Advanced Materials Research Vols. 44-46

Abstract: Centrifugal pump is a kind of important industrial installation for fluid delivery. The research on the unsteady flow in centrifugal pump is very meaningful to reducing vibration. Particle image velocimetry (PIV) system and test pump designed for PIV measurement were introduced. The experimental scheme and the methods of numerical simulation were discussed. PIV technique was used to measure the unsteady velocity field near the volute tongue under the mode of external synchronization. The unsteady pressure field was simulated by using Sliding Mesh (SM) model provided by Fluent. The results show that the velocity and pressure fluctuate periodically with the rotation of impeller. Partial fluid flows back to the impeller passage and the velocity in the inlet of diffusion tube decreases significantly due to shunt effect of the volute tongue. On the section VIII, the magnitude and fluctuation range of velocity show a decreasing trend in radial direction. The fluctuation of circumferential velocity is related to the position of high-speed flow in impeller passage, and the fluctuation of radial velocity is influenced by blade interference and Coriolis force. The static pressure increases and the dynamic pressure decreases in the radial direction of volute. The velocity and the pressure on the section VIII and the outlet total pressure fluctuate intensively when the blade tail end passes the section VIII and the volute tongue. The vibration of pump can be reduced by increasing the volute tongue mounting angle and decreasing the blade outlet mounting angle properly.

Abstract: A new kind of sealing composite material reinforced mainly with carbon and glass hybrid fibers was developed with calendar preparation method. In consideration of the difference of surface behavior, carbon fiber and glass fiber were pretreated by various surface treatment methods, and the effect of these methods on the material properties and interface bonding between fibers and matrix was studied through the transverse tensile test and SEM analysis. The optimum prescription of the sealing composite material was obtained by regression design method, adopting stress relaxation at 300°C as evaluating indicator. The performances of the developed sealing composite material were tested, and the results indicated that the main performances of the material coincided with the requirements prescribed in Chinese national standard and some performances were even better than that of the products of some famous corporations.

Abstract: The configuration phase for a new machine design is expensive and time consuming for special purpose machine manufacturers. This papers presents a modelling approach that can aid such companies reduce the configuration phase time and its respective costs. The approach is demonstrated with an industrial case study.

Abstract: In today’s highly volatile global market, design activities become more and more important in the whole lifecycle of product. The process of different developments should adopt appropriate modeling approaches at each stage. Different modeling technologies exert a great impact on different design stages. Therefore, modeling design is crucial to achieve success in the process of product development. This paper presents an integrated modeling of design process for product development. Its objective is to realize concurrent design towards ever-growing demands of market that has already integrated design process and production activities. It can manage to develop product towards early design activities. Different design stage model relations and activities are presented for product development. At first, the characteristics of different development stages are analyzed. The performances and attributes of product are established through considering component, constraints and environment. Second, the process of product modeling is described in detail for early design, and the time interval between the two activities is evaluated for concurrent engineering during the design modeling. Third, a promising framework is given to describe the process of design. Finally, an application example and knowledge are presented to illustrate the process of product development.

Abstract: A new flux based on NaCl – CaCl2 – CaF2 – Na3AlF6 was developed for the gas welding of aluminium and its alloys. The flux was generated by the application of the Hadamard multivariate chemical composition model. The model uses a 8 x 8 matrix and a full factorial analysis to generate several compositions within given ranges of the constituent flux elements. Mechanical and field tests were carried out on weldments made with the flux. The tensile strength, Izod impact strength and hardness of the all – weld metal were 310MPa, 5.35J and 100BHN. The weld deposition efficiency was 90.3%.The new flux and two popular commercial fluxes were given to five expert aluminium welders to use for three months, and were requested to rate the performances. The results showed that there was an agreement between the responses of the welders that the new flux performed better than the commercial versions available in Nigeria.

Abstract: Based on the human engineering theory the structure of the new Basketball wheelchair is designed. And the three dimensional model is drawn by means of the PRO/E software after the design. Next, the finite element analysis computation on the wheelchair structure is completed under the four work conditions by I-DEAS software. The result shows that its intensity satisfies the operation requirements and proves that the new Basketball wheelchair is comfortable, safe and reliable. The research of this paper has a more vital significance for enhancing the performance of basketball wheelchair and the development level of sport wheelchair.

Abstract: In the process of products design, most input information for Quality Function Deployment always possess the characteristics of fuzziness and language, so, various input information of house of quality are regarded as language variable, glossary convene of fuzzy language and fuzzy numeral. The main idea of modeling of fuzzy information with house of quality is explained in detail, and fuzzy integrating of custom needs and fuzzy modeling of products planning with HOQ are proposed. Thus, the fuzzy or qualitative information can be dealt with efficiently, and the significative decision in fuzzy circumstance can be made.

Abstract: With the development of science and technology, harmonious design will be one of the latest trends in modern mechanical products development. Based on the harmonious design method, the well synthesized quality products will be invented. It will have little negative influence on society and the natural environment, and the high utilization rate of resources and the most comprehensive benefits in the full lifecycle from planning, designing, manufacturing, packaging, and discarded. The harmonious state can be obtained between products with political, economic, cultural, legal, scientific, natural and social environments. The harmonious design is investigated from the harmony of design methods; the harmony of product function with performance; and the harmony of product with product, with human, with technology, with society environment and with natural environment. And the evaluation of harmonious degree and management system are studied in this work, too. Based on system engineering and economic, cultural, legal, scientific, natural and social environment factors, the formula of the complete system of products design is established. Therefore, the new vitality and higher market competitiveness of product can be achieved. Not only the design is for human but also for nature, for the harmony of human and nature.

Abstract: The aim of this paper is to propose the Classification syllogism, a method for the vehicle design based on the Kansei Engineering. And thus a smart data acquisition and analysis system for FATV design is constructed. The Classification syllogism gives a classification according to the product’s perceptual arrangement of ideas, by comparing, it finds out the relationship of physical elements from different feeling levels and then deduces the product physical parameter till final outcome appears. The paper introduces the content and procedure of the method, as the actual case confirms the validity of the obtained systemic model.

Abstract: Double-crank ring-plate-typed pin-cycloid gear planetary drive conquers shortcomings of a traditional pin-cycloid gear planetary drive, whose load-capacity is restricted by rotation-arm bearing dimension. The load-capacity of this kind of new drive is improved greatly and the efficiency of whole machine is 94%. In order to know dynamics reliability of this drive , nonlinear characteristics of double-crank ring-plate-typed pin-cycloid gear planetary drive are analyzed from two sides of transmission error and dynamic meshing process in this paper. A sensitive analytic mathematic model of rod dimension error is set up by kinematics theory. Based on ring-plate-type cycloid drive dynamic meshing characteristics, a rigidity-flexibility combined model of pin-cycloid planetary drive is set up by ANSYS/LS-DYNA module. Meshing process between pin-cycloid gear is simulated by FEM. Instantaneous stress, distortion and dynamic meshing rigidity are computed. Analytical results show that nonlinear meshing rigidity and transmission errors are two main dynamic exciters which cause prototype to vibrate. So, rod dimension error should be reduced in order to increase meshing accuracy, and meshing rigidity of new prototype should be increased in order to reduce vibration. Nonlinear characteristics of the drive can offer some theoretical bases for design of new prototype.