Yang P.,Dalian University of Technology |
Lin L.,Dalian University of Technology |
Liu C.,Bohai Shipbuilding Heavy Industry Co. |
Gao H.,Bohai Shipbuilding Heavy Industry Co. |
Li X.,Dalian University of Technology
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2011
Lateral resolution of phased array is measured experimentally with the array aperture of 8 to 30 mm and focus length of 30 mm, 40 mm, 60 mm, 80 mm, respectively. In the experiments a 60 element linear array transducer with wedge is used and sectorial scanning method is adopted. Experiment study reveals that increasing the aperture will improve the lateral resolution while the focus length is fixed; the lateral resolution will decrease with the increase of focus length while the aperture is fixed. The focus length and aperture have great impact on the resolution. Experiment results show good agreements with theoretical analysis and numerical simulation results reported in literatures. The study results are of great value to the applications of phased array ultrasonic testing.
Zhong X.,CAS Shenyang Institute of Automation |
Zhong X.,University of Chinese Academy of Sciences |
Liu C.,CAS Shenyang Institute of Automation |
Zhu J.,CAS Shenyang Institute of Automation |
And 2 more authors.
2015 IEEE International Conference on Cyber Technology in Automation, Control and Intelligent Systems, IEEE-CYBER 2015 | Year: 2015
In order to solve the problem that, from the current practical perspective of semiconductor assembly and test manufacturing (ATM), the traditional multi-objective optimization algorithm is difficult to realize the practical decision of the enterprise, this paper proposes a new multi-objective estimation of distribution algorithm (EDA) to solve the ATM scheduling problem. According to the demand of the ATM enterprise, based on sub-module using two modeling ideas, objectives were divided into two categories: constrained objective and optimized objective, and the different objective had the different searching process. Finally, it used the new algorithm to solve the multi-objective ATM scheduling problem. The result shows that the novel algorithm has the good feasibility and it also has an obvious advantage, the better practicability and maneuverability, compared with the traditional multi-objective optimization methods. © 2015 IEEE.
Liu D.,Harbin Institute of Technology |
Liu D.,Bohai Shipbuilding Heavy Industry Co. |
Li F.,Harbin Institute of Technology |
Tan C.,Harbin Institute of Technology |
And 2 more authors.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2011
EH36 steel thick plate is widely used in shipbuilding industry. In this paper, double-sided arc welding (DSAW) vertical welding of EH36 steel is carried out by robots, which exhibits distinctive merits and broad prospective in application. Backing weld is the most significant procedure in the multi-layer and multi-pass welding, which exhibits important impact on weld joint. Microstructure and performance of back welding joint were studied. The results indicated that proeutectoid ferrite (PF) and acicular ferrite (AF) were the main structure in the weld joint after DSAW. The structure in the back weld was refined after reheating effect in the subsequent multi-layer and multi-pass welding. Microstructure at coarse-grained zone of backing weld joint was bainite and martensite lath. The hardness of back weld was slightly lower than that of the second layer bead. Joint tensile strength was higher than that of base metal, and the characteristic of fracture appearance was dimple.
Chen Z.,Nuclear Power Institute of China |
Liao L.-T.,Nuclear Power Institute of China |
Liu L.-X.,Nuclear Power Institute of China |
Li W.,Bohai Ship Building Heavy Industry Co.
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2012
Considering the problems of small water inventory and inferior heat accumulation capacity of the secondary side of the once through steam generator(OTSG), and the need of rapid match of feedwater flowrate and the reactor power to ensure the steam quality, the T-S fuzzy neural method is incorporated into the OTSG feedwater control system to design a T-S fuzzy neural controller based on input and output data acquired by numerical simulation. The control results are verified by simulation method. The simulation results show that the control results under this control manner are better than those under the PID control manner and meet the control requirements satisfactorily.
Yang J.-Y.,Shenyang University of Technology |
Liu J.-H.,Shenyang University of Technology |
Qiu G.-L.,Shenyang University of Technology |
Chen K.,Shenyang University of Technology |
Wang D.-Y.,Bohai Shipbuilding Heavy Industry Co.
Shenyang Gongye Daxue Xuebao/Journal of Shenyang University of Technology | Year: 2012
In order to further improve the control precision of direct thrust control (DTC) system of permanent magnet linear synchronous motor (PMLSM), a control method based on predictive voltage modulation and Takagi-Sugeno (T-S) fuzzy strategy was proposed. The predictive voltage modulation technology was used to control the next periodic flux linkage, and the space vector pulse width modulation (SVPWM) technology was applied to approach the predictive voltage values. In addition, a T-S fuzzy controller was adopted to control both mover speed and electromagnetic thrust. The comparison and analysis on the simulation results in Matlab/Simulink environment reveal that the proposed DTC control system based on predictive voltage modulation and T-S fuzzy control strategy not only obviously reduces the electromagnetic thrust and flux linkage pulsation, but also exhibits the stronger robustness on the pulsation caused by nonlinear perturbations such as the time variation of motor parameters.
Lei N.,Northeast Petroleum University |
Tang Y.,Northeast Petroleum University |
Lei Y.,Bohai Shipbuilding Heavy Industry Co.
Journal of Vibroengineering | Year: 2016
Vibration signal of reciprocating compressor gas valve represents nonlinear, non-stationary and multiple impulse characteristics. To extract the features of the signal, an integration approach based on local mean decomposition (LMD) method and autoregressive-generalized autoregressive conditional heteroscedasticity (AR-GARCH) model is proposed. First, the property of LMD is investigated in the paper, which indicates that LMD method not only can effectively alleviate non-stationary feature and restrain the end effect of non-stationary signal, but also can accurately improve the resolution of time-frequency analysis. Then, the first five PF components of gas valve signal are modeled by AR(1)-GARCH(1, 1) model as the feature vectors without any prior knowledge about the fault mechanism. Finally, the BP neural networks are applied to diagnose the faults of reciprocating compressor gas valve based on the feature vectors above. The results indicate that high diagnosis accuracy can be obtained by integrating LMD method and AR-GARCH model. So the approach proposed in the paper provides an effective measure to extract the fault feature of reciprocating compressor gas valve. © JVE INTERNATIONAL LTD.
Youfu T.,Northeast Petroleum University |
Longqing Z.,Northeast Petroleum University |
Yong L.,Bohai Shipbuilding Heavy Industry co.
Journal of Vibroengineering | Year: 2014
Vibration signal of reciprocating compressor gas valve presents a typical characteristics of non-stationarity and nonlinearity. An integration approach based on local mean decomposition (LMD) and Lempel-Ziv complexity (LZC) is proposed in this paper for improvement of diagnosis accuracy. First, the LMD method is applied to decompose original gas valve signals into a set of product functions (PFs), each of which is stationary signal. Then, the main PF components are selected by mutual information (MI) method with the original signal, and the LZC of each main PF is computed to form the feature vectors. Finally, the BP neural networks is applied to diagnose the faults of reciprocating compressor gas valve based on the feature vectors above. Experimental results indicate that the fault features of reciprocating compressor gas valve can be extracted by the integration of LMD and LZC. So the proposed approach is one of ways to achieve more accurate diagnosis of reciprocating compressor. © JVE INTERNATIONAL LTD. JOURNAL OF VIBROENGINEERING.
Zhang Y.,China Institute for Radiation Protection |
Yang Y.,Bohai Shipbuilding Heavy Industry Co.
Hedianzixue Yu Tance Jishu/Nuclear Electronics and Detection Technology | Year: 2011
Proportional counter can be used as low-energy particles detector because of its gas gain. According to charging manner, proportional counter can be divided into sealed and gas-flow proportional counters. Compared with gas-flow counter, although sealed proportional counter can be operated simply but it is short-lived, needs to replace the sealed gas periodically. It introduces the aging phenomenon of sealed proportional counter and a method for optimising the gas replacing period.
Wu W.,Dalian Maritime University |
Zhang H.,Bohai Shipbuilding Heavy Industry Co. |
Feng X.,Dalian Maritime University
Advanced Materials Research | Year: 2011
Attempt to reduce the CO2 emission from ships and sailing cost, the rate of propeller cut is calculated by established models of propeller diameter cut and propeller blade shape cut. According to the results, after cutting the edge of propeller under equal power, the rev is increased, but the open water efficiency and the speed both are decreased. However, the increase of the rev is quicker than the decrease of the speed. and the AVL BOOST is used to simulate MAN B&W 5S60MC main engine. The main running parameters under the 25%, 50%, 75% and 85% load are calculated. The result indicates that cutting the edge of propeller can increase the rev, improve lubricating and vibrating, reduce oil consumption and improve the economical efficiency. © (2011) Trans Tech Publications.
Xia G.,Harbin Engineering University |
Liu J.,Harbin Engineering University |
Chen X.,Harbin Engineering University |
Wang D.,Bohai Shipbuilding Heavy Industry Co. |
Yang R.,Bohai Shipbuilding Heavy Industry Co.
2015 IEEE International Conference on Mechatronics and Automation, ICMA 2015 | Year: 2015
The extended Kalman filtering (EKF) based identification is an effective identification technology. It has made successful applications in ship model identification fields to cruise-speed ships. This paper introduces it to the dynamic positioning (DP) ship model identifications. The DP ship is of different motion characteristics with that at the cruise-speed. Because the ship speed is close to zero, DP ships are easily affected by the sea environment disturbances, which makes the identification difficult. In order to assure the correctness and improve the accuracy of the DP ship model identification, the batched identifications regarding to different degree of freedom (DOF) is necessary and must. The main hydrodynamic parameters which affect the ship motion characteristics primarily are need to successfully identify firstly, and then, other hydrodynamic parameters are identified in 3 DOF coupling ship motions. After the identification, the identified ship model is tested, to verify whether the motion characteristics of the identified model is basically consistent with the actual ship. Also a model based control method - nonlinear model predictive control (NMPC) is designed to test the controlling performance which reflects the correctness and accuracy of the identified ship model meeting requirement from aside. © 2015 IEEE.