Papers by Keyword: Simulation Analysis

Abstract: Most conventional methods cannot get effective performance during multi-fault diagnosis of rotating machines. Blind source separate techniques have applied to this problem, but the results show some limitations. Some prior knowledge considering the spatial or temporal characteristics of signals can be incorporated into these BSS approaches. Here spatial topography information will be chosen as spatial constraints and combine them with FastICA algorithm to get spatially constrained ICA (SCICA) method. This new technique will deal with multi-fault signals of rotating machinery through simulation process. SCICA is effective to multi-fault diagnosis and can separate all the source signals.

Abstract: The failure of brake performance, which is caused by thermal recession under the emergency brake, results in traffic accident frequently. Based on excellent wear-resisting properties of locust’s non-smooth surface structure, bionic brake disc with special surface micro-structure was designed. According to the thermal analysis theory, transient temperature field analysis of the bionic brake disc during the braking process under different initial velocity was analyzed. The results showed that bionic brake disc has excellent heat dissipation ability, which is beneficial to improve the brake performance. The non-smooth surface can store air and dissipate heat, thus reducing the thermal fatigue and thermal wear caused by temperature rise. This research provides a theoretical basis for designing bionic brake discs with excellent heat dissipation performance.

Abstract: Copper stripping machine is an alternative to traditional artificial device. It is one of the key parts of the stripping device. It realizes stripping the sponge copper from the surface of the sheet nickel and ensures the subsequent automation. This article has carried on the simulation by using ADAMS to the movement of device, and base on theory of fluid mechanics and calculates the vibratory force on sheet nickel. By analysis, under the current hoisting height, the device can effectively guarantee shaking off the sponge copper on the surface of the sheet nickel. The electrolyte flushing of sponge copper removal effect is not obvious.

Abstract: In surface grinding, the shape error is occurred by the thermal deformation of a ground workpiece. To finish the workpiece with high accuracy, it is necessary to understand the temperature distribution of the workpiece during grinding process. However there is no study to analyze the temperature distribution of a large workpiece during surface grinding process. In this study, an advanced simulation analysis method of the temperature distribution for a large workpiece was developed. In the developed simulation analysis method, the temperature distribution was calculated from the power consumption of the wheel motor. The power consumption can be obtained easily without any specialized equipment. To evaluate the developed simulation analysis method, in-process measurement of the temperature distribution of a large workpiece was also carried out. A large workpiece ground in this study weights about 1.3 tons. The temperature distribution was measured with thermistors mounted in many places of the ground workpiece. At the area close to the grinding surface, it was found that temperature rises immediately after the passage of grinding wheel with measuring the developed in-process measurement system. On the other hand, at the area far from the grinding point, temperature does not change quickly. The in-process measured temperature distribution agreed well with the simulated results.

Abstract: In this article, a direct numerical method is developed to solve two-dimensional interaction problems of wave and floating body with ADINA software. Motion’s equation of the floating body and hydrodynamic parameters are expressed based on potential flow theory. The force and response on the floating body boundary is described in terms of linear minor wave theory. The numerical test is carried out. The result intuitively shows the dynamic response and the stability of floating body under incident waves.

Abstract: Mobility is the urgent requisite of post spinal cord injury (SCI) patient. Since the alternative and compensatory approach is considered as the major function of mobility assistive device for post-SCI patients, the device should possess capability to acclimate to the ‘abnormal’ gait generate by the patients who usually undergo alternative and compensatory rehabilitation in their neural circuit. The functional ability of individual should be taking into account. Yet according to the requirement of neuro-protective treatment in post-SCI rehabilitation processing, locomotor-like activity is still an essential factor to patient. This study presents a novel concept and prototype of assistive technology base on foot control strategy to take an equilibrium between mobility and gait realization. To demonstrate that foot-induced over-ground locomotor assistive method is capable of achieving locomotor-like activity (dragging step), simulation analysis and prototype preliminary experiment have been conducted. Simulation analysis show that foot-induced assistance can allow more volitional activity compare to the hip-knee-induced assistive device. Yet the input and disturbance act on such kind of device may be increased. Surface electromyography (sEMG) from muscles of lower limb (right rectus femoris, right biceps femoris and right gluteus maximus) have been recorded during the preliminary experiment, and the mean of integrated EMG (iEMG) was used as evaluation of muscle activity. The result of the testing show that the mean of iEMG in the right gluteus maximus was reduced in the swing phase when the subject moving ahead with the prototype, but no significant change in the right rectus femoris. It may imply that foot-induced over-ground locomotor assistive device can reduce the muscle activity when patient complete locomotor-like movement and retain some amount of residual recruitment of lower limb, instead of substituting arbitrarily.

Abstract: Passing ability of articulated vehicles is analyzed, which are combined of different 6×4 tractors and different semitrailers. According to the requirements of GB 1589, the passing ability of different structure articulated vehicles are simulated using AutoTURN. In order to analyze the passing ability impact factor of articulated vehicles in type and structure, simulation analysis is used to study how the tractor front overhang, the distance between center of tractor fifth wheel and the tractor first axle, and the semitrailer first wheel space impact on the passing ability. Reasonable suggestions are proposed by analyzing how the changes of parameters impact on the passing ability. The validity of the simulation model is validated by the test. The results serve as a useful reference for optimizing the articulated vehicle passing ability and promoting the development of vehicle industry technology.

Abstract: The model of the water-mass-to-collector-area ratio (WMCAR) of a flat-plate solar water heating system has been built based on the energy output model of the solar collector. The results show that the calculation values of the WMCAR model are highly consistent with the experimental values and their relative errors do not exceed 10%. The WMCARs of the flat-plate solar collector integrated with large-tilt-angle (70^o-90^o) into the south façades of the high-rise buildings in five climatic regions including 133 cities in China have been calculated and analyzed. For convenient use in practice, parameter relationships between the values of WMCARs and the main meteorological data have been analyzed by using the linear polynomial regression technique. The regression equations and regression coefficients in summer months and winter months have been given in this paper.

Abstract: A novel topology circuit of active compensation was discussed to be used to manage negative sequence caused by locomotive load in electrified railway. The main circuit used a three-phase two-leg compensator as active elements of shunt hybrid active compensator topology. The number of switch device in this topology was reduced by comparing with three-phase full-bridge active inverter and the cost was lower. The simulation model was developed with SIMULINK. The simulating results indicates that the shunt hybrid active compensator can restrain the problem of negative sequence which generated by locomotive load, and reduces the effect of reactive power, negative sequence, improves electric energy quality and verifies the correctness of the proposed structure and control method.

Abstract: RED algorithm is a kind of implementation which is relatively simple, and better solutions to optimize the network congestion problem, but the RED algorithm of control for the network changes is relatively sensitive, So in practical applications may be to enhance the practical utility of RED algorithm by artificially setting control parameters. In this paper, analysis the effect of maximum drop probability on the queue and average queue based on the discrete TCP/RED feedback network model. And discuss when the queue length stabilized at the desired target, the relationship of the maximum drop probaility value with other network parameters. Based on theoretical analysis, proposed an improved RED algorithm, based on NS-2 simulation results show that this algorithm has good average latency and packet loss rate in a complex network environment, superior FRED and BLUE algorithm.