Abstract: Nonlinear movement will be generated on the crane ship lifting load with multi-factors coupling such as marine environmental loads, mass of load and the length of wire rope. The thesis bases on the technique of virtual prototype to establish a rigid-flexible multiply model of the crane ship with utilizing the software platform of ADAMS and ANSYS. Through analyzing the characteristics motion of the lifting load, providing a basis for the effective control of the crane ship lifting load.
Abstract: Based on gear transmission system of 1.5MW wind turbine, dynamic characteristics are analyzed under the effect of both external and internal incentives. Using lumped parameter method, the dynamic model involving 6 degrees of freedom for every helical gear is established with taking the time-varying mesh stiffness and error into account. The results show that the transmission system is quasi-periodic under the operating speed, and the vibration direction of gear with a large amplitude is obtained. This study can be referred to the engineering applications.
Abstract: Longitudinal vibration of a nonlinear viscoelastic rod system with one end fixed and another end subjected to an axial periodical excitation was studied under the consideration of transverse inertia. By using Galerkin method, a combined Parametric and Forcing Excited cubic nonlinear dynamic system is derived for hard stiffness nonlinear material. Furthermore, arc-length technique is used for an accurate integral procedure, and numeric results are given detailedly. The process of the system evolved from stable periodic motion to chaos is illustrated in a period-doubling bifurcation graph in a parameter space, and the Lyapunov exponent spectrum is also given that is perfectly consistent with bifurcation process. The strange attractor obtained from Poincaré Map is present, which has different fractal dimension from Duffing’s one, so it may be a new chaotic attractor.
Abstract: The dynamic model of the reaction mass system in the large-scale vibration test system is set up, and the crossover frequencies are calculated in order to determine the operation capability and the interval between reaction mass and foundation. On the basis of the finite element method (FEM) analysis and theory of analysis mechanics, the dynamic response of the reaction mass is studied. The results show that the maximum amplitude of the dynamical system is obtained at the natural frequency of the system. The results of theoretical and FEM calculations indicate that the maximum displacements responses are all much lower than the design of the interval, which means the design is satisfied and reasonable. This method can calculate the operation capability of the reaction mass effectively and can be used for vibration test system design and optimization.
Abstract: In order to obtain the engine’s performance and related characteristics accurately and completely, engine dynamometer of motorcyclewas developed based on CAN bus in this paper. The system structure was decreased, the system reliability and level of control management were greatly improved. Due to the strong interference and high requirement of control accuracy, a PID control algorithm was proposed for the rotational speed contro1. Moreover, Kalman filter was designed to eliminate the random noise and industrial frequency disturbance. The experimental results demonstrated that the dynamometer’s accuracy and efficiency were improved significantly. Moreover, the testing platform worked stably and reliably.
Abstract: The track measuring beam is installed in the bogie frame to measure the geometry parameters of the rail. In this paper, the dynamic model of the inspection car was established in order to compare the dynamic properties of the vehicle with and without track measuring beam installation. The motion stability, ride quality, vibration acceleration and curve negotiation performance of the vehicle after the track measuring beam installed were investigated. The results show that after the track measuring beam installation the critical velocity of the inspection car decreases, but the running at speed of 120km/h can be guaranteed. The track measuring beam has no influence on the ride quality and curve negotiation performance and the effect of it on vibration mode is little.
Abstract: Self-pierce riveting (SPR) is a new high-speed mechanical fastening technique which is suitable for point joining dissimilar materials, as well as coated and pre-painted materials. In this study, an experimental measurement technique was provided for the prediction of the free vibration behavior of single-lap cantilevered SPR beams. The dynamic test software and the data acquisition hardware were used in the experimental measurement of the dynamic response of the single-lap cantilevered SPR Beams. The frequency response functions of the SPR beams of different rivet number were measured and compared. The main goal of the paper is to provide a basis for further research on vibration based non-destructive damage detection in single-lap cantilevered SPR beams.
Abstract: The influence upon kinematics performance of a family of 3-PRS parallel mechanisms affected by kinematic chain layout has been studied in this paper. Firstly, the locality arrangement parameters of single PRS kinematic chain are identified. According to these parameters values and their combinations, different arrangement of PRS kinematic chain are proposed, and variant configurations of 3-PRS parallel mechanisms are enumerated. Then, the inverse kinematic problems are solved, and the influential actions of kinematic chain layout on kinematic performance of these mechanisms are carried out. Simulation results illustrate that kinematic chain layout has direct influence upon kinematic performance of the 3-PRS parallel mechanisms.
Abstract: Abstract. A glare shield is usually installed on the cement crash barrier to block strong light from the vehicles in contrary direction. It is useful to prevent car accidents and increase the safety of driving. This study uses the contradiction matrix in the TRIZ method, 39 engineering parameters, and 40 inventive and innovative principles to identify the areas of improvement to address the above problems. There are two features of our study. (1) We install a spring structure for the sake of reducing the damage rate of glare shields. When glare shields suffer from strong wind, a flexible structure located at base can let glare shields curve and spring back to original position, and therefore endures more powerful wind hit. In addition, the spring back function lets the guide post automatically return to original position to block strong light and protect drivers. This structure will have more durable service life, so, it can be used to reduce the maintenance times, and cost for the users.(2) We add solar LED light on the body of a glare shield, that can enhance the alert function when attacked by strong wind on the night time or insufficient light and then reduce the accident rate.