Applied Mechanics and Materials Vols. 670-671

Abstract: Through theoretical analysis of a suspension mechanism used for aircraft recovery vehicle, the mapping relationship between the hydraulic cylinder axial force and scale parameters of the suspension mechanism was built. With coordinate values of each hinge joint of the suspension mechanism in the initial position as design variables, the minimum hydraulic cylinder axial force was taken as evaluating index with reasonable constraints and optimal design of the hydraulic suspension mechanism was studied. The influence law of scale parameters to the axial force was discussed and coordinate alternation method was applied to find the optimal solution. The effectiveness of the method was indicated by an example.

Abstract: This paper studied the difference between the static analysis and dynamic analysis on the mobile refuge chamber. The structure strength static analysis of KJYF96/8 mobile refuge chamber was made by the finite element software SolidWorks Simulation and the stress cloud chart and the displacement cloud chart were obtained. The corresponding relation between the dynamic analysis result and the static analysis result was obtained based on the comparison with the result of the dynamic analysis. The results indicate that the values of the max stress and displacement by static analysis with a uniform external pressure of the dynamic pressure peak value are greater than those by dynamic analysis. And the weighting method of static analysis can be used in the coal mine mobile refuge chamber structure design process instead of dynamic analysis.

Abstract: The influence of the state of assembly and entity on modal simulation data in the computer simulation is different. In this paper, a typical modal analysis of hydraulic manipulator with the finite element method is conducted to discuss the different. The assembly is assembled by Boolean operations to makes surfaces merging together directly and then converted into the solid model. This way can ensure the validity of the comparable data. The conclusion shows that properly setting the assembly model can make the simulation results closer to the actual working conditions in the computer simulation by comparing the modal simulation data.

Abstract: In the field of topology optimization problems, the Evolutionary Structural Optimization (ESO) method is one of the most popular and easy to use. When dealing with problems of reasonable difficulty, the ESO method is able to give very good results in reduced times and with a limited request of computational resources. Generally, main applications of this method are addressed to the definition of the optimal topology of a component subjected to a single load condition. In this work, a new methodology, based on the ESO approach, is introduced for the study of the optimal topology of a component subjected to multiple load conditions. The new procedure, entirely developed in the APDL programming language, has been tested with a holed plate subject to two different load conditions; the obtained results are promising in terms of mass reduction and structural performances.

Abstract: With the increase of mining depth, rock mechanics conditions become complicates. So the surface subsidence law caused by deep mining is different from the shallow. Based on the finite difference method and rock mechanics theory, the surface subsidence law cased by deep caving mining was studied, the strata movement rule and characteristics of stress distribution of different excavation stage was analyzed systematically. The results of the study can provide certain reference significance for the deep mining to confirm the displacement angle and range of surface subsidence.

Abstract: In industrial and construction process, some precise equipments should be assembled on site. The assembly requirement is very high, and it is hard to assemble the accessories together. The paper is based on a real situation in construction to study the precise equipment assembly method. First, it introduces the situation on site and the parameter of the parts of equipment need to be assembled. Then show the cost for the traditional assembly method. Put forward a new method to do the work. At last, compare the advantage and disadvantage of the two methods. The new method mentioned in the paper will greatly improve the installation efficiency in the construction.

Abstract: Proton exchange membrane (PEM) fuel cells intended for new energy automotives require a high efficiency and reliability motorized compressor to supply pressurized air. This paper presents a study and development of a motorized centrifugal air compressor using water-lubricated bearings. Comparing the performance of water-lubricated bearing with gas-lubricated bearing, we found that under the same power consumption the load capacity of water-lubricated bearings are more suitable for high speed motorized compressor system. A prototype was built and tested to verify the possibility of the developed motorized centrifugal air compressor. The results show that the system can operate at a stable rotating speed up to 80,000 rpm. The flow rate of the pressurized air is 350Kg/h and pressure ratio is 1.52 at 60,000 rpm, with a global efficiency of approximately 80%.

Abstract: As for jacket dragging load-out foundations, the concrete skidway blocks were prone to be sheared and wrecked, especially the outer blocks, for they generally swung with the tugboat. This paper takes dragging load-out of LS36-1 jacket on 3# skidway for example, and proposes a design analysis for dock apron skidway blocks. The design philosophy is replacing original concrete blocks with steel blocks, and the new steel blocks not only have good shear strength and compressive strength, but they are also easier to connect and fix with skidway. In addition, some essential strengthen measures are adopted, reformed 3# skidway blocks are ready for much heavier modules and jackets dragging load-out works.

Abstract: A multistage groove sealing structure in Micro Internal Combustion Swing Engine (MICSE) was designed. By machining several grooves on the center-swing, it provides non-contacting control of internal leakage. The sealing principle of this structure may be described as follows. Gas at high pressure enters through the clearance of adjacent grooves to accelerate, then expands isentropically in the grooves. Once crossing several such grooves, gas emerges at the other end of the sealing structure at significantly reduced pressure. Numerical simulations were utilized to analyze the influences of pressure ratio and groove depth on leakage characteristics. The results demonstrate that at pressure ratio smaller than 2.0, turbulence eddy dissipation process in grooves cannot dissipate kinetic energy obtained during the throttling process completely, which results in poor sealing effect, at pressure ratio lager than 2.5, the two processes reach dynamic balance and sealing effect no longer changes. There is an optimal value in groove depth, undersize or oversize may lead to imperfect throttling effect or turbulence eddy dissipation process.

Abstract: 3D printing as additive manufacturing enables to give concept proposers and designers a great possibility of producing physical parts and concept models at acceptable cost during a short time. Such technology is quite distinct from traditional machining techniques adopting subtractive process. The purpose of this study is to briefly describe new micro-scale manufacture utilizing a series of process of 3D printing, including 3D modeling, 3D model slicing, printing, and products. Especially, 3D modeling is one of major components in 3D printing process and becomes a barrier to entry the business of micro-scale manufacture for everyone with a 3-D printer. This paper introduces two low-cost approaches to generate 3D models, including active and passive approaches. 3D scanning as an active approach allows the replication of real objects without the need of moulding techniques. On the other hand, image-based modeling as a passive is an alternative of un-touch model reconstruction without a threat of destructive impact to the modeled object. Also, a statue in gypsum was made by a 3D printer based on a digital 3D model generated through the low-cost active approach for demonstration.