Key Engineering Materials Vols. 419-420

Abstract: In this paper, based on CFD method and dynamic mesh technology, the ship maneuvering performance is predicted in viscous flow. Numerical computation models are built to realize the simulation of the ship maneuvering motions such as static drift test, static rudder test, pure yaw test and pure sway test. Hydrodynamic forces and moments acting on a maneuvering ship are obtained in the body-fixed coordinate system. The computational results are compared with data of potential theory method. Then based on VC code, a simulator of ship maneuvering motions is built to simulate ship Zigzagging and Turing test. The results show that the present numerical simulation method and the ship maneuvering motion simulator are able to be used in numerical simulation of the real size ship maneuvering motions in viscous flow field.

Abstract: The paper analyzed external effects of enterprises’action in industrial symbiosis network using external effect theory; constructed an externality analysis model and obtained the condition of enterprises’ participation in industrial symbiosis network through analyzing the model solution. The condition is that the actual marginal expenditure of participation in industrial symbiosis network is not more than the marginal expenditure of pay sewage charges The paper construed the reasons of negative externalities of enterprises’ action transforming into positive ones through participation in the industrial symbiosis network, put forward that the implementation of this transformation is the new method to solve the problems about external effects of environmental pollution.

Abstract: The three-dimensional parameterized model of the planetary reducer was established on the platform of Pro/E. Especially, the parameterized gear model was built through transforming the accurate equations of the involute and the tooth root transition curve into the expressions that can be identified by the Pro/E. Therefore, the accuracy of the model is relatively high and the method used in the paper can eliminate tooth interference effectively. Then, the three-dimensional assembly model for planetary reducer was obtained through the Virtual Assembly Technique and the Assembly Module in Pro/E. In brief, the method used in the paper has supplied a relatively accurate model for the dynamic analysis. At the same time, it can reduce dramatically research cycle and cost, and has supplied an effective development approach for the planetary reducer.

Abstract: Network-based collaborative product development has become a trend in manufacturing industry, which depends on two key information technology: the Semantic Web and the standard for the exchange of product model data (STEP). EXPRESS is the STEP product data modeling language, and OWL is the standard ontology representing language used in the Semantic Web. Only when the EXPRESS models are converted to OWL models, product information can be exchanged at the Web. The ontology meta-modeling theory was employed to analysis the ontology definition metamodel of EXPRESS and OWL, in order to build up the mapping relationship between them. A formal EXPRESS-to-OWL mapping algorithm is then proposed, represented by abstract syntax.

Abstract: The structure and properties of diesel fuel injection system directly influence the performance of diesel, and calculation and analysis are important methods to improve engine performance. So, by analyzing the structure, math models and working process theory of the electronic control PPVI fuel injection system, this paper founds initial and improved simulation models of the diesel electronic control PPVI fuel injection system, completes simulation and analysis. The simulation results show that the improved model has better cushion effect than the initial model by adding a constant pressure delivery valve between the nozzle and electromagnetic valve, what is more, the improved model can avoid the instability of the work state, such as second injection, cavitation and anomaly injection, etc., therefore, the diesel forms perfect unloading characteristic, and its performance has also been improved.

Abstract: Underwater interfacing technique is the key technique of the underwater vehicle. Now the technique is mainly used in the submarine rescue. Based on the structural characteristics of the model of BSAV-Ⅰand the interfacing apparatus with the manipulators which are made by Harbin Engineering University, a group of equations were defined and solved based on the six freedom motion of the model. The software Creator and Vega were used to build virtual ocean geographic environment and the deep submergence rescue vehicle(DSRV), the virtual simulation system is created，with which the virtual simulation of the docking process of DSRV and the disable marine is done. Except this, the research on simulation system of the interfacing apparatus of the underwater vehicle based on VR can test the docking strategy, find the problems in docking and improve the structure of the interfacing apparatus.

Abstract: In company with medical instruments ' development, the corresponding software plays more and more role in the application. And medical image processing software has become an important component of the medical ultrasonic instruments. Image segmentation plays an important role in both qualitative and quantitative analysis of medical ultrasound images. But state-of-arts methods in the aspect of segmentation can not get satisfactory results. We propose an intelligent image segmentation method for medical ultrasonic images. The algorithm improved active contour model with relevance vector machine, where the advantages of supervised learning classification and the global region distribution information can be exploited to enhance the performance. In order to improve the segmentation speed and get precise initial contour, relevance vector machine also is used to obtain initial contour firstly. A large amount of experimental results have proved that our method outperforms many state-of-arts methods in the aspect of segmentation, and the method can be used in ultrasonic instruments effectively.

Abstract: The jack-knifing tendency of aircraft traction system during braking was discussed and analyzed using multi-body dynamics models that consist of aircraft-towing tractor, aircraft draw link and aircraft. The braking critical conditions of the aircraft traction system for straight-line braking and turning braking were discussed and analyzed respectively. In the case of straight-line braking, the effect of friction coefficient on the maximum braking torque is described. In the case of turning braking, the relationship between the maximum baking torque and relative angle is obtained.

Abstract: By the approaches of the theory of complex functions, propagation problems concerning mode Ⅲ asymmetrical dynamic interface crack were studied. The problems can be transformed into Riemann-Hilbert problem easily by the measures of self-similar functions, and the universal expressions of analytical solutions of the edges of mode Ⅲ asymmetrical dynamics interface crack subjected to variable loads and respectively, were attained.

Abstract: Based on dSPACE real-time simulation system and LabVIEW measuring system, semi-physical simulation platform of DC motor speed-adjusting system was established. Fuzzy PID algorithm was designed based on analyzing fuzzy control and PID control for speed-adjusting system. The simulation results show that compared to standard PID algorithm, fuzzy PID algorithm improves the performance of speed-adjusting system for DC motor. On this basis, the speed-adjusting system was developed based on ATmega128 single-chip and original algorithm. Compared with simulation speed-adjusting system, there is no obvious difference on response characteristics.