Model reduction methods for rotor dynamic analysis software

The solid rotor interface for modeling a rotor as a full 3d geometric model made with cad software or using the builtin cad. Originally, the substructure method or modal reduction technique was used to analyse linear dynamics problems such as modal analysis. This is to certify that the work presented in this dissertation entitled dynamic analysis, identification and control studies of aeroengine model rotorbearing systems by m. Modeling and dynamic characteristics analysis of bladedisk. Rotor dynamic systems require careful consideration in their dynamic models as they include unsymmetric stiffness, localized nonpropor. Pratt and whitney is to analyze large engine models. In this paper, a simplified dynamic model of a dual rotor system coupled with blade disk is built, and the effects of blade parameters of an aircraft engine on the dynamic characteristics of a dual rotor system are studied. New methods are presented that allow straightforward application of complex nonlinearities to finite element based rotor dynamic analyses. The verification of this analysis method has been done by comparison with the results obtained using an analytical model of a smart jeffcott rotor with and without control. Chapter 3 presents the main mathematical models used in rotor dynamic analysis. Model reduction methods for rotor dynamic analysis. Depending on the installation method, the disk can be mounted to a rotor station by. The groups of methods discussed in this paper for reduction of the linear dynamic model are based on singular perturbation analysis, modal analysis, singular value decomposition, moment matching. Model reduction methods for magnetic fields based on modal analysis article in ieee transactions on magnetics 5011.

Mainly deals with the vibration of rotating structures. Application of the mixed finiteelement method to rotor blade. Seal dynamic coefficients, gas laby seal dynamic coefficients, squeeze film damper stiffness and damping calculation, massinertia properties calculation, rotor orbit analysis, balancing calculation, and autobalancing analysis a number of examples are included in the software package to demonstrate the programs features and capabilities. Students will prepare models utilizing imported geometry and geometry created in simxpert. Lateral vibration of a shaft rotor is due to instability, unbalance, or other forces acting on the rotor. Data collection and analysis software development for rotor dynamics testing in spin laboratory ali abdul aziz 1. An improved user interface and supplementary capabilities. That is how the development took place of software for rotor dynamic. The balanced representation technique developed in ref. Johnson of the armynasa rotorcraft division at ames research center.

In the earlier analysis of the 70 mw gas turbine system, the transfer matrix method of rotor dynamics was employed. The objects of research gasturbine engines, power plants, air compres. Bauchau of the georgia institute of technology, whose excellent study on using the mixed finiteelement method for the dynamic analysis and modal reduction of rotor blades was a key motivation for this study. It makes learning complex power system concepts, models, and. The effectiveness of reduced model was evaluated by comparing critical speeds, damping ratio, first natural frequencies and the response of both the full system and reduced system. An analytical model for dynamic simulation of the composite rotor with internal damping yongsheng ren1, xingqi zhang2, yanghang liu3, xiulong chen4 college of mechanical and electronic engineering, shandong university of science and technology, qindao, 266590, china 1corresponding author. A dismbuted fluidshaft interaction model bas been given for rotorbearing analysis in. Thus, based on the combination of the model reduction technique and. Imparts the theory and analysis regarding the dynamics of rotating machinery in order to design such rotating devices as turbines, jet engines. As well as managing and performing a large variety of projects for various nasa centers and both large and small aerospace companies, dr. Modeling and dynamic characteristics analysis of blade. Student 2assistant professor 1,2department of mechanical engineering 1,2l d college of engineering, ahmedabad abstractin this paper an analytical model is proposed to study behavior of overhung rotordefective bearing system. Dynamic analysis and intelligent electro dynamic control of aeroengine rotor bearing system written by y.

The efficiency of the reduced model depends upon the determination of the number and. Solid rotor and stator models are developed in cad software, such as. Nastran rotor dynamics provides a standard rotor dynamics code, enabling much faster transfer of data and models, and a more streamlined capability for rotor dynamic analysis. An overview of available techniques with application to power systems savo d. We have two different structural model, the first one in house solver based on a beamlike model which is an extension of the blade dynamic model of hdges and dowell see, nonlinear equation for the elastic bending and torsion of twisted nonuniform rotor blades, nasa tn d7818, december 1974. Multiple timesaving modal solution methods are available in ansys software for mode. Originally, the substructure method or modal reduction technique was used to analyse linear dynamics problems such as modal analysis and time integration, 12, while later researchers 14,15 came to use the technique in the context of multibody dynamics. In this paper, a dynamic model of a complex dual rotor bearing system of an aeroengine is established based on the finite element method with three types of beam elements rigid disc, cylindrical beam element and conical beam element, as well as taking into account the nonlinearities of all of the supporting rolling element bearings. Dynamic analysis and intelligent electrodynamic control.

A dynamic analysis of overhung rotor system with bearing. Dynamics r4 program system for turbomachinery rotordynamics. Good agreement with some results from the abaqus software, testing. Rosyid et al 7 used substructuring method for the analysis of rotor bearing system using model reduction technique. The authors also acknowledge the many valuable inputs they received from w. Another problem is that 3d rotor dynamic analysis is a brand new area. Only the substructures are repeatedly analyzed and the re analysis of the global structure is thereby avoided. Rotor dynamic systems require careful consideration in their dynamic models as they include unsymmetric sti. Program system for turbomachinery rotordynamics analysis dynamics r4 the software package is specifically developed for design, analysis and trouble shooting of many kinds of rotating machinery. The rotordynamics module provides five dedicated physics interfaces that you can use to accurately model rotors and bearings. In the methodology, the blade is simplified as a cantilever structure, and the dynamical equations are obtained by the means of a finite element method. The transfer matrix method is widely used for rotor dynamic analysis, but it encounters difficulties modeling a crack.

Provides students with an understanding of the modeling and practice in power system stability analysis and control design, as well as the computational tools used by commercial vendors bringing together wind, facts, hvdc, and several other modern elements, this book gives readers everything they need to know about power systems. Lateral analysis also called rotordynamics analysis simulates the rotating system, calculates the critical speeds, predicts vibration amplitudes, and provides recommendations to reduce vibration risks. Pdf model reduction methods for rotor dynamic analysis. Results of reduced model are compared with those of full degrees of freedom model, to obtain the acceptable reduction of degrees of freedom without significant loss of accuracy in predicting free and forced vibrations. Describe or derive the model, and explain why it should be reduced.

Dyrobes is a complete rotordynamics software tool that is powerful and versatile, yet easy to learn. Computational techniques of rotor dynamics with the finite. A reduction method for nonlinear structural dynamic analysis. Modal analysis of rotating flexible structures aiaa journal. Dynamic analysis, identification and control studies of aero. It also can serve as a starting point for another moredetailed dynamic analysis, such as harmonic response or full transient dynamic analysis. The finite element method fem is used to get the system model including the gyroscopic effects and then, the obtained model is experimentally validated. The remaining listed methods fall into the category of projectionbased reduction. A reduced solver, utilizing automatically or manually selected master degreesoffreedom dofs, is used to drastically reduce the problem size and solution time. The current w501d model represents a power enhancement over the earlier westinghouse 70 mw units which have been in service for many years.

Methods for rotor aerodynamic and dynamic analysis. In order to reduce the model order degree, transfer functions of. Kahraman1 dynamic analysis of geared rotors by finite elements. Rotordynamics software for predictive analyses of rotating. Mathematical models for rotor dynamic analysis springerlink. Application of the mixed finiteelement method to rotor. Rma develops and supports software for rotating machinery analysis. Rajasekhar, roll number 510me810, is a record of original research carried out by him under our supervision and guidance in partial fulfilment of the requirements. The study of the dynamic behavior of geared rotor systems usually requires the coupling between torsional and transverse vibration modes to be included in the model, although this is. Idelsohn and alberto cardona mechanics laboratory, institute of technological development for the chemical industry, universidad nacional del literal, and national council for scientific and.

Rotordynamics, also known as rotor dynamics, is a specialized branch of applied mechanics concerned with the behavior and diagnosis of rotating structures. This study proposes a finitewidth crack model that simulates the local stiffness reduction effect of a gaping crack in transfer matrix method. Dynamic analysis and reduced order modelling of flexible. A beam to 3d model switch for rotor dynamics applications. The primary purpose of the software is to illustrate features of rotating machines described in the. Whirl speed and stability analysis a revolution in rotor. A dynamic analysis of overhung rotor system with bearing defect bhoomi. Computer methods in applied mechanics and engineering 49 1985 253279 northholland a reduction method for nonlinear structural dynamic analysis sergio r. The authors are grateful for the valuable assistance provided by professor o. Dynamics model and equation of a nonlinear flexible rotor bearing system were established based on rotor dynamics. Lateral vibration analysis vibration, dynamics and noise. A finitewidth crack model for rotor dynamic analysis by. Introduction this software is a set of scripts written in matlab to accompany the above book. Rotor dynamic systems require careful consideration in their dynamic models as they include unsymmetric stiffness, localized nonproportional damping, and.

Apply and analyze the result of model reduction method 1 r1 3. Different modeling techniques enable to describe the dynamic response of the unbalanced rotor. Dynamic and control analysis of a smart rotor by combining. Smx122 dynamic analysis using simxpert smx122 is an introductory course in vibration simulation using the structures workspace in simxpert. Rotor dynamic systems require careful consideration in their dynamic models as they include unsymmetric stiffness, localized nonproportional damping, and frequencydependent gyroscopic effects. Power system modeling, computation, and control wiley. Data collection and analysis software development for. This report describes the theoretical background of the epri dynamic reduction dynred v 1. Nonlinear dynamic analysis of a complex dual rotorbearing. The study of the dynamic behavior of geared rotor systems usually requires the coupling between torsional and transverse vibration modes to be included in the model, although this is not a problem for rotors without gears. With substructuring methods, a global structure is divided into a number of independent substructures. The commonly used software for rotorcraft aeroelastic dynamic analysis is camrad, which is a commercial software. Rotor aerodynamic and dynamic analysis 125 in the twodimensional model, the tangential velocities arising from the spiral nature of the wake induced wake rotation may be computed by assuming that the vortex lines are inclined through an angle 2r where 2 is the local induced velocity divided by blade tip speed and r is the radial position. Rotor dynamic analysis of steam turbine rotor using ansys nagaraju tenali 1 and srinivas kadivendi corresponding author.

Epri initiated research under project rp763 to develop the original reduction program dynequ. In recent days, the study about rotor dynamics has gained more importance within steam. May 17, 2012 model reduction methods for rotor dynamic analysis. This paper summarises the model reduction techniques used for the reduction of largescale linear and nonlinear dynamic models, described by the. The solid rotor interface for modeling a rotor as a full 3d geometric model made with cad software or using the builtin cad capabilities of comsol multiphysics. Application of the second dimension reduction method in. Dynamic analysis of structural systems using component modes. Solid modeler implemented rotordynamics software for rotating. These four processes are accomplished in the five main modules highlighted in. This paper summarises the model reduction techniques used for the reduction of largescale linear and nonlinear dynamic models, described by the differential and algebraic equations that are. Sridhar published on 20191205 download full article with reference data and citations. Cad import and automatic meshing library of elements all analysis types including prestress dedicated postprocessing multispool dynamics simulation direct connection to bearing codes account for the flexibility of the supporting structure andor the disks connect directly. Use guyan reduction method and modal synthesis to enhance computational speed.

However, this approach is not often the topic of discussion in the context of model order reduction as it is a general method in science, engineering and mathematics and is not the subject of the current article. Keywords rotordynamics, finite element analysis, gyroscopic effects, modal. Turbopump rotor dynamics because of high power density and low damping in rocket turbopumps, these machines exhibit in their most extreme form a variety of vibration effects, which are either absent or masked by normal damping mechanisms in other turbo machines. Mechanical vibrations overview of experimental modal analysis. Technology, whose excellent study on using the mixed finiteelement method for the dynamic analysis and modal reduction of rotor blades was a key motivation for this study. The disc brake rotor implemented on the front axle of perodua myvi 1. Engineering consultants for lateraltorsional rotordynamics, rotorbearingseal design, structuralpiping analysis, failuremetallurgical investigations developers of advanced rotating machinery dynamics armd software for rotorbearing analysis.

Since 1994, rma has been helping engineers model and analyze rotating equipment quickly, efficiently, and reliably. Data collection and analysis software development for rotor dynamics testing in spin laboratory ali abdulaziz1. The space state model is created next so that the reliable control software available in matlab can be used. At its most basic level, rotor dynamics is concerned with one or more mechanical structures. Pdf nonlinear dynamic analysis of a complex dual rotor.

Modal analysis is one of the most basic dynamic analysis types available in ansys software yet it can be more computationally time consuming than a typical static analysis. Apply and analyze the result of model reduction method 2 r2 4. Dynamic analysis and field balancing of 100 mw utility gas. Model reduction methods for magnetic fields based on modal.

This book equips the reader to understand every important aspect of the dynamics of rotating machines. Kahraman1 dynamic analysis of geared rotors by finite. This paper deals with some of the challenges in the dynamic analysis and field balancing of the w501d gas turbinegenerator system currently used in a number of utilities. In this paper the problem of modeling, analysis and unbalance response control of a rotor system with two disks in an asymmetrical configuration is treated. A 3d finite elementbased model order reduction method for parametric resonance and whirling analysis of anisotropic rotor bearing systems journal of sound and vibration, vol.

The most important and fundamental procedures to reduce unfavorable vibration is to. Nasa glenn research center is using the new rotor dynamics capability in msc. Dynamic behaviors of helical geared multishaft rotor systems. In a balanced representation, the controllability and observability gramians, which represent the inputstate and outputstate maps, respectively, are equal and diagonal. Wagner, amir younan, paul allaire and randy cogill no static citation data no static citation data cite. Developed for the working engineer, dyrobes offers complete rotordynamic analysis, vibration analysis, bearing performance and balancing calculations based in finite element analysis. Nonlinear dynamic analysis of a complex dual rotor bearing system based on a novel model reduction method article pdf available in applied mathematical modelling 75 june 2019 with 145 reads. The selection of the component modes is critical in the modal reduction procedure. This program was the first to be based on the concept of aggregating of coherent groups of synchronous generators into a single equivalent generator model. It is commonly used to analyze the behavior of structures ranging from jet engines and steam turbines to auto engines and computer disk storage.

Component mode synthesis for model order reduction of. Consequently, it is necessary to obtain a reduced order model for dynamic analysis. Student 2assistant professor 1,2department of mechanical engineering 1,2l d college of engineering, ahmedabad abstractin this paper an analytical model is proposed to study behavior of overhung rotor defective bearing system. Then, with the help of this method, dynamic behaviors of helical geared multishaft rotor systems are investigated.

On the dynamic analysis of rotating shafts using nonlinear. Dynamic analysis of rotorbearing systems using t hree. The book develops this understanding initially using extremely simple models for each phenomenon, in which at most four equations capture the. Blelloch has developed advanced methods for model reduction of dynamic systems, damping of coupled systems, analysis of controlstructure interaction problems, nonlinear dynamic response, fluid slosh. The disc brake rotor surface thicknesses on both sides were reduced into 3 steps, 0.

Dynamic analysis and field balancing of 100 mw utility gas turbine generators edgar j. Dynamic behaviors of helical geared multishaft rotor. Nasa studies improved engine performance with new rotor. The finite element software that we are using in the scope of. Lees cambridge university press, 2010 rotordynamics software manual 1. New methods are presented that allow straightforward application of complex nonlinearities to finite.