The loss of fan blades in an aeroengine, or fanblade out fbo, is a type of accident that causes a sudden imbalance and large impact load, which leads to complex vibration of a system. Dynamic and control analysis of a smart rotor by combining the. Transient thermal and structural analysis of the rotor disc of disk brake is aimed at evaluating the performance of disc brake rotor of a car under severe braking conditions and there by assist in disc rotor design and analysis. The bearings have support stiffness of kx and ky associated with damping cx and cy in x and y direction respectively. Jeffcott published a paper to resolve the conflict between.
I have done a modal analysis of jeffcott rotor in ansys workbench for the extraction of natural frequencies but the. Virtual commissioning of large machines with comsol. The analysis of a smart jeffcott rotor with direct velocity feedback control in the supercritical range 206 journal of low frequency noise, vibration and active control figure 1a. Frozen rotor is useful for quickly simulating rotating devices without the complexity of. After the generation of the geometry and building the model in ansys, the finiteelement. A jeffcott rotor with a transverse crack has been considered in the present study.
Describe and apply the essential rotordynamics analysis capabilities. The simplest rotor configuration consists in a simple supported shaft with an accompanying disk. Ansys blademodeler is used to design axial, mixedflow and radial blade components in applications such as pumps, compressors, fans, blowers, turbines, expanders, turbochargers. Vibration and stability analysis of rotorbearingpedestal. Rotordynamisk analys av 3dmodellerad gasturbinrotor i ansys. Papers dyrobes a revolution in rotor dynamics software.
Stability of a flexible rotorbearing system with a. I would like to have a good approximation between a real jeffcott rotor laval rotor and one simulated in ansys. The bar is rotating about the z axis oriented along its length. Rotordynamic modal analysis of impeller in ansys part2. The purpose of this paper is to study the dynamic response of a complex dualrotor system. Rotordynamics users guide msc nastran 2016 mafiadoc. Finding critical speeds campbell diagrams calculating unbalance response calculating response to base excitation predicting rotor whirl and system stability simulating transient startup and. This text describes the development of an efficient approach to the analysis of the dynamics of a rotor with a structure that contains active elements. This document introduced dynamic behavior of a rotor of a disc rotor laval having a transverse crack in the elastic axis.
Brno, czech republic technical support for rotordynamics ing. Rotor dynamic analysis of rm12 jet engine rotor using ansys. Analysis of rotor dynamics acceptance criteria in large. Ansys is a common tool for finite element analyses and it is widely used in research and development of rotating machinery. Cfd analysis on the mainrotor blade of a scale helicopter. Pdf forward and backward whirling of a rotor with gyroscopic. Table of contents download pdf acknowledgements references. To conduct a dynamic analysis of an aeroengine rotor system is an important requirement for relevant departments.
Completion of ansys mechanical getting started is required. This model, historically referred to as a jeffcott or laval model, is a single. It explains the critical speed, approach to solve rotordynamic analysis, balancing machine, campbell diagram, rotordynamic equations, jeffcott rotor, references, and types of analysis for. A simple rotating machine the rotating machinery equivalent to the single springmassdamper system is a lumped mass on a massless, elastic shaft. A novel framework is proposed, in which the sophisticated geometrical structure is considered by finite solid element method and efficient model order reduction is applied to the model. The method provides clear understanding of dynamics, behavior of the components as well as the assessment of properties and characteristics before assembling a complex rotating structure. This training course will give attendees the tools required to utilize the powerful rotordynamics modelling and simulation capabilities within ansys. Bearing forces by integrating pressure profile on fluid area pressure profile by solving short reynolds equation laminar flow fluid with constant density and viscosity. The aim of this thesis work is to build a rm12 jet engine rotor model in ansys and. The jeffcott rotor is the most used model to describe rotordynamics and is a tool to. The generalized lavaljeffcott rotor consists of long, flexible mass less shaft. Gasch15, investigated the dynamic behavior of a laval jeffcott rotor with a transverse crack on its elastic shaft, and developed the nonlinear motion equations which gave important clues on the crack diagnosis. Ansys computes a displacement at bearings locations. Frozen rotor is an optional setting for rotating analyses that reduces simulation time and produces an approximate solution.
Response of aeroengine with fusing design suffering fbo. This configuration is known as monorotor or jeffcott rotor 11. Demonstration of the free vibration analysis of structural frame using ansys modal analysis in this tutorial you learn about some. The rotor and blade design were previously developed using ansys structural module which provides the mass and inertia of the complex. I used solid185, combin14 for the bearings and contac52 for a crack.
The history of rotordynamics is replete with the interplay of theory and. Since the ansys software, according to our experience, has limitations in the area of rotor dynamics and due to the fact that the use of control algorithms is difficult to implement in ansys, a new analysis approach to the study of smart rotors. This video explains the rotor dynamic analysis of impeller in ansys. Model reduction methods for rotor dynamic analysis. Rotor dynamic analysis of 3dmodeled gas turbine rotor in ansys. Introduction to rotordynamic fe analysis, part1 youtube. Rotordynamics background industry and rotating machinery features unique to rotordyanmics analysis of rotating components theory rotordynamics reference frames applicable elements applicable eigensolvers bearing elements analysis process in ansys rotor dynamics is the study of rotating machines and has a very important part to play throughout the. The disk from the single disk rotor jeffcott rotor is mounted little skew with an angle. Using frozen rotor for solving rotating analyses cfd.
This is followed by the analysis of an actual industrial rotor in ansys in order to understand its dynamic. Definition of rotating frame 0z, c centre of the rotor, p point mass. Seals very small rotorstator clearances flexible bearing supports rotor instability rotordynamics analysis aims at. Disc brake model and analysis is done using ansys workbench 14. Consider a massless bar attached to springs and dampers at its ends a and b. The study of flexural behaviour of jeffcott was carried out by many authors. Fundamentals of rotorbearing dynamics using dyrobes the jeffcott rotor, e. Natural frequencies in a jeffcott rotor with crack ansys.
Generalized laval jeffcott rotor model the generalized lavaljeffcott rotor consists of long, flexible mass less shaft with flexible bearings on both the ends. Predicting the stability of rotor systems with the comsol. Optimization of the parameters of the tilting pad bearings and rotor to. Nonlinear dynamical behaviors of a complicated dualrotor. After the generation of the geometry and building the model in ansys, the finite element. The aim is to determine whether the vibrational power coming from the static residual imbalance, which is generally considered to be an undesired and useless sideeffect of the rotation, can be converted into. Equations of motion for transient response have been developed and dynamic analysis has been carried out to. The natural frequency of the cracked rotor increases in comparison to uncracked rotor. The rotor is also simulated using finite element method by ansys, and campbell diagram is plotted. The finite element method fem used in ansys gives an attractive approach for. I have created a parametric macro to make changes very easy in which the variables are.
Table 1 set code i code r jc ps, jc ps, ss, jc description 1 0. The present paper deals with the promising energy harvesting applications of a composite piezoelectric metal support that is properly designed for the rotor of a mechanical system. The purpose of this book is to give a basic understanding of rotor dynamics phenomena with the help of simple rotor models and subsequently, the modern analysis methods for real life rotor systems. The analysis carried out is the modal analysis from ansys workbench.
An example of this kind of rotor is displayed in figure 1. Simplified jeffcott rotor many of the concepts of rotordynamics can be explained using a simplified jeffcott rotor jeffcott, 1919 as shown in figure 11. The analysis of a smart jeffcott rotor with direct. The natural frequencies of a jeffcott rotor are split in the presence of gyroscopic effect. In this paper, the nonlinear dynamical behaviors of a complicated dualrotor aeroengine with rubimpact are investigated.
This background will be helpful in the identification of rotorbearing system parameters and its use in futuristic modelbased condition monitoring. The effect of which is seen on the natural frequency of the system. Dynamics of a jeffcott rotor with slant crack sciencedirect. Pdf rotordynamic modelling and analysis of a radial inflow. The student community is a public forum for authorized ansys academic product users to share ideas and ask questions.
Balancing, rotordynamics introduction to rotor dynamics critical speed and unbalance response analysis, e. Responsedependent nonlinear breathing crack model is used to evaluate unbalance response of the cracked rotor. Rotor behavior is described in the descriptions column. The effect of varying bearing stiffness on the rotating shaft system has been analyzed. Dynamic and control analysis of a smart rotor by combining. Unlike a traditional rotating analysis, the rotating region does not rotate during the simulation. A simple jeffcott rotor model of a rotor with a slant crack is presented.
The jeffcott, a single mass flexible, rotor was used by rotor dynamacs despite its simplistic formulation and assumptions to analyze complex rotor systems and effects. In this paper, the dlf has been calculated to the offset jeffcott rotor with crack. Flexibility matrix of the rotor with slant crack is developed and the stiffness coefficients based on the flexibility values are used in the equations of motion. It explains the basic procedure to perform the rotor dynamic analysis, like how to define analysis setting, rotational velocity. The validity and efficiency of the reducedorder model are verified through critical. Vibration analysis of pump shaft using finite element analysis software. Determining the optimal dimensioning of bearings and rotors takes no time at all with tribox and can be visualized. Lectures will be given for each topic and the attendees will be able to create and run models in different handson exercises.
Rotordynamics dynamic analysis and balancing of an aircraft gas turbine, e. Jeffcott rotor example flexible shaft and rigid bearings yoon,2012. However, with the development and needs for analysis of more complex systems such as gas turbines and jet engines, the jeffcott rotor would not suffice to accurately model these. Dynamic behaviour of the laval rotor with a transverse crack92008. The finite element model of the rotor bearing system is modeled in ansys software. This paper outlines the vibrational response of a cracked rotor in static and rotating condition through campbell diagram. Structural and thermal analysis of rotor disc of disc. Our primary use of ansys is restricted to mesh generation, modal analysis nonspinning and other nonwhirling calculations required for our modal projections. Jeffcott rotor is analyzed in detail to determine its natural frequencies, critical speeds from the campbell diagram, the forward and backward whirl modes.
Rotation and associated momentum terms are imparted to the flow, however. In this study, a double disc rotor bearing system is analyzed. The jeffcott rotor is a mathematical idealization that may not reflect actual rotor mechanics. Abbreviations are jeffcott jc, prestressed ps, spinsoftening ss.
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