水下无人系统学报

Modal Analysis on the Composite Structure of High Altitude Delivery Carrier

SHUAI Zhi-hao, YAN Hai, CAO Xiao-juan, WANG Zhi-jie

2015, 23(2): 081-85. doi: 10.11993/j.issn.1673-1948.2015.02.001

[Abstract](875) [PDF 514KB](437)

Abstract:
A new method for modeling the composite structure of high altitude delivery carrier through the way of ‘subsection meshing and joint binding’ is proposed, and a corresponding model is constructed by means of the finite element analysis software Abaqus. Then, the modal analysis on the composite structure is conducted in the case of free boundary condition, and the natural frequencies and mode of vibration of first 30 orders are obtained, respectively. The results show the individual vibration magnitude distribution of different composite structure part and the weak areas for vibration, and reveal the characteristics of vibration modals in different natural frequencies, which may provide a reference for structural improvement and optimization design of the delivery carrier

Application and Development of New Materials in Torpedo Designs

ZHANG Meng, SUN Shu-ri, FENG Dian-zhen

2015, 23(2): 086-89. doi: 10.11993/j.issn.1673-1948.2015.02.002

[Abstract](975) [PDF 374KB](561)

Abstract:
This paper introduces the basic characteristics of several new materials in torpedo designs with focus on such metal materials as Al-Li alloy, magnesium alloy, titanium alloy, and high temperature alloy, as well as such nonmetallic materials as vibration damping material, ceramic material, and carbon graphite impregnated with silver. Their applications to modern torpedoes are described, and their development trends in intending torpedo designs are forecasted

Working Reliability Assessment Method for Torpedo in Sea Trial Based on Weibull Distribution

ZHANG Yuan-biao, YE Hao-jie, ZHU Wen-zhen

2015, 23(2): 090-92. doi: 10.11993/j.issn.1673-1948.2015.02.003

[Abstract](1133) [PDF 186KB](393)

Abstract:
To compensate the shortage of working reliability assessment of a torpedo in sea trial with indistinguishable long range and short range based on the conventional binomial distribution, a new assessment method based on the Weibull distribution is proposed. The features of modern torpedoes, such as complex system structure and fault states, larger range, and longer working time, are considered in this method. Example shows that the new method is simple and practical, and it can assess working reliability of a torpedo more intuitively and scientifically. This method may be applicable to reliability assessment of modern torpedo in sea trial

Numerical Simulation on Echo Signal of Optical Wake Detection System

MA Qing-shan, CHEN Ya-lin, HAO Bao-an, LIU Kun-lun, HE Chen, YAN Bing

2015, 23(2): 093-97. doi: 10.11993/j.issn.1673-1948.2015.02.004

[Abstract](861) [PDF 385KB](478)

Abstract:
To simulate the influences of optical wake detection system parameters on echo signal, we calculated the light scattering characteristics of single bubble by Mie theory, and solved the optical thickness of a wake cross-section in different ages. Considering the application of an optical wake detection system we designed its principle of optical path, and obtained the wake echo signal under certain system parameters by numerical method according to the principle of optical path. Simulation results show that the system parameters have significant influences on echo signal. This study may provide a theoretical reference for parameters optimization of optical wake detection system

An Improved Blind Speech Separation Algorithm via Time-frequency Masking Based on a Single Acoustic Vector Sensor

CHEN Xiao-yi, WANG Ying-min

2015, 23(2): 098-103. doi: 10.11993/j.issn.1673-1948.2015.02.005

[Abstract](837) [PDF 484KB](459)

Abstract:
An improved blind speech separation algorithm is presented based on the direction of arrival(DOA) estimation, which is obtained by the precise direction finding ability of a single acoustic vector sensor(AVS). The proposed algorithm works in time-frequency domain, in which the probability at each time-frequency unit of a specific source is estimated via an expectation-maximization(EM) algorithm based on the von Mises distribution mixture model. Because the mean value is difficult to estimate when the reverberation level is high or the sources are placed closely, a simple but effective improved algorithm is proposed, and is verified via simulation under different reverberation level, direction difference and source number. Simulation results show that the improved algorithm is superior to the binary time-frequency masking algorithm and the soft time-frequency masking algorithm in terms of signal-to-distortion ratio(SDR) and perceptual evaluation of speech quality(PESQ)

A Facticity Judgment Method for Target Detection of Torpedo Active Acoustic Homing

XIONG Qian-kun, TANG Shi-xuan

2015, 23(2): 104-107. doi: 10.11993/j.issn.1673-1948.2015.02.006

[Abstract](1200) [PDF 191KB](422)

Abstract:
To solve the instability problem in target detection of torpedo active acoustic homing, a quantitative facticity judgment method for target detection is put forward. In this method, according to the target parameters detected by a torpedo, such as the range and azimuth, inverse coordinate calculation is adopted to calculate target point in torpedo inner coordinate system, then the coordinate of the target point is transferred. The distance between detected target point and actual target point is calculated in the same rectangular coordinate system to judge the facticity of the target detected by torpedo active acoustic homing. This algorithm is implemented with the programming language Python, and two examples prove the feasibility of the proposed method

Study on Feasibility of Torpedo Active Concealed Detection Technology

WU Ya-jun, LU Ding-ding

2015, 23(2): 108-112. doi: 10.11993/j.issn.1673-1948.2015.02.007

[Abstract](1577) [PDF 350KB](502)

Abstract:
To discuss the feasibility and realization of torpedo active concealed detection technology, a model of low probability of intercept(LPI) homing system are established, including a model of homing receiver, a model of reconnaissance receiver and a model of underwater acoustic channel. Then theoretical analysis and simulation evaluation on the performance of torpedo active concealed detection are performed, and forecasting of torpedo active concealed detection range is given. In addition, feasibility analysis of torpedo active concealed detection is carried out from the aspects of the generation and process of large time-bandwidth product signal, and technical route for realizing the torpedo active concealed detection through active continuous wave homing is proposed, which may provide an approach for engineering implementation of the torpedo active concealed detection

Strategy and Parameter Selection for Motor Optimization Based on Quantum Genetic Algorithm

WU Song, CHEN Gang

2015, 23(2): 113-118. doi: 10.11993/j.issn.1673-1948.2015.02.008

[Abstract](1191) [PDF 283KB](390)

Abstract:
When the quantum genetic algorithm is applied to optimization design of motor structure, it is necessary to deal with the relative strategies and parameters properly, which needs more user′s experience. In this study, taking a permanent magnet brushless DC double-rotor motor with an outer rotating magnetic system for example, the selection of rotation angle adjusting strategy and convergence criterion is discussed, the effects of different quantum crossover probabilities and quantum mutation probabilities on optimization result are analyzed, and the setting idea of population size and number of optimization variables is introduced. As a result, a scheme for applying quantum genetic algorithm to motor structure optimization is obtained. This scheme can also be adopted for solving other similar problems

An Accurate Computation Method of Vibration Level Based on Comb Band-stop Filter

SUN Tao, GAO Hui-zhong

2015, 23(2): 119-123. doi: 10.11993/j.issn.1673-1948.2015.02.009

[Abstract](1276) [PDF 537KB](711)

Abstract:
The existing 1/3 octave spectrum approaches are usually supposed to test signals without interference. Obviously, this strategy is no more effective when confronted with the signals containing band noise. In this paper, aiming at the regular noise interference, such as comb noise, the Fourier kernel function is employed to construct a comb band- stop filter, and further the filter is combined with the 1/3 octave spectrum to remove the effects exerted by noise. The proposed strategy can remove the interference in frequency domain and calculate the filtered vibration level more efficiently and conveniently, compared with the existing approaches. For the vibration signals with regular noise interference in the power test of a propulsion system, proper revision and consequent reevaluation can avoid repeated tests and save test costs

A Thrust Test Method for Water Ramjet Engine

WANG Xiao-xin, DANG Jian-jun, ZHANG Xue-lei, LUO Kai

2015, 23(2): 124-128. doi: 10.11993/j.issn.1673-1948.2015.02.010

[Abstract](861) [PDF 497KB](371)

Abstract:
To explore a reasonable thrust test method for the water ramjet engine used in supercavitating underwater vehicle, an associative theoretical model between the engine nozzle thrust value and flow field parameters is established by means of theoretical analysis and simulation, and an underwater test and estimation method of the thrust value is proposed. Numerical calculation of the flow field is performed according to the shape and typical working conditions of a particular supercavitating vehicle. And the thrust value calculated with the proposed test method is compared with the design value to verify the feasibility of the proposed method. Furthermore, the conditions of over-expansion and under-expansion of the engine nozzle are analyzed, and the flow field characteristics of the nozzle outlet section are obtained, which may facilitate the key parameters measurement at the engine nozzle outlet section by the proposed method

Influence of Eccentric Initiation on Torpedo Directional Warhead Power:

QU Da-wei, WANG Tuan-meng

2015, 23(2): 129-133. doi: 10.11993/j.issn.1673-1948.2015.02.011

[Abstract](946) [PDF 515KB](540)

Abstract:
Directional initiation technology can increase the power utilization ratio of directional warhead for a torpedo, and enhance the damage to large ship target. In this study, numerical simulation and experiment were conducted to investigate the shock wave overpressure of the scale-reduced prototype of heavyweight torpedo directional warhead at same testing point in three different initiation ways. The results show that in certain distance range, the 3-point eccentric initiation of the warhead generates higher shock wave overpressure in the direction of target than central initiation, and the shock wave overpressure increases significantly with the increase in eccentricity. Therefore, the 3-point eccentric initiation becomes the preferential initiation way for heavyweight torpedo directional warhead. This research may provide a reference for optimization design of heavyweight torpedo directional warhead

Characterization of Joint Source-channel Coding in Buoy Wireless Communication

XUE Qing-tian, XU Yu-yang, ZUO Xiao-ya, ZHU Yun-zhou, ZHOU Hu, LI Bo, YAN Zhong-jiang

2015, 23(2): 134-138. doi: 10.11993/j.issn.1673-1948.2015.02.012

[Abstract](888) [PDF 1206KB](819)

Abstract:
Buoy wireless communication system can transmit and analyze battlefield environment information in time. But its working environment has limited resources, time-varying characteristics, and so on. Coding based on the principle of separation is not suitable for this complicated situation. This paper analyzes the characteristics of different sources in buoy wireless communication, and proposes two joint source-channel coding methods based on unequal error protection and low density parity check(LDPC) coding for sensor information and image/video information, respectively. Simulation results show that the proposed methods can significantly improve the restorability of important sensor data and image/video information while improving the efficiency of transmission, and ensure the transmission reliability. This study may help to enhance integrated operational capability of Chinese Navy

Research on Anti-Shock Capability of Shipborne Torpedo Launcher Based on Dynamic Design Analysis Method

HE Jia-lei, ZHOU Chuan

2015, 23(2): 139-144. doi: 10.11993/j.issn.1673-1948.2015.02.013

[Abstract](1115) [PDF 1766KB](1014)

Abstract:
The anti-shock capability of marine equipment and system is an important factor in determining the vitality of a ship in wartime. Based on the modal test for shipborne torpedo triple launcher and the finite element modeling technology, we establish a finite element analysis model of the launcher to investigate its anti-shock capability. In terms of the dynamic design analysis method(DDAM), with which American navy assess the anti-shock capability of marine equipment, we design launcher shock input spectrum according to the GJB1060 Standard to simulate and assess the anti-shock capability of the triple torpedo launcher. Simulation results demonstrate that on the turntable tile plate the maximum shock response displacement and the maximum Von-Mises stress appear in transverse direction, but the max transverse Von-Mises stress is less than the yield strength of material. The transverse, longitudinal and vertical anti-shock capabilities meet the requirements of the ship anti-shock assessment

An Aiming Point Selection Method for Wake Homing Torpedo Against Elusive Maneuver

ZHANG Hong-gang, WANG Peng, ZHANG Jing-yuan

2015, 23(2): 145-149. doi: 10.11993/j.issn.1673-1948.2015.02.014

[Abstract](964) [PDF 366KB](627)

Abstract:
With torpedo alarm distance increasing, a surface ship can effectively evade the attack of a wake homing torpedo by elusive maneuver. In this study, aiming at typical elusion mode, the critical alarm distance for a surface ship to successfully evade a wake homing torpedo is simulated with different aiming points. Simulation results show that the critical alarm distance is relative to the azimuth of an incoming torpedo, and increases with the increase in proportionality coefficient. As a result, moving the aiming point backward can improve the anti-countermeasure effect of a wake homing torpedo against elusive maneuver of a surface ship.

Research on Capability of Attacking Submarine by Cruise Assisted Torpedo with Instruction Correction

JIA Yue, LIANG Liang, REN Lei

2015, 23(2): 150-156. doi: 10.11993/j.issn.1673-1948.2015.02.015

[Abstract](1344) [PDF 505KB](493)

Abstract:
This paper introduces the instruction correction function of a cruise assisted torpedo and the process of attacking submarine, and analyzes the principles and correction occasion of instruction correction shooting. The influencing factors on instruction correction shooting are investigated in terms of torpedo′s correction capability and attitude, and target’s motion elements. Subsequently, a simulation model of attacking submarine capability for the cruise assisted torpedo is established, hence the optimum corrected flight distance and its changing rule are obtained, and the attacking submarine capability of the cruise assisted torpedo with instruction correction is analyzed. This study may provide a theoretical basis for practical application of instruction correction shooting

Application of Prognostics and Health Management Technology to Design of Torpedo PHM Model

WANG Hao, GAO Jiang

2015, 23(2): 157-160. doi: 10.11993/j.issn.1673-1948.2015.02.016

[Abstract](760) [PDF 238KB](969)

Abstract:
Taking the successful application of the prognostics and health management (PHM) technology for example and considering the maintenance features of large weapon systems in service, the key theory and techniques, as well as the complexity of PHM technology, are discussed. And a torpedo PHM model is designed by analyzing the design idea and application approach of the condition based maintenance (CBM) opening system frame. The duty and function of each module in the model are analyzed, and the model′s structure is improved

2015 Vol. 23, No. 2

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