Applied Mechanics and Materials Vol. 163

Abstract: The geometrical configurations of ball-valve micropumps have great influence on its efficiency. In particular, the ball valve channels have great influence on the efficiency of ball-valve micropumps because the prevention of backflow directly affects the performance of ball-valve micropumps.This study used water to investigate the optimal size of channels for piezoelectric ball-valve micropumps. The results show that the optimal angle for micro ball valve seats is 30°. The piezoelectric film vibrates rapidly and the back pressure in the water outlet channel is higher than it in the water inlet channel . This phenomenon indicates that channels are optimal sizes for a distance of 0 mm in the water inlet channel and 0.3mm in the water outlet channel.

Abstract: A single-effect ammonia absorption-ejection heat pump system is set up. Combined with T-S diagram, performance analysis is presented on the heat pump system with ejector or without ejector. The results show that, with the ejector coefficient equal to 0.5, and the cooling coefficient of performance of the single-effect ammonia absorption heat pump equal to 0.3, 0.45 and 1.45 can at least be gained for the heating coefficient of performance and the cooling coefficient of performance respectively. In this paper, relation curve diagram is also presented for the heating coefficient of performance of absorption-ejection heat pump system, the cooling coefficient of performance of single-effect absorption heat pump system and the ejector coefficient.

Abstract: Compliant mechanisms gain at least some of their mobility from the deflection of flexible members rather than from movable joints only. Dynamic effects are very important to improving the design of compliant mechanisms. An investigation on the dynamics and synthesis of the compliant mechanisms is presented. The dynamic model of compliant mechanisms is developed at first. The natural frequency and sensitivity are then studied based on the dynamic model. Finally, optimal design of compliant mechanism is investigated. The experimental study of natural frequency is performed. The comparison between the experiment results and the theoretical results verifies the validity of the experiment system and theoretical model.

Abstract: Geometric tolerances are assigned to avoid parts rejection in a manufacturing process while ensuring fulfillment of intended function. Selection of tolerance value is an important task which affects the overall product cost and performance both. The significance of tolerance value is more evident in case of mating parts where the dimension of more than one parts share responsibility of successful assembly and design. The objective of this research is to determine appropriate tolerance value based on assembly clearance analysis which takes into account relationship between assembly clearance and product performance parameters. The study is conducted through CAD-CAE integrated finite element analysis (FEA) simulations of the product process model. The results output help in distinguishing different tolerance levels which can be further probed for optimal, using available manufacturing resource capability data. The research output is a more practical tolerance value achieved based on product performance analysis as well as available resources and appropriate cost. The results obtained validate the utility of the approach presented in this paper.

Abstract: This paper describes a system for product design and management. The system based on Citrix XenApp and Web to take advantage of common CAD softwares own interfaces for product design as well as provide user friendly web interfaces to manage product models. The innovation of this work lies in its concept concerning integrating Citrix XenApp and Web application to produce a highly interactive product design environment while keep those merits of the Web, such as ease of use, collaboration, cross-platform capability, controlled access, etc. In this paper, we first give an overview of the system architecture and then describe the highly-interactive product design environment and product model management interfaces. And at last we talk some issues and approaches used to achieve integration of Citrix XenApp and Web application to realize the efficient design and management system.

Abstract: The authors investigate the component fabrication of a flapping ornithopter with 21.6 cm wing span by using precision injection molding. For making a bio-mimicking flapper like birds, two fold of plastic injection moldings have been done. Firstly the flapping mechanism of a 4-bar linkage gear transmission module has been studied, and the according plastic components for the gear transmission module were designed as light as possible. Thereafter the injection flow analysis in the multi-mold cavity and the fabrication parameters of the molding process has been implemented. The finished polyoxymethylene (POM) components for the transmission module of 1.2 gram in mass finally verify the design and process of the precision injection molding. After the ornithopter Golden Snitch was assembled and tested with the fore-mentioned plastic 4-bar linkage, a maximum flight record of 480 sec was created in 2010. The second framework of injection molding is to design a bird-like expandable polystyrene (EPS) fuselage with 19.5 cm in length as the mechanical protection. After this ornithopter Golden Snitch-Pro was assembled, it has a successful flight of 230 sec and 100 times of landing capability. In summary, the fabrication of a polymeric bird-like flapper is proved, and the precision injection molding technique shows its feasibility in realization of ornithopters.

Abstract: Traditional method of buoy gauge design is rather complicated, so an advanced method by building and solving fluid mechanics equations is proposed in this paper. The curve of the taper pipe inner surface is calculated, according to different buoy gravity and diameter. In order to examine the effect of this improved method, an experiment is carried out. Results show that linear property of the buoy gauge improved by new method is excellent.

Abstract: General CNC milling machine for special transformation in the middle and low numerical control system of internal control software does not change under the premise of achieving the original system does not have the linear movement and rotary movement of the operating linkage function. The numerical control system of linear movement into rotary movement of the operation, and expansion of two straight line linkage CNC system functions, cleverly converted to a straight line movement control of a rotary movement of the linkage, thereby achieving the surface of the cylinder rotating cam track surface CNC machining. CNC Milling through the difficult parts of the application examples to explain the design principles of transformation CNC milling machine, design approach,As well as the design parameters in the programming of data conversion. And data conversion processing errors resulting from the measures and the elimination of error analysis.

Abstract: Facing the increasing competitive environment of globalization, companies are forced to make careful decisions so as to get the competitive advantage. The analytic hierarchy process (AHP) method has be proposed and popularly applied in many disciplines over three decades. In the past, many scholars also developed various improved methods such as Delphi AHP , fuzzy AHP, or Analytic Network Process (ANP) to enhance the decision quality. However, all the current AHP related methods have no function to provide enough reference information and a friendly environment to support the decision makers. Recently, Knowledge Management (KM) has attracted a great deal of interest in industry and academy. Therefore, in this paper, we proposed a KM-based AHP decision-making method to provide the questionnaire designer a guideline or reference and developed a decision-support web questionnaire system based on the knowledge chain model. A case study of selecting a 4-axis machine tool was illustrated the implementation and applicability of this method, a mold manufacturing company was invited as the survey objective. The method proposed in this research provides a different research direction and it is general in form to be applied for the other multi-criteria decision making cases.

Abstract: Using guided wave dispersion characteristics, a procedure based on articial neural network (ANN) is presented to inversely determine the elastic constants of orthotropic plate. The Legendre polynomial method is employed as the forward solver to calculate the dispersion curves of SH wave for orthotropic plates. The group velocities of lowest modes at five lower frequencies are used as the inputs for the ANN model. The outputs of the ANN are the elastic constants of orthotropic plates. This procedure is examined for an actual orthotropic plate. The results indicate that the identified elastic constants are sufficiently close to the original one. The developed inverse procedure is concluded to be robust and efficient.