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Identification of moving vehicular parameters based on glowworm swarm optimization algorithm
Get PDFThis paper presents an indirect method for the identification of parameters of moving vehicle based on Glowworm Swarm Optimization (GSO) algorithm. And a local search method is introduced in the movement phase of GSO to enhance the accuracy and convergence rate. The moving vehicle is modeled as 2-DOF systems with five parameters. And Newmark direct integration method is used to calculate the dynamic response of the system. Acceleration measurements at selected stations on the vehicle are used only to identify the parameters of the moving vehicle. Several test cases are carried out to illustrate the efficiency of the method and the results show that the vehicle parameters can be identified precisely with the proposed method and it is not sensitive to measurement noise
Pharmacognostic study of Clematidis armandii the determination of index components
Get PDFObjective: to provide definite science bases for its accurate identification and quality control. Methods: comparative identification on the stem, petiole and leaf of the two original plants of Clematidis armandii Caulis was carried out by the classical paraffin technique. Explore the index component for identification of Clematidis armandii Caulis by TLC and establish the quantitative analysis method by HPLC. Results: the rattan stems of Clematidis armandii Caulis, originated from Clematis armandii Franch and Clematis montana Buch.-Ham., are similar. However, they can be differentiated from each other by the structure of vascular bundle. Moreover, the structure of petiole are entirely different. The characteristic spots of beta-sitosterol in Clematidis armandii Caulis from six different places were detected by TLC. HPLC is high accurate, good reproductive, the mass concentration of beta-sitosterol in Clematis armandii Franch. was 189.18-190.27 μg·g-1 and in Clematis montana Buch.-Ham. was 336.90-338.34 μg·g-1. Conclusion: the spots were apparent and effective separated, when we used trichloromethane-ethyl acetate (10:1) for development, 10 % vitriol ethanol to color, and detected under the UV light (365 nm). This could be the TLC identification condition of beta-sitosterol in Clematidis armandii Caulis. Calculated on dry product by HPLC, the beta-sitosterol in Clematidis armandii Caulis could not be less than 0.018 %
Design verification of stress and sag for 500 kV transmission line
Get PDFTransmission line stress directly affects the tower sag force structure and a safe distance from the safe operation of the transmission lines play a crucial role. Calculation method for the preparation of the design process were complied, simply enter transmission liner parameters can be automatically obtained stress and sag. According to a 500 kV transmission line tests carried out stress sag design verification, checking ground found stress design errors and were corrected to ensure the safety of the project. Calculation program can be developed for different voltage levels for line stress on cables sag design verification
Aerodynamic performance analysis of wind-sand flow on suspension bridge suspender cables
Get PDFWith the deterioration of global climate and environment, the phenomenon of wind-sand flow frequently occurs in many regions. Suspension bridge suspender cables suffer corrosion and impact from wind-sand flow. The riding-type suspender cable with four strands which is commonly used in suspender cables of long-span suspension bridges is taken as an example to investigate the influence of wind-sand flow on the suspender cables. The wind-sand flow field around the suspender cables of a long-span suspension bridge is simulated within the FLUENT software on the basis of the numerical simulation of computational fluid dynamics. The forces produced by the wind-sand flow on the suspender cables are analyzed from the simulation, and then the numerical results and the calculated results based on a theoretical equation which was used to obtain the pressure on a building in a wind-sand area are compared together. Results show there are big differences between them. The reasons will be investigated in future research, and finally a new suitable theoretical equation for the pressure of wind-sand flow on suspender cables will be proposed
Comparative blast study of simulation and approximation method of armored vehicles
Get PDFTo protect the troopers, it is important to consider the assessment of hazardous areas inside the military vehicle. For armored vehicles, the design, analysis, and test of explosive seat protection are significant to ensure the trooper survivability. Particularly, we note that the significant factor affecting the trooper survivability is ability of trooper seat to absorb shock generated by the explosion. Therefore, this research focused on the allegorize between blast simulation method and blast approximation method of armored vehicle. A crucial step for armored vehicles design is to analyze the pressure caused by the explosion. However, the blast simulation method does not always provide accurate results. To ensure that the models are reliable, the purpose of this research is to determine and compare the results between the created model and the theory. Results showed that the simulation models provided the force that affects the vehicle similar to the theoretical-based method. The simulation model designed can be developed and applied to design the various components of the armored vehicle to predict the blast behavior
Analysis of vibration reduction for brake judder based on vibration transmission path
Get PDFThis paper presents a technique for minimizing vibrations of the steering wheel from vibration transmission path based on the method of shift frequency vibration reduction. At first, a road experiment was conducted on a vehicle with brake judder. Transmission path and excitation frequency of the vibration were determined through analyzing the experimental data. Then, modal analysis on the whole structure of the steering wheel was carried out by the finite element method. In this way, its inherent frequencies and modes could be obtained. In order to verify the accuracy of the finite element model, the modal experiment was carried out and its results were compared with the simulated one. Sensitivity analysis and optimization design were carried out on the fixation support of the steering wheel by using Optistruct in Hyperworks. In this way, the inherent frequency of the whole structure could avoid the excitation frequency. Finally, an experimental verification was also carried out on the vehicle, and the results show that the vibration acceleration value of the steering wheel reached the allowable value. The technique for minimizing vibrations of the steering wheel is feasible in this paper
Multirate input based quasi-sliding mode control for permanent magnet synchronous motor
Get PDFPermanent magnet synchronous motor field oriented control system often uses dual-loop (speed and current) cascade structure, and the dynamics speeds of the two loops mismatch. The motor’s mechanical and electrical subsystems have the typical multirate characteristics. Based on the multirate control theory, this paper proposes multirate input quasi-sliding mode algorithm for the speed control loop. Under the situation of the output data loss, the proposed algorithm builds the extended input vector with the output prediction information. Due to the extended input vector, the proposed algorithm reduces the system steady state chatterring, and then improves the performance of the whole system. Simulation and experimental results demonstrate the effectiveness of the proposed algorithm
Investigation of radial force and hydraulic performance in a centrifugal pump with different guide vane outlet angle
Get PDFIn order to investigate the effect of the guide vane outlet angle on the performance of centrifugal pumps, a centrifugal pump with guide vanes was used as the research model and its specific speed is 165. Keep all the other geometry parameters of the pump as constants, the guide vane outlet angle was designed to be 28°, 20°, 15°,10°, 5° and 3° respectively. The whole flow field in the pump under different guide vane outlet angles was simulated by commercial code CFX and the simulation was unsteady. The simulation results were validated by experiment results. According to the simulations, the hydraulic performance, internal flow and radial force of the pump under different guide vane outlet angles were compared and analyzed in detail. The research results indicate that the head and efficiency of the pump are the best when the guide vane outlet angle is 10°. With the decrease of the blade outlet angle of guide vane, the length of flow channels in the guide vane become bigger and its width gets smaller, the uniformity of inner flow in the centrifugal pump gets better, and therefore the radial force on the impeller reduces. With the decrease of the guide vane blade outlet angle, the pulsation frequency of radial force does not change, but the pulsation amplitude of the radial force reduces obviously. The vector distribution of the unsteady radial force is symmetric around the origin and mainly lies in 5 regions, which is same as the blade number of impeller
Damping multi-model adaptive switching controller design for electronic air suspension system
Get PDFThis paper presents the design and verification of a damping multi-model adaptive switching controller for electronic air suspension (EAS) system. In order to improve the convergence rate of identification algorithm of conventional adaptive controller, multiple local linear full-car vehicle models of EAS system with fixed parameters are established according to the actual damping control process of EAS for different vehicle driving conditions and an adaptive model whose initial value of parameters can be re-assigned is introduced to enhance the system control precision. The model switching control strategy based on minimum error is used to select the best matching model online and the optimum damping force is regulated by adaptive control algorithm, thus constituting the damping multi-model adaptive control for EAS. Simulation results show that the control method proposed in this paper can improve the damping regulating performance of EAS effectively in wide range driving conditions, especially for the case of sudden change in driving conditions
Seismic performance of tuned mass damper on Shazand Railway Bridge induced by train
Get PDFShazand Railway Bridge is located in Markazi province, Iran in north to south-west railway. The bridge consists of ten spans. In 1984, during Iran-Iraq war, that’s main span, which has a length of 72 m, was attacked and severely damaged. Eight month later, damaged span replaced with a steel deck. The deck is straight in plan, but the railway is curved and this causes eccentricity. Excessive vibration was observed during the train passage. Although the bridge was retrofitted in two stages, the problem has not been solved yet, and the trains’ speed should be reduced to around 10 km/h in order to avoid excessive vibration. The present study addressed the effectiveness of tuned mass damper (TMD) in reducing train-induced vibrations of Shazand Railway Bridge. A three dimensional finite-element model of the bridge is developed and dynamic time history analyses under train passage in both as-built and passively controlled with TMD are conducted. Sensitivity analyses are performed to demonstrate the effects of the damper parameters on structural response. The results show that considerable reduction in acceleration response of the bridge can be achieved by employing proper TMD