Applied Mechanics and Materials Vol. 525

Abstract: High speed railway noise caused serious noise pollution to human living environment around the railway. This article mainly analyzes the causes and characteristics of the high-speed railway noise from the wheel/rail noise, aerodynamic noise and collector system noise. And take these three aspects as objects, the high-speed railway noise control measures are detailed analyzed to reduce the high speed railway noise harmful to the environment and human life, which has more practical significance to human being.

Abstract: An equipment for separating fish flesh from steaks was designed. The law of separation with the device was investigated, which lay a solid foundation for further amplification experiment. The optimum separation conditions are: heating the fish steaks at 121°C for 40min, pumping the liquid to the separation vessel in tangential direction, and the flow velocity was 35L /min. The fish steaks were separated to pure fish flesh, fishbone and fish soup efficiently under the above conditions. There are many advantages of the equipment, including the simple structure, the efficient separation effect and the high quality of the separation products. Additionally, this equipment can also be applied to other livestock and poultry products processing, which is worthy for further research and application.

Abstract: The flow around three cylinders in isosceles left-triangle and right-triangle configurations at Reynolds number of 200 are investigated using lattice Boltzmann method (LBM). Vortex shedding pattern and evolution process in the wake of each cylinder in the two cases are analyzed with a spacing ratio of 4. Results show that the flow pattern in the right-triangle configuration is symmetrical and the vortex shedding is anti-phase. Meanwhile, vortex shedding in-phase is observed in the left-triangle configuration which is due to the effect of the periodical vortex shedding behind upstream cylinder. The evolution process of vortex in the wakes of the cylinders for left-triangle configuration is simulated numerically.

Abstract: Based on a large quantity of experimental work and study of the two-dimensional MHD (Magnetohydrodynamic) simulation describing the implosion dynamics of X-pinch, at the same time taking basic physical processes of implosion into account, this paper seeks to build a two-dimensional MHD simulation model on implosion dynamics throughout the whole constriction evolution (including formation of dense plasma, compression, generation of hot spot, X-ray pulsed radiation), determine the target area for numerical simulation, as well as the initial time for simulation and plasma initial state. As for two-dimensional MHD models which indicate the physical process during different stages, a clear boundary condition is explored along with Lagrange-Euler numerical method which strives to reproduce the dynamics of the X-pinch implosion and better study the physical properties during the X-pinch implosion dynamics. Results of this thesis will enrich the X-pinch research areas of basic theories and analytical methods, which is of great theoretical significance and application value.

Abstract: In order to improve the energy harvesting efficiency of piezoelectric cantilever beam (PCB) in the environment. This paper presents a new type of piezoelectric cantilever beam which is the single-sided trapezoidal loop shaped PCB. By theory analysis, the equivalent circuit model was established, resonant angular frequency is inversely proportional to the length of cantilever beam. Based on finite element analysis method, the piezoelectric performance of single-sided trapezoidal loop shaped PCB and that of single-sided rectangular loop shaped PCB are compared with the same areas. The analysis results show that the coupling voltage of the former is larger, the output power of single-sided trapezoidal loop shaped PCB is improved, and the theoretical derivation of the inverse relationship between the frequency and length is verified.

Abstract: As the rapid development of warship equipment automation, warship cabin fire protection design in many developed countries has transformed from the prescription approach to Performance-based Fire Protection Design (PFPD). Since the warship is moving offshore structures, its PFPD can fully learn from building PFPD on land. This paper firstly outlined the concepts and methods of building PFPD. Through comparing the similarities and differences of structure and fire-fighting capacity both on warships and in building, the warship cabin PFPD roadmap was proposed. From the perspectives of warship structure and personnel protection, warship PFPD parameters were proposed. Applied field simulation model into quantitative and numerical analysis of the fire compartments and adjacent ones to determine the cabins not meeting the demands of PFPD parameters. According to the analysis, take active or passive optimization fire protection measures making these compartments optimized design to meet structure fireproof parameters, ultimately achieve the fire protection purpose.

Abstract: A kind of recirculating ball-type power steering system for electric power bus was designed. The control strategy of EPS is divided into two layers that are top layer strategy and bottom layer strategy. The assist mode of top layer strategy is researched. The simulation model based MATLAB/Simulation was build and verified by the simulation experiments. The results validate the effectiveness of the proposed strategy, which creates the research basis for further research and development of EPS.

Abstract: The paper studies control strategy of electronic differential for four in-wheel motors independent drive vehicle. For the in-wheel motor independent drive electric vehicle, the differential speed relationship among the two wheels is analyzed according to the Ackermann&Jeantand steering mode, building the steering differential speed mode which adapt to bench test. When a vehicle drives on a straight line, the speed of each drive wheel is equal. While on a curve, the speed between the inner wheel and the outer one must be different in order to maintain vehicle stability and avoid vehicle skid. The all wheels must meet the requirement of angular speed. Based on Matlab/Simulink software , As a input, vehicle structure parameter, steering angular and so on, this model of differential speed was structured, drive wheel differential speed relationship at different steering wheel angles was determined .Finally, this electronic differential speed control for in-wheel motor drive electric vehicle is validated through PID control closed loops bench simulation test .

Abstract: The piezoelectric power generating device can convert the vibration energy into electrical energy in vehicular environment. So it can provide energy for electronic components. Firstly, the mathematical model of road-vehicles-piezoelectric device coupled vibration was established under the random road excitation. Then vibration simulation analysis of the established model was made. The acceleration and spectrum of the vehicles body and its connection with the suspension were researched under B-class. The car body vibration is low-frequency vibration. Further studies shows that expanding the speed range and changing the roads level almost have no effect on the natural frequency of vehicles body vibration. Secondly, in order to make the maximum generating capacity, the influences of cantilever beam parameters have on its nature frequency were researched. The research results provide basis for parameters design in cantilever beam.

Abstract: An electronic differential control system (EDS) has been designed based on a mini electric vehicle (EV) with dual in-wheel-motor rear drive. In view of imperfection of current strategy with speed and moment as control variables, a new control strategy for EDS in a two in-wheel-motor drive EV is proposed with the moment of driving wheel torque as control variable and the slip rate equilibrium of two driving wheels as control objective, considering the effects of axle load transfer. The differential control experiments are conducted with steering mode and straight acceleration mode based on the vehicle prototype. The results show that the control strategy is reasonable, and the controller can effectively realize EV electronic differential by coordinating the moment of two driving wheels.