Applied Mechanics and Materials Vols. 490-491

Abstract: Numerical simulation method is adopted to simulate and research Self-Recirculation Casing Treatment (SRCT) on expanding the scope of steady work of high-pressure-ratio centrifugal compressor, and increase the compressor surge margin. Contrast the influences which are caused by structure sizes of the SRCT on the performance of compressor. The results showed that SRCT make the compressor stable operating range average broaden more than 13% on all kinds of speed, the surge margin increased by 11% at most. During the structure sizes, the distance between the bleed slot and the splitter blade has the largest affect on the performance of centrifugal compressor, followed by the bleed slot width, others have less affect. SRCT make the distribution of the compressor impeller inlet relative Mach number is more uniform, weaken the phenomenon of blade leading edge local high Mach number. It is also decrease the blade inlet positive incidence, inhibit separation of the blade surface boundary layer.

Abstract: The digital imaging technology based on underwater laser line-scanning is one of the developing and effective technologies for underwater electro-optical imaging. According to the requirements of ocean salvages, rescues and marine resources explorations, the technical features of the digital imaging system are analyzed comprehensively, the structural characteristics are discussed and the hardware components are introduced. The design gives the supports to develop the digital imaging system using underwater laser line-scanning technology and has great significance for application.

Abstract: Based on the central-limit theorem and the stress-strength interference theory, a mathematical model is presented to predict confidence level and confidence interval of reliability. The equations of the lower and upper limit of unilateral confidence interval of reliability, and the limit of bilateral confidence interval of reliability are obtained. And then by an example about a rotor spindle of aviation alternator, a method of reliability optimization design involving confidence level of reliability is proposed. The study result has certain theoretical meaning and engineering value for reliability optimization design of mechanical parts.

Abstract: This paper aims at establishing the empirical equations of the qualitative relationship between the inspection periods of the grinder rods eccentric wear of the rod-pumped well and its influencing factors and putting a hypothetical test of it to find out the scientific evidences for the solutions to the eccentric wear wells on the basis of multi-linear regression equation.

Abstract: Its simulated in this paper that the diesel particulate filter (DPF) works without regeneration in the beginning 300 seconds. In this process, the internal parameter settings of the DPF simulation was described in detail, while the simulation results was obtained by analysis. The main conclusions are: The inner flow speed showed higher in the center part and lower in the peripheral part of DPF; the flow speed decreased in the direction of inlet channel. The soot distributed more in the frontal and rear part of DPF and less in the middle part. This is because the inlet channel of DPF at a large rate so the soot accumulated more. The accumulated soot in the middle part due to the role of air migration in the channel will move to the end of the channel. And all these reasons lead to the situation that the soot distributed more in the front and rear part. Because DPF soot accumulation will affect performance, the processor of regeneration needs to take in order to ensure regeneration of soot filters.

Abstract: The drawings archive of a company is an important font of information that could be used during the design process. In fact, it is a collection of known and proven solutions to design problems and, also, the drawings include a variety of information useful to design such as physical principles to achieve a function or solutions of particular machine design problems. The use of these data is however conditioned by easiness of access to the information. Normally, the drawings archive is not structured in a useful manner for the design and the retrieve of the information contained requires effort and time that are not often available to the designer. The use of database systems and informatics tools, as Product Data Management (PDM) or Product Life-cycle Management (PLM) systems, can allow company to add more attributes to the drawing during its storage, allowing a different access to the information. This work proposes an example about the organization of the information based on the functional structure of a product. The organization proposed was also used to catalogue the data stored in relation to the standards required to the product. This to demonstrate how much information is hided into the historical archives of a company and how much it could be useful during the design process.

Abstract: This paper applies efficiently topology optimization technique to the conceptual design of a bed structure of machining center, which achieves for sufficient rigidity and reasonable distribution of weight of the bed. Firstly, conceptual design of the bed structure is obtained by using SIMP method under the conditions of a multi-objective optimization considering both the weighted structure compliance and the first-order natural frequency on multiple load cases and volume constraints. Subsequently, size design is employed to determine the main dimensions of the supporting plates and reinforcing ribs. During this stage an exhaustion method is identified to select suitable dimensions to optimize the structure performance. Finally, The Finite Element Analysis (FEM) is utilized for comparison of optimal and original bed structure. The FEM results indicate that the optimal design structure can reduce the mass by 6.6% with the less stiffness fluctuation and the first-order natural frequency can also improve by 7.9% compared with the original structure.

Abstract: The process parameters of electrical discharge machining, such as : workpiece polarity, pulse width, pulse interval, peak current, peak voltage, all have influence on TC11’s surface roughness.But general methods are difficult to determine the relationship between the process parameters and the process indicators. This article established a artificial neural network model of EDM TC11 surface discharge mark diameter which can forecast. Neural network algorithm used BP algorithm, the network structure was the 2-4-1.

Abstract: After the design project of diamond wire cutting machine, we try to optimize the design of its main structurebed. In this paper, we shall first make three-dimensional modeling on the bed with Solidworks, and then do modal analysis with Ansys, from which we can get its five natural frequencies and vibration patterns, verify the accuracy of the finite element model. Finally, the optimization measures will be summarized.

Abstract: Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.