Applied Mechanics and Materials Vols. 16-19

Abstract: To manufacture the complicated turbo molecular pumps (TMP) rotor by NC machine tool, a geometric modeling for unitary rotor of TMP is created by UG NX 4.0. Based on the optimized geometric parameters of turbo blades, the coordinate system was defined, the wheel and blades were created, and the unitary rotor was built, then the outline of rotor and blade root were modified by cylinder and arc on UG CAD platform. The geometric model of the TMP rotor will be used in the next manufacturing step: NC programming. The result of TMP rotor geometric modeling is shown that UG NX CAD is an available tool to design and manufacture TMP unitary rotor.

Abstract: The effects of the lubricant properties on the lubricating performance of the tripod sliding universal joint were studied under thermal condition by numerical method. The obtained results show that increasing lubricant viscosity increases the film thickness whereas increasing viscosity-pressure coefficient or viscosity-temperature coefficient is just the reverse. The pressure hardly depends on the viscosity-pressure coefficient or viscosity-temperature coefficient, and a larger lubricant viscosity induces only a remarkable second pressure peak. Increasing lubricant viscosity or viscosity-pressure coefficient increases the temperature whereas the increasing viscosity-temperature coefficient reduces it.

Abstract: Based on the stimulation and restriction of road simulation, the 5-DOF motorcycle multi-body dynamic model is derived, and the differential equation of motion and state-space formulation are developed according to Lagrange Equation. By iterating the load spectra, which was sampled on Hainan Proving Ground, the driving signal of motorcycle road simulation is obtained. With the driving signal as input, the motorcycle dynamics is simulated using MATLAB program, then the simulation and experiment are compared. The result shows that motorcycle dynamics can be analyzed and estimated precisely by combining road simulation with computer simulation.

Abstract: This paper introduces the working principle of the impact mechanism which is belonging to the double-chamber scavenge oil hydraulic rock drill. On the basis of some fundamental hypothesis, a mathematical model of hydraulic impact mechanism is established, then carrying out a dynamic simulation. Focusing on the influence of supply pressure, supply flow and precharge pressure on the working performance of impact mechanism, some research is implemented, and some regularity conclusions are obtained.

Abstract: The motorcycle dynamics simulation method based on the road simulation test and virtual prototype is developed, and a rigid-flexible coupling virtual prototype with test platform of motorcycle is created with CATIA, NASTRAN and ADAMS software. According to two-channel tire-coupled road simulator of MTS Systems Corporation, the simulation model and platform are repetitively refined to fairly high precision by comparing simulation results with experimental results. The iterated excitation signal based on real road load or typical spectrum of different roads is imported into the virtual test platform, the comfort and durability tests of motorcycle can be undertaken to replace road simulator, the test period and cost are greatly reduced, and test security is increased.

Abstract: A square-type rotary ultrasonic stator using longitudinal vibration transducers is proposed. The proposed stator contains four longitudinal vibration transducers, which are located in square-type. Every longitudinal transducer includes two exponential shape horns located on each end. And the horns of adjacent transducers intersected at tip ends where located the driving feet. The longitudinal vibrations of transducers are excited by the longitudinal vibrations of PZT ceramics. Longitudinal vibrations of adjacent transducers are superimposed in the driving foot and generated elliptical trajectory. The actuating mechanism is analyzed, and the motion trajectories of driving feet are deduced. The stator is designed and analyzed by using FEM method. The vibration characteristic of stator is gained by transient analysis. Results indicate that the motion trajectories of the four driving feet have good consistency, and the proposed motor has potential good output characteristics. The results of this paper verify the theoretical feasibility and provide instructions for the development of proposed stator.

Abstract: In order to enhance the processing precision of the numerical control lathe, affected the processing precision to the numerical control lathe to feed system in the primary factor to conduct the analysis research. Rested on the mechanical kinetics principle to establish the engine bed to feed transmission system mathematical model, has constructed the lathe to feed system simulation model using MATLAB in software dynamic simulation tool Simulink, and obtained the reflection system performance simulation curve. Has analyzed gap, dead area and so on non-linear using the simulation model and the simulation curve the factors to the system processing precision influence and gave enhanced the transmission system performance the effective action. The analysis research result indicated that, carries on the dynamic simulation in Simulink, may revise the parameter repeatedly, very quick can obtain the best design variable. For the mechanical drive system design, the parameter choice as well as the performance improvement has provided the good method and the effective way.

Abstract: As a non-linear finite element analysis software ANSYS/LS-DYNA is used to carry out virtual reliability test in transmission mechanism of reciprocating compressor and response surface method is used to analyze reliability and sensitivity of sliding bearing according to testing data. This paper uses ANSYS to preprocess testing models of virtual prototype and put out the K file; designs sample points of random variables based on central composite method and modifies the K files to carry out random sampling of prototype and uses LS-DYNA970 to solve the submitted K files repeatedly; plots relationship curves of output responses and time history and gets a group of sample points of structure response with post-processing results of LS-PREPOST. Lastly this paper uses response surface method to build limit state equation and analyze reliability and sensitivity of sliding bearing, and provides theoretical basis for design of bearing.

Abstract: Reverse engineering has an increasing use in shoemaking process for rapid prototyping of shoe lasts. Foot shape reconstruction is one of the most important techniques in custom-made scheme. A system for reconstruction a foot shape from its 2D views using a coded structured light projection combining with the optical triangulation method is presented. A set of multiple gray coded patterns are projected to the target object through a projector and the distorted stripes patterns produced by its surface are captured by a digital camera. By adopting the optical triangulation method with the projector-camera parameters known in advance, the foot shape surface is reconstructed. The results show that the implemented system is able to reconstruct dense and precise 3D foot shapes.

Abstract: Coordinate measuring machine (CMM) plays a more and more important role in the flatness evaluation. The pre-processing for eliminating error data is an important process to improve the quality of flatness evaluation. So, flatness uncertainty estimation becomes a key problem. To solve the problem, a flatness uncertainty estimation method based on data elimination is presented. Firstly, a method for excluding the error data based on statistical theory is expatiated with the consideration of probability theory and mathematical statistics. Secondly, details of calculating flatness uncertainty based on least-square method are analyzed. Then the measured 3-dimensional data are processed so as to put the excluding method into use. So the error data can be deleted and the flatness uncertainty can be decreased and can achieve a good evaluation quality. Finally, an example is given and the result shows that the method proposed in this paper is feasible.