Applied Mechanics and Materials Vols. 541-542

Abstract: the suspension system of an automobile helps to support the car body, engine and passengers, and at the same time absorbs shocks received from the ground while vehicle moves on rough roads. There are two types of suspension systems which are being used in the automobiles, namely, conventional suspension system and independent suspension system. in this paper it is aimed at studying the dynamic behaviour of the two types of suspension systems, using full car model.

Abstract: Cutterhead is the key part of full-face rock tunnel boring machine (TBM), the design method of mucking slot of TBM is directly related to its tunneling efficiency. In this paper, the coupling model of ballast and mucking structure of TBM is built used the discrete element method (DEM), and the simulation of TBM discharge ballast is made by PFC3D discrete element software. The simulation results show that, the number of particles generated is larger than the eliminated ones at the beginning of the mucking process, but with the change of time, the difference between the numbers of generated and eliminated particles is gradually reduced; the fluctuation of the number of particles within cutterhead is progressively smaller until it becomes stabilized, it fluctuates around the mean and the amplitude of fluctuation is no more than 100. The results in this paper can provide technical support for engineers.

Abstract: The applications of the static mixers are widely applied in many industries to obtain the desired type of mixing. In this context, to perform the mixing process should have two different fluids that also have different properties which will combines it in a single equipment to make an another fluid. The main objective of this research study is to propose a new approach of fractal concept (circle grid perforated plate) for internal rapid mixing by determining the coefficient of variation (COV). This study was implemented by fully numerical simulations. The simulations of mixing fluid were carried out with the help of commercial computational fluid dynamic (CFD) package ANSYS CFX 14.0 software. The simulation was done primarily in cylindrical pipe with insertions of circle grid perforated plate with porosity of 50%. Three levels of laminar flow have been chosen to result in Reynolds numbers (Re) equal to 100, 200 and 400. The effectiveness of circle grid perforated plate static mixer has been evaluated by comparing the homogeneity level of mixing fluids to the Kenics static mixer that readily available in industries applications. Based on the research findings, the COV value for circle grid perforated plate with 50% porosity at Re 100 was 0.0744 which is out of the range while Reynolds number at 200 and 400 were 0.0483 and 0.0247 respectively which are in the range in term of reasonable target of mixing homogeneity. The values of COV between 0.01 and 0.05 are the reasonable target for many applications. In term of manufacturing cost and energy loss due to static mixer, definitely this new approach of 50% porosity circle grid perforated plate is better design compared to the Kenics static mixer because of lower number of inserts and simpler design of static mixer to produce.

Abstract: The mud pump damming technology is a new idea put forward for the realization of the warping dams constructed mechanization and automation. The mud pump damming machine is researched and developed. The FEA model of the machine frame is built. The deformation state, stress distribution, natural frequencies, mode shapes and also the biggest stress under loading the exciting force are obtained by processing the static analysis, modal analysis and harmonic analysis. The results show that the mud pump damming machine can basically meet the design requirements, while the vibrating screen driving motor should be improved to adjust its working frequency to avoid severe vibration, and the welding quality should be ensured to increase its service life.

Abstract: A 2DOF ankle joint mechanism with cross rotation axis was designed to imitate the human ankle joint structure. The kinematic model of the ankle joint mechanism was established by D-H method. The synergistic influences of the angle of ankle joint and subtalar joint on the foot motion of inversion/eversion, adduction/abduction, dorsiflexion/plantar flexion were analyzed by kinematics simulation. The simulation results show that the designed ankle joint has similar motion range and function to that of human ankle. This study provides a theoretical basis for the development of high performance ankle joint for humanoid robots.

Abstract: The paper argues the possibility of utilising artificial muscles actuated with compressed air in the construction of industrial gripper systems. Their utilisation as motors comes as a response to the increasingly sophisticated requirements these have to satisfy, related to the developed force, structural rigidity, compliance and dexterity. The paper presents a variant of symmetrical gripper system with two mobile jaws actuated by a pneumatic muscle. The main requirements for this gripper are defined, the structure of the mechanism is presented and the transmission functions of forces and velocities are determined. Eventually the paper discusses the construction of the system and its functional limitations.

Abstract: Friction energy dissipating bracing is the kind of efficient system in reducing seismic of buildings. The main parameters are bracing stiffness and yielding displacement of friction energy dissipating devices in this system, which are important to the design of reducing seismic systems. Five-story steel frame building model with friction energy dissipating bracing in each floor is established, whose dynamic response of structure is studied when the value of main parameters is changed. The results show that the displacement of structure are decreased obviously and the acceleration of structure is first decreased and then increased when the bracing stiffness and yield displacement of friction energy dissipating devices are increased. In addition, the rational range of parameters is suggested for the design of friction energy dissipation systems.

Abstract: A quantitative risk assessment method of primary equipments based on power grid safety analysis is presented in this paper, and the risk assessment model of power grid primary equipments is established. On the basis of the calculated losses caused by various faults of N-1 and N-2 under the normal operation mode and the equipment maintenance mode, whether an equipment needs to be maintained is determined by comparing the size of the possible losses in two operation modes of a power grid. Then, the purpose of guiding the condition based maintenance of the power grid primary equipments is achieved. Finally, the presented risk assessment model of power grid primary equipments is applied to a certain practical power system.

Abstract: In order to overcome the shortcomings of the present accuracy assessment methods of power system dynamic simulation, this paper focuses the permanent single phase short-circuit fault which occurs in a large probability in power grids,and selects the typical electrical quantities which is very concerned in engineering after the fault happened. A time-scale based error criteria on simulation validation is proposed, and a comprehensive error criteria according to the average errors between simulation data and actual data is proposed to evaluate objectively the simulation accuracy of the typical electrical quantities. Considering the variation characteristics of the electrical quantities, the simulation accuracy evaluation of a single electrical element is expended to the simulation accuracy evaluation of the entire network, so not only the comprehensive evaluation about the model and its parameters but also the information for model modification and parameter correction can be obtained. The effectiveness of the proposed method is verified by the numerical results on the New England 10 Unit 39 Bus powers system.

Abstract: Microgrid is one of the most important contents of smart distribution network, and also the most effective way to converting the distributed generation into full efficiency. The connection mode of microgrid has to suite for the traditional distribution network, and also has its own characteristics. This paper discusses the principles of choosing the connection mode for microgrid, analyzes three connection modes meeting the requirements of dual power supply, and puts forwards suitable connection modes and operating modes for Chenjiazhen microgrid.