Papers by Keyword: Coupling

Abstract: Based on the coupled precise time integration method and basic assumptions of constant average acceleration method in Newmark family, implicit series solution of structural dynamic equation is put forward by introducing the Taylor series expansion. Relevant time step integration formulas were designed. Stability and accuracy of the method were analyzed. Stability analyses show that the coupling implicit method is stable when damping ratio is equal to 0, and is conditionally stable when damping ratio are other values. The results show that the accuracy of the algorithm can be controlled by choosing the number of truncation order of Taylor series expansion and is better than that of traditional scheme with the increase of time step. Number examples are given to demonstrate the validity of the proposed method.

Abstract: A power system on hybrid electric vehicle (HEV) was chosen for research. On the basis of analysis of characteristic parameters of motor on system, the hybrid system’ dynamics characteristic under electro-mechanical coupling was completely studied. The vibration of hybrid power system was qualitatively studied on theory and experiments when motor were under two different kinds of mode from electricity to push, and two results were consistent with each other well.

Abstract: In this paper, The use of the basic mechanics model, based on the use of fluid-structure coupling of thinking, the use of finite element software simulations, And Then quantitative study the effect of perforation parameters such as perforating depth, aperture,shooting density,shot phasing,drawdown on hole stability and well yield,make sure the weight size relationship of each perforation parameters about hole stability and well yield based on the orthogonal analysis. In the end based on the actual lithology information and original crustal stress distribution in longxi area of Daqing ,to design optimum perforating parameter of this block well.

Abstract: In the injecting steam wellbore, insulated tubings are connected with couplings. The coupling is short, but its insulation performance is poor. There are two different coupling types: couplings with insulation bushing and couplings without insulation bushing. By combining on-site experiments and fluent simulation, thermal insulation performance of coupling with insulation bushing and without insulation bushing were discussed. The results showed that the apparent heat conductivity of the coupling with insulation bushing is about 0.4W/(m•K), the apparent heat conductivity of the coupling without insulation bushing is about 3.6 W/(m•K). Insulation bushings promote insulation performance of vacuum insulated tubing coupling significantly.

Abstract: Based on a transient analysis code that developed with coupled neutron and thermal hydraulic calculation model for supercritical water reactor, the transient characteristics under feed-water parameter changing is detailed analyzed, including temperature decreasing, flow-rate decreasing and pressure increasing. The results show that, if no control system action given, flow rate or temperature decreasing would lead to the increase of main steam temperature and decrease of core power, but pressure increasing shows a little influence. If control systems are put into operation, transient characteristics will be obviously changed but finally recovered to normal level. As the same changing percentage 3% is selected, main steam temperature during pressure decreasing transient can reach its highest level in 510.9°C, and return to normal at the time of 90s. But for feed-water temperature decreasing transient, main steam temperature shows an obvious fluctuation during its adjustment and returns to normal until 170s from 503°C. In addition, compared with the results calculated by non-coupling calculation model, main steam temperature calculated by above coupling model shows a smaller deviation but a little longer time needed for returning to its normal value.

Abstract: This paper presents a high-performance lowpass filter (LPF) using periodical inter-coupled compact microstrip resonator cells (CMRCs) in series. The CMRC consists of high impedance transmission line and symmetrical T-shaped structure at both sides with ended transmission line arms. By using a bridge structure to introduce controllable inter-coupling between the adjacent tapered CMRC units, the proposed CMRC structure exhibits quasi-elliptic lowpass response with improved stopband performance. Final design of an exemplary LPF using proposed design structure and methodology verify the feasibility of the structure and its high performance including compact structure, low insertion loss, sharp transition and expanded stopband.

Abstract: Dropout may be happen to round thread connection by main reasons of design and process of product, material’s property, make-up torque or make-up position, field operation problems etc.. Casing’s property has get a high improvement with the development over the past decade in China. But the number of connection dropout accident didn’t declined obviously. These lead to great economy loss and safety hazard had taken place. Research on a round thread connection pullout case was carried out combining relative theorys with tests. Macroscopic analysis and dimension measurement and material’s physical and chemical properties were checked for casings and couplings. Thread inspection and full-scale tests were done for casing simples that are same lot with dropout. Comprehensive analysis was carried out on these results. The results showed that dropout failure was ascribe to two main causes. One is make-up location cann’t reach standard location at field end, and the other is incorrect holding position on coupling in the course of making up.

Abstract: the coulped neutronics and thermo-hydraulics model for supercritical water-cooled reactor (SCWR) is developed by internal coupling method. It is based on the two group neutron diffusion equations and the one-dimensional junction thermal analysis mode, in which the cross sections used for SCWR are generated by Dragon tool. Compared with the calculation results based on the non-coupling calculation model, the steady state characteristics under coupling calculation condition are detailed analyzed by considering parameters feedback at each axial node. The results show that, as coupled model is chosen its axial power distribution would give an obvious deviation from the cosine function that used for non-coupled model. Although the cladding temperature at most of the axial nodes rises with a shifted power peak, the maximum cladding temperature is finally decreased. For the above coupling condition, the maximum cladding temperature would appear at the external assemblies with lower coolant temperature but not at inner assemblies with higher coolant temperature. As the detailed description for coupling characteristics of supercritical water-cooled reactor is given, a certain theory reference for its system safety could be provided.

Abstract: Relative to serial robot, parallel robot gets more and more attention of scholars because of its many advantages. However, there are some problems in the current research such as the chains’ coordination and coupling control, which has became one of the key problems in the motion control of parallel robot. To further enhance the motion control performances, a novel sliding mode control method base on synchronization error is proposed in this paper. The simulation and experiment results show that the designed control system has good tracking performance, small system error and strong robustness, which can satisfy the high-precision requirements of the parallel robot control.

Abstract: Aim at Individual Soldier Automatic Weapon (ISAW), three-dimensional FE model and thermoelasticity coupling model of barrel were built. The coupling temperature field and coupling stress field of the barrel were calculated. Laws of the coupling temperature field and coupling stress field were obtained. The coupling temperature field and coupling stress field of different set of barrel aim at automatic fire were compared. The results show that the Material Properties of the barrel is security. Current research work will be helpful the Individual Soldier Automatic weapon design and the life of barrel study.