Advanced Materials Research Vols. 314-316

Abstract: As the key part of offshore drilling drawworks brake system, the brake disc plays a vital role in guaranteeing the working reliability and operational security of the drawworks. To obtain the distributions and variations of thermal stress field in the water-cooling bake disc in an emergency braking, the 3D thermo-mechanical coupling theoretical model and FEM were established in this paper. Meanwhile the displacement and thermal boundary conditions for solution were determined, and then fully coupled analysis of thermal stress field in the disc was carried out by using ABAQUS software. The analysis results showed that, temperature field and stress field in the process of emergency braking were fully coupled. The temperature, radial stress and circumferential stress on the disc surface were presented as a hackle. The circumferential stress was significantly greater than the radial stress. Thermal stress has a periodic effect on the brake disc during braking, so the circumferential stress is the main factor that accounts for the initiation and propagation of crack on the brake disc surface.

Abstract: Five-axis machine tools with two additional rotational degrees of freedom provide more flexibility in tilting the tool axis to various orientations than conventional three-axis machine tools do, subsequently increasing the cutting efficiency and avoiding tool collision against a workpiece. Also, the risk of programming error can be avoided by simulating the five-axis Numerical Control (NC) code before real machining. This work presents a five-axis machine tool cutting simulation system with a nonorthogonal linear axis configuration. A window-based cutting system written by Borland C++ Builder and OpenGL is also developed based on the kinematics model of the proposed machine tool. Furthermore, implementing and verifying the five-axis NC code demonstrates the effectiveness of the proposed scheme.

Abstract: A new Rollover Protective Structure (ROPS) of the large-scale wheel loader was designed based on a buffer-induced structure. Dynamic Finite Element analysis model of the entire vehicle was created and boundary conditions of typical rollover cases were given. Optimization design of this new ROPS was obtained through a comprehensive analysis of 16 dynamic simulation samples, which were designed by Orthogonal Experimental Method. Comparison analysis of dynamic response results between original ROPS and optimal new ROPS indicates that this new ROPS effectively prolonged the duration time of the first collision and reduced the acting time of peak force. Deformation extent of main structure of this new ROPS is significantly smaller than that of the original ROPS. Buffer-induced structures can increase the kinetic energy absorption capability of ROPS. Therefore, it can reduce the possibility of brittle fracture of ROPS and improve the probability of operator survival.

Abstract: According to the situation that surface grid models are widely used, this article summarizes the research status of numerical control machining based on Triangle facets models, introduces the STL files in detail, expounds the process of machining STL files by using Pro/Toolmaker system, designs an independent post processor for generating NC code for Fagor machine, simulates the virtual machining process through Vericut software, verifies the actual machining process on Fagor three axis CNC milling machine. Proves the method of numerical control machining based on STL files is actually feasible for planar milling、cavity milling、profile milling, Realizes the machining of STL files based on Fagor CNC system.

Abstract: Taking 2K-H differential gear train as study object, dynamic equation of torsion vibration was established with influence of time-varying meshing stiffness. The virtual-prototype with nonlinear meshing force was modeled using Virtual.Lab Motion software. Gear contact force was simulated, and it was verified by theoretical data. The reason of meshing vibration is analyzed. The results show that time-varying meshing stiffness is the main excitation of gear system, and gear system is vibratory although the input and output are stable, and the basic frequency is meshing frequency. This research lays foundation for strength checking, optimum design and fatigue life prediction.

Abstract: Engineering change is an important and complex activity for manufacturing enterprises. In order to improve the efficiency of engineering change, designers should pay different attentions to different nodes of product development network. In that case, a method of classifying the nodes was proposed. First, we proposed a method to cluster the nodes based on design structure matrix; then, we analyzed the indexes for evaluating the importance of nodes and studied the method of classifying the nodes of product development network; finally, the experiment of managing a type of motorcycle engine was employed to validate our method and it showed the correctness of the proposed method.

Abstract: This design is a redevelopment of Mastercam. The cutting dosages are varies with the basic conditions, which contains parts material, tool materials, machine tool rigidity coefficient and so on .The problem is that we must modify cutting dosages one after another when the basic conditions changed. In view of the above problems, we using VB software design a specialized software. We can realize the automatic generation of cutting parameter of Mastercam by debugging this specialized software and Mastercam software. This software is convenient and practical, using it, We can save the processing time and increase work efficiency.

Abstract: The resource selection and optimization is the key point in the application of manufacturing grid. The limitation of the existing manufacturing resource finding methods is analyzed in this paper. Based on mathematical description of the resource selection process, a GA-based optimize model is proposed and its algorithm is designed. Finally, a typical instance is illustrated to validate the model and algorithm.

Abstract: This article appeared in foreign countries, the B-axis tilt of 45 ° with a turntable for a special non-orthogonal body Rocker 5-axis machining center, the correlation is derived post-processing algorithm, through a combination of UG/Post Builder post-processor development tools, the development of models for DMU125FD processing center dedicated post-processors, and implements the turning&milling complex processing functions, and further proved by experiments that the special post-processor is correct and practical.

Abstract: Post processing is to change the cutter location files into each axis motion files according to the structures of machine movements and control instruction formats. The case study of 5-axis double rotary table of the CNC machine is researched in this paper. The machine structure and the machine kinematics are analyzed to get the coordinate transformation matrixes, then specified post processing procedures of this machine are developed, the system achieves good effects in practical application.