of control surfaces, the force measurement tests with ducted propeller and rudder in wind tunnel were carried out. Based on these results of model tests, the authors developed a simulation program which employs proper mathematical models for each force components, namely cushion skirt, wind, propellers, rudders and thruster. The output of simulation showed fairly good agreement with the results of actual sea trial. Especially in the case of course keeping in beam wind, the reverse of check-helm direction around Froude number of 1.0 experienced in actual operations were confirmed through computer simulation. Lastly the results of extensive investigations on the sea-going maneuverability of the hovercraft are explained.

著者

小池 裕二 吉海 研 広重 栄基 谷田 宏次 牟田口 勝生

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1994, no.176, pp.137-143, 1994 (Released:2009-01-08)

参考文献数

3

被引用文献数

1 2

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An actively controlled anti-rolling system has been developed with a view of reducing the rolling motion of a ship by the movement of the mass controlled by actuator. It is of hybrid type combining the pendulum-base passive type with active type driven by a relatively small electric motor. The hybrid type has merits of (a) providing almost the same damping performance as active type (depending solely on actuators for obtaining controlled movement of damper mass), while requiring only a much smaller control force for moving the damper mass, and (b) continuing to function solely on its passive mechanism in the event of power failure. This system consists of a sliding mass on the rail shaped in a circular arc, and the compact, passive pendulum mechanism is realized that does not require a suspension structure such as a simple pendulum or spring mechanism. The driving force to control the movement of the damper mass is imparted from the electric motor through reduction gearing connected to a gear and pinion mechanism. The LQ control theory has been adopted for controlling the damper mass. At-sea experiments were performed with a ship (weight approx. 190t) to verify damping effects of the hybrid anti-rolling system. The rollings were reduced to about 1/3 in beam seas under the condition that the ship was stationary. The performance was further compared between hybrid type and passive type. Hybrid type promised better damping performance by 15% than passive type. The hybrid type also attenuated rollings with a forward speed of ship to about 1/2 in following seas, in the case of which passive type presented difficulty of providing damping effects markedly. Good agreement was obtained between measurement and calculation.

著者

福地 信義 小山 清文 篠田 岳思

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1999, no.186, pp.545-558, 1999 (Released:2009-09-04)

参考文献数

13

被引用文献数

4 3

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In the safety design of marine systems, it has to justly give a matter over human life in the case of outbreak of a marine accident such as fires and collisions. It may be difficult to establish a safe evacuation system by the cause of uncertain behavioral patterns based on human factors with ambiguity. Besides, the psychological effect on behavior of evacuee that is terrified under the stimulus by accident, should be considered in the redundancy system for safe evacuation. Accordingly, the safe evacuation system with the intention of securing evacuation routes and reducing escape time, is desirably designed by grasping the personnel behavior with psychological intelligence process in an emergency of marine accident.In this paper, the evacuation behaviors can be predicted by using the proposed walking model with individual capacity of visible length and avoidance process for obstacles. Further, the mathematical model of psychological intelligence process in an emergency is contrived herein, in which the evacuation movement is simulated in the consideration of the decrease of walking speed and the occurrence of self-isolation in psychological action according to the magnitudes of accident stimulus. By applying these models to common spaces in a dinning cruise ship, taking account of the human factors with psychological action is rather valued in the safe evacuation system and the validity of the proposed models can be confirmed.

著者

板垣 浩 豊田 政男 真島 篤 朝田 洋雄

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1981, no.149, pp.287-297, 1981 (Released:2010-01-25)

参考文献数

20

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The role of adequate non-destructive inspections and following repairs of detected flaws is essential in order to continue the integrity of welded structures. It is, however, pointed out that catastrophic failures sometimes happen due to insufficient repairs having no regard for unfavorable effects of repair.In case of welded joints, when a detected flaw is repaired by renewed welding, the fracture toughness of a flaw which is not discovered and adjacent to the detected flaw becomes smaller because of so-called the Hot Straining Embrittlement. Therefore, if such effect mentioned above is not taken into account, the reliability of the welded joint must be overestimated.The purpose of the research is to investigate the effect of the Hot Straining Embrittlement giving rise to serious deterioration of fracture toughness and evaluate the optimum range of repair in order to prevent an unexpected failure with the aid of reliability analysis.This report, at first, describes deterministic or probabilistic factors which should be adopted in the reliability analysis, a model and formulations of the analysis, and then, presents the comparison between estimated reliabilities of various cases, i. e., no repair, repair with or without the Hot Straining Embrittlement (HSE).From the results of numerical examples, it is shown that, 1) the probability of failure of repair with HSE is extremely larger than that of repair without HSE, 2) when the detected flaw is small, the probability of failure of no repair becomes smaller than that of repair with HSE, and 3) the important results are obtained on the range of repair with HSE.

著者

岩崎 紀夫 加藤 昭彦 川原 正言

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1981, no.149, pp.268-278, 1981 (Released:2009-09-16)

参考文献数

7

被引用文献数

1

---

Fatigue crack growth under random loading has been extensively studied since nearly a decade in relation with the design of offshore structures, ship hulls, pressure vessels and so on.For the sake of simplicity, random loads in service conditions are often simulated by block programmed loads in laboratory fatigue tests. However, very few studies have been conducted on the difference of fatigue crack growth behaviour between random loads and block programmed loads.The authors previously presented an experimental study on fatigue crack growth under block programmed loads, and discussed on the effect of block size on fatigue crack growth life. A proposed model gave a good prediction of fatigue crack growth life in block programmed loading tests. In the present paper, fatigue crack growth tests were performed under three different types of block or random loads. Experimental results show that fatigue crack growth behaviour under random loads is very similar to that under block programmed loads with short periods. Miner's rule gave a non-conservative estimation for crack growth life under both random and short block loads. Life estimation by the model previously proposed agreed well to the experimental results.

著者

藤田 譲 野本 敏治 仁保 治

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1978, no.144, pp.437-445, 1978 (Released:2010-01-20)

参考文献数

23

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In the previous paper, studies on the ultimate strength of stiffened plates with initial deformations were made, and a new analytical method was proposed. In this paper, the effects of initial imperfections due to welding on the ultimate strength are investigated.It is well known that these welding-induced imperfections which inevitably occur during the manufacturing process reduce the compressive strengh of structural elements. Almost all the strength analyses that have been made so far are based on the measured or assumed initial imperfections.Firstly, in this paper, the practical method to predict welding-induced imperfections such as welding distortion and welding residual stress is introduced.Secondly, an analytical method reported in the previous paper is further developed for describing welded plate behavior in compression.Finally, making use of aboved-mentioned results, the ultimate strength of stiffened plates is discussed.The following conclusions are obtained.1) It is introduced how to predict welding-induced imperfections according to welding conditions. The authors extended their method in order to estimate the ultimate strength of welded plates with these imperfections. Since this method is an analytical one that the ultimate strength can easily be estimated comparing with other numerical methods.2) The obtained results are checked against available results from numerical analyses and experimental data. It is confirmed that this proposed method is fairly efficient one.3) The imperfections due to welding reduce compressive strength of plates. Reduction in ultimate strength is most remarkable in case of the square plate having both slenderness ratio b/t√σY/E=1.9 and small intial deformation. For slenderer plates, reduction ratio caused by welding-induced imperfections is approximately constant. For thicker plates, the effect of residual stress on the ultimate strength disappears.4) The welding residual stress in stiffened plates lowers the panel element strength so that minimum stiffeness ratios (γBmin, γUmin) of stiffened plates becomes smaller than those (γBmin, γUmin) of stress-free stiffened plates.

著者

町田 進 的場 正明 吉成 仁志 新村 豊

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1990, no.168, pp.605-614, 1990 (Released:2009-09-16)

参考文献数

13

被引用文献数

1

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Ship life depends on many factors. The factors will be divided into three groups, the law of nature, performance and economy. The laws of nature are mainly fatigue and corrosion which reduce the retained structural toughness in aged ships. The performance factors of social impact will sometimes act key point. For example, marine pollution has a great influence on types of ships. In economy factors, investment and its recovery are basic ones that should be analyzed, and cost sensitivity of each of the factors should be analyzed on the point of effect on life. And some investigations show low finantial merit in ship life extention. The authors investigated the factors for proper ship life in basic and fundamental aspect, and confirmed that it should be taken heads to link the factors together. The points to be cleared in engineering point of view are the properties of corroded plates, and some results show very low fatigue strength and fracture toughness that warn low strength redundancy of aged ships.

著者

飯高 一郎

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

造船協會會報 (ISSN:18842054)

巻号頁・発行日

vol.1931, no.48, pp.165-187, 1931-10-31 (Released:2009-07-23)

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1. Aluminium light alloys are all very weak for sea water corrosion. Even Duralumin, the best rolling alloy, and Silumin, one of the best casting ones, are not good on this point. Some alloys are really non-corrodible but not used due to their inferior mechanical properties and difficulties in casting, rolling or forging A new alloy was invented in our laboratory 6 years ago, industrial researches were completed and the products are now used in some works. It was named “Chlumin” as it contains chromium, but a few per cent of magnesium and iron are also added. A brief description will be given of it in the following pages.2. Non-corrodibility. Castings of Chlumin and of an alloy of composition Cu 8%, Al 92 %, the most common one, both made by metallic mould, were immersed in 5 NaCl solution. Photo. I shows the result after 4 years. Chlumin gave only little deposit retaining even some luster, while, the other was severely corroded precipitating considerable mass of aluminium hydroxide. The machined surfaces of Chlumin and Silumin plates were exposed to air being sprayed by salt water every day. Photo. 2 shows the result after 2 months. Many black spots appeared on Silumin but Chlumin remained bright. This difference was observed also on specimens immersed in sea water for a year. Experiments were next carried out somewhat quantitatively. Specimens were immersed in 5% NaCl solution in separate bottles. The quantity of deposit and the weight decrease of specimen were measured after 40 days. The results are summarized in Fig 1. Chlumin was a little better even than aluminium. Silumin, Y-alloy, Duralumin and all others containing Cu or Zn were attacked severely. The variations of mechanical properties due to corrosions are shown in Fig. 2. Many test pieces of wire were immersed in 5 % NaCl solution and the solution was renewed at times to expose them to air for a day to accelerate the corrosion. Chlumin and aluminium wires, annealed or not, lose scarcely their strength by 5 months' immersion. The elongation decreases in some cases. While, Duralumin, variously heat-treated or not, loses both qualities rapidly. After 3 months the strength reduces to 80 to 20% of the original value and the elongation to 50 to 20%.3. As a casting alloy. The mechanical properties of a cast alloy depend much on casting conditions. Fig. 3 shows the data on ingots made similarly using same metallic mould. Silumin was in perfectly “modified” condition. Chlumin is a little inferior to Y-alloy in strength and yield point but is superior to it in elongation and impact resistance. It is better than Silumin in every respect and is more easy to cast and safe to use as no special process (modification) is wanted on manufacturing. Any complex form can be cast resisting to severe water pressure test. Pistons of internal combustion engine and parts of electric motor have been used for more than a year with better result than Y-alloy.4. As a rolling alloy. Wires of Chlumin are compared with those of pure aluminium and Duralumin in Fig. 4, being annealed at various temperatures. Duralumin aged after quenching from 510°C into water is exeedingly good indeed when annealed at temperatures below 200°, but becomes worse than Chlumin at 300°. Besides, it may not be a safe process of manufacturing to quench an alloy of melting point of 620° from above 500°. It may be very dificult to heat a large article uniformly above 500°. A little over heating will set in local melting, and when the temperature is too low some parts must meet the worst heat-treatment of Fig. 4. Heating on welding will spoil the good properties given by quenching and aging and it is often impossible in practice to quench, the article again.

著者

Yoshiho IKEDA Jaswar

出版者

THE JAPAN SOCIETY OF NAVAL ARCHITECTS AND OCEAN ENGINEERS

雑誌

関西造船協会論文集 (ISSN:13467727)

巻号頁・発行日

vol.2002, no.238, pp.238_215-238_224, 2002 (Released:2004-02-27)

参考文献数

9

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In the present study, a new prediction method of travel demand of cruise ships is proposed in which the characteristic of each demand for choosing a tour, the characteristics of tours, and factors of expense, time, seasickness, and popularity are taken into account. In the method, firstly, potential share of each tour, which is hot spring, cruising, theme park, and traveling abroad, is determined based on age and gender by using the characteristic of each demand for choosing a tour and the characteristics of tours. The characteristic of each demand for choosing a tour is analyzed by determining weights of nine elements, which are communication, relaxing, resting, nature, feeling of free, knowledge, curiosity, luxuriant and thrilling, based on taste and behavior of each demand by using the Analytical Hierarchy Process (AHP) model from survey data of general people who want to travel. The characteristics of the tours are analyzed by determining their weights for the nine elements by using AHP model from survey data of professional people who properly understand about all the tours. Then, using the predicted potential share for cruising, the number of demand of cruising is determined by using distributions of travel demand for traveling expenses and days, and factors of seasickness and popularity. Using the predicted number of demand, an economical analysis is carried out to determine the optimum fleets based on economic margin ratio and business impact. This method is applied to the Japanese cruise market and the results are discussed.

著者

井上 真一 佐々木 紀幸 村上 恭二 藪下 和樹 鈴木 勝雄

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1996, no.180, pp.1-11, 1996 (Released:2009-09-16)

参考文献数

10

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The amplitude functions measured by wave analysis experiment for a ship model are expanded in Mathieu function series in order to obtain the informations of improving the hull form. The expansion gives sectional area curve of the model as assumed as a source generating the measured wave system in linear wave-making theory. The expansion coefficients correspond with the coefficients of Mathieu expansion of the assumed sectional area curve and give the strengths of wave pattern resistance components. In order to reduce the total wave resistance the sectional area curve components corresponding with the dominant wave resistance components is to be subtracted.The amplitude functions measured for three ship models are expanded in Mathieu function series and their wave resistance components are compared with each other at various Froude numbers. The direction of improving hull form obtained by the present method corresponds with the design philosophy of the three ship forms.

著者

中村 昌彦 浅川 賢一 渡 健介 百留 洋洋 川谷 哲也

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本船舶海洋工学会論文集 (ISSN:18803717)

巻号頁・発行日

vol.19, pp.213-226, 2014

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A prototype of a 3000m-class underwater glider for virtual mooring is being developed by JAMSTEC (Japan Agency for Marine-Earth Science and Technology) with RIAM (Research Institute for Applied Mechanics) of Kyushu University. The vehicle houses an observation equipment and glides back and forth between the sea surface and the seabed collecting ocean data in a specific area (virtual mooring area) for more than one year. This paper summarizes our restudy on the hydrodynamic coefficients of the vehicle by constant acceleration tests and the simulated results of gliding angle control are compared with the experimental results carried out in a towing tank.

著者

新開 明二 万順 濤 小西 陽一

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1997, no.182, pp.435-444, 1997 (Released:2009-09-16)

参考文献数

33

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This paper deals with a new statistical prediction method for the propeller racing of ships sailing in rough seas. The propeller racing is one of the most important sea keeping quality in relation to the safety of main engine and shafting system. The trend of the racing has been investigated mainly in order to estimate allowable maximum propeller diameter, operability of ocean-going ships etc.. In those studies, the propeller racing generally and mainly means the situation (propeller exposed) in which the relative motion amplitude between ship hull and wave surface would exceed a depth of point in rotary disk propeller. Therefore, it seems that the magnitude of the amplitude and its exceeding frequency have been examined as a principal subject of study as usual. However, the time during which the amplitude exceeds a depth of point, that is, the propeller exposes in the air over sea surface, must be also one of most important factor affecting the trend of propeller racing. Then, this paper proposes a new practical method for estimating the time lasting of exposed propeller related to propeller racing in rough confused seas on the basis of the statistics.

著者

田中 義照 遠藤 久芳

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1988, no.164, pp.456-467, 1988 (Released:2010-05-07)

参考文献数

23

被引用文献数

17 30

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Though a lot of experimental and theoretical investigations on the strength of stiffened plates in compression have been carried out, there are few to suggest the rational correlation between panel and stiffener associated with their local buckling and collapse. The main purpose of the paper is to present a method of analysis which may be effective not only in estimation of ultimate strength but also in mode shape analysis taking account of the interaction between panel and stiffener.The proposed procedure is composed of two parts, elastic large deformation analysis and rigid-plastic analysis. The fundamental concept of method was proposed by Fujitao and it has been developed to be applicable to the problem relating with panel-stiffener interaction. The presented method has been verified through comparing its results with the experiment and FEM calculation and it has been found to be practical for the estimation of ultimate load and post-buckling behavior of stiffened plates with flatbar stiffeners.Through the mode shape analysis, has been obtained a clear scope for the local collapse mode, which had been most commonly observed in the experiment conducted with continuous multi-span models.The critical slenderness ratio of flatbar stiffener has been studied through the analyses. They show that there is a threshold of the slenderness ratio, h/ts, over which the dominant buckling mode in a stiffener changes from a panel-buckling-induced one to an inter-frame overall and the buckling strength rapidly decreases. The critical value is found to be about 18, which indicates the existing rule requirements are a little too conservative.

著者

加藤 絹秀

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

造船協會會報 (ISSN:18842054)

巻号頁・発行日

vol.1937, no.60, pp.73-117, 1937-07-25 (Released:2009-07-23)

参考文献数

3

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The auther briefly touches, in the first place, on the signification of “Air Conditioning, ” its origin and development and describes on air conditions v.a.v. human susceptibility. Then he generally explains the methods of conditioning the air, now usually employed; and tries a short survey on the present state of air conditioning of communication means such as railway wagons, tram ears on land, and vessels on water. He, finally, enters into the explanation of the design, lay-out and the results of provisional tests of the air conditioning equipments on board the two ships above named, which are not only the pioneer ships in Japan furnished with these equipments, but also the foremost vessels in the world in which the equipments are most extensively employed, viz. all public rooms and all cabins in the quarters for all classes of passengers have been completely air conditioned throughout.

著者

沢村 鶴松

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

造船協會論文集 (ISSN:18842062)

巻号頁・発行日

vol.1965, no.118, pp.337-347, 1965 (Released:2010-01-20)

参考文献数

2

被引用文献数

1

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At the beginning of the initial design of ship, the breadth of ship has been determined by the formulas B=L/10+α (α=4.56), B=L/9+β (β_??_3.2) or L/B ratio (6.57.5 for cargo boat). But the above formulas have no connections with KG, GM and the freeboard. The author has delived the relation between B and D from the GM equation. The result is as following.[2Q/GM (d/D) D+1] 2-4QP/GM2 (d/D) 2B2=1whereP=Cw/Cb (0.0106+0.0727 Cw) =1/RQ=n (d/D) - (d/D) 2Cw/Cb+CwThe above equation is a hyperbola of B and D. So B can be put for an asymptote of this hyperbola.B=√RQ/L/Dratio·L+GM (d/D) √R/4Q where L=D×L/D ratio.The above equation can be expressed as following.B=L/const1+GM+ (d/D) const2 (1) Flush DK Shelter DK Three isl Well DK Oil Tanker(KG/D) (0.60) (0.60) (0.65) (0.52) Const1 8.38.7 7.78.2 8.48.8 12.513.2Const2 4.64.5 4.54.4 4.2 5.7Fore figure is U shape, aft figure is V.The const1 varies by the D/d ratio and KG/D, but the const2 varies very small.When the second term of the equation (1) is large in case of an oil tanker, a correction value [= (the second term of eq (1)) 2×1/2B] must be subtracted from B in the equation (1).The author has drawn the curves of R and Q for the general application.

著者

増淵 興一 小椋 陽 石原 芳忠 星野 二郎

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

造船協會論文集 (ISSN:18842062)

巻号頁・発行日

vol.1954, no.95, pp.161-171, 1954 (Released:2007-05-28)

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In case of constructing the welded steel ships, the wavy deformation of the shell plate is liable to occur by the fillet welding of shell plates and frames or floor plates.This unfairness may not only spoil the appearance of the shell plate but also reduce the buckling strength of it.This study was performed for the purpose of surveying the mechanism of origination and the method of reducing this deformation.The specimen used in this experiment is a constrained frame works as shown in Fig. 1. The deformation and the reaction stress originated in the plate due to welding were measured by the dial gauge and the electric resistance wire strain gauges respectively. These measurement were performed after the welding of each layer.The results obtained are summarized as follows:-1) Fundamental nature of this problemThis problem of residual stress can be treated as the problem of reaction stress originated by constraining the angular change due to welding. Accordingly, the angular change and the reaction stress can be calculated from the measured deformation using“beam theory.”2) Effect of welding procedures on the angular change(i) Weight of deposit metalAngular change due to welding increases as the increase of the weight of the deposit metal. There approximately exists a linear relation between the logarithm of the weight of the rod consumption and the angular change. Accordingly, it seems to be a benefit-able practice for reducing the deformation and reaction stress to decrease the weight of deposit metal or the leg length.(ii) Effect of rod diameterSize of rod diameter seems to have little effect on the angular change when the weight of deposit metal is equal.(iii) Effect of the degree of constraintDegree of constraint seems to have a remarkable effect on the angular change.Accordingly, the additional constraint, such as a kind of strong backs, attached to the shell plate may reduce the deformation and reaction stress.

著者

増山 豊 深沢 塔一 北崎 隆雄

出版者

The Japan Society of Naval Architects and Ocean Engineers

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

vol.1997, no.181, pp.1-13, 1997 (Released:2009-09-16)

参考文献数

17

被引用文献数

2 7

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Sail forces were measured in a full-scale sailing boat with the use of a sail force dynamometer. This apparatus consisted of an aluminum frame fixed to the hull by way of several load cells. The sailing boat was modified so that the dynamometer frame could be installed inside the hull. The mast, stays, winches, and other sailing rig were fixed on the frame so as to transmit all the forces acting on sail to the frame. By transforming the measured forces, the lift force, drag force, thrust, side force, or the center of effort of the sail force could be obtained. The sailing conditions of the boat, such as the boat speed, heel angle, wind speed, wind angle, and so on, were also measured.Sail shapes of the boat in the up-wind condition were also measured with the use of CCD cameras installed in the boat. The sail shape images taken by the cameras were transformed to bit-map files, and then processed by an SSA-2 D, a sail shape analyzing software. With the use of this software, sail shape parameters were obtained. The relationship between the measured sail forces and the sail shape parameters is discussed in this paper. Moreover, the measured sail shapes were used as the input data for the numerical calculations.Numerical calculations were performed to estimate the sail forces of the boat. In the calculations, two sails, a mainsail and a jib, were modeled in the form of a vortex lattice. The vortex lattice method was adopted as the numerical calculation method. Step by step calculations were conducted up to attaining the steady state of the sail in steady wind. Calculated sail forces were compared with the measured forces, and the validity of the numerical method was studied.