2015 Vol. 10, No. 6
Research and revision on the scale effect of the wake field based on the method of SDM…GUO Chunyu,ZHANG Qi,CHEN Ge,et al(1)Hull lines optimization based on the evaluation of seakeeping performance…ZHANG Yao,WANG Kai,YANG Shuai,et al(8)Method of reducing the roll amplitude of a deep-vee hull at zero speed…DONG Runpeng,DONG Wencai,YAO Chaobang(15)Analysis of the feasibility of installing deep-sea detectors in large public vessels…CHEN Rui,HUANG Wugang(21)Typical shape and topology optimization design of the ship grillage structure…ZHANG Huixin,YANG Deqing(27)Analysis and experimetal verification of the catenary component with the finite element method…WANG Han,XIE De(34)The low-cycle fatigue life model and the accumulative plastic strain model for stiffened plates under cyclic loading …WANG Dan,YANG Ping,DENG Junlin,et al(39)Numerical analysis of the damage on I-core sandwich panels subjected to combined blast and fragment loading…DUAN Xinfeng,CHENG Yuansheng,ZHANG Pan,et al(45)Numerical simulation of steel plates subjected to the impact of both impact waves and fragments…LI Mao,ZHU Xi,HOU Hailiang,et al(60)Analysis on the vibration and sound radiation characteristics of double cylindrical shells using wave number spectrums …TAN Lu,JI Gang,ZHOU Qidou,et al(68)The course and speed cooperative control method for unmanned surface vehicles…CAO Shijie,ZENG Fanming,CHEN Yutao(74)Transmission characteristics of propeller excitation for naval marine propulsion shafting…YU Qiang,WANG Lei,LIU Wei(81)Effects of blade skew on the hydrodynamic and deformation performance of propellers…ZHANG Rui,WANG Xianzhou,ZHANG Zhiguo,et al(87)Classification method of nuclear events for marine nuclear power plants…Yang Guangsheng,Chen Bao,LIU Boxin,et al(95)Structure design and optimization on the tooling of side-fixed equipment installation attitude control…GAO Yakun,ZHANG Sheng,LIU Yang,et al(101)Numerical simulation of the air distribution in a typical ship cabin…QUAN Chongren,WANG Yang,YU Liqing,et al(107)A mission-oriented simulating and optimizing method for the shipborne system information flow…YUE Lin,XIANG Guofu,HU Weihao(114)Thermally sprayed metallic coatings and the corresponding potential applications for ships…ZHANG Misi,GAO Xinhua,NING Hui,et al(120)General cargo ship loading problems based on the hybrid genetic algorithm…ZHU Ying,XIANG Xianbo,YANG Yuntao(126)Chinese Journal of Ship Research vol.10 contents(2015)…(133)
The seakeeping performance of ships is an important index of evaluating ship performance. With an increasing number of instruments and weapons systems being used in shipbuilding, the issue con-cerning how to keep these systems working is of vital importance to ship designers. However, as the ship's seakeeping performance is contradictory with its speed performance, a reasonable evaluation scheme of the seakeeping performance is essential. In this paper, five sets of data of the sea-keeping performance that re-ceive most attention-pitch amplitude, heave amplitude, acceleration in the bow, the amidships, and the stern-are obtained through model tests. The hull lines are then optimized to improve the sea-keeping per-formance with the added resistance being limited within a certain threshold. Meanwhile, in order to ensure the accuracy of the tests, the response of ship motion in irregular waves is compared with the experimental values, and results show that the five indicators for sea-keeping performance of modified ships are success-fully optimized to meet the design goals.
A series of resistance and roll decay model tests are conducted in order to solve the large roll amplitude problem of one kiloton deep-vee ship with zero speed under rough sea condition. The roll re-sponse in regular waves is first obtained by solving the nonlinear roll motion equation, and the roll ampli-tude of the full scale hull in seaway is then predicted in the ITTC wave spectrum. The influences of length, width, location, and continuity of blige keel on resistance, roll damping, and roll amplitude are studied, re-spectively. The results indicate that incorporating a kind of bilge keel can reduce the rolling amplitude at zero speed by 25% and control the drag addition within 4.5% from cruising speed to maximum speed. These tests provide technical support to reduce the roll amplitude of kiloton deep-vee hull under the moor-ing state in seaway.
Taking the typical ship grillage structure as the study object, this paper mainly describes the ap-plication of optimized design of ship structures. Specifically, the size and shape optimization is applied onto the grillage structure at the bottom, with the weight of the structure being objective and the stress being the constraint condition. After optimization, the weight has decreased by 15.82%. As for deck grillage, to im-prove the spatial layout of the top of superstructure cabins, raise the natural frequency of grillage structure on top, and seek for the optimal distribution of materials, the topology optimization is applied with its static analysis and modal analysis being discussed. Based on the above obtained data, the volume fraction is set as the restriction condition of the model, and the structural natural frequency is set as the objective func-tion. Finally, new structure type which optimizes the spatial layout of the top of superstructure cabins are presented, which renders more reasonable material distribution, increases grillage structure's natural fre-quency, and meets expected goals. Research shows that, at present, the grillage structure design can be widely used in the topology and shape optimization design technology.
In order to analyze the increasing accumulative plastic damage of ship stiffened plates, this pa-per combines the interaction coefficients of stiffeners and plates, and with plastic strain of damage evolu-tion being the control parameter, the low-cycle fatigue accumulative increasing plastic damage model and low-cycle fatigue life model for stiffened plates have been derived based on the theory of damage mechan-ics. The fatigue damage variable of the stiffened plate under cyclic loading is then introduced into the accu-mulative plastic strain equation. Next, by means of integral transformation, the evolution equation of axial accumulative plastic strain and the constitutive model for low-cycle fatigue life are deduced under low cy-clic loading. The general high strength steel 402 is adopted, with its related material fatigue characteristic parameters introduced to be compared with the low-cycle fatigue life model of stiffened plates. The theoreti-cal evolution results from the presented models of the accumulative plastic strain damage are compared with finite element modeling results, and the influences of mean stress and rib stiffness ratio on the accumu-lated plastic strain are discussed. The results indicate that the established model well reflects the evolution-al law of the axial plastic strain of the stiffened plate under cyclic loading and brings convenience into the evaluation of low-cycle fatigue strength of ship structures.
In this paper, the combined blast and fragment loads due to close-in warhead explosion is simu-lated by placing prefabricated fragments at the bottom of bare TNT explosive, and the corresponding dam-age on I-core sandwich panels are evaluated using the software LS-DYNA. The differences of failure modes of sandwich panels subjected to only blast and combined blast and fragment loads are analyzed, and the effects of core configuration and thickness configuration between the front and back plates on the fail-ure modes are studied. The anti-damage performance of sandwich panels is then compared with that of the equivalent solid plate. In addition, the energy absorption characteristics of I-core sandwich panels under different loads are also analyzed. Numerical results show that the overall damage of both the sandwich pan-els and solid plates subjected to combined blast and fragment loads is more severe than that caused by blast only. The performance of I-core sandwich panels is superior to equivalent solid plates when the load-ing intensity is small. It is also found out that the loading intensity, loading type (blast loading or combined blast and fragment loading) and the thickness configuration between the front and back plates yield signifi-cant influences on the failure modes of the I-core sandwich panel. From the results of energy analysis, it can be concluded that the front face plate and the core are the main energy-absorbing parts under blast loading, while the front and back face plates become the main energy-absorbing parts when combined blast and fragment loading is considered.
The main objective of this study is to explore the deformation feature and damage pattern of a steel plate under the synergetic effects of blast and fragments loading. The combined blast and fragments loading effects under the condition of cast TNT and prefabricated fragments acting on a steel plate, are sim-ulated using the finite element program ANSYS/LS -DYNA. The flight of fragments driven by the charge is predicted, and the blast loading and fragments loading are analyzed respectively, while the deformation and damage characteristic under the combined loading are compared with experiment results. The simulation re-sults agree relatively well with the experimental results. Meanwhile, it is seen that the fragment at the cen-ter of the charge bottom has the highest velocity and the lowest velocity occurs at the edge. Under the exper-imental condition, blast reaches the structure first and fragments impact subsequently, and the total kinetic energy of fragments is much larger than that of blast wave and explosion products transmitted to the struc-ture. The punched hole appearing in the central region of the steel plate is mainly caused by the dense frag-ment cluster, which should be treated as the main target load for protective structures.
In order to explain the universal rules between the vibrational model and the sound radiation of double cylindrical shells, the coupling vibration responses of the structure are obtained with Finite Element Method combined with Boundary Element Method (FEM/ BEM). Then, the radial vibration on the cylindri-cal coupling surface is transformed into the wave number domain with the wave number analysis spectrum method, which generates the vibration and radiation power spectrums. Next, the vibration and sound radia-tion characteristics are obtained by comparing the vibration power and radiation power associated with each component of regular waves. It is seen that the vibration of outer shell consists of many components in cir-cumference and is dominated by short waves in the axial direction. Meanwhile, the sound radiation is domi-nated by low order vibration components in circumference and long waves in the axial direction.
In order to solve the problem of autonomous dynamic control for unmanned surface vehicles (USV) under unknown conditions, a course and speed cooperative control method based on the adaptive fuzzy algorithm is studied in this paper. The fuzzy control algorithm is designed as to the inputs are the devi-ation of course and position, and the outputs are the rudder angle and throttle. The self-adaptive control method is applied, of which the input is the deviation rate of course and the output is the control cycle, to make the system effectively response to external changes. The objective function of the optimization is the weighted minimum of the arrival time and the changing frequency of rudder. The specific effects of the pa-rameters, like domains and the control cycle, are analyzed. The results of optimization analysis show that the method enables the USV to successfully reach the target point in random disturbance conditions with different wind, current and wave, and to achieve the point to point autonomous voyage.
During the operation of submarine propellers, the fluid mechanical pressure load on the blades could result in a structural load on the component, which in turn causes deformation of the blade. In this pa-per, the structural response is analyzed with the finite element method, and the coupling simulation is ac-complished by using ACT_Transient FSI in ANSYS Workbench. The geometries of the propeller DTMB 4381~4383 are then taken as the research objects, where the deformation characteristic and hydrodynamic performance of these propellers are studied. The results show that the max blade displacement worsens with the increase of skew angles, and the vibration of the blade decreases simultaneously.
Due to the lack of time and limited communicative capacity during operation, the nuclear pow-ered ship requires more concise and accurate event reporting capability than common nuclear power plants, which ensures the actual conditions of the marine nuclear power plant can reach multiple parties quickly. This paper focuses on the events reporting problem of marine nuclear power plants: by combining with the mature experience of the international nuclear and radiological event scale(INES), a unified system of rules is established, and the classification standards helping different parties to realize the severity of nucle-ar events are formed. The research work is of great significance to the safety assurance of marine nuclear power plants.
针对舰船舱室空调系统的末端形式不同于民用建筑空调系统末端形式的特点,提出对采用布风器方式的舰船舱室的气流组织形式进行研究。采用计算流体动力学(CFD)技术,建立实船典型两人舱室的数值试验模型,根据舰船的实际边界条件对该舱室夏季设计工况和冬季设计工况下的气流组织进行数值模拟计算,并对典型截面的速度场及温度场进行分析。模拟结果表明:在夏季设计工况下,虽然布风器周围风速较高、温度较低,但舱内人员活动区域速度场分布较均匀,舱内风速小于0.3 m/s,温度场分布也较为均匀,温度约为26～27 ℃;在冬季设计工况下,除布风器周围风速较高、温度较高外,舱室大部分区域风速较低,小于0.2 m/s,温度约为20 ℃。无论是夏季还是冬季设计工况,采用布风器末端形式的典型两人舱室人员活动区域内的气流速度及温度均满足舒适性标准要求,结果验证了该典型舱室空调系统布置的合理性。
Due to the peculiar serving condition of the ships, the onboard equipment is often out of order, resulting in reduced life cycle;meanwhile, the maintenance cost rises correspondingly. In this paper, the advantages and disadvantages of arc spraying, super-sonic flame spraying, and plasma spraying for metal-lic thermally sprayed coatings are summarized. It is found that supersonic flame spraying best fits for large area metallic coatings for new ships. Certain factors that affect the corrosion resistance, adhesion, and poros-ity of the coatings are discussed, with the applications of metallic coatings on the ship being introduced. Fi-nally, in accordance with the requirements of metallic coatings, it is suggested that the integrated technolo-gy of supersonic flame spraying for large area spraying on the new ship should be studied, and the specific working procedure is described. Also, in order to meet the demands of the applications of large area metal-lic coatings for new ships, it is important to use post-treatment technologies with sealing agent to reduce the porosity of metallic coating, thus increasing the adaptation of metallic coatings to corrosive environ-ments.
General cargo ship loading problems belong to general three-dimensional container loading problems. In this paper, based on the analysis of general cargo ship loading problems and taking the goal of maximizing the space utilization, a mathematical model of general cargo ship loading problems is estab-lished. By analyzing the characteristics of the model, a hybrid genetic algorithm combined with the heuris-tic algorithm and the genetic algorithm is presented, and a new type of three-space partition method is de-signed, both of which being realized along with simulation and experimental confirmation. By examining a classic set of test data of Loh & Nee as an example, the space utilization is seen to reach 92.94%, which demonstrates distinct advantages to similar algorithms for the container loading problems. The experimental results show that the hybrid genetic algorithm is feasible on solving general cargo ship loading problems.