Key Engineering Materials Vols. 419-420

Abstract: With structure small and weight light, Variable Vector Propeller (VVP) can provide moving to any direction. In this paper, the mechanical and kinematical character is analyzed with taking disc-rod adjustment mechanism of VVP developed by Harbin Engineering University as an example. Combining the work environment of VVP, the kinematical model is established according to spatial mechanism knowledge. Several typical movement forms’ results are obtained. The study lays the foundation for the further research on kinematical simulation, system control algorithm and trajectory planning.

Abstract: The heat sealing process of Al/PE film mechanism based on diffusion theory is investigated in this paper. Parallel horizontal sealing mechanism is designed and heat sealing strength test is conducted. Considering the sealing performance of Al/PE film as the objective function, establish ternary quadratic mathematical sealing strength model about the heat sealing temperature, dwell time and film thickness three factors. Through analyzing the impact of heat sealing process parameters on sealing performance, the optimization heat sealing process parameters are determined. All the work provides a practical guidance and theoretical basis for heat sealing packaging machine design and parameters determination.

Abstract: There are some undetermined parameters that can be get values only in a certain range about products and other objects in the product design rules and calculations. The parameters to be determined are usually affected by many factors and constraints, which are often bound with fuzzy. The problem is solved in the past usually by the designer getting values of undetermined parameters in a limited range based on their experiences. That is inevitable to deal with subjectivity. Two algorithms about solving undetermined parameters are proposed based on evidence theory and fuzzy comprehensive decision-making methods in this paper. The algorithm is as a reasoning method applied in a knowledge-based intelligent system.

Abstract: Using the concept of support degree in rough set theory for reference, two new concepts, namely dominant support degree and recessive support degree were proposed in this paper. By utilizing these new concepts, two simple weight assignment methods by which dominant weight and recessive weight of attributes could be obtained. Nonetheless both the methods had drawbacks. Hence a further method was developed below. The first step was to construct two items of evidence by deploying dominant weights vector and recessive weights vector of the attribute set and then assigned weights for the evidence to construct weighted evidence. Next was to combine the two items of weighted evidence in reference to the D-S evidential theory. Finally the weight assignments for the attributes could be procured after further processing the combination result. Furthermore, the concept of joint dominant weight of multiple attributes and related methods to assign weights for attributes in some particular situations were proposed. The rationality and wide scope of application of above methods were proven.

Abstract: Based on total life cycle assessment (TLCA) and a research project on auto engine remanufacturing, this article look forward to make certain what is "Remanufacturing Rate" of engine remanufacturing and how to express it on the occasions of OEMs, independent remanufacturers and subcontracted remanufacturers in China. The concepts of ‘Remanufacturing rate’ of engine are put forward at first, and then the estimate methods are studied based on remanufacturing environment of China.

Abstract: . Modular design technology is one of the ways to realize the product variety. It has been widely used in increasing fields. Module partition which has been the hot spot in and around the world is the key part of modular technology. In this paper, the combination of system clustering and the fuzzy ISODATA algorithm is used to achieve the rough-to-fine division according to the principles of module partition. Finally, the automobile security system has been taken as a case to justify the validity of the method and the result of the division accorded with the function of it.

Abstract: A cylindrical type traveling wave ultrasonic motor using orthogonal longitudinal composite transducer is proposed. The composite transducer contains two longitudinal transducers, which are located orthogonal to each other. Each longitudinal transducer includes one exponential horn located on leading end, and the horns insect with each other at tip ends. The composite transducer is attached to the cylinder on its outer surface to excite two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder. Thus, a flexural traveling wave in the cylinder could be excited. The working principle of proposed motor is analyzed. The stator is designed with FEM. The vibration modals of stator are degenerated. Transient analysis is developed to gain the vibration characteristics of stator, and results indicate that the motion trajectories of nodes on the teeth are ellipses. The results of this paper verify the theoretical feasibility and provide instructions for the development of proposed motor.

Abstract: The Mechanics between belt and pulley in flat belt drive running is complicated. Since no inertial force or only partial inertial force was taken into account before, it is necessary to add in the inertial affection fully for more accurate dynamic analysis modeling of the flat belt drive. In the assumption that belt material is deformed in linear elasticity and the flat belt drive is running in steady state, the dynamic equilibrium equations of radial and tangent directions are presented and simplified through the belt infinitesimal element processing and the equations associated with mechanical coefficients and dimensions are also derived. After building up the relations of constitutive equations and geometric boundary equations, the solutions to the dynamic differential equations have been found. The sample flat belt drive is introduced for performing method application and obtained adequate calculation results. It is concluded that the presented method calculation results make the maximum transmission momentum tends to be smaller and the slip angle tends to be bigger than the traditional one. And the fluctuation range is mainly depending on the belt speed and the belt stiffness. This method is valuable for dynamic analysis and the design methodology of belt drive.

Abstract: Improving the knowledge about the influence factors of the allowable free-span length which required in pipeline design, this study provides information about an evaluation of fatigue life due to vortex induced vibration (VIV). Standard finite element techniques are used to the eigen value analyses of a oil-conveying free-span on seafloor. Combined with VIV response model, the fatigue life under three different end boundary conditions (fixed, pinned and elastic seabed) is evaluated. The influence parameter study has shown that the allowable span length is very sensitive for structural natural vibration characteristic, controlled by axial force, end conditions and internal flow. The natural frequencies of free span increase while both the internal flow speed and compression decrease, and internal flow velocity was found less important for VIV response than other functional load factors, because the speed in reality is not high enough.

Abstract: . The paper used spline function fitting the curve of the waviness and its derivative throught measuring vibration and waviness measurement to samples of the bearing, and analysised the nature of the curve of the effects on the bearings vibration. Simulation calculation be done in accordance with the established model of ball bearing vibration. Conclusion have a major role for studying the mechanism of bearing vibration and noise and improving the quality of bearing.