This paper deals with a combined test rig for a traction system in the laboratory environment. An experimental system was designed and implemented to verify the performance of the traction system for a metro train. For a highly accurate control of the system, a hybrid control algorithm combining vector control and slip frequency control was applied to control the traction inverter. The design method of the flywheels, which represent the equivalent model of the train moment inertia, was elaborated. A train runtime diagnosis system was completed by adopting the multifunction vehicle bus (MVB) protocol. The dynamic performance of the metro power traction system was emulated under the control of the train runtime diagnosis system. Using the combined test rig, the performances of the traction system in traction, braking, temperature rise, etc., were verified through traction and breaking experiments.
The finite element analysis (FEA) technology by hydraulic-mechanical-chemical-damage (HMCD) coupling is proposed in this paper for inclined wellbore stability analysis of water-sensitive and laminated rock, developed basing on the recently established FEA technology for transversely isotropic rock with hydraulic-mechanical-damage (HMD) coupling. The chemical activity of the drilling fluid is considered as phenomenological hydration behavior, the moisture content and parameters of rock considering hydration could be determined with time. The finite element (FE) solutions of numerical wellbore model considering the chemical activity of drilling fluid, damage tensor calculation and weak plane strength criterion for transversely isotropic rock are developed for researching the wellbore failure characteristics and computing the time-dependent collapse and fracture pressure of laminated rock as shale reservoirs. A three-dimensional FE model and elastic solid deformation and seepage flow coupled equations are developed, and the damage tensor calculation technology for transversely isotropic rock are realized by introducing effect of the hydration and the stress state under the current load. The proposed method utilizing weak plane strength criterion fully reflects the strength parameters in rock matrix and weak plane. To the end, an effective and reliable numerically three-step FEA strategy is well established for wellbore stability analysis. Numerical examples are given to show that the proposed method can establish efficient and applicable FE model and be suitable for analyzing the timedependent solutions of pore pressure and stresses, and the evolution region considering the hydration surrounding wellbore, furthermore to compute the collapse cycling time and the safe mud weight for collapse and fracture pressure of transversely isotropic rock. 相似文献