Table of Content

01 August 2012, Volume 33 Issue 8

Previous Issue    Next Issue

Paper

Optimum Design for Solid Rocket Motors Based on Individual Discipline Feasible Strategy

ZHU Da-lin, TANG Sheng-jing, GUO Jie, GAO Feng

2012, 33(8):  897-901.  doi:10.3969/j.issn.1000-1093.2012.08.001

Asbtract ( )   PDF (907KB) ( )  

References | Related Articles | Metrics

In order to deal with the complexity of optimum design for solid rocket motors (SRM), the way of multidisciplinary design optimization analyzed the complicated system was introduced. Taking optimum design for SRM with star perforation grain for instance, the design model was partitioned into several subsystems whose functions were defined in accordance with the design requirements and the respective computation models were provided. Subsequently the coupling relationship between subsystems was analyzed in a manner of multidisciplinary design optimization. Finally the instrumental variables were introduced to decouple subsystems from each other by the individual discipline feasible strategy and the optimization variables of concurrent design for SRM were determined. The feasible sequential quadratic programming was selected to optimize the resulting problem and the calculation example has verified the validity of this design pattern. Such a pattern can take full use of modularized and parallel design, so it is helpful to improve the optimization efficiency and model versatility and provides a preferable method to optimum design for SRM involving more comprehensive design factors.

Planar Gaze Parameter Detection in Gaze Tracking System with Active Infrared Light Source

CHI Jian-nan， ZHANG Chuang， CHEN Kai， HU Tao

2012, 33(8):  902-911.  doi:10.3969/j.issn.1000-1093.2012.08.002

Asbtract ( )   PDF (5289KB) ( )  

References | Related Articles | Metrics

In order to meet the requirements and improve the existing methods for parameter detection in gaze tracking system, an approach based on difference image of bright and dark pupils for planar gaze parameter detection was proposed. First, an iteration algorithm called AdaBoost was used to find human face, and according to the priori knowledge of facial features, the eye region was determined and marked in the dark pupil image preliminarily. Then, in difference image, a projection method was applied to locate the possible area of pupil, and pupil would be detected accurately by analyzing its shape and scale. Furthermore, edge detection and an ellipse fitting were used to extract the pupil center parameters, and in the corresponding pupil region in dark pupil image, Purkinje spot and its center parameters were detected. The planar gaze parameters were then calculated according to the center parameters of pupil and Purkinje spot. Applications in gaze tracking system show that the method can detect the planar sight parameters accurately.

Modeling of Magnetic Signatures of Thin-sheet Objects

GUO Cheng-bao, LIU Da-ming

2012, 33(8):  912-915.  doi:10.3969/j.issn.1000-1093.2012.08.003

Asbtract ( )   PDF (1120KB) ( )  

References | Related Articles | Metrics

This paper analyzed the magnetic characteristics of thin-sheet objects and presented a new method combining magnetic moment method and multilevel adaptive cross approximation. It can be used to treat real objects with complex geometry by using very dense meshes and reduce the numerical complexity in both memory requirement and CPU time for the coefficient matrix of magnetic moment method. Several application examples validate the effectiveness of the method.

Load Calculation for Submarine Launched Missile Based on Scaled Model Test

LIU Yu-biao, LIU Wei-wei, CHENG Zai-bin, LIANG Nai-gang

2012, 33(8):  916-920.  doi:10.3969/j.issn.1000-1093.2012.08.004

Asbtract ( )   PDF (935KB) ( )  

References | Related Articles | Metrics

Even if the trajectory, rocket shape, bubble generation, development, retro-reflection and collapse in the scaled test satisfy the similarity law, the structural dynamic characteristics are hardly similar, thus, the prototype's load can not be calculated from the test data easily and directly. In this paper, a modified method to calculate the lateral dynamic response of submarine launched missile prototype from the pressure data of scaled model test was presented. The test data was divided into two parts in the method. The first one was related to the bubble retro-reflection and collapse, and the other to the missile body structure vibration. The dynamic response of the prototype was calculated on the basis of the modified method by building mathematical model of the first part of hydrodynamic pressure and expressing the second by added mass and added damping. The modified method and the direct transform method were compared. The results show that their difference can not be ignored. It provided a beneficial reference for load calculation of submarine launched missile.

Research on the Anti-bullet Performance of Composite Structure with Aerogel Interlayer

YANG Jie, LI Shu-kui, WANG Fu-chi

2012, 33(8):  921-926.  doi:10.3969/j.issn.1000-1093.2012.08.005

Asbtract ( )   PDF (2310KB) ( )  

References | Related Articles | Metrics

The composite targets made of bulletproof fibers，SiC/Al composite material and ceramics in which the aerogel is an interlayer were tested, and the anti-bullet performance of composite structure with aerogel interlayer were studied. The results show that, when the aerogel is combined with bulletproof fibers, the aerogel interlayer could improve the anti-bullet performance of composite target because the deformation of bulletproof fibers is greater due to the low strength of aerogel interlayer. Thus the energy absorption capacity of composite targets improves significantly, and the non-penetrability damage of projectile can also be prevented. When the aerogel is combined with SiC/Al composite material, the anti-bullet performance of composite target improves slightly. The aerogel interlayer could improve the integrality of composite material faceplate after ballistic experiment obviously. When aerogel is combined with ceramics, ceramic faceplate may be bent due to the insufficient support of the aerogel interlayer, resulting in the decrease in the anti-bullet performance of composite target.

Vector Array for 3D Source Location Based on Matched Field Principle

WANG Xue-zhi, TU Ying, WU Ke-tong, WU Jin-rong, CAI Hui-zhi

2012, 33(8):  927-933.  doi:10.3969/j.issn.1000-1093.2012.08.006

Asbtract ( )   PDF (1065KB) ( )  

References | Related Articles | Metrics

The matched field processing approach was applied to horizontal and vertical vector arrays for 3D source location by using exhaustive search. The influence of pressure and particle velocity on the location performence was discussed and analyzed. The parameters leading to better performance were given for horizontal and vertical arrays respectively. For vertical array, the combination of acoustic pressure, cosinusoidal horizontal velocity and sinusoidal horizontal velocity or vertical velocity, sinusoidal horizontal velocity and cosinusiodal horizontal velocity was needed for 3D location, while for horizontal array, the combination of vertical velocity, cosinusoidal horizontal velocity and sinusoidal horizontal velocity is needed.

Hydrodynamic Characteristics Analysis of UUV Parking on Seabed

ZHU Xin-yao， SONG Bao-wei， WANG Peng

2012, 33(8):  934-943.  doi:10.3969/j.issn.1000-1093.2012.08.007

Asbtract ( )   PDF (1753KB) ( )  

References | Related Articles | Metrics

In order to obtain the hydrodynamic characteristics of the unmanned underwater vehicle (UUV) parking on the seabed and the effect of vertical thrusters on it, two kinds of UUV, with and without vertical thrusters respectively, were modeled and meshed using the software ANSYS ICEM in different distances from the seabed and different seabed oblique angles, and the flow fields around these UUVs were simulated by using CFX. From the simulation, the lateral forces and lifts of these two UUVs under different conditions were obtained and the curves of lateral forces and lifts changing with distance from the seabed, oblique angle and water velocity were analyzed. Finally, the effect of vertical thrusters on the hydrodynamic characteristics was analyzed according to the simulation results. The results reveal that the effect of the distance from the seabed on the lateral forces is minor while that on lifts is great; both of the lateral forces and lifts increase rapidly with the increase of water velocity; the lateral forces decease slowly with the increase of the absolute value of seabed oblique angle while lifts increase rapidly; the lateral forces of UUV with vertical thrusters are 5%~15% larger than that if UUV without vertical thrusters while lifts are several times larger.

Application of Modified Space-Time Adaptive Processing in Sonar

LU Wei, WANG Zhi-jie, LI Jian-chen, WANG Ming-zhou, HU Qiao, YANG Bao-min

2012, 33(8):  944-950.  doi:10.3969/j.issn.1000-1093.2012.08.008

Asbtract ( )   PDF (2890KB) ( )  

References | Related Articles | Metrics

In order to solve the problem of anti-reverberation in shallow water, a modified method of space-time adaptive processing (STAP) for sonar was proposed. Firstly, the principle of STAP was analyzed according to the echo model of radar. Secondly, comparing the echo model of sonar with radar, the space-time coupling guiding vector was used in space-time processing. Finally, the proposed method was applied in optimization processing and object detection. The simulation results illustrate that the modified method is beneficial to underwater object detection, and the application of space-time coupling guiding vector can increase the accuracy of the direction estimation of targets.

A Wide-band Method for Measurement of Reflection Coefficient Based on Pulse Compression Technique

YU Sheng-qi， SONG Yang， HUANG Yi-wang

2012, 33(8):  951-955.  doi:10.3969/j.issn.1000-1093.2012.08.009

Asbtract ( )   PDF (926KB) ( )  

References | Related Articles | Metrics

The reflection coefficient is one of the most important acoustic parameters of materials. In order to measure it in water tank, a method based on pulse compression technique was proposed to extrct the directive and reflective waves from the received compressing signal. This method can overcome unavoidable multi-path disturbance in experiments and easily obtain the reflection coefficient at different frequencies in the measured frequency band. That is, the wide-band measurement for reflection coefficient was realized. The method was verified through simulation. Further more, the experiment results in water tank for an aluminum plate in the frequency range of 30-40 kHz were given also. Comparison of experimental results with theoretical value shows that, although the experiment curve exhibits some deviation and fluctuation, a more accurate result would be obtained by increasing the frequency band of transmitting signal to improve the compression effect or applying appropriate window functions to suppress the level of side lobes.

Kinematic Modeling and Trajectory Simulation for Underwater Supercavitating Vehicles

LI Dai-jin, LUO Kai, DANG Jian-jun, WANG Yu-cai, ZHANG Yu-wen

2012, 33(8):  956-961.  doi:10.3969/j.issn.1000-1093.2012.08.010

Asbtract ( )   PDF (1001KB) ( )  

References | Related Articles | Metrics

Considered time-delay effects, the kinetic model of supercavitating vehicles was established, and the dynamic forces and moments caused by the deviation of the vehicle's body axis from supercavity axis under maneuver conditions were contained in it. To verify the veracity of the model under the strong maneuvering condition, a trajectory simulation was carried out. The results show that the motion characteristics of the strong maneuvering vehicles can be well described by the model; under the up-and-down rudder control mode, the limited rudder angle is an important factor to influence the oscillation of rudder angle.

Study on Lever Effect of Accelerometer in Two-loop Autopilot

HE Jing， XIA Qun-li₂， SUN Jing₁, LIU Da-wei₁, SUN Xu-guang₁

2012, 33(8):  962-967.  doi:10.3969/j.issn.1000-1093.2012.08.011

Asbtract ( )   PDF (976KB) ( )  

References | Related Articles | Metrics

Based on the pole assignment, the influence of performance was analyzed and the principle on rapidity and stability was clarified with the methods of root locus and feedback. It is concluded that the positive lever effect obviously decreases the velocity of frequency of autopilot, which varies along with the open loop gain. Hence, a two-loop autopilot with a high gain can be designed without compensation network. Or it can enhance the stability. So it is a method that the accelerometer is fixed before the gravity to improve performance of autopilot. The simulation result shows that the conclusion is proper and important.

Modeling and Simulation Analysis for Dynamic Reliability of Navigation System

TAO Jun-yong， CHENG Hong-wei， WANG Yong

2012, 33(8):  968-974.  doi:10.3969/j.issn.1000-1093.2012.08.012

Asbtract ( )   PDF (1256KB) ( )  

References | Related Articles | Metrics

It focuses on the dynamic reliability assessment of navigation system. Firstly, the sampling criterion of the scenarios was studied based on the Monte Carlo simulation and the sampling criterion was given by calculating Shannon information entropy. Then the model of the dynamic reliability of navigation system was built based on SimPRA（simulation-based probabilistic risk analysis）and finished the dynamic reliability analysis. The results show that dynamic reliability assessment is advantage and effectiveness in engineering.

Demand Prediction Model for Spare Parts Based on Fill Rate Allocation

TAO Xiao-chuang， GUO Lin-han， XIAO Bo-ping， LIU Rui

2012, 33(8):  975-979.  doi:10.3969/j.issn.1000-1093.2012.08.013

Asbtract ( )   PDF (927KB) ( )  

References | Related Articles | Metrics

Considered the disjunction between current spare part demand prediction methods and system top-level design requirements, as well as the large deviation between prediction results and readiness requirements of equipment system, the relationship between achieved availability and system level fill rate should be established by using augmented achieved availability. Analyzed the influence factors on the fill rate, the fill rate could be allocated to subsystems and LRU level for the prediction of spare part demand. A case on aircraft spare part demand prediction was introduced, and the prediction results verified the method's feasibility and applicability. The spare part demand prediction integrating equipment bottom-level design elements can be well consistent with the system top-level design requirements, and the proposed method is helpful to realize the design requirement and enhance the prediction operability.

Research on Reliability Modeling for Real-time Repair System

TANG Kou-lin

2012, 33(8):  980-985.  doi:10.3969/j.issn.1000-1093.2012.08.014

Asbtract ( )   PDF (932KB) ( )  

References | Related Articles | Metrics

Aimed at the shortage of command information system which needs to use reliability algorithm model reflecting repair characteristics, a concept of real-time repair system was put forward. The reliability definition of the system consisting of some similar real-time repair parallel/voting sub-systems was given also. Firstly, the reliability model consisting of parallel sub-systems was derived according to the definition of real-time repair system. Secondly, the reliability model with n sub-systems was deduced according to the similar method.

Research on Effects of Ship Motion on Interface Fatigue Damage of Solid Rocket Motor

QU Kai， ZHANG Jie， ZHANG Xu-dong

2012, 33(8):  986-990.  doi:10.3969/j.issn.1000-1093.2012.08.015

Asbtract ( )   PDF (1258KB) ( )  

References | Related Articles | Metrics

It is very difficult to evaluate SRM (solid rocket motor) damage due to ship motion. In order to solve this problem, a fatigue damage evaluation method of interface between propellant and liner under swing loading was established for some SRMs. The damage property between propellant and liner was acquired by using cyclic loading test with fixed shear stress. The nodes' shear stress spectra of SRM were obtained by means of finite element analysis method. A rain-flowing counting method and Miner's linear cumulative damage theory were applied to evaluate the interface fatigue damage. The test and simulation results show that the shear stress amplitude and logarithmic number of damage accords with exponential equation; the life of SRM under certain shipboard conditions is at least 8.62% shorter than that under storage situation.

Fault Prediction Method Based on Improved AdaBoost-SVR Algorithm

DENG Sen₁, JING Bo₁, ZHOU Hong-liang₁, ZHU Hai-peng₁, LIU Xiao-ping₂

2012, 33(8):  991-996.  doi:10.3969/j.issn.1000-1093.2012.08.016

Asbtract ( )   PDF (955KB) ( )  

References | Related Articles | Metrics

In order to increase prediction precision of SVR (support vector regression) for catastrophic failures, an improved AdaBoost algorithm was proposed. It could obtain the weights of abnormal data in training sample set by AdaBoost algorithm and a weighted SVR was used to enhance the training of abnormal data, which could improve the prediction precision for catastrophic failure. The samples with small weight were discarded by using an adaptive weight trimming method to improve the training speed. The method was used to predict time series of an engine wear element and the one-step relative prediction error was 0.025. The experiment results demonstrate that the method can improve the speed of fault prediction effectively under desired accuracy.

Non-probabilistic Reliability Analysis for Supercavitating Projectile Based on Dynamic Stability

SONG Xiang-hua， AN Wei-guang， JIANG Yun-hua

2012, 33(8):  997-1003.  doi:10.3969/j.issn.1000-1093.2012.08.017

Asbtract ( )   PDF (985KB) ( )  

References | Related Articles | Metrics

Aimed at the axial disturbed load to the head of supercavitating projectile at high speed motion underwater, its indefiniteness was considered, and the structure reliability of supercavitating projectile was analyzed on the basis of dynamic stability. The partial differential dynamic equation of the projectile's cut-off-cone structure was established, then it was transformed to a second-order ordinary differential Mathieu equation, and the numerical calculation for the dynamic stability of supercavitating structure was performed with Bolotin method，finally, the dynamic stability safety margin equations of supercavitating structure was given. The influences of length-diameter ratio, velocity and length of supercavitating projectile on the dynamic stability were analyzed. Based on those, the structural non-probabilistic reliability was analyzed and obtained, the effectiveness of the method was demonstrated by using some examples.

Research Notes

Preliminary Experiments for Shock Sensivity Test of ExplosivesBased on Underwater Small Cardboard Method

HE Zhong-qi, CHEN Wang-hua, PENG Jin-hua, LIU Rong-hai, WANG Hui-jun, JIANG Wei

2012, 33(8):  1004-1008.  doi:10.3969/j.issn.1000-1093.2012.08.018

Asbtract ( )   PDF (906KB) ( )  

References | Related Articles | Metrics

According to the standard “Explosive Test Method”, the test for shock sensitivity of explosives is much consumptive, inconvenient, and the results are affected by personal factors easily. Combining small cardboard test with underwater explosion experiment, an underwater cardboard test method for shock sensitivity was proposed, which could be much safer, less consumptive, environment-friendly and fairly worthwhile. The underwater explosion device, components and materials, test system, operation procedure and data processing of the experiment method were also given. Five common explosives, including TNT, were tested. The results show that the new method can acquire abundant information, needs only less samples, and has better accuracy. It can be used for test of high sensitivity explosives, and can be carried out under general experiment circumstance.

Experimental Study on Effect of Aggregate Size to Anti-penetration Ability of Concrete Targets Subjected toHigh-velocity Fragments

ZHANG Wei， MU Zhong-cheng, XIAO Xin-ke

2012, 33(8):  1009-1015.  doi:10.3969/j.issn.1000-1093.2012.08.019

Asbtract ( )   PDF (3322KB) ( )  

References | Related Articles | Metrics

In order to investigate the effect of aggregate size on the anti-penetration ability of concrete targets subjected to high-velocity fragments, a two-stage light-gas gun as the accelerate facility and laser light barrier measurement system were employed to conduct the penetration experiments for plain concrete targets and steel fiber-reinforced concrete targets, and the projectile pose and the dynamic damage process of targets were recorded by a high-speed camera. In the experiments, three different aggregate sizes on 5～10 mm, 10～15 mm and 15～20 mm were involved. The results of penetration depth, crate volume and debris spall processes indicate that the large aggregate size corresponds to the increase of anti-penetration ability for plain concrete targets, but the target with 10～15 mm of aggregate size has the optimum efficiency in terms of anti-penetration ability when comparing to the other two kinds of concrete targets for steel fiber-reinforced concrete targets with 1% steel fiber in volume. Considered the effect of aggregate size on the fracture energy of concrete materials, it indicates that there exists an optimum ratio between the content of steel fiber and aggregate size, and under the optimum ratio, the ability of anti-penetration of concrete targets can reach the maximum value. The results in this paper is very beneficial to the design of protection engineering.

Application of Two Kinds of Combined Probes in Detonation Experiments

JIN Shan, TANG Tie-gang, CHEN Yong-tao, LI Qing-zhong, WANG Jian

2012, 33(8):  1016-1019.  doi:10.3969/j.issn.1000-1093.2012.08.020

Asbtract ( )   PDF (888KB) ( )  

References | Related Articles | Metrics

The arriving time of the metal flyer at some point was measured by two kinds of combined probes for checking their uniformity. Meanwhile, the free-surface velocity and displacement of the metal flyer were measured by double-sensitive VISAR for contrast with combined probes. Experiment results show that the first stage probe of the vertical combined probe coincides well with the horizontal combined probe; the second stage probe has a little difference with the horizontal combined probe; the difference increases along with the stage of vertical combined probe, and the reason is the interference of the probe on the flyer. The maximum differences at the measuring point 1 between two kinds of combination probes and VISAR are 0.71% and 0.67% respectively, and the maximum differences at point 2 are 0.98% and 0.90% respectively. Two kinds of combined probes can be used together to acquire more data in the experiments.

Formation Optimization for Cooperative Localization Based on Moving Long Baseline with Two Leader AUVs

FANG Xin-peng， YAN Wei-sheng

2012, 33(8):  1020-1024.  doi:10.3969/j.issn.1000-1093.2012.08.021

Asbtract ( )   PDF (1372KB) ( )  

References | Related Articles | Metrics

A cooperative localization method for multiple autonomous underwater vehicles (AUV) based on moving long baseline (MLBL) and range observation was presented, the internal and external information was fused to locate the follower. Considered the influence of AUV formation on the localization performance, an evaluation criterion based on Cramer-Rao lower bound (CRLB) and Fisher information matrix (FIM) was developed to derive the optimal formation configuration. The optimal formation of cooperative localization with two leaders was studied, and the optimal formation with the separation angle of 90° between the leaders and follower was found out. Simulations were performed to evaluate the conclusions from two aspects of range and separation angle, respectively.