Key Engineering Materials Vol. 693

Abstract: High speed railway system in China has developed rapidly in recent years but the operation environment of China has a great deal of differences between Europe and Japan. In the paper, a definition of wide-area operation environment is proposed and its effect on the bogie of high-speed train is analyzed, also some solutions are given.

Abstract: The interface of bolted joint commonly focuses on the research of non-linear damping and stiffness, which affect structural response. In the article, the non-linear damping model of bolted-joint interface is built, consisting of viscous damping and Coulomb friction. Energy balancing method is developed to identify the dry-friction parameter and viscous damping factor. The corresponding estimation equations are acquired when the input is harmonic excitation. Then, the vibration experiments with different bolted preloads are conducted, from which amplitudes in various input levels are used to work out the interface parameters. Also, the fitting curves of dry-friction parameters are also obtained. Finally, the results illustrate that the most interface of bolted joint in lower excitation levels occurs stick-slip motion, and the feasibility of the identification approach is demonstrated.

Abstract: Mechanical joints have a significant influence on the dynamics of assembled structure due to its discontinuity, uncertainty, frictional contact and micro-slip along the interface. To study the effect of mechanical interface on vibration behavior of industrial product, it is necessary to capture vibration data and investigate modal properties. In order to study effects of typical mechanical joints, double plates coupled with bolted joint are manufactured. Corresponding welded specimen was also manufactured for comparison and reference. Specimens were suspended by two flexible nylon cords for a free–free boundary condition and series of modal tests were carried out. Experimental results reveal that the preload in bolted joint affects the vibration behavior of assembly greatly, and the dynamic stiffness and natural frequency could be enhanced by increasing preload values of specimen. Bolted joints give rise to more frictional damping capacity within lower preload range in this test and welded specimen shows up much higher frequency and similar damping ratio.

Abstract: As the most important component of moving parts in the wheel set system, the rolling bearings’ performance is the key to the safety of locomotive running. In this paper, the finite element model of rolling bearing with fault of inner ring stripping was established in ABAQUS, the first twenty orders of natural frequency and mode characteristic was analyzed. The highest frequency was used as the center frequency of the band pass filtering in the process of resonance demodulation and this technique was validated with simulation. Then fault vibration signal of rolling bearing was collected using wheel set running-in test bench and was analyzed with this method, the comparison proved that the simulation and test results basically tallied.

Abstract: Through the dynamic and static analysis of SMF6020 precision grinder bed, the maximum deformation is obtained in the machining process of the bed, and the natural frequency and vibration mode. It provides a theoretical basis for improving the design of the whole structure of precision grinding machine.

Abstract: Take water hydraulic slide valve core as the research object. Laser surface texturing (LST) technology was used to improve the valve core carrying capacity and hydrodynamic lubrication characteristics, which can process micro-texture on the surface of the core. And CFD method was taken to calculate flow field of smooth and laser surface texturing core respectively. For studying the influence of valve core micro-texture and valve core overlap lengths on hydrodynamic lubrication characteristic and carrying capacity of the core, core surface pressure distribution, surface pressure and friction force curves were drawn. Results show: The smooth valve core does not produce hydrodynamic lubrication effect, but textured valve core can bring the oil film load capacity, so as to make the effect of mixed friction between valve core and sleeve weaken. And along with the decrease of the core overlap length, the carrying capacity on the surface of the textured valve core does not decrease but increase when the valve core overlap length amount is greater than 2.5mm.The results provide important theoretical reference of studying and applying LST process technology to the valve core friction pair’s lubrication performance.

Abstract: To meet the need of modernized coal dressing, topology theory was used to build a kind of hybrid mechanism 2PRRR-R which can work as a main excitation mechanism of three freedom degree hybrid vibration screen with two-translation and one-rotation. Next, D′Alembert’s principle was introduced to establish a kinetic model of vibration screen frame and surface, and kinematic equations of directions of vibration screen frame and surface was achieved. Then, ADAMS was used to perform kinetic simulation of vibration screen, and kinetic parameters of the hybrid vibration screen was finally tested on multi-dimensional vibration screening test bench. The research shows that kinetic parameters’ numerical simulation of hybrid vibration screen with two-translation and one-rotation basically agrees with spot test value, which verifies the feasibility of the mechanism design, that the screen frame is of two motion freedom, that screen surface is of three motion freedom degree, that the rotation of the screen surface is relatively independent and controllable. The research provides further study of kinetic properties and development of hybrid vibration screen with two-translation and one-rotation with workable reference.

Abstract: This research is focused on dynamic performance of water hydraulic single hydraulic prop, the mathematical and AMESim model of single hydraulic prop are established. And the drop hammer is introduced to simulate the impact load of the surrounding rock acting on the prop. The performance parameters of prop retract displacement and cavity pressure are used as the research objects. The working process of single hydraulic prop is reproduced by the simulation. And the influence of safety valve parameters on the support system is analyzed. The results show that: increasing maximal valve core stroke and dead volume or reducing valve damping hole diameter can improve the support performance of the single hydraulic prop. But the influence of equivalent damping has two sides. For support system, decrease damping can improve the support performance, but for the safety valve, reduce the damping make the valve core stability decline. In addition, the pressure overshoot of the optimized system is 18.3%, adjusting time is 0.5s and the retract displacement is 10mm. The dynamic performances meet the technology requirements of the coal mine safety production of China.

Abstract: In this paper, the Hamilton theory was applied to describe the dynamic model of Thermal Power Pipeline nonlinear fluid solid coupling vibration. The model includes the control equation of axial vibration and the transverse vibration of the pipeline, taking full account of the vibration characteristics of the fluid in the pipeline, effect of thermal deformation and constant support, as well as the friction coupling, Poisson coupling and junction coupling. The model is an attempt to the heating pipes and need to be further improved.

Abstract: This paper utilizes SolidWorks to establish accurate Hooke hinge model and imports it into ANSYS using the data switching interface between SolidWorks and ANSYS. The stress-strain behavior of the Hooke hinge is analyzed using finite element method, and the reliability and stability of the structure is evaluated, which provides some theoretical guidance for the design of Hooke hinge.