Advanced Materials Research Vols. 694-697

Abstract: Because of easy for the bomb-stirring system of feed mechanism to reverse at its non-working position, which can affect the stability of the whole system. Virtual Prototyping Technology can help people to complete the design of overall structure of feed mechanism and anti-reversion mechanism of automaton. ADAMS, one kind of dynamics simulation software, can help to complete the motion characteristics analysis of anti-reversion mechanism, achieving the motion law of mechanism parts and movement dynamic characteristics, as well as verifying the rationality of the design of mechanism.

Abstract: Aerodynamic drag of compact electric vehicles is of significant interest in reducing energy consumption. This study focused on how to reduce drag for a compact electric vehicle by shape optimization such as lengthening the tail, changing the front-windshield inclination, modifying the diffuser angle and filling up the front structure details of the vehicle model. Some separately refined models and one integrated refined model were built. The simulation was conducted using the RANS k-epsilon turbulence model by Computational Fluid Dynamics. The results show that nearly every refined model has a lower drag, and the drag coefficient of the integrated refined model has an 8.4% slash compared to the original vehicle model.

Abstract: In the paper, on the basis of three-dimensional Reynolds-averaged Navier-Stokes equations and the RNG κ-ε turbulence model, adopting Three-dimensional unstructured grid and pressure connection the implicit correction SIMPLEC algorithm, and using MRF model which is supported by Fluent, this paper carries out numerical simulation of the internal flow of the centrifugal pump in different operation points. According to the results of numerical simulation, this paper analyzes the bad flow phenomena of the centrifugal pump, and puts forward suggests about configuration perfected of the centrifugal pump. In addition, this paper is also predicted the experimental value of the centrifugal pump performance, which is corresponding well with the measured value.

Abstract: For the non-harmonic vibration conveyor, a single-degree-of-freedom dynamics model is built for the horizontal motion of bulk materials, in which the dry friction force is piecewise nonsmooth. The effect on conveying velocity is studied for six vibration parameters in the excitation force with two harmonic components. The conveying velocity increases with the increase of frequency and amplitude, but the optimum frequency ratio is 2, and the optimum amplitude ratio approaches 1/3. The initial phase has no effect on conveying velocity, and the effect of phase difference is periodic, i.e. the forward conveying is best on phase difference π/2, and the backward conveying is best on phase difference -π/2.

Abstract: This paper deals with a method for rigidity and flexibility coupling dynamic analysis of the 6-6 Stewart parallel mechanism with the ADAMS/APDL and VC++ software. Develop a virtual simulation platform for the mechanism, perform dynamic simulations, and the mechanism motion curves are obtained. Using this method, mechanism random errors effect on its motion can be analyzed and the simulation approaches the real value, including simplicity (no need to solve complex mathematic model) and high accuracy which make it highly promising for application in mechanism design.

Abstract: Critical speeds are the important indicators when evaluating the dynamic performance of the rail vehicle. In this paper, the whole multi-body dynamic model of the rail vehicle was proposed based on the theory of multi-body dynamics in the software of Simpack. And the linear and nonlinear critical speeds of the whole rail vehicle inspirited by the track spectrum were simulated. This will provide a basis for analyzing on the whole rail vehicle.

Abstract: A brake pedal stroke simulator is a key component of realizing a Regenerative Braking System. It provides a good pedal feeling to a driver, improves energy recovery and ensures braking security. This paper presents the hardware solution of the braking control system, the structure and key design parameters of a brake pedal stroke simulator. Through simulation, the energy recover rate and brake pedal feeling of drivers can be improved. The simulator can be used to realize the regenerative braking system in hybrid or electric vehicles.

Abstract: To better reflect the dynamic performance of landing gear, a hybrid modeling method based on Matlab/SimMechanics is proposed as our approach and drop simulations were carried out for it to verify our approach. Firstly, a widely used levered-suspension landing gear is chosen as studying subject. Secondly, the mathematic models of the respective landing gear subsystem were established for the bumper and the tire, while braking control system was imposed via Simulink. Thirdly, SimMechanics was used to integrate all the subsystems into a comprehensive unit by taking advantage of its capability of showing the joint constraint, force reaction of each part, and on-line control law imposing. Lastly drop simulation tests were done on the landing gear model to verify its validity. The simulation results show that our approach can effectively simulate the drop feature, and accordingly provides a foundation for retrofit design in the next step, and thus makes it is valuable for real engineering applications.

Abstract: Based on study of the power transmission system theory for hybrid car, a silent chain drive system which is used to transmit power between motor and gear box was designed. Using multi-body dynamic software RecurDyn, the dynamic behavior of the silent chain system was simulated, the chain tension, meshing impact load and instantaneous transmission ratio of the drive system under different velocity was analyzed. The results show that, at the whole speed range, the chain tension is always less than the chain rotation fatigue strength (including a safety factor of 1.3 times), its able to meet the working requirements, the instantaneous impact load when link plate meshing into sprocket relate to chain tension and sprocket rotation speed, the transmission error of silent chain system is within the allowable range and can meet the transmission requirement.

Abstract: The multi-body dynamic model of the high-speed train is established in order to study the failure effects of anti-hunting damper. Four kinds of failure case of the anti-hunting damper are compared, specifically including: one anti-hunting damper of the front bogie is broken; two anti-hunting dampers of the front bogie are broken; three anti-hunting dampers of the front bogie are broken; all four anti-hunting dampers of the front bogie are broken. The results have shown: when only one anti-hunting damper is broken, the influence to the dynamic performance of the high speed train is small, but once two anti-hunting dampers or more out of work, the critical speed of the vehicle decreases much more and the curve-passing performance also become worse.