2016 Vol. 11 No. 2
column
2016, 11(2)
Abstract：
[1] Method of the catapult quantity deployed by using closed queuing network…CHEN Hongzhao,YANG Dapeng(1)[2] Warship's RMS modeling and simulation based on the task process…YUAN Zong(5)[3] Influences of ventilation modes on the coughing droplet dispersion process in a cruise cabin…ZHENG Lijie,XU Jian,WU Fangliang,et al(12)[4] Vulnerability assessment for dead-ship stability failure mode of the damaged warship…LV Zhenwang,MA Kun,LI Xinmeng(21)[5] Time-frequency characteristics analysis of free-field pressure with underwater explosion…XIE Yaoguo,CUI Hongbin,LI Xinfei,et al(27)[6] Residual strength analysis of vessels under near-field underwater explosion loads…TIAN Zhengdong,LI Ye,LI Pengbo,et al(33)[7] Novel Research on the hatch corner's fatigue life of a V-shape non-ballast water ship…WANG Lin,XIA Menglong,XIE De(39)[8] Investigation on the stress state along the crack front in the fatigue crack growth rate test for thick high strength steel plates…DANG Zhifan,YUE Jingxia,DONG Yan(51)[9] The influence of variation of thickness for crashworthiness ability of stiffener plate structures…HUANG Dong,GONG Yufeng,LIU Jingxi(58)[10] The effect of optimized structures on the spudcan bearing capacity…ZHANG Zhaode,LV Guoxing,ZHANG Xin(66)[11] A review of the progress for computational methods of hydrodynamic noise…LI Huan,LIU Congwei,WU Fangliang,et al(72)[12] The effect of the sea opening structure on the ship side on the structural acoustic characteristics…XU Jianlong,ZHANG Sheng,PAN Guoxiong,et al(90)[13] Composite propeller's strain modal and structural vibration performance…HUANG Zheng,XIONG Ying,YANG Guang(98)[14] Vibration characteristics analysis of finite cylindrical shells semi-filled with liquid…LI Tianyun,WANG Lu,GUO Wenjie,et al(106)[15] A computation method of the combat capability of the weapon channel considering the restricted shipboard condition…PEI Xuebing,XU Wenqing,CHEN Jichao(111)[16] Fault tolerant control of the water-feeding system of steam generators…ZHAO Shuqin,ZHANG Yongsheng(117)[17] Shaft-ground active compensation technology of the ship shaft-rate electric field…ZHANG Anming,ZHANG Haipeng,CHENG Zhenghua(121)[18] Stealth evaluation and improvement of mast configuration in the preliminary design stage…DU Xiaojia,CUI Mei(127)[19] Effects of operating parameters of MBR on the treatment of ship's restaurant oily wastewater…LIU Xiyuan,LI Shu,XIE Chengli,et al(133)
[1] Method of the catapult quantity deployed by using closed queuing network…CHEN Hongzhao,YANG Dapeng(1)[2] Warship's RMS modeling and simulation based on the task process…YUAN Zong(5)[3] Influences of ventilation modes on the coughing droplet dispersion process in a cruise cabin…ZHENG Lijie,XU Jian,WU Fangliang,et al(12)[4] Vulnerability assessment for dead-ship stability failure mode of the damaged warship…LV Zhenwang,MA Kun,LI Xinmeng(21)[5] Time-frequency characteristics analysis of free-field pressure with underwater explosion…XIE Yaoguo,CUI Hongbin,LI Xinfei,et al(27)[6] Residual strength analysis of vessels under near-field underwater explosion loads…TIAN Zhengdong,LI Ye,LI Pengbo,et al(33)[7] Novel Research on the hatch corner's fatigue life of a V-shape non-ballast water ship…WANG Lin,XIA Menglong,XIE De(39)[8] Investigation on the stress state along the crack front in the fatigue crack growth rate test for thick high strength steel plates…DANG Zhifan,YUE Jingxia,DONG Yan(51)[9] The influence of variation of thickness for crashworthiness ability of stiffener plate structures…HUANG Dong,GONG Yufeng,LIU Jingxi(58)[10] The effect of optimized structures on the spudcan bearing capacity…ZHANG Zhaode,LV Guoxing,ZHANG Xin(66)[11] A review of the progress for computational methods of hydrodynamic noise…LI Huan,LIU Congwei,WU Fangliang,et al(72)[12] The effect of the sea opening structure on the ship side on the structural acoustic characteristics…XU Jianlong,ZHANG Sheng,PAN Guoxiong,et al(90)[13] Composite propeller's strain modal and structural vibration performance…HUANG Zheng,XIONG Ying,YANG Guang(98)[14] Vibration characteristics analysis of finite cylindrical shells semi-filled with liquid…LI Tianyun,WANG Lu,GUO Wenjie,et al(106)[15] A computation method of the combat capability of the weapon channel considering the restricted shipboard condition…PEI Xuebing,XU Wenqing,CHEN Jichao(111)[16] Fault tolerant control of the water-feeding system of steam generators…ZHAO Shuqin,ZHANG Yongsheng(117)[17] Shaft-ground active compensation technology of the ship shaft-rate electric field…ZHANG Anming,ZHANG Haipeng,CHENG Zhenghua(121)[18] Stealth evaluation and improvement of mast configuration in the preliminary design stage…DU Xiaojia,CUI Mei(127)[19] Effects of operating parameters of MBR on the treatment of ship's restaurant oily wastewater…LIU Xiyuan,LI Shu,XIE Chengli,et al(133)
2016, 11(2): 1-4,26.
DOI: 10.3969/j.issn.1673-3185.2016.02.001
Abstract：
The catapult's quantity deployed is a major influencing factor on carrier aircrafts' sortie generation rate.In the incipient designing period, the catapult quantity is also one of the important factors.Considering the queuing characteristic of the launch process as well as the closed characteristic of the launch and recovery process, this paper proposes a closed queuing network based model for evaluating the influence of the catapult's quantity on sortie generation rate, which can be applied to the design of catapult's quantity. For validation, an example is designed based on the F/A-18's sortie and the recovery process in the Surge operation, whose calculating results agree well with the Surge operation.
The catapult's quantity deployed is a major influencing factor on carrier aircrafts' sortie generation rate.In the incipient designing period, the catapult quantity is also one of the important factors.Considering the queuing characteristic of the launch process as well as the closed characteristic of the launch and recovery process, this paper proposes a closed queuing network based model for evaluating the influence of the catapult's quantity on sortie generation rate, which can be applied to the design of catapult's quantity. For validation, an example is designed based on the F/A-18's sortie and the recovery process in the Surge operation, whose calculating results agree well with the Surge operation.
2016, 11(2): 5-11,26.
DOI: 10.3969/j.issn.1673-3185.2016.02.002
Abstract：
Reliability, Maintainability and Supportability(RMS) are important design features that significantly affect the availability of the warship.In order to enrich the design and analyzing methods of war-ship's RMS, this paper, based on the task process, proposes a modeling method for warship's RMS simulation by using the computer simulation modeling technology, establishes a dynamic description model reflecting the relationship among the warship's tasks, equipment, and support resources, and designs a simulation process of the warship's RMS by exploiting the simulation method for the discrete event system.Finally, the modeling and simulation software system is implemented, which includes the overall frame, function module, and main user interface.It is concluded that the proposed system could provide technical and analytical support for the design of warship's RMS.
Reliability, Maintainability and Supportability(RMS) are important design features that significantly affect the availability of the warship.In order to enrich the design and analyzing methods of war-ship's RMS, this paper, based on the task process, proposes a modeling method for warship's RMS simulation by using the computer simulation modeling technology, establishes a dynamic description model reflecting the relationship among the warship's tasks, equipment, and support resources, and designs a simulation process of the warship's RMS by exploiting the simulation method for the discrete event system.Finally, the modeling and simulation software system is implemented, which includes the overall frame, function module, and main user interface.It is concluded that the proposed system could provide technical and analytical support for the design of warship's RMS.
2016, 11(2): 12-20.
DOI: 10.3969/j.issn.1673-3185.2016.02.003
Abstract：
Aiming at problem of the high infection rate of respiratory diseases on cruise ships and the corresponding lack of quantitatively research, the Computational Fluid Dynamics(CFD) method is adopted in this paper to analyze the droplet transmission and dispersion process coughed by an infected passenger accommodated in an enclosed cabin quantitatively.The air flow equation is solved by solving the unsteady Reynolds averaged Navier-Stokes equations while the Eulerian model is used to simulate the coughed droplet dispersion.The controlling effects for reducing the droplet concentration are also investigated under various conditions of changing ventilation modes and increasing ventilation rates.The results show that the displacement ventilation mode is superior to the mixed ventilation mode when increasing the ventilation rate to control the droplet dispersion.The mixed ventilation mode needs at least three air changes to empty the droplet, while the displacement ventilation mode needs only two, and the reduction of averaged droplet concentration obeys exponential distribution.In addition, the sleeping gestures of the infector have big influences on the droplet concentration in the breathing zone and inhaled dose of the susceptible.
Aiming at problem of the high infection rate of respiratory diseases on cruise ships and the corresponding lack of quantitatively research, the Computational Fluid Dynamics(CFD) method is adopted in this paper to analyze the droplet transmission and dispersion process coughed by an infected passenger accommodated in an enclosed cabin quantitatively.The air flow equation is solved by solving the unsteady Reynolds averaged Navier-Stokes equations while the Eulerian model is used to simulate the coughed droplet dispersion.The controlling effects for reducing the droplet concentration are also investigated under various conditions of changing ventilation modes and increasing ventilation rates.The results show that the displacement ventilation mode is superior to the mixed ventilation mode when increasing the ventilation rate to control the droplet dispersion.The mixed ventilation mode needs at least three air changes to empty the droplet, while the displacement ventilation mode needs only two, and the reduction of averaged droplet concentration obeys exponential distribution.In addition, the sleeping gestures of the infector have big influences on the droplet concentration in the breathing zone and inhaled dose of the susceptible.
2016, 11(2): 21-26.
DOI: 10.3969/j.issn.1673-3185.2016.02.004
Abstract：
The vulnerability assessment method for dead-ship stability failure mode of intact ships has already been proposed by International Maritime Organization(IMO).However, the relevant method for the damaged ship has not yet been presented due to the complexity of the damaged ship's motion under dead-ship conditions.Based on the theory of the former case, this paper presents a way of assessing the capsizing probability of the damaged warship.The method is then verified with the calculating results of actual examples, and the influence of each parameter is discussed.Furthermore, the cases of cross flooding and unsymmetrical flooding are investigated.The method provides certain references for calculating the capsizing probability of the damaged ship.
The vulnerability assessment method for dead-ship stability failure mode of intact ships has already been proposed by International Maritime Organization(IMO).However, the relevant method for the damaged ship has not yet been presented due to the complexity of the damaged ship's motion under dead-ship conditions.Based on the theory of the former case, this paper presents a way of assessing the capsizing probability of the damaged warship.The method is then verified with the calculating results of actual examples, and the influence of each parameter is discussed.Furthermore, the cases of cross flooding and unsymmetrical flooding are investigated.The method provides certain references for calculating the capsizing probability of the damaged ship.
2016, 11(2): 27-32,50.
DOI: 10.3969/j.issn.1673-3185.2016.02.005
Abstract：
To obtain the characteristics of the free-field pressure with underwater explosion, the time-frequency characteristics of the monitored free-field pressure signals are studied through wavelet analysis, based on the experimental free-field pressure data subjected to underwater explosion.By using these signals, the pressure-time curves and the energy distributions in different blasting frequency bands are obtained.The result shows that the obtained time-frequency characteristics of free-field pressure can be used to generate the shock wave signal, the after flow signal, and the second pressure pulse, and by analyzing the energy and frequency component, it is easy to get the detailed time-frequency information of the free-field pressure signal intensity, frequency and duration.More than 90% of the energy of the shock wave pressure signals condenses in the band lower than 8 kHz, and the highest level of energy appears below the frequency of 4 kHz, and special attention should be directed to the low frequency band below 250 Hz of the after flow signal as well as the second pressure pulse for ship structure and equipment.Overall, this paper provides reference for shock-resistance analysis of the ship structure.
To obtain the characteristics of the free-field pressure with underwater explosion, the time-frequency characteristics of the monitored free-field pressure signals are studied through wavelet analysis, based on the experimental free-field pressure data subjected to underwater explosion.By using these signals, the pressure-time curves and the energy distributions in different blasting frequency bands are obtained.The result shows that the obtained time-frequency characteristics of free-field pressure can be used to generate the shock wave signal, the after flow signal, and the second pressure pulse, and by analyzing the energy and frequency component, it is easy to get the detailed time-frequency information of the free-field pressure signal intensity, frequency and duration.More than 90% of the energy of the shock wave pressure signals condenses in the band lower than 8 kHz, and the highest level of energy appears below the frequency of 4 kHz, and special attention should be directed to the low frequency band below 250 Hz of the after flow signal as well as the second pressure pulse for ship structure and equipment.Overall, this paper provides reference for shock-resistance analysis of the ship structure.
2016, 11(2): 33-38.
DOI: 10.3969/j.issn.1673-3185.2016.02.006
Abstract：
The damaging effect and residual strength of ships under the near-field underwater explosion loads has remained as one of the most crucial subject in the field of vessel research.In this paper, the structural response under explosive loads is simulated based on the common FEM software by assuming a typical near-field condition of underwater explosion.Loss of the modulus for typical sections is then analyzed according to the crevasse and plastic deformation results of near-field blast, and the loss is within 8%~10%.The wave bending moment and still water bending moment are also calculated after the buoyancy redistribution.Finally, the residual strength in the damaged cases is analyzed simultaneously for the near-field underwater explosion combined with military regulations.The results show that the vessel still meet the requirements of residual strength under torpedo attack.
The damaging effect and residual strength of ships under the near-field underwater explosion loads has remained as one of the most crucial subject in the field of vessel research.In this paper, the structural response under explosive loads is simulated based on the common FEM software by assuming a typical near-field condition of underwater explosion.Loss of the modulus for typical sections is then analyzed according to the crevasse and plastic deformation results of near-field blast, and the loss is within 8%~10%.The wave bending moment and still water bending moment are also calculated after the buoyancy redistribution.Finally, the residual strength in the damaged cases is analyzed simultaneously for the near-field underwater explosion combined with military regulations.The results show that the vessel still meet the requirements of residual strength under torpedo attack.
2016, 11(2): 39-50.
DOI: 10.3969/j.issn.1673-3185.2016.02.007
Abstract：
A novel method to calculate the hatch corner's fatigue life of the V-shape non-ballast ship is proposed in this paper.The proposed method comprehensively studies the wave data provided by integrated marine decision support system, from which both the scatter diagram and operational profile are obtained through programming.The load for the operational profile is calculated with SESAM and the hot spot stress is acquired through ABAQUS modeling.Finally, the structural fatigue life is calculated.It is concluded that the hatch corner's fatigue life of the V-shape non-ballast ship is extended after hatch optimization.
A novel method to calculate the hatch corner's fatigue life of the V-shape non-ballast ship is proposed in this paper.The proposed method comprehensively studies the wave data provided by integrated marine decision support system, from which both the scatter diagram and operational profile are obtained through programming.The load for the operational profile is calculated with SESAM and the hot spot stress is acquired through ABAQUS modeling.Finally, the structural fatigue life is calculated.It is concluded that the hatch corner's fatigue life of the V-shape non-ballast ship is extended after hatch optimization.
Abstract：
Complex environmental loads would unavoidably lead to the fatigue damage in marine structures, and the case worsens in high strength steel thick-welded structures which have typical tri-axial stress and the feature of brittleness.To study the stress state along the crack front, a standard fatigue crack growth rate test for high strength steel Q370QE with a thickness of 36 mm is conducted, and the corresponding material parameters and the threshold of stress intensity factor are obtained.Next, the abnormal behavior of a crack front during crack growth and the stress state along crack front during crack growth are analyzed with the finite element method.Accordingly, the varying tendency of crack front shape could be qualitatively defined.Finally, local constraint factors are introduced in order to quantitatively describe the stress state along the crack front with the growth of fatigue crack based on plasticity analysis, which provides proper explanation to why the crack front changes from slant to flat with the crack growing.The calculated stress intensity factor could only describe the stress state in the center area, but distortion is inevitable on the surface, while the local constraint factor can fully describe the stress state along the crack tip zone.
Complex environmental loads would unavoidably lead to the fatigue damage in marine structures, and the case worsens in high strength steel thick-welded structures which have typical tri-axial stress and the feature of brittleness.To study the stress state along the crack front, a standard fatigue crack growth rate test for high strength steel Q370QE with a thickness of 36 mm is conducted, and the corresponding material parameters and the threshold of stress intensity factor are obtained.Next, the abnormal behavior of a crack front during crack growth and the stress state along crack front during crack growth are analyzed with the finite element method.Accordingly, the varying tendency of crack front shape could be qualitatively defined.Finally, local constraint factors are introduced in order to quantitatively describe the stress state along the crack front with the growth of fatigue crack based on plasticity analysis, which provides proper explanation to why the crack front changes from slant to flat with the crack growing.The calculated stress intensity factor could only describe the stress state in the center area, but distortion is inevitable on the surface, while the local constraint factor can fully describe the stress state along the crack tip zone.
Abstract：
This paper discusses the influence of variation of the thickness for the crashworthiness ability of stiffened plates based on scaled model experiments and with simplification analysis.Two experimental results of stiffener plate scaled model tests are presented, which are then compared with the theoretical results obtained with simplification analysis.It is seen that the two results agree well, and it is also concluded that increasing the thickness of stiffened plates would significantly improve the crashworthiness ability.
This paper discusses the influence of variation of the thickness for the crashworthiness ability of stiffened plates based on scaled model experiments and with simplification analysis.Two experimental results of stiffener plate scaled model tests are presented, which are then compared with the theoretical results obtained with simplification analysis.It is seen that the two results agree well, and it is also concluded that increasing the thickness of stiffened plates would significantly improve the crashworthiness ability.
2016, 11(2): 66-71.
DOI: 10.3969/j.issn.1673-3185.2016.02.010
Abstract：
Based on the engineering practice about the pile-soil penetration interaction of Shengli No.5 Jack-up in Bohai Bay, a numerical model for the pile-soil penetration process is established to investigate the bearing capacity of an optimized spudcan structure which is then compared to that of the real spudcan. The results show that the spudcan bearing capacity first increases and then decreases from inside to outside along the radial and vertical optimized position.At the radial r'/r=0.6 position and vertical h/H=0.4 position, the optimized structure satisfies expectation.It is concluded that the supports in reasonable positions can increase the spudcan bearing capacity and maintain the stability of the penetration process by changing the flow mechanism of soil, which decreases the impulse and velocity deficit of the soil at the top and bottom of the spudcan.
Based on the engineering practice about the pile-soil penetration interaction of Shengli No.5 Jack-up in Bohai Bay, a numerical model for the pile-soil penetration process is established to investigate the bearing capacity of an optimized spudcan structure which is then compared to that of the real spudcan. The results show that the spudcan bearing capacity first increases and then decreases from inside to outside along the radial and vertical optimized position.At the radial r'/r=0.6 position and vertical h/H=0.4 position, the optimized structure satisfies expectation.It is concluded that the supports in reasonable positions can increase the spudcan bearing capacity and maintain the stability of the penetration process by changing the flow mechanism of soil, which decreases the impulse and velocity deficit of the soil at the top and bottom of the spudcan.
2016, 11(2): 72-89.
DOI: 10.3969/j.issn.1673-3185.2016.02.011
Abstract：
It is of great importance to accurately evaluate submarine's hydrodynamic noise in order to develop anti-submarine surface warships, stealthy submarines and torpedoes as well as to optimize their hydrodynamic and acoustic performance.Specifically, the three dimensional unsteady flow field over the vehicle is usually caused by the changes of profile, discontinuity of surface curvature, and various perturbations.In this paper, the research progress of the vehicle's hydrodynamic noise induced by the turbulent boundary layer on the surface, cavity oscillations, cavitation, and roughness are introduced, respectively. By analyzing the difficulties in the numerical prediction of hydrodynamic noise, different computational methods of flow induced noise are summarized.A comparison is finally made among three methods in particular, all of which are potential schemes that can be applied in predicting vehicle's hydrodynamic noise.
It is of great importance to accurately evaluate submarine's hydrodynamic noise in order to develop anti-submarine surface warships, stealthy submarines and torpedoes as well as to optimize their hydrodynamic and acoustic performance.Specifically, the three dimensional unsteady flow field over the vehicle is usually caused by the changes of profile, discontinuity of surface curvature, and various perturbations.In this paper, the research progress of the vehicle's hydrodynamic noise induced by the turbulent boundary layer on the surface, cavity oscillations, cavitation, and roughness are introduced, respectively. By analyzing the difficulties in the numerical prediction of hydrodynamic noise, different computational methods of flow induced noise are summarized.A comparison is finally made among three methods in particular, all of which are potential schemes that can be applied in predicting vehicle's hydrodynamic noise.
Abstract：
Typical marine ships contain large amount of piping systems, and the relevant sea opening structures directly influence the acoustic characteristics of the hull.In this paper, the sea opening of typical piping systems is taken as the research subject, and an analyzing model is established in Fluent, which includes pump, piping system, hull and sea opening.Meanwhile, the sound pressure of the flow field and external field is analyzed.By comparing the optimized models for different fluent areas of the sea opening, a low noise structure is confirmed that is capable of improving the structure's acoustic characteristic significantly.Besides, the variation of the hydrodynamic noise of the whole piping system unit that uses low noise sea opening and the original structure is studied.The results indicate that the low noise sea opening of structure optimization plays a key role in noise reduction, which improves the stability of the whole fluent area and reduces the fluid pressure in the far-field.
Typical marine ships contain large amount of piping systems, and the relevant sea opening structures directly influence the acoustic characteristics of the hull.In this paper, the sea opening of typical piping systems is taken as the research subject, and an analyzing model is established in Fluent, which includes pump, piping system, hull and sea opening.Meanwhile, the sound pressure of the flow field and external field is analyzed.By comparing the optimized models for different fluent areas of the sea opening, a low noise structure is confirmed that is capable of improving the structure's acoustic characteristic significantly.Besides, the variation of the hydrodynamic noise of the whole piping system unit that uses low noise sea opening and the original structure is studied.The results indicate that the low noise sea opening of structure optimization plays a key role in noise reduction, which improves the stability of the whole fluent area and reduces the fluid pressure in the far-field.
2016, 11(2): 98-105.
DOI: 10.3969/j.issn.1673-3185.2016.02.013
Abstract：
The natural frequency and displacement strain modal's vibration mode is comparative studied using validated finite modal algorithm and strain modal experiment, the result showed that the deviation of tested and calculated first three natural frequency of copper and carbon fiber propeller is within 3% and 12%.The carbon fiber propeller has smaller natural frequency, similar strain modal and four times structure damping compared with copper propeller.Further calculation of the wet modal of two propellers, the first four wet modal natural frequency of copper propeller reduced 18%~33% compared with the corresponding dry modal, while the carbon fiber propeller's reduction is 54%~64%.More research on vibration performance of propeller is carried out, the fiber orientation beneficial for vibration attenuation is obtained, the total acceleration level of optimized carbon fiber propeller is 2 dB less than the tested carbon fiber propeller.
The natural frequency and displacement strain modal's vibration mode is comparative studied using validated finite modal algorithm and strain modal experiment, the result showed that the deviation of tested and calculated first three natural frequency of copper and carbon fiber propeller is within 3% and 12%.The carbon fiber propeller has smaller natural frequency, similar strain modal and four times structure damping compared with copper propeller.Further calculation of the wet modal of two propellers, the first four wet modal natural frequency of copper propeller reduced 18%~33% compared with the corresponding dry modal, while the carbon fiber propeller's reduction is 54%~64%.More research on vibration performance of propeller is carried out, the fiber orientation beneficial for vibration attenuation is obtained, the total acceleration level of optimized carbon fiber propeller is 2 dB less than the tested carbon fiber propeller.
2016, 11(2): 106-110.
DOI: 10.3969/j.issn.1673-3185.2016.02.014
Abstract：
Free vibration and forced vibration characteristics of finite cylindrical shells semi-filled with liquid are studied in this paper, based on the energy functional variational principle.The combined form of the triangular series and the Fourier series is used to represent the displacement of the cylindrical shell, and the orthogonality is then used to eliminate the displacement on the other two directions after the variation, where only the radial displacement is kept.The relationship between the amplitudes of fluid load and the amplitudes of the radial displacement is established with the orthogonal processing of the continuous conditions of the solid-liquid coupling contact surface and the boundary conditions of the free liquid surface.Finally, the fluid structure coupling control equation is obtained.The results show that the proposed method is both correct and effective;in addition, it provides a new thought for solving similar problems.
Free vibration and forced vibration characteristics of finite cylindrical shells semi-filled with liquid are studied in this paper, based on the energy functional variational principle.The combined form of the triangular series and the Fourier series is used to represent the displacement of the cylindrical shell, and the orthogonality is then used to eliminate the displacement on the other two directions after the variation, where only the radial displacement is kept.The relationship between the amplitudes of fluid load and the amplitudes of the radial displacement is established with the orthogonal processing of the continuous conditions of the solid-liquid coupling contact surface and the boundary conditions of the free liquid surface.Finally, the fluid structure coupling control equation is obtained.The results show that the proposed method is both correct and effective;in addition, it provides a new thought for solving similar problems.
Abstract：
Based on the combat procedure for the weapon channel of shipboard combat systems, this paper gives a comprehensive analysis on the performance parameters of the weapon equipment, including sensor horizon, weapon range, and time delay.A novel computation method of combat capability is proposed with the consideration of the restricted condition on ships and the performance matching requirement of the weapon channel.The main tactical and technical parameters of the weapon channel are demonstrated after analyzing the performance matching and degrading degree for the weapon equipment in the same channel in accordance to the actual shipboard condition.Then, the obtained parameters are converted into normalized indexes with different effectiveness models.Finally, the combat capability of the weapon channel is calculated through the Analytic Hierarchy Process(AHP) model.The computation results show that the performance matching of the response time, striking area, and multi-objective capability is of vital importance to the combat capability of the weapon channel, particularly during the mission of air defense and anti-missiles.
Based on the combat procedure for the weapon channel of shipboard combat systems, this paper gives a comprehensive analysis on the performance parameters of the weapon equipment, including sensor horizon, weapon range, and time delay.A novel computation method of combat capability is proposed with the consideration of the restricted condition on ships and the performance matching requirement of the weapon channel.The main tactical and technical parameters of the weapon channel are demonstrated after analyzing the performance matching and degrading degree for the weapon equipment in the same channel in accordance to the actual shipboard condition.Then, the obtained parameters are converted into normalized indexes with different effectiveness models.Finally, the combat capability of the weapon channel is calculated through the Analytic Hierarchy Process(AHP) model.The computation results show that the performance matching of the response time, striking area, and multi-objective capability is of vital importance to the combat capability of the weapon channel, particularly during the mission of air defense and anti-missiles.
2016, 11(2): 117-120,138.
DOI: 10.3969/j.issn.1673-3185.2016.02.016
Abstract：
In order to improve the reliability of the secondary circuit control system, a steam generator is taken in this paper as the research object, and a fault tolerant control system of the water level is accordingly designed based on BP neural network.Fault tolerant control simulation is also conducted on the Matlab/Simulink platform, where the lumped parameter dynamic models of the steam generator are joined, and the calculated water level of the steam generator, with the fault of constant deviation, constant gain, or locked, is simulated respectively on the water level sensor.The experimental results show that the sensor faults could be diagnosed accurately and rapidly with the fault diagnosis model, and the fault tolerant control should be implemented when sensor faults occur.Meanwhile, the water level of the steam generator could be regulated close to the target value, and the system works steadily.In brief, the proposed fault tolerant control system based on BP neural network is effective to correct the water level sensor fault of the steam generator, and the system can be applied into the design of the steam generator water-feeding control system, which significantly improves the system reliability.
In order to improve the reliability of the secondary circuit control system, a steam generator is taken in this paper as the research object, and a fault tolerant control system of the water level is accordingly designed based on BP neural network.Fault tolerant control simulation is also conducted on the Matlab/Simulink platform, where the lumped parameter dynamic models of the steam generator are joined, and the calculated water level of the steam generator, with the fault of constant deviation, constant gain, or locked, is simulated respectively on the water level sensor.The experimental results show that the sensor faults could be diagnosed accurately and rapidly with the fault diagnosis model, and the fault tolerant control should be implemented when sensor faults occur.Meanwhile, the water level of the steam generator could be regulated close to the target value, and the system works steadily.In brief, the proposed fault tolerant control system based on BP neural network is effective to correct the water level sensor fault of the steam generator, and the system can be applied into the design of the steam generator water-feeding control system, which significantly improves the system reliability.
2016, 11(2): 121-126.
DOI: 10.3969/j.issn.1673-3185.2016.02.017
Abstract：
In order to reduce marine shaft-rate electric field influence and the exposure rate of the ship, the mechanism of the electric field is analyzed in this paper, along with the principle of the active compensation system.Specifically, the electrical properties are studied based on the analysis of the mechanism of shaft-rate electric field of the ship.The ship shaft-rate electric field suppression is proposed according to the compensated negative potential.The framework and function framework of the system are designed.The weak signal monitoring and processing technology of ship shaft is investigated, and the judgment and control technology of the system is studied.The driving and power output module of the negative potential is designed, where the simulation results show that the ship shaft-rate electric field can be suppressed effectively with the proposed system, and the stealth property of the ship is simultaneously enhanced.
In order to reduce marine shaft-rate electric field influence and the exposure rate of the ship, the mechanism of the electric field is analyzed in this paper, along with the principle of the active compensation system.Specifically, the electrical properties are studied based on the analysis of the mechanism of shaft-rate electric field of the ship.The ship shaft-rate electric field suppression is proposed according to the compensated negative potential.The framework and function framework of the system are designed.The weak signal monitoring and processing technology of ship shaft is investigated, and the judgment and control technology of the system is studied.The driving and power output module of the negative potential is designed, where the simulation results show that the ship shaft-rate electric field can be suppressed effectively with the proposed system, and the stealth property of the ship is simultaneously enhanced.
2016, 11(2): 127-132.
DOI: 10.3969/j.issn.1673-3185.2016.02.018
Abstract：
The stealth performance of warships is directly affected by its mast;therefore, the analysis and evaluation of the stealth performance of the ship's mast in the preliminary design stage is the main research purpose of this paper.By taking a typical enclosed ship mast as the research model, the influences of several important parameters on the stealth performance are analyzed, with the major scattering characteristic of the mast being investigated.It is seen that most of RCS peak points are caused by the specular reflection, and the optimal adjustment of mast configuration is presented.When the ship is rolling, the dihedral angle effect caused by the affiliated platform and main structure would intensify.This paper provides a reference for the stealth performance evaluation and improvement of mast configuration in the preliminary design stage.
The stealth performance of warships is directly affected by its mast;therefore, the analysis and evaluation of the stealth performance of the ship's mast in the preliminary design stage is the main research purpose of this paper.By taking a typical enclosed ship mast as the research model, the influences of several important parameters on the stealth performance are analyzed, with the major scattering characteristic of the mast being investigated.It is seen that most of RCS peak points are caused by the specular reflection, and the optimal adjustment of mast configuration is presented.When the ship is rolling, the dihedral angle effect caused by the affiliated platform and main structure would intensify.This paper provides a reference for the stealth performance evaluation and improvement of mast configuration in the preliminary design stage.
2016, 11(2): 133-138.
DOI: 10.3969/j.issn.1673-3185.2016.02.019
Abstract：
Membrane bioreactor(MBR) has been widely applied to the treatment of ship's oily wastewater. To study the operating parameters of MBR on the treatment of oily wastewater produced by onboard restaurants, wastewater is first produced from axunge which simulates the water characteristics of ship's oily wastewater, and a small shore-based MBR system is subsequently founded.Chemical Oxygen Demand(COD), Biochemical Oxygen Demand(BOD), ammonia nitrogen are tested with the measuring device like spectroscope.The relationship between the Hydraulic Retention Time(HRT) s, COD, BOD, ammonia nitrogen, membrane pressure and sludge concentration during the 70 days operation of the MBR system is also studied, which shows that the MBR could remove the COD, oil, TOC, BOD by over 80% and ammonia nitrogen by over 50% in oily wastewater.Furthermore, the research also indicates that the oil greatly affects the membrane fouling.
Membrane bioreactor(MBR) has been widely applied to the treatment of ship's oily wastewater. To study the operating parameters of MBR on the treatment of oily wastewater produced by onboard restaurants, wastewater is first produced from axunge which simulates the water characteristics of ship's oily wastewater, and a small shore-based MBR system is subsequently founded.Chemical Oxygen Demand(COD), Biochemical Oxygen Demand(BOD), ammonia nitrogen are tested with the measuring device like spectroscope.The relationship between the Hydraulic Retention Time(HRT) s, COD, BOD, ammonia nitrogen, membrane pressure and sludge concentration during the 70 days operation of the MBR system is also studied, which shows that the MBR could remove the COD, oil, TOC, BOD by over 80% and ammonia nitrogen by over 50% in oily wastewater.Furthermore, the research also indicates that the oil greatly affects the membrane fouling.
