Applied Mechanics and Materials Vols. 373-375

Abstract: Owing to harmful gas emissions and high accident rate of diesel engine in the coal mine trackless auxiliary transport, the spring of trackless rubber tyre electric vehicle powered by the battery pack comes. This paper considers the drive system to improve the performance of the electric vehicle. In order to adapt to the complex environment of coal mine, the analysis of basic structure for trackless rubber tyre electric vehicle was based on the three-phase AC induction motor. After elaborating the vector control theory of induction motor, the field-oriented vector control system model of trackless rubber tyre electric vehicle drive system with induction motor rotor was built in Matlab/Simulink. The simulation shows that the proposed control algorithm permits the drive system to achieve good steady and dynamic performance.

Abstract: In this paper, we consider the vector method of solving one of the most important problems of the dynamic analysis of mechanisms - kinetostatic analysis, which is to determine the reactions in the kinematic pairs and the balancing moment (force) on the leading link of a given law of motion of the mechanism [. This problem has a great practical importance in the selection of electro engines and in the calculation of the bearings in kinematic pairs. For example, setting the constant angular velocity of the driving link can be made kinematic and kinetostatic analysis of the mechanism and determine for all site of motion the balancing moment and the reactions in the kinematic pairs. By the average value of the balancing moment define the parameters of the electro engines and on the extreme values of the reactions produce calculation and selection of the bearings that will be installed in the hinges. In addition, knowledge of analytical expressions reactions will most clearly solve the problems of dynamic mechanisms with friction in the kinematic pairs.

Abstract: As the development of space structures is increasing fast, analysis on the characteristics of those deployable structures deserve to be paid enough attention to ensure a reliable deployment on orbit. For a deployable truss structure, more than one position can be chosen as the driving positions, especially when the structure has not only 1 degree of freedom (DOF), an available choice of the driving positions shows significant importance on the performance of the space deployable structure. This paper mainly deals with a planar deployable support truss structure for space antenna by means of the closed loop equations and the Kane equation to discuss the deployment characteristics by comparison of the driving torque needed over time. A full comparison of all the possible examples of deployment analysis results under different driving modes is presented. The results show the importance of the choice of driving movements and the design of parameters and also provide a useful reference to other related truss structures.

Abstract: The interaction characteristic between lunar soil and coring drill is studied in this paper. According to the failure forms of lunar soil, the stress area is divided into two parts, central failure area and lateral failure area. The impacts of different drill parameters on cutting force are obtained by a rotary cutting model. And the process of lunar soil coring is simulated basing on a special built DEM (discrete element method) model, which accord to the special mechanical properties of lunar soil. By analyzing the simulation results, the correctness of the cutting model is proved.

Abstract: A novel compliant mechanism with three degree of freedom (DOF) is proposed, based on the method of Freedom and Constraint Topology (FACT). One movement and two rotations are obtained in Case 3, Type 2 freedom space. A redundant constraint is added to improve the symmetry. The finite element modal (FEM) is established and static force analysis is conducted. Results demonstrate that the compliant mechanism is decoupled. Modal analysis is carried out with the finite element method. And four orders natural frequency and main vibration mode are obtained.

Abstract: Based on 3D digital model of motorcycle constructed in UGNX, motorcycle multi-body model was established for dynamic behavior analysis under inbuilt assembling of coefficient matrix of dynamical equation in computation code of ADAMS. Through the comparison of simulation analysis for dynamics of different models in accelerations in time and frequency domains, it is concluded that realistic multi-body model better represents the dynamic behavior of motorcycle while simplified one with less physical parameters only provides qualitative analysis for the dynamic behavior. The simulation results shows that model IV with accurate parameters of components influences the dynamic response of frame, simplified models could not represent the influence of mass and inertia moment of subsystems on dynamic behavior, which means advanced motorcycle multi-body improves simulation effectiveness and approximates the dynamic behavior of motorcycle well so that the simulation developed to replace experiments in bad working conditions will promote the advancement of engineering.

Abstract: Blades are the one of significant component in aero-engine, 70% mechanical faults are caused by blades failure. In this paper, a spectrum analysis on straining signals of rotating blades has been done through fiber Bragg grating sensors (FBGs) and Hilbert transform (HT). In order to obtain the dynamic characteristics of rotating blades, dynamic strain was monitored by four FBGs located on one blade in aero-engine with rotating speed up to 840 rpm. According to the measured and analyzed results, the FGBs are effective to measure the dynamic strain of blade in operating aero-engine. Moreover, it is capable of providing the state of rotating blades based on the envelope analysis in HT.

Abstract: In this paper, the nonlinear analysis of the motion structures is studied by using the vector form intrinsic finite element (VFIFE, V-5) method. The main object of this research is to develop an internal hinge of two ends of the plane frame element. In this study, the hinge function of frame element is used to compute the nonlinear dynamic responses of the motion structures. A fictitious reversed rigid body motion can be used to separate the rigid body motions and the pure deformations of the frame element. It is not requires any iteration or any parameters for the VFIFE method during computation process. Four examples illustrate the accuracy of the proposed procedures in computing large motions of a flying flexible structure.

Abstract: This paper establishs a coupled model on kinetic and tribological of cylinder liner-piston-piston ring system and takes the cylinder liner-piston system as an automatic control system based on the finite difference method and overrelaxation iteration method; the numerical solutions of the model is put forward and designed the overall the calculation process of coupling model, providing theoretical basis for further analyzing the piston system dynamic performance.

Abstract: taking the rail spectrum of high-speed railways suggested by the China Academy of Railway Sciences for example. maked spectrum estimation of sample space using the equivalent method based on power spectrum in frequency range and obtains the power spectral density of rail irregularity through Matlab programming. Results show that the smaller the mean square value is, the smoother the rail is. For v=200km/h, the simulated peak values of rail irregularity are all smaller than 12mm; when the high-speed train travels at 350km/h, the sensitive wavelength that causes strong vibration of the body can reach 100m.