Simulations of a Dual-Rotor System with Local Rub-Impacts Based on Rigid-Flexible Multi-Body Model

2009 ◽  
Vol 413-414 ◽  
pp. 677-682 ◽  
Author(s):  
Qing Kai Han ◽  
Hai Tao Luo ◽  
Bang Chun Wen
Keyword(s):  
Rotor System ◽  
Elastic Rod ◽  
Frequency Spectra ◽  
Motion Patterns ◽  
Nonlinear Dynamical ◽  
Body Model ◽  
Nonlinear Motion ◽  
Aero Engine ◽  
Set Up ◽  
Multi Body

The nonlinear dynamical analyses of a dual-rotor system of an aero-engine are investigated with considering local rub-impacts based on rigid-flexible multi-body simulations. The dual-rotor system is set up from a practical aero-engine prototype, which includes an inner shaft (lower-pressure shaft) and an outer shaft (higher-pressure shaft). The two shafts are in internal-external arrangement and connected by six different rolling bearings. Firstly, a rigid-flexible multi-body model of the dual-rotor system with local rub-impacts is established with MSC.Adams. Then, for the rub-impacts happening between the higher-pressure disk and the fixed elastic rod, the rub-impact forces are described as a nonlinear one with piecewise stiffness and a constant friction. At last, the transverse vibrations of the dual-rotor system are simulated. From the obtained frequency spectra and shaft center orbits of given shaft nodes, many of them are composed of multi-frequencies and demonstrate nonlinear motion patterns.

Analysis on Vibration Response Based on Suspension Stiffness for Full-Floating Cab

2012 ◽  
Vol 476-478 ◽  
pp. 1412-1415
Author(s):  
Peng Ji ◽  
Yong Bo Zhao
Keyword(s):  
Vibration Mode ◽  
Vibration Response ◽  
Rear Suspension ◽  
Body Model ◽  
Vibration Problem ◽  
Suspension Stiffness ◽  
Set Up ◽  
Multi Body ◽  
Vibration Performance

In this paper, aiming at vibration problem existed in the development of full-floating cab, a multi-body model of full-floating cab was set up and used to analyze its mode and vibration response. The influence of suspension stiffness for cab vibration performance was optimized. The results indicate the key vibration mode of full-floating cab was decoupled by reasonable match of front and rear suspension stiffness and vibration response was improved obviously.

Research on the Workpiece Kinematics in Face Lapping with Friction Drive

2012 ◽  
Vol 565 ◽  
pp. 318-323 ◽  
Author(s):  
Uwe Heisel ◽  
Philipp Jakob
Keyword(s):  
Material Removal ◽  
Motion Tracking ◽  
Removal Rate ◽  
Motion Patterns ◽  
Body Model ◽  
Precise Knowledge ◽  
Rigid Body Model ◽  
Reaction Forces ◽  
Multi Body

In face lapping, the achievable material removal rate and surface quality depend strongly on the workpiece kinematics. Hence, the precise knowledge of the kinematics is an important requirement for increasing the efficiency and quality of the superfinishing process. The main focus of experiment is to identify how different workpiece geometries influence the resulting kinematics. The process kinematics in face lapping with friction drive is performed by means of motion tracking. Multi-body simulation allows extending the understanding of the process. Apart from the motion patterns of the lapping process, which were determined before, experimentally established reaction forces are used for verifying the considered rigid body model. A deviation of less than 10 % between the forces determined experimentally and by simulation verifies that it is a promising possibility to assess the kinematics by simulation.

Simulation of Motor-Scooter Drop Testing by a Multi-Body Finite Element Integrated Approach

2005 ◽  
Vol 219 (4) ◽  
pp. 383-391 ◽  
Author(s):  
F Frendo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Procedure ◽  
Integrated Approach ◽  
Element Analysis ◽  
Experimental Activity ◽  
Body Model ◽  
Experimental Apparatus ◽  
Set Up ◽  
Multi Body

The drop test is employed in the motor-scooter industry for evaluating the frame performance under particularly severe conditions. In this work, a numerical procedure developed for simulating the test is presented. The procedure includes a multi-body model for the evaluation of the maximum loads acting on the scooter frame during impact at ground. Such loads were then employed in a non-linear static finite element analysis in order to obtain the permanent frame deformation. The experimental activity carried out for vehicle characterization and the experimental apparatus set up for tests are also presented in detail. The multi-code approach appeared versatile and straightforward, and furnished results in satisfactory agreement with experiments.

A Multi-Body Model of a Mechanical Transmission to Simulate Failures on Bearings

2014 ◽  
Author(s):  
Simone Cinquemani ◽  
Carlo Gorla ◽  
Francesco Rosa ◽  
Edoardo Sabbioni ◽  
Emanuele Osto
Keyword(s):  
Condition Monitoring ◽  
Numerical Models ◽  
Operating Conditions ◽  
Mechanical Transmission ◽  
Rolling Mills ◽  
Body Model ◽  
Standard Operating ◽  
Condition Monitoring System ◽  
Set Up ◽  
Multi Body

The paper deals with a project aimed to improve the reliability of a condition monitoring system applied on gearboxes installed on rolling mills. In this context, to properly set up the algorithm, it is necessary to have measurements associated both to standard operating conditions and to malfunctioning. The latter, not being able to be experimentally generated, can be simulated by developing numerical models of the machine under varying conditions. The outputs generated, corresponding to different fault conditions associated with the main common failures of the elements that constitute the transmission, will provide a useful data base to tune the algorithm of condition monitoring.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Research on Chaotic Behavior of Concrete under External Load Based on Discontinuous Medium Mechanical Model

2009 ◽  
Vol 79-82 ◽  
pp. 1145-1148
Author(s):  
Hao Qin ◽  
Shu Cai Li
Keyword(s):  
External Load ◽  
Mechanical Model ◽  
Dynamical Equation ◽  
Chaotic Behavior ◽  
Concrete Material ◽  
Nonlinear Dynamical ◽  
Load Change ◽  
Nonlinear Science ◽  
Set Up ◽  
Discontinuous Medium

Outburst and random are typical characters of concrete when under external load. Traditional mechanics methods are difficult to be applied in. Depend on nonlinear science to set up the nonlinear dynamical equation that is fit for its characteristics. The subsystem dynamical equation of concrete is set up based on discontinuous medium mechanical model, and find that the concrete dynamical equation under external load is a Duffin equation. Then analyze and discuss the effect of external load on concrete by math analysis soft of maple. Results show that the concrete material take on complicated response to external load change.

Statics Analysis of the Mechanical Model of Nucleosome

2011 ◽  
Vol 343-344 ◽  
pp. 661-667 ◽  
Author(s):  
Yun Xue ◽  
De Wei Weng ◽  
Gang Ming Gong
Keyword(s):  
Mechanical Model ◽  
The Other ◽  
Elastic Rod ◽  
Equilibrium Equations ◽  
Constraint Force ◽  
Precession Angle ◽  
Nutation Angle ◽  
Analytic Expression ◽  
Set Up ◽  
Calculated Analysis

Mechanical model of nucleoside and its equilibrium equations are set up, and the mechanical properties on the equilibrium position are analyzed. In the case constraint force and electrostatic attraction between cylinder OH and elastic rod are balanced, the analytic expression of nutation angle of the section and its conditions of existence are given. It is show that the cylinder OH can maintain equilibrium at any range of the precession angle. In the other case when unbanced, there is phenomenon of separation of elastic rod from cylinder OH in the spiral wound 2 circles, and numerical solution of the precession angle at separation points are calculated. Analysis of equilibrium of cylinder H1 illustrates that the generatrix of cylinder H1 and OH are not parallel, and the angle between them is obtained

Dynamic Behavior Analysis of Three-Span Rotor-Bearing System with Rub-Impact Fault

2012 ◽  
Vol 460 ◽  
pp. 160-164 ◽  
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Behavior Analysis ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Rotor System ◽  
System Response ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The dynamic model of the three-span rotor-bearing system with rub-impact fault was set up. The influence to nonlinear dynamics behaviors of the rotor-bearing system that induced by rub-impact of one disc, two discs and three discs were numerically studied. The main influence of the rotor system response by the rub-impact faults are in the supercritical rotate speed. There are mutations of amplitudes in the responses of second and third spans in supercritical rotate speed when rub-impact with one disc, and there are chaotic windows in the response of first span, and jumping changes in second and third spans when rub-impact with two or three discs.

Nonlinear Dynamic Study on Effects of Rub-Impact Caused by Oil-Rupture in a Multi-Shafts Turbine With a Squeeze Film Damper

2014 ◽  
Author(s):  
T. N. Shiau ◽  
C. R. Wang ◽  
D. S. Liu ◽  
W. C. Hsu ◽  
T. H. Young
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Equations Of Motion ◽  
Rotor System ◽  
Squeeze Film ◽  
Speed Ratio ◽  
Frequency Spectra ◽  
Squeeze Film Damper ◽  
Assumed Mode Method ◽  
Nonlinear Dynamic Behavior

An investigation is carried out the analysis of nonlinear dynamic behavior on effects of rub-impact caused by oil-rupture in a multi-shafts turbine system with a squeeze film damper. Main components of a multi-shafts turbine system includes an outer shaft, an inner shaft, an impeller shaft, ball bearings and a squeeze film damper. In the squeeze film damper, oil forces can be derived from the short bearing approximation and cavitated film assumption. The system equations of motion are formulated by the global assumed mode method (GAMM) and Lagrange’s approach. The nonlinear behavior of a multi-shafts turbine system which includes the trajectories in time domain, frequency spectra, Poincaré maps, and bifurcation diagrams are investigated. Numerical results show that large vibration amplitude is observed in steady state at rotating speed ratio adjacent to the first natural frequency when there is no squeeze film damper. The nonlinear dynamic behavior of a multi-shafts turbine system goes in its way into aperiodic motion due to oil-rupture and it is unlike the usual way (1T = >2T = >4T = >8T etc) as compared to one shaft rotor system. The typical routes of bifurcation to aperiodic motion are observed in a multi-shafts turbine rotor system and they suddenly turn into aperiodic motion from the periodic motion without any transition. Consequently, the increasing of geometric or oil parameters such as clearance or lubricant viscosity will improve the performance of SFD bearing.

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