Abstract: Landslide Body, which is a combination part between Knife Tower and Saddle, plays a significant role in the working performance of the NC (numerical control) Lathe. So it is essential to optimize Landslide Body’s structure to improve static and dynamic characteristics. At first, the structure of NC Lathe is introduced. And then, static and dynamic analysis of Landslide Body is carried out before optimization. At the last, optimization process which consists of topology and size optimization is carried out. Based on the optimization results, a new structure of the Landslide Body is generated. It is proved that both static and dynamic characteristics are improved to some extent.
Abstract: Machining simulation can quick supply valuable data to help improving machine processing quality and efficiency. And it is playing an important part in the development of modern machining theory. In this paper, the drilling process of an engine block was simulated in the software of DEFORM-3D. The geometry models of cutter and workpiece were simplified to avoid too low efficiency of simulation running. The mesh weight factors were specified to keep geometry models from changing too much from the real situation. 11 simulation experiments were carried out. And through regression analysis of the result data, the drilling load formulas were obtained to predict the axial force and moment in the drilling process of engine block.
Abstract: Precise control of the inclination and azimuth is of great significance for the efficient drilling of dynamic point-the-bit rotary steerable drilling tool. The design details of offsetting steerable mechanism for rotary steerable drilling tool based on inner and outer double eccentric rings are demonstrated in the paper. While drilling, the tool collar rotates and passes the torque and drilling pressure to the drill bit efficiently, and the stable platform mounted inside the collar is maintained geostationary by rotating it counter to collar rotation at the same frequency. And an offsetting steerable mechanism in the stable platform provides selectively and axially inclination to the collar by adjusting the relative position of the inner to the outer double eccentric rings. It is shown that the maximum oriented inclination can be reached as 1.0 degree flexibly for the presented structure.
Abstract: To solve the five-axis machining accuracy problems that caused by assembly precision and direction error of rotary axes of inclinable head in high precision five axis machine tool. By selecting the five axis machine tool with inclinable head AB, GMC1230u, as the research object and analyzing the causes of the inclinable head error, the kinematics relationship of the rotation center position error and axis tilt error is established. By that, the direction vectors of each rotation axis and the position vector of rotation center are calculated based on the regression analysis of on-line measurement of the tool center point position and the calibration of five-axis RTCP function parameters is also accomplished. Finally, the compensation for inclinable head error in five-axis machine tools is fulfilled efficiently and remarkable improvement of RTCP machining accuracy is achieved.
Abstract: In the defect test of plate-like structure, acousto-ultrasonic technique can stimulate a multi-mode Lamb wave. This paper used an FEM method to investigate the Lamb wave propagation, the simulating signals are decomposed and reconstructed by MP and compared with the theoretical parameter curve of the frequency dispersed curves. It was proved that matching pursuit based on tEP can accurately search the characteristic parameters of the signal, realize the rapid signal decomposition and reconstruction, and identify the defect signals.
Abstract: Through the analysis of factors affecting the efficiency of auto transmission system, the power loss models of all parts of the transmission system were established, and the formula of the transmission efficiency was obtained. On the basis of formulating the minicar transmission efficiency test standard, the transmission system was tested. Test results indicated that the transmission efficiency values which obtained theoretically by calculation were in reasonable agreement with experimental results, the relative errors were less than 6%，especially in commonly used input torque and input speed range. This model provides theory basis for the design and optimization of auto transmission system.
Abstract: The mechanics models formed by packed circular discrete elements and randomly distributed in a specified region were used to investigate the mechanics properties of granite, and some different sizes of discrete element models were carried out to study the size effect of mechanics properties. The simulation results suggest that there is no obvious size effect for Poisson’s ratio, compressive strength and Young’s modulus. However, the value of bending strength decreases with the increasing of the model size.
Abstract: In order to investigate the drag reduction mechanisms of vibration digging shovel from the kinematics and mechanical aspects, and to estimate the magnitude of its traction resistance, we performed kinematic analysis when the velocity of the digging shovel was undergoing sinusoidal changes. Based on the analysis of the relationship between vibration direction angle, ascending direction angle and the edge motion curve, we evaluated the efficacy of different mining modes and proposed the ideal working conditions. We found that when the vibration direction angle φ <0 it could produce favorable cutting conditions. When the cutting direction angle θ was slightly less than or equal to the buried angle α and the ascending direction angle λ <π/2, the traction resistance was the least and soil-crushing effect was enhanced. The application of the moving viscous friction resistance model of mining shovel to analyze the force, including the impact of cutting speed on vibration viscous friction, could optimize the ideal working state and deduce the horizontal traction resistance formula of cutting and ascending. This model will be conducive to the structural design of vibration digging shovel and the estimation of its traction resistance.
Abstract: This paper has designed a new type of mechanical structure for a coin-wrapping machine; It’s three-dimensional model has been established by Pro / E 3D modeling software and the kinematic of the Integrated model analysis has been carried out. The simulation results have shown that the coin wrapping process can be simplified and the efficiency can also be improved with the new structure, thereby reducing the costs.