Advanced Materials Research Vols. 228-229

Abstract: In this study, solid state diffusion welding behavior of titanium alloys was investigated. Formation mechanism of diffusion welding process in six stages is proposed, which is based on cavitation process. The specimens were diffusion welded at elevated temperature under a hydrostatic pressure in an inert environment and the results confirmed the formation mechanism at each corresponding stage. This includes clear evidence of void closure and grain boundary migration at the final stage.

Abstract: The stress-strain response at notch root for notched specimen was computed by elastic-plastic finite element analysis (FEA) under multiaxial loading for GH4169. A uniform gouge length of the specimen was selected as the dimension of the FE model. The uniaxial fatigue data were used to describe the stress-strain curve. One cycle is divided to different load steps according to phase difference. Tension-torsion strain cyclic loading was implemented in FEA. Fatigue crack initiation life was predicted by Smith-Watson-Topper model, Shang-Wang and Sun-Shang models with the calculated stress-strain data at notch root. The result shows that the three models are suitable for life prediction of notched specimen under multiaxial cyclic loading for GH4169 alloy.

Abstract: A three-dimensional mathematic model is developed for a 100kw single-end recuperative radiant tube and the simulation is performed with the CFD software FLUENT. Also it is used to investigate the effect of distance between combustion chamber exit and inner tube on heat transfer process. The results suggest that the peak value of combustion flame temperature drops along with the increasing of distance, which leads to low NOX discharging. Also radiant tube surface bulk temperature decreases, which causes radiant tube heating performance losses.

Abstract: Based on elastic hydrodynamic lubrication (EHL) theory, an EHL model of the meshing between the sun gear and planet gear in planetary gear transmission was established. The EHL oil film thicknesses at meshing areas and those distributions for two operation cases were calculated: one case with the sun gear as the driving gear and another case with the ring gear as the driving gear. The Lubrication with second case was worse. Through the many comparing calculations the lubrication film thickness can be significantly increased by right parameter design. Reasonable raise of lubricant viscosity can get better gear lubrication. Increased gear pressure angle can greatly increase the oil film thickness. The increase of oil film thickness can improve the lubrication of gears and prevent wearing and reduce the production cost of gears, which have great practical value.

Abstract: The Burmester curve plays an important role in rigid-body guidance of four-bar linkage, but it still had serious blindness because two center points or circle points should be assigned arbitrary. So a method of Type Map for rigid-body guidance was proposed in this paper. All the four-bar linkages synthesized by burmester curve can be classified in accordance to their attributes. Using this method, satisfactory four-bar linkages can be obtained quickly for the given four rigid-body positions. An algorithm was proposed to define the discrimination of the Type Map in depth. Based on the platform of Matlab, a program was developed to realize the automatic design and visualize the guidance synthesis for four-bar linkage. The result proved the method to be feasible and effective.

Abstract: Materials as the basis of product design, with its own inherent characteristics and emotional semantics formed the indispensable elements of the design concept. The texture of different materials give people different feelings, direct impact on the artistic style and the feel of product. This paper describes that the factors which affect the material properties , the use of sensory properties of materials in product design and the correct use of product material is the right way to design products accurately in which to serve the public life better. Designers should pay attention to materials, color, texture, texture, harmony and contrast, designers to increase the texture of the product through the artistic effect; Correct understanding of materials design is to do the prerequisite and guarantee of product design.

Abstract: Change is now a general phenomenon of Business environment. Managements are compelled to adapt with the changes to survive. The term re-engineering rises to adapt with the changes in terms of the process of business. However, critics doubt about the fad of re-engineering as a number of Business Process Re-engineering (BPR) initiatives have failed. Tempt of object orientation is increasing regarding the implementation of re-engineering. This paper reveals the relative relationship among the fundamental blocks of production process regarding the implementation of re-engineering in the SMEs sector. Relationships have been identified empirically through the survey conducted in the SMEs (manufacturing) sector of Bangladesh.

Abstract: According to such properties of DME as high saturated vapor pressure, low viscosity and easy formation of mixture with air, a CPC (Controllable Premix Combustion) low-pressure common rail electrical control fuel injection test bench of DME engine is developed through this research. In addition, an overall design of the test system, hardware and software development of electrical control unit (ECU) and a test on the test bench are undertaken. The software of ECU is programmed by using real time modular programming. It has the advantages of flexible programming, convenient transplantation and wide extending possibility. Test results show that the injector switch timely, spray powerfully and pulverize perfectly. The software accomplishes many tasks such as signal acquisition as well as real-time control requirement of engine operation. Test result also shows the feasibility and good comprehensive performance of low-pressure common rail electronic system for DME fuel.

Abstract: The micro crowled integral impeller is one of the key parts of aeroengine. It is difficult to machine for its complex structure and small dimension. In this paper, the tool path planning scheme of micro crowled integral impeller is researched, which lays foundation for the numerical control machining of the part. To begin with, considering the feature of impeller’s structure, a kind of processing route is proposed and the processing regions are divided, which satisfy the demand of accuracy and efficiency. Then, the tool path planning scheme of the impeller is put forward, which is regular and is more suitable for a large-diameter tool to fulfill the machining process. Finally, machining simulation is carried out to prove the feasibility and correctness of the proposed path planning scheme.

Abstract: The excellent biocompatibility and antithrombotic properties of Diamond-like Carbon films (DLC) have been widely confirmed in several clinical trials of artificial heart valves and blood vessels. In recent years many researchers were doing a lot of research coating DLC as the surface of coronary stents. Considering coronary stents’ plastic deformation occurred in installation and expansion process, surface coating was required to follow the plastic deformation of substrate materials, and it should be with excellent adhesion, without cracking and falling off. According to this, we created a method with different concentration gradient of silicon content on different thickness of DLC coating, and found a plastic deformation required by DLC coated stent, which with excellent adhesion and not cracking. In order to facilitate analysis and comparison, we compared it with two products abusing on the market under the same conditions and got a good result, which provided strong evidence for the product development of DLC coated coronary stents.