Papers by Keyword: Vibration

Abstract: The paper dealt with surface micro-geometry and influence on generation of unwanted vibrations of bearing units in textile machinery. Any deviation of ideal shape of contact surface of shaft and inner bearing ring considerably influence the shape of bearing rolling race. The dimension and geometry accuracy of shaft is very important for intended lifetime, operating speed and mounting of bearing. Moreover, paper evaluates dependency of dimension and geometry shaft accuracy on bearing lifetime according to experimental measuring.

Abstract: In the present article the response of layered plates to the effects of wind is analyzed. The computational model of layered plate meets the conditions of equilibrium shear stresses at the contact layers. The numerical experiment is applied to the layered glass plate with hinge supports at its edges. The dynamic effect of wind is analyzed in a dynamic calculation.

Abstract: The vehicle-bridge interaction (VBI) is the actual problem of many work places. The mid-span deflection of a bridge versus speed vehicle motion is interested from a practical point of view. Within the solution of the task the numerical methods based on Finite Element Method (FEM) are applied mainly. The task of VBI described in the submitted article is solved by using commercial software ANSYS. The 2-D sprung model of vehicle is modeled as combination of mass, spring and beam elements. The bridge with the mid-range is modeled by simple beam created with beam elements.

Abstract: The paper have described the vibration and damping analysis of carbon fiber wind turbine blade with viscoelastic damping treatment using commercial ANSYS program. The wind turbine system including a carbon fiber layer and a viscoelastic damping layer was attached on inside of carbon layer. Firstly, the natural frequencies and mode shape of pure carbon fiber turbine blade were compared with viscoelastic damping treated turbine blade using modal analysis. There were 1mm, 2mm, 3mm thickness damping layer finite element model to be constructed. The results show the little changes in lower first mode but getting smaller with higher modes. Finally, the frequency response functions of damped and undamped turbine blade were calculated for investigating the damping effect of viscoelastic damping layer. As shown in the results, the viscoelastic damping layer has good damping effect for vibration control of carbon fiber wind turbine blade.

Abstract: According to the theory of solar energy and vibration energy harvesting, an energy harvesting system based on energy conversion scavenging technology has been designed to convert the solar energy and vibration energy into the electric power. Piezoelectric materials and the solar cells are used as core power conversion section, and the system also consists of the lithium battery charge chip, the rectifier, comparators and switch chips as the control segments, combined with the super capacitor, etc. The energy harvesting experiment shows that the lithium battery can be charged through solar and vibration by the solar and vibration energy harvesting system, and the charging chip adopted in this work has input voltage limited current mode which can fulfill intermittent charge smoothly.

Abstract: Based on the study of a dual component system with elastic constraints, the stability and local bifurcations of the soft-impacts system, such as piecewise property and singularity, was analyzed by using the Poincaré map and Runge-Kutta numerical simulation method. The routes from periodic motions to chaos, via Hopf bifurcation and period-doubling bifurcation, were investigated exactly. In the large constraint stiffness case, the period-doubling and Hopf bifurcation exist in the two-degree-of-freedom system with elastic constraints and clearances. The clearances of the system, stiffness and damping coefficient of the elastic constraints is the main reasons for influencing the chaotic motion. The steady 1-1-1 period orbits or 2-1-1 period orbits will exist within a wideband frequency range and the value of velocity will be higher when appropriate system parameters are chosen.

Abstract: The study explores the vibration sensing effect of Ni-Mn-Ga shape memory alloy, based on the experimental results, researched the characteristics of this alloy applied in mechanical vibration signal sensors, and describes the feasibility of this alloy used for vibration measurements.

Abstract: An orbital grinding system is developed for manufacturing high precision crankshafts for 5ton-5m class ship engines. Structural analysis is carried out by 3D modeling and FEM simulation using a commercial software. The grinding system can conduct high precision grinding process for crankshafts of ship engines as well as normal small crankshafts.

Abstract: Corrector lens assembly is used to expand the field of view of a Cassegrain Telescope. There are usually three to five lenses in it. For the assembly of such a kind of high precision optics, decenter and tilt of each optical component and air space between components are key issues to be qualified. In the present study, four lenses were designed. Individual control of centering of the component and air space were achieved by assembling the component into a precision machined subcell. The lens positions were defined by precision spacers according to the designed values. To compensate various thermal expansions of glass and metal, elastomer material was used. Considering the deviation of manufacturing from design data, manufactured data were put into optical software for re-optimization, and air spaces between lenses were obtained. This gives excellent accuracy at low cost. Base on present lens mounting design and lens manufacturing quality, centering error was eliminated by lateral adjustment, which leaded to a good alignment. In this paper, the method for aligning the optics with the barrel assembly is presented and centering error measured by a double autocollimator is listed. In addition, test results of thermal cycling and vibration tests on the corrector lens assembly are discussed.

Abstract: In this paper a 6-DOF(Degree of Freedom) vibration isolation platform with structural configuration of 3CPS (3 Cylindrical-Prismatic-Spherical)-1UPS (1 Universal-Prismatic-Spherical) parallel mechanism is proposed. Firstly, the dynamic model is developed through virtual work principle. The transfer function and the complex frequency response function were obtained from the dynamical equation. Then, 36 amplitude frequency diagrams are obtained from the frequency response function. By analyzing the 36 amplitude frequency diagrams, 10 vibration coupling terms were chosen. The range of the spring stiffness coefficient and the range of the damping coefficient of the magneto-rheological damper are determined by analyzing the acceleration transmissibility of the 10 vibration coupling terms. At last, an integrated optimization combining structural and controller optimization is developed. The optimal parameters of the parallel mechanism are obtained through Genetic Algorithm (GA). This work is significant for the prototype design and verification of the vibration isolator.