Applied Mechanics and Materials Vols. 300-301

Abstract: The friction resistance accounts for a large proportion of the total resistance, during the navigation of ships and underwater vehicles. Drag reduction techniques can significantly reduce the friction resistance of the wall and improve the speed of navigation. This paper combine microbubbles drag reduction technology and nonsmooth and hydrophobic surface technology. Building different analysis models, considering the dimples size of nonsmooth surface , the contact angle of surface and wall roughness, study the law between drag reduction and parameters of the wall by gas-liquid two-phase flow model. Under the same conditions, analysis results show that the performance of drag reduction is mainly determined by the dimple size of nonsmooth surface. The lager dimples cause stronger turbulence and loss more energy. The drag reduction effect is declined. There is a linear relationship between the drag reduction and the contact angle of hydrophobic surface. The drag reduction is enhanced by increasing the contact angle. But the principle is complicated between drag reduction and the roughness of the wall. There are different roughness to achieve the best effect under different flow velocities.

Abstract: Rake-car’s driving system of ore reclaimer originally used crank and connecting rod mechanism as driving mechanism. The driving mechanism got some trouble that parts got severe wear and failure rate of mechanism was high. The hydraulic system is used to drive rake car in view of hydraulic driving system’s advantage. By analysis on existing problem of crank and connecting rod mechanism, the actual working load of equipment is tested and the working situation is analysed. The working situation of the hydraulic system is also analysed by computer simulation. By optimization of the hydraulic system design, the final design is determined. The whole system is actually used. It works well.

Abstract: The application of sequence injection in large-scale automobile air inlet grille plastic part are described. The CAE comparative experimentation of between the simultaneous injection and sequence injection were processed and a series of the data such as weld mask, temperature and pressure were gained. Through the comparatively experimentation it was discovered that sequence injection can raise the quality of large-scale flat palstic part availability and cut down expenses

Abstract: The coupling dynamic characteristics of the vibrating system with dual mass are analyzed quantitatively. Through numerical computation, the effects of translation and rotation in the system regarding self-synchronization are discussed. The phase difference of two eccentric blocks is caused by the difference of the rated revolution of two motors. The stability of the synchronous operation is dependent on the structural parameters of the system. Simulation is carried out to verify that the system can be synchronized and the model can guarantee the stability of synchronization if the parameters of the system meet the conditions of synchronous implementation and stability. Simulations are also performed for the self-synchronization of two motors with different rated revolutions.

Abstract: This article introduces the development of domestic and foreign small power multi-cylinder diesel engines which are below 37kW. It analyzes the structural characteristics of foreign products and clarifies the status of domestic small power multi-cylinder diesel engines as well as the causes which limit their development. It also points out that with the tightening of the emission regulations of non-road diesel engines, We need to develop high-performance small power multi-cylinder diesel engines which are compact, energy saving and environmental friendly to meet market demands at home and abroad. Based on the status quo of the domestic industry, it illustrates the development problems of small power multi-cylinder diesel engines that deserve our attention and the corresponding technical countermeasures, and provides recommendations on the development of the domestic industry.

Abstract: The method of supplying fuel for an electronic-controlled fuel injection system is calculating the required fuel amounts under various operating conditions of engine and controlling the opening and closing timing of fuel injection. After fuel injection, the effects of condensation and atomization of injected fuel as well as fuel mixing for combustion are strongly dominated by the opening timing and duration of intake valves. This can further affect the emission composition and performance for an engine. As the emission regulation is getting more stringent and the requirement for minimizing specific fuel consumption is becoming more urgent, investigating the effect of closing timing of fuel injection has turned out to be a major issue. Therefore, this paper presents a study about a series of engine tests to investigate the effect of end of injection angle on the performance and emission formation for a gasoline engine. In these tests, the values of end of injection angle are adjusted using a control software for electronic-controlled fuel injection system so that the results can be analyzed under various engine speeds and loads.

Abstract: In order to manage the complex simulation data management in the process of mechanical dynamics simulation, a new management model was presented which is Performance Simulation Model(PSM). The model was based on PDM product structure and the concepts and elements of PSM were defined in this paper. Furthermore, the functional framework of PSM was proposed which based on the hierarchical relationship of product structure and the data stream relationship of data structure matrix. Finally, PSM was applied on ship planetary reducer collaborative simulation platform. The result indicates that the simulation data in mechanical collaborative simulation are managed by PSM, and the problem of interaction between collaborative simulation and PDM is solved.

Abstract: This paper represents a hierarchical pipe system disassembly method by using dynamic self-adaptive tree (DSAT) based motion planning to perform disassembly for a complex pipe system. A pipe system CAD model is prepared initially to indicate the environment of the disassembly procedure. The improved motion planning method provides basic algorithm support for indicating the feasible escape path of a single part. Our technic gradually reduces the complexity of the pipe system to generate a hierarchical structure which takes all geometric information of the system. The hierarchical structure is preserved and used for the generation of a disassembly relationship graph which indicates the feasible disassembly sequences.

Abstract: In winter, aircraft icing or frost is serious potential accident for flight safety which needs equipment to deice. However, until now, there have been no relevant manufacturing enterprise and technology at home. According to design requirements of aircraft deicing vehicle and firing boiler, through comparative analyses of various designs at home and abroad, operating scheme and key devices of deicing system were designed, including deicing firing boiler and hydraulic burner system. Finally a hydraulic oil-fired deicing system suitable for aircraft deicing vehicle was developed successfully. New deicing system and firing boiler have the advantages of reasonable design, reliable working, economic usefulness and convenient operation, which meet the design requirements and fill in the domestic blank. The products not only can be applied in domestic airports but also in civil fields, being of important innovative and practical significance.