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Article type: Cover
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Cover1-
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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Article type: Cover
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Cover2-
Published: June 30, 1975
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Article type: Appendix
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App1-
Published: June 30, 1975
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Katashi TAGUCHI, Yoshisada MUROTSU, Takashi TOYAMA, Takashi HONJO
Article type: Article
Pages
1-12
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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In the previous paper, basic mathematical models relating the transport costs to a fleet were developed for the case of crude oil carriers, and a problem was solved to determine the optimum fleet-size to meet a transport demand in an arbitrary route with one port loading and one port unloading, where the fleet was assumed to be composed of identical type ship. In this paper, some improvements are made of the mathematical models so that a route selection problem may be treated. Further, a different optimization procedure is developed, by which the fleet that does not necessarily consists of identical type ship can be optimized. For this purpose, the concept of dynamic programming and nonlinear programming techniques are applied, and a versatile software program is developed. The effects of various factors in transportation system, such as the transport demand, the draught limits, the tolls, the storage costs at terminals, etc., are discussed concerning the resulting optimum fleet-size.
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Teiichi MIYATA, Jiro OKAMOTO, Saburo TOMOSADA, Hiroshi FUJIMURA, Yasuh ...
Article type: Article
Pages
13-23
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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On May 31, 1974, the 151,900 LT DW motor tanker "AMOCO TRINIDAD" for the Mammoth Bulk Carriers, Ltd. was launched by Mitsubishi Heavy Industries at their Kobe yard. The ship has wide breadth and shallow draft: L/B=5.0 and B/D=2.68. The launching weight is about 29.600 ton, the largest value in Japan for sliding launching. Many problems came from these causes and it was necessary for us to investigate and solve them to succeed in the launching. In this paper, the results of these works and the data measured at the launching are shown.
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Ichiro NAKAMURA, Yoshihiro KUDOMI, Takashi JONO, Chiaki KISHIDA
Article type: Article
Pages
25-31
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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At the stage of the IMCO draft text for segregated ballast tanker, 1973, the volume of segregated ballast tanks was based on deadweight, and smaller draft compared with conventional tanker was obtained as the optimum one. But the volume of segregated ballast tanks was finally so decided as to satisfy the requirement for the draft of ballast condition, and on the contrary, it was concluded that the optimum draft of the segregated ballast tanker is deeper than that of the conventional tanker.
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Yoshinori TESHIMA, Matsuji SUGITA
Article type: Article
Pages
33-37
Published: June 30, 1975
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Throughout this experiment we try to examine the effect of an anti-rolling tank when a ship is under the condition of steady wind, having 1.5 time's wind pressure of the steady wind at the maximum angle of roll windward. By using dynamical stability curve, we confirm that this anti-rolling tank is not sufficiently effective for a gust of wind and that the calculated value approximately agrees with the experimental value of rolling angle for a gust of wind.
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Shigeru YAMAMOTO
Article type: Article
Pages
39-43
Published: June 30, 1975
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Recently tankers become very large, therefore we need to estimate the added mass when they come alongside the quay. This paper presents the calculation examples for this purpose. Two-dimensional potential flow is assumed and the numerical calculation is done by the finite element method. According to the results, the effect of the water depth on the added mass is considerably large, but the distance between the ship and the quay has small influence on it. In order to examine the accuracy of this method, a result is compared with the one calculated by the hypercircle method. They agreed very well.
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Shoichi NAKAMURA, Ryusuke HOSODA, Shigeru NAITO, Kiyoshi NEMA
Article type: Article
Pages
45-55
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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With a ship model of single screw high speed container ship of L/B=8, resistance and self-propulsion tests in regular and irregular head waves were carried out in the Experiment Tank of Osaka University. The experimental results of ship motions and resistance increases in regular head waves are compared with the results obtained from the theoretical calculations and also with those obtained for a container ship model of L/B=6.89 in the first report. The self-propulsion factors in regular head waves are analysed by assuming that the mean characteristics of a propeller are identical with those in still water. The significant amplitudes of heave and pitch and the mean increases of resistance, propeller thrust, torque and revolution measured in irregular head waves are compared with the predicted values by the linear superposition technique. Furthermore, the effects of mean wave period and significant wave height of irregular waves on the ship motions and the mean increases of resistance, propeller thrust etc. are investigated.
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Tsutomu FUKASE
Article type: Article
Pages
57-62
Published: June 30, 1975
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In the towing tank, seiche with the amplitude of several millimeters is frequently observed. In this report, some characteristics of the seiche concerning its development and decay, the effect of flow and inclination of surface due to seiche on the resistance and propulsion tests are discussed. Seiche in the towing tank is generated from many causes. Model running and launching into the trimming tank, in the ordinary testing practice, are the most remarkable causes. The maximum double amplitude of seiche in the ordinary tests is possible to increase to about 5 millimeters. Seiche in the towing tank is usually composed of one-node basic oscillation and other multi-node oscillations which decay rapidly. The one-node oscillation remains for a long time. Half-time period of the decay of the seiche of lengthwise one node is about 6 hours in this tank. The fluctuation of resistance due to seiche is calculated and compared with the experiments. The agreement between the calculation and experiment is fairly good. The fluctuation is composed of a part proportional to the model displacement and the change of the relative speed. It becomes about 50 gr per 1 mm of double amplitutude of seiche. This order of the fluctuation should not be neglected from the view point of accuracy. In the propulsion tests, the calculated speed change of the model is the order of the speed of water particle due to seiche. The maximum speed change is about 1.5 mm/sec per 1 mm of double amplitude of seiche.
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Seiko OGIWARA
Article type: Article
Pages
63-72
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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There are several methods to investigate the blockage effect, among which the method of imaginary arrays for a model has advantages to take account of the influence of ship form parameters and the distribution of speed increase due to blockage around a model. On the contrary, the impropriety of this method applied to a model in a towing tank is to neglect the effect of wave motion on the free surface. However, it is supposed that the effect of the free surface may be very small for a practical range of low Froude number, and for usual dimensions of models and tank. In this paper, therefore, the calculations are based on the method of images for a body of revolution which is represented by a source ring distribution over the body, and some practical results are obtained concerning the blockage effect of a rectangular channel, speed correction for the current meter ahead of a model, the effect of finite depth of water and the effect of wake on the blockage corrector.
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Hiroshi ISSHIKI, Hisaaki MAEDA
Article type: Article
Pages
73-82
Published: June 30, 1975
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Expressions of velocity potentials for two dimensional pulsating sources, the so-called Green functions, in a water of finite depth are obtained from a new standpoint, when (1) the water is horizontally unbounded and permits wave radiation, and when (2) the water is bounded by vertical walls and does not permit wave radiation. A general expression of the velocity potential for water motions in a rectangular tank is obtained by using the results of the case (2). Methods of the numerical calculation for the Green function in the case of (1) are discussed.
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Ichiro NAKAMURA, Taiji KATAZA, Masaru MOKUNAKA, Yoichi HATTORI
Article type: Article
Pages
83-91
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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Recently calculations of long-term distribution of random variables tend to be carried out extensively. The process of obtaining long-term distribution is somewhat complicated and it is not easy to make even a rough estimation of expected values. Authors have developed a calculation method for given data of ocean waves and have made calculation charts for wave data of North Atlantic Ocean by Walden and those of Northern North Pacific Ocean and South Adjacent Seas of Japan by Yamanouchi and others. If the standard deviations of random variables are obtained for irregular seas, the long-term distribution can easily be obtained by using these charts. Furthermore from these charts quantitative comparison of long-term distributions of North Atlantic Ocean and North Pacific Ocean or those of four seasons on each ocean can easily be made.
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Hiroshi SAKAMOTO, Humio SHIMIZU
Article type: Article
Pages
93-105
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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The strength of bollards used for mooring and towing is specified by JIS. But recently some examples of damage of bollards are reported from some shipyards and so it will be an interesting problem to know the actual ultimate strength of bollards both for builders and for ship owners. In view of the circumstances stated above, it was decided to have a better understanding on the standard for bollards by the Japanese Association of Marine JIS. Accordingly, in order to examine the strength of JIS type bollards full scale tests were carried out and the weak points of those were found out. Then several test bollards deemed to be of improved type were manufactured for trial and tested so as to get the data for the improvement of the weak points about JIS type bollards. This is the report about those test result.
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Ken-ichi KITAURA, Sakito KAMEI, Hiroo OKADA, Yoshio FUKUMOTO
Article type: Article
Pages
107-117
Published: June 30, 1975
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In this paper, the "effective breadth" of orthotropic plates with girders under lateral loads, is discussed from the viewpoint of the strength and the rigidity, respectively. Varying non-dimensional parameters that specify elastic characteristics and dimensions of plates and girders, numerical calculation is executed for some typical structures subjected to various bending loads. And effects of anisotropy of the plate on the "effective breadth" are clarified. Besides, a way of application of these results on the orthotropic plate to plate-stiffener combination system, is shown.
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Junkichi YAGI, Yasumitsu TOMITA
Article type: Article
Pages
119-128
Published: June 30, 1975
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Fatigue crack initiation life of notched plate under axial load for mild steel and high tensile strength steel, HT 60, was experimentally investigated to apply a formulae derived from a cumulative damage law proposed by the authors. From the test results, validity of the proposed formulae was proved. and a relation between cyclic plastic strain range Δ_<εp> at the notch root and crack initiation life N_c was expressed by a function of elastic stress concentration factor of the notch K_t. This formula showed that both unnotched and notched specimen have approximately the same life when the plastic strain rang of specimen with K_t smaller than three is equal to that of unnotchod specimen.
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Junkichi YAGI, Yasumitsu TOMITA, Yasumi TOYAMA, Akira NAKAMOTO
Article type: Article
Pages
129-139
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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Problems of one-dimensional elastic-plastic longitudinal impact were studied theoretically and experimentally. Impact stress and strain produced in a bar by a tensile or compressive impact load were calculated by the following methods without consideration of the effect of strain rate. 1) a numerical solution of the wave equation (exact solution) 2) the finite element method, and 3) an approximate solution neglecting the wave propagation. Elastic-plastic impact tests were carried out on cylindrical bars of mild steel and the results were analysed by the above three methods. An analysis of the wave propagation considering nonuniform contact at the end of a bar shows good agreement with the observed strain-time records. The finite element method is useful to estimate the wave propagation. When the mass of a specimen is much less than that of impact testing system, the approximate solution is fairly good agreement with the exact solution and experimental results.
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[in Japanese]
Article type: Article
Pages
141-148
Published: June 30, 1975
Released on J-STAGE: March 30, 2018
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Article type: Appendix
Pages
149-151
Published: June 30, 1975
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Article type: Appendix
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Published: June 30, 1975
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Article type: Appendix
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Published: June 30, 1975
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Article type: Appendix
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App4-
Published: June 30, 1975
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Article type: Cover
Pages
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Published: June 30, 1975
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