Advanced Materials Research Vol. 744

Abstract: Spherical stern bearing is kind of new bearing, which combines ordinary water lubricated stern bearing with sphere bearing. It has function to adjust contact situation of stern bearing and stern shaft automatically, decreases pressure peak, leads to pressure distribution on the bearing being more uniform, helps to overcome the problem of local overload to avoid edge effect and improves damping performance. On the base of the ANSYS software, the contact deformation and pressure calculation of spherical stern bearing are carried out to compare with ordinary stern bearing and analyse the effectiveness of reducing pressure on bearing, optimization problems of the sphere position and sphere diameter are discussed, which shows that the contact pressure achieves a minimum when the sphere is located at intermediate position of bearing bush and the maximum contact pressure decreases with the increase of sphere diameter, and they have linear relation.

Abstract: Water pipeline scaling serious by prolonged use, result in a substantial diameter narrowed, reduced water efficiency. Mechanical cleaning is a kind of economic and security cleaning method, current drilling scaling equipment cannot clean effectively. In order to solve this problem, analyzes the dill descaling method. Choose multi-tooth bit as a foundation. Established finite element model for static analysis, gets three direction force diagram. Optimal design drill structure, created a new type of scaling drill. Compared two kinds force analysis results, by improving the structure, distributed stress on multiple cutting tooth, improved cutting conditions, enhanced the drill descale and feed ability, and improved the working life of the unit. Carried out static and dynamic finite element analysis, provide a theoretical basis for follow-up design.

Abstract: The application of API threaded connections for casing and tubing is limited due to their imperfect sealing ability and weak connecting strength. To overcome these prominent drawbacks of API threaded connections, new WSP series of premium threaded connections are developed by Wuxi Seamless Oil Pipe Corporation for HTHP(High temperature, High pressure) wells, deep wells, steam injection wells, highly deviated and long horizontal wells, etc. Characteristics and application ranges of eight kinds of these high performance premium threaded connections are compared and analyzed thoroughly in this paper. The comparison results are not only a good reference for technicians to design new connections, but a technical proof for users to choose the proper connections in different applications.

Abstract: This article mainly discusses the dynamic characteristics of the experimental rotor system under the abrupt power shut circumstances, and to search the distribution of the power consumption during special working processes with an experimental method. On the basis of the experimental results, the simulation analysis is carried out on the Andritz RCP, and therefore, the dynamic characteristics of the real nuclear reactor coolant pump can be forecast, which just meets the need of the safety running in nuclear plant.

Abstract: Telescope structure is used to support and position the optical mirrors in the right place during the period of telescope observation, so it will have such capability to withstand a certain load. In order to ensure SONG telescope has such capability, FEM analysis and calculation are finished in this paper. With the help of ANSYS, firstly the finite element model of SONG telescope is built. Then using this model, the analysis and calculation of static and dynamic are performed, including the deformation under the gravity load with the tube in different directions, eigenfrequency calculation of the whole system and the responses under the seismic acceleration spectra. The results show that the max. offsets and max. relative tilt angles between primary mirror and secondary mirror are very little under the gravity load. The first natural frequency is 20.083Hz, larger than the design requirement 8Hz. The results of seismic load analysis show that the deformation in the telescope structure is 0.42mm and the stress is 33.8MPa, less than the allowable stress of the structure material. The above analyses verified that the structure design of SONG telescope is reliable and acceptable.

Abstract: Structural synthesis of super-redundant mechanism is a key to design of painting robot for S-shape duct. Based on the principles of modular structure design, the painting robot for S-shape duct falls naturally into three separate control and design components: a moving platform, a locating mechanism, and a painting manipulator. The moving platform consists of a robot body, wheels, gasbags for position adjustment, and screw jacks. The 3PR-type serial mechanism is adopted for location. The super-redundant 3P7R-type serial mechanism is used for the painting manipulator. The restriction of the distance between connecting rods and the axis of the duct is employed to control self-motion of the painting manipulator for joint trajectory planning. Experiment result shows that minimal distance between robot joints and duct interior is 18mm and that average dynamic accuracy is ±6.8mm, which satisfies the working requirements.

Abstract: According to the clinical rehabilitation medicine theory and the characteristics of human upper limb rehabilitation robot, a dexterous rehabilitation mechanical arm with 6-DOF is designed to satisfy the need of rehabilitation in this paper. By analyzing the six cases of the 3-DOF serial distribution and the kinematic relation of the shoulder joint, the spherical joint motion of the shoulder joint is achieved by using the circular arc guide rail. Two serial mechanism approaches of the shoulder joint using PRR and RRP type are provided. After comparing these designs, the PRR type is selected, the kinematics positive solution of this type is given.

Abstract: A new tracked triangular wheel structure was introduced. A whole tracked triangular wheeled vehicle model was built in multi-body dynamics simulation software RecurDyn, and its climbing obstacle performance on the dry soil road was simulated. The author put the simulation results as loading conditions of finite element model. Finite element calculation and lightweight design for tracked triangular wheel base frame were completed. The results showed that the weight of the base frame reduced by 69.8%, the structure properties of the base frame improved, and the lightweight design goal was achieved.

Abstract: A method for analyzing the value of cepstrum without taking the logarithm is proposed. The bottom of abscissa of cepstrum is cycle of power spectrum.Ordinate of the cepstrum can identify how many lines in the sideband of power spectrum without logarithmic.Application to fault diagnosis of the test bench and the gearbox is successfully, and thus significant results are achieved.

Abstract: In the wind turbine system, high strength bolt is always used in important joint. For example, whether the bolt between wind turbine tower is safe is one important side of wind turbine protecting. However, the gearbox always loses oil even if wind turbine runs well, even the oil would leak on the bolt joint of each layer. So it is important to analysis the influence of oil-leak to bolt joint. Through analyzing the property of gear oil and the stress situation of bolt in wind turbine tower, the paper obtains the equilibrium formula of bolt joint in different stress situation and the influence of oil to frictionfactor and torque coefficient. At last, making a conclusion about the reson of causing bolt joint loosing when gearbox oil leaks on the bolt joint of wind turbine tower.