Advanced Materials Research Vols. 655-657

Abstract: Based on the kinematic equation of index finger, the trajectory space of fingertip is analyzed, and the structural parameters of underactuated prosthetic hand have been optimized by ADAMS, which compare the trajectory space with the index-finger. Using the modeling methods of Lagrange dynamics equation, the dynamic model is established for the three-joint underactuated prosthetic finger, whose kinematic and dynamic characteristics also are analyzed. Finally, by the construction of the virtual prototype and its introduction into ADAMS for the dynamics simulation, the correctness of kinematics and dynamics model is verified by the dynamics simulation of virtual prototype.

Abstract: Establishing the corresponding relationship between radius at tooth tip and tooth root fillet by the curvature of conjugate flank based on the generating method to manufacture for gears. According to the Visual Basic, a 2-D mathematical model of relationship between undercutting phenomena and modulus, teeth and modification coefficient of involute gear was built, and then simulated undercutting influence level caused by modulus, teeth and modification coefficient. The generating method dynamic processes, generating profile and the root drawing obtained by the simulation will directly reflect the influences that modulus, teeth and modification coefficient with gears meshing processions, and provided a reliable basis for design gear transmission and machining involute gears.

Abstract: Conventional models for mechanical rotors based on Automatic Dynamic Analysis of Mechanical Systems (ADAMS) are over-constraint. This paper proposes a new method for simulating the stiffness and damping of bearings using bushing and other kinematic pairs. Analysis and Simulation for balance of rigid rotors by ADAMS were performed. To reduce the imbalance inertial force, the balance weight of a take-up machine has been optimized. The results were verified by the prototype test. Our results suggest a more effective method for balance of mechanical rotors in the design stage.

Abstract: The coupler mechanism is a key component of vehicle connection. The geometric shape of parts are very complex. Between the working parts there is a certain clearance, and mechanism function is implementated by the collision contact of these parts. So, it is very difficult to analyze how coupler works exactly. The RecurDyn software, the latest research results of multi-body dynamics (MBD), is used for modeling and simulation. The working state of the coupler device was reproduced in the software. The modeling and simulation of coupler irregular mechanism was created by using the rigid-flexible hybrid MBD system. Through the simulation results, including main parts parameter curves about mass centre motion, force curves on the joints, contact force between parts, and key components stress concentration area as well, the functional reliability and the structural reliability of coupler were analyzed in operating environment. Applying the MBD theory and technology above, the structural and functional reliability can be predicted for coupler liked complex mechanism.

Abstract: The impact problem is analyzed when the complex-surface cutting metamorphic mechanism changes the configuration through ADAMS, assuring that the impact is decreased to minimum by changing the motion law of driving joint. The effectiveness of this method is verified through simulation, ensuring the stability of metamorphic mechanism in configuration transformation.

Abstract: The rigid-flexible hybrid modeling of the wind tunnel test platform is established by means of ANSYS and ADAMS for more accurate analysis of the motion performance of the test platform in this paper. We get the kinematical characteristic curve based on the three working conditions of the pitching motion, yawing motion, rolling motion of the test platform. According to the characteristic curve indirectly reflects the rationality of the design configuration. So as to provide fundamental basis for the precision dynamics simulation analysis and make the real physical prototype are offered.

Abstract: It is of great importance of studying the influence of structural parameters on centrifugal fan performance. Considering the structural characteristics, parametric numerical simulation platform was developed based on parameterization and VB software. The platform includes fast automatic modeling, numerical simulation and post processing modules, which can be used to research the variation of performance parameters and flow fields when structural parameters of centrifugal fan changes and provide basis for design and optimization. The influence of blade numbers on total pressure of centrifugal fan was studied as an example to validate the feasibility and practicability of simulation platform.

Abstract: In the case of multiple loading conditions, a moving blade adjustable axial flow fan structure parameters are optimized by ANSYS. It is to achieve greater efficiency and less noise for the optimization goal. For different conditions, establish efficiency, noise comprehensive objective function using weighted coefficient method. Select impeller diameter, the wheel hub ratio, leaf number, lift coefficient, speed as design variables, Choose blade installation Angle, the wheel hub place dynamic load coefficient, cascade consistency, allowable safety coefficient as optimization of the state variables. Design variables contain continuous variables and discrete variable. Through the optimization method, we get the optimal structure parameters finally. And at the same time get the corresponding optimal blade installation Angle,under different working conditions.

Abstract: The influences of the conventional header configuration used in industry at present on the fluid flow distribution in plate-fin heat exchanger were numerically investigated. The numerical results showed that the fluid flow maldistribution is very serious in the heat exchanger. The header configuration with perforated plate was brought forward for the first time. The computational results indicated that the improved header configuration can effectively improve the performance of fluid flow distribution in the heat exchanger. The fluid flow distribution for the header configuration with curving perforated plate is more uniform than for the header configuration with plane perforated plate. The absolute degree of fluid flow nonuniformity in plate-fin heat exchanger has reduced from 3.47 to 0.32 by changing the header configuration. The numerical results are compared with the experimental results. They are basically consistent which indicates that the mathematical model and the calculating method are reliable.

Abstract: The paper presents numerical prediction of cavitation erosion on a Francis turbine runner using CFD code. The SST turbulence model is employed in the Reynolds averaged Navier–Stokes equations in this study. A mixture assumption and a finite rate mass transfer model were introduced. The computing domain is discretized with a full three-dimensional mesh system of unstructured tetrahedral shapes. The finite volume method is used to solve the governing equations of the mixture model and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators(PISO) procedure. Comparison the numerical prediction results with a real runner with cavitation damage, the region of higher volume fraction by simulation with the region of runner cavitation damage is consistent.