Applied Mechanics and Materials Vols. 278-280

Abstract: Electrohydrodynamic printing draws much attention as it is a promising micro/nano patterning method and can ejects high-viscosity solution. The solution is pulled out of a nozzle under a high voltage. A used tip-plane electrode configuration is composed of a conducting plane collector and a hyperbola-shaped solution pendant adhered to a steel nozzle in electrohydrodynamic printing. The electric field between electrodes is extremely non-uniform owing to structural complexity of electrode configuration. We disintegrate the overall electric field into three components: a charge-free space field, a charged droplet field and an ion field. Proper models for those fields are set up and analyzed. The result shows that the elliptic-cylinder model, a dominant component for the jetting, is available for the field. The charged droplet field hardly deforms the space field in low-frequency pulsation mode, but influences the jetting in high-frequency pulsation mode. The ion field caused by space ions is little and negligible.

Abstract: The muscle of the body’s joint always appears in the form of a pair of antagonistic muscles. Based on the establishment of the humanoid elbow joint’s mathematical model and focused on the force distribution of the antagonistic muscles, a force distribution system consisted of a fuzzy controller and a force distribution planner is proposed. The fuzzy controller is used to ensure the control performance of the whole system and the force distribution planner to implement the force distribution of the flexor and extensor. The simulation show that in the case of confirming the good control performance, the system can get different force distribution results through regulating the algorithm and parameters of the force distribution planner. Among these,we can find a more suitable and energy-efficient way to distribute the force.

Abstract: In this article, the application of Computational Fluid Dynamics (CFD) technology in the field of Heating Ventilation & Air Condition was introduced, and the research progress in optimizing the simulation of air-conditioned room was summarized. Some domestic and foreign studies on air conditioning operation and energy saving were illustrated about the effects of different installation locations, blow angles and air supply modes, which would provide a theoretical basis and scientific guidance for air-conditioning systems to optimize the design. Based on previous results, the development of further research on CFD in the simulation of air-conditioning in future was analyzed.

Abstract: This paper proposes a novel type of tactile device using magnetorheological (MR) fluid which can be applied in minimally invasive surgery (MIS) robotic system. The remarkable feature of rheological properties of MR fluid by the intensity of the magnetic field makes this potential candidate of the tactile device. As the first step, in order to determine proper input magnetic field the repulsive forces of the real body parts such as hand and neck are measured. Secondly, an appropriate size of the tactile device is designed and manufactured base on magnetic analysis. The final step of this study is to measure the repulsive forces of dividing 5 areas in the tactile device.

Abstract: Air-lock valve is an important part of the mesh roller-type unginned cotton and film remnant separator. To improve the structure of the air-lock valve, the cotton flow condition in the separator was analyzed by using high speed imaging technology firstly. Then friction coefficient between unginned cotton and mesh roller was tested by experiment. Meanwhile, some parameters of the air-lock valve were obtained by analyzing different phenomenons that are blockings in the air-lock valve during running of the separator. Finally, the validation test was done, the results indicate that the improved air-lock valve is more reasonable than before, and the blocking can be avoided successfully.

Abstract: Characteristics of a water-cooled non-thermal plasma (NTP) reactor used to reduce diesel emissions were experimentally studied. The effects of working voltage, operating frequency and air flow rate on discharge power and concentrations of O3 and NO2 generated by NTP system were investigated at different surface temperatures of discharge zone. The experimental results show that, the discharge power of the reactor would increase with the increasing of working voltage, operating frequency and surface temperatures; air flow rate had little influence on discharge power; variation of O3 and NO2 concentration were different with the increasing of working voltage and operating frequency at different surface temperatures of discharge zone; when the surface temperature of discharge zone was constant, concentrations of O3 and NO2 increased firstly and then declined with the increasing of air flow rate; and concentrations of O3 and NO2 were higher at lower temperature.

Abstract: With the rapid increase of wind farms, a set of specific requirements have been established or are developing. The objective of these grid guidelines is to ensure wind farms not adversely affecting the power system. The control strategies and theories on low voltage ride through (LVRT) have been focused on for a long time, how to deal with the gird high voltage is seldom discussed. This paper introduces the main types of wind turbines, discusses the major grid requirements of high voltage ride through (HVRT). The capability of HVRT for current wind farms is introduced. The technology and its implementation of the HVRT of wind turbines are focused on. The technical feasibility to increase the capacity of HVRT for wind turbines and the cost are analyzed in detail. Finally a conclusion is achieved, that is installing DC chopper can help converters to realize HVRT.

Abstract: Usually the gear modification is a main measure to reduce the vibration and noise of the gears, but in view of the complexity of the gear modification, topology optimization method was used to optimize the structure of the gear. The minimum volume was set as the direct optimization goal. To achieve the target of reducing contact stress, tooth root bending stress and improving flexibility, the upper bound of the stress and lower bound of the flexibility were set appropriately, thus realizing multi-objective optimization indirectly. A method for converting topology result into parametric CAD model which can be modified was presented, by fitting the topology result with simple straight lines and arcs, the model can be smoothed automatically, after further regulating, the geometry reconstruction was finished. After topology optimization, the resulting structure and properties of the gear are consistent with cavity gear. While reducing the weight of the gear, the noise can be reduced and its life would be extended through increasing flexibility and reducing tooth root stress.

Abstract: This paper presents the use of Taguchi methods in optimizing a PMSM for reducing peak value of cogging torque. The analytical model of cogging torque is derived by the energe method. The Taguchi optimization method was used to generate the experiment samples, which were calculated in 2-D and 3-D FEA. Three different parameters of PMSM, such as skew ratio, pole embrace and stator slot width were optimized. ANOVA was used to analysis the effect of different factors in Taguchi method.

Abstract: Abstract. Variation modeling is one of the most significant tools for assembly variation analysis. Considering dimension and geometric errors, and part situation errors, the error source that affects assembly accuracy is classified into two types: error of geometric location and orientation, error of geometric form. And unify these different types of error or deviation by the concept of Virtual Fixture. So a rigid assembly state space model is developed for stream of variation analysis in multi-station assembly processes. And an aeroplane-cabin-assembly process is analyzed in this model. The developed methodology outperforms the current simulation based techniques in computation efficiency, the model is validated using Monte Carlo series Simulations.