Applied Mechanics and Materials Vols. 494-495

Abstract: The rotor of ultra supercritical steam turbine runs in bad condition with high parameters of steam. The large heat stress of rotor may appear when the operating conditions of turbine unit is changed, for example, adjusting load to meet the requirements of peak and valley of grid, especially, improper operation causing serious damage to rotor. According to theory of thermal stress analysis, first, the steam parameters and their heat transfer coefficients of all cascades of 1000MW ultra supercritical steam turbine is calculated. Then the temperature field and stress field of the high-pressure rotor in the process of cold startup calculated by the finite element software are analyzed and discussed. The results are important to the startup and changing conditions of 1000MW ultra supercritical steam turbine unit.

Abstract: This project was to design the shafts for a new type dispatching winch, the author has improved much base on the original plan. By adopting involute gear transmission of two-stage NGW type, the transmission pattern has been changed from fixed shaft pattern to moving shaft pattern and the DOF of the mechanism has increased, which has achieved the composite motions between the components and has catered to the target of decelerating.

Abstract: For the tubular C/C-weaving composite is often loaded on thermotics and mechanics loads together in using, adopting the sequential coupling method, utilizing the finite element analysis software: firstly analyze the stress distribution on loading temperature and pressure loads together, the maximums and changing rules of displacement, stress and strain have been obtained. Based on the works above, further to analyze the thermo-mechanical coupling of different loads, the curves of displacement, stress and strain in the specified paths have been obtained, it shows that the influence from temperature on every parameters is little when loading on the larger loads. So come to the conclusion that the tubular C/C composite has good temperature stability and can be used in the condition of high temperature or temperature changes greatly.

Abstract: The advanced manufacturing technology is developing rapidly and it has gained more and more attention from manufacturing industry and other related fields. It has permeated into every subjects and majors by its characteristics of progressiveness, universality, practicability and integration, and has played an immeasurable role in promoting the development of industry product modeling design. This paper discusses and analyzes concretely the application of advanced manufacturing technology in product modeling design from some aspects such as advanced manufacturing technology, computer aided design, rapid prototyping technology and virtual manufacturing technology.

Abstract: Finite Element Method numerical simulation has been carried out to analyze mechanical deformation of thrust bearing under the point and line supporting condition. The simulation results indicate that the torsion deformation of the point supporting is the larger, torsion deformation is mainly radial bending deformation, and circumferential bending deformation is small, it becomes more and more obvious with the decrease of bearing pad length-width ratio under the same working conditions for the same pad. Line supporting torsion deformation is mainly the circumferential bending deformation, and the left and right sides are symmetrical along the circumferential, the radial bending deformation is small, torsion deformation related to the length and width of supporting, with their size increasing the torsion deformation decreased.

Abstract: In order to solve thermal deformation, the finite element numerical simulation of two kind of tilting pad thrust bearing is made for the same pad surface, and thermal deformation is made to analyze comparatively. The results show that the temperature field, the deformation field and the values of pad are similar for two different supported thrust bearing (point, line support) under the same operating condition. The pad temperature and deformation will increase with the increasing of pv values. According to the calculation conditions, the temperature field rose about 1°C, and the thermal deflection increased 0.002mm with pv value increased by 10%.

Abstract: For the problem of bamboo structure safety caused by bamboo culms splitting, the bamboo culms splitting capacity test method is studied, bamboo culms splitting capacity finite element model based on brittle fracture mechanics is proposed in the work. The results calculated by FEM are consistent with the experimental results, and the error is in 20% or less. The bamboo culms splitting capacity finite element model established above can provide supports for bamboo culms wide engineering applications. The developed model has theory and engineering significance for digital bamboo building optimal design.

Abstract: The form wheel generating curve is always a composited curve which is composed of lines and arcs, and the calculation of the envelope surface is more complex than conventional rotary cutter. Therefore, a method of envelope to a two-parametric family of point vectors is proposed, which defines the point and its normal vector on the wheel generating curve as a point vector. Each point vector corresponds to a virtual ball uniquely. The rotation of point vector forms latitude circle and the valid envelopment movement forms sectional circle. The intersection of latitude circle and sectional circle is grazing point; The analytical calculation model is established, in which the geometry parameters of virtual ball can be directly calculated from point vector; An example is presented to demonstrate the effectiveness of the method which can be used for form grinding geometry simulation, accuracy evaluation and optimization of the wheel path.

Abstract: Ultrasonic cutting technique is an advanced processing method of cutting honeycomb materials. An ultrasonic pointed cutter was designed. Combined with the principle of ultrasonic cutting, the mathematical model of the tool was established. Modal analysis of the tool was calculated with the finite element software to study the effects of tool geometry on the natural frequency. The results show that the natural frequency increases as the tool thickness increases, but it decreases as the tool length increases. And it obtained the modal shapes and natural frequencies of the tool which meet design requirements. The optimal geometry of the tool was also determined. Finally, it verified the rationality of tool design by amplitude measurement experiment of the tool.

Abstract: In order to provide a theoretical basis for the research on processing tomato harvester, three kinds of processing tomatoes which were largely cultivated and suitable for mechanization harvest in Xinjiang location of China were sampled, and after measuring the red-ripe fruit weight, fruit transverse and longitudinal diameter, the regression equations about the fruit weight and the fruit transverse diameter, fruit longitudinal diameter, fruit shape were established, and the fruit-stem separation force test on the samples was carried out, so the regression equations about the processing tomato fruit-stem separation force and the fruit weight were established. Finally, the mathematical models about fruit-stem separation force and fruit shape of processing tomatoes were built.