A Parametrization Describing Blisk Airfoil Variations Referring to Modal Analysis

2017 ◽  
Author(s):  
Thomas Backhaus ◽  
Thomas Maywald ◽  
Sven Schrape ◽  
Matthias Voigt ◽  
Ronald Mailach
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Design Parameters ◽  
Surface Mesh ◽  
Main Mode ◽  
Airfoil Surface ◽  
Parametrization Method ◽  
Surface Meshes ◽  
Geometric Variation

This paper will present a way to capture the geometric blade by blade variations of a milled from solid blisk as well as the manufacturing scatter. Within this idea it is an essential task to digitize the relevant airfoil surface as good as possible to create a valid surface mesh as the base of the upcoming evaluation tasks. Since those huge surface meshes are not easy to handle and are even worse in getting quantified and easy interpretable results, it should be aimed for an easily accessible way of presenting the geometric variation. The presented idea uses a section based airfoil parametrization that is based on an extended NACA-airfoil structure to ensure the capturing of all occurring characteristic geometry variations. This Paper will show how this adapted parametrization method is suitable to outline all the geometric blade by blade variation and even more, refer those airfoil design parameters to modal analysis results such as the natural frequencies of the main mode shapes. This way, the dependencies between the modal and airfoil parameters will be proven.

The Elastic Slider-Crank Mechanism: A Study of the Intrinsic Configuration-Dependent Modal Properties

1992 ◽  
Author(s):  
Ashok Midha ◽  
D. Karam ◽  
B. S. Thompson
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Design Parameters ◽  
Geometrically Nonlinear ◽  
Vibrational Response ◽  
Modal Properties ◽  
Elastodynamic Response ◽  
Increasing Demand ◽  
Crank Mechanism

Abstract In recent years, an ever-increasing demand has been placed on manufacturing for increased productivity, requiring machines to run faster, quieter and with greater precision. This has necessitated that the elastodynamic behavior of mechanisms be carefully evaluated if better machinery must be designed. Although numerous works have been presented for computing the response of mechanisms containing elements characterized by distributed mass and elasticity, very little has been revealed about their modal properties. This paper addresses the modeling of planar slider-crank mechanisms, a popular class of mechanisms, for geometrically nonlinear, elastodynamic response. A modal analysis is performed for varying positions of the crank, and configuration-dependent natural frequencies and mode shapes are presented as functions of the crank position. The results, which includes a study of the effects of some design parameters on these modal properties, should provide new and valuable insights to the designer and researcher alike. These intrinsic modal properties will directly affect the parametric vibrational response and stability characteristics of elastic slider-crank mechanisms.

scholarly journals Modal analysis of an iced offshore composite wind turbine blade

2021 ◽  
pp. 0309524X2110116
Author(s):  
Oumnia Lagdani ◽  
Mostapha Tarfaoui ◽  
Mourad Nachtane ◽  
Mourad Trihi ◽  
Houda Laaouidi
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Wind Turbine Blade ◽  
Resonance Phenomenon ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Numerical Work ◽  
Composite Blades

In the far north, low temperatures and atmospheric icing are a major danger for the safe operation of wind turbines. It can cause several problems in fatigue loads, the balance of the rotor and aerodynamics. With the aim of improving the rigidity of the wind turbine blade, composite materials are currently being used. A numerical work aims to evaluate the effect of ice on composite blades and to determine the most adequate material under icing conditions. Different ice thicknesses are considered in the lower part of the blade. In this paper, modal analysis is performed to obtain the natural frequencies and corresponding mode shapes of the structure. This analysis is elaborated using the finite element method (FEM) computer program through ABAQUS software. The results have laid that the natural frequencies of the blade varied according to the material and thickness of ice and that there is no resonance phenomenon.

Split Vibration Modes in Acoustically-Coupled Disk Stacks

1995 ◽  
Author(s):  
Jung-Ge Tseng ◽  
Jonathan Wickert
Keyword(s):  
Natural Frequencies ◽  
Three Dimensional ◽  
System Level ◽  
Thin Plates ◽  
Mode Shapes ◽  
Design Parameters ◽  
Phase System ◽  
Acoustic Coupling ◽  
Annular Plates ◽  
Vibration Model

Abstract Vibration of an array of stacked annular plates, in which adjacent plates couple weakly through an acoustic layer, is investigated through experimental and theoretical methods. Such acoustic coupling manifests itself through split natural frequencies, beating in the time responses of adjacent or separated plates, and system-level modes in which plates in the array vibrate in- or out-of-phase at closely-spaced frequencies. Laboratory measurements, including a technique in which the frequency response function of all in-phase modes but no out-of-phase modes, or visa versa, is measured, demonstrate the contribution of coupling to the natural frequency spectrum, and identify the combinations of design parameters for which it is important. For the lower modes of primary interest here, the natural frequencies of the out-of-phase system modes decrease as the air layer becomes thinner, while those of the in-phase mode remain sensibly constant at the in vacuo values. A vibration model comprising N classical thin plates that couple through the three-dimensional acoustic fields established in the annular cavities between plates is developed, and its results are compared with measurements of the natural frequencies and mode shapes.

scholarly journals Dynamics Characteristics of Blast Furnace Shell

2011 ◽  
Vol 2-3 ◽  
pp. 1018-1020
Author(s):  
De Chen Zhang ◽  
Yan Ping Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blast Furnace ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Theoretical Foundation ◽  
Structural Mechanics ◽  
Mode Shapes ◽  
The Future ◽  
Element Method

Finite element method and structural mechanics method are used to study the blast furnace shell modal analysis and the natural frequencies and mode shapes have been calculated. The two methods were compared and validated , and the results provide a theoretical foundation for the anti-vibration capabilities design of blast furnace shell in the future .

scholarly journals Modelling of the Coupled Beam-Piezoelectric Material With Hysteresis Non-Linerity Effect

2018 ◽  
Vol 217 ◽  
pp. 02001
Author(s):  
Mohd Hafiz Abdul Satar ◽  
Ahmad Zhafran Ahmad Mazlan
Keyword(s):  
Modal Analysis ◽  
Piezoelectric Material ◽  
Piezoelectric Actuator ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Stress And Strain ◽  
Sinusoidal Voltage ◽  
Correction Algorithm ◽  
Beam Structure ◽  
Piezoelectric Patch

Hysteresis is one of the non-linearity characteristics of the piezoelectric material. This characteristic is important to be characterized since it can affect the performance of the piezoelectric material as sensor or actuator in many applications. In this study, the model of the coupled aluminium beam with single piezoelectric patch material is constructed to investigate the hysteresis effect of the piezoelectric material to the whole beam structure. A P-876 DuraActTM type piezoelectric patch material is used in modelling of the piezoelectric actuator. Firstly, the modal analysis of the coupled beam-piezoelectric actuator is determined to get the natural frequencies and mode shapes. Then, the piezoelectric patch material is investigated in terms of actuator by given a sinusoidal voltage excitation and output in terms of deflection, stress and strain of the piezoelectric actuator are investigated. From the results, it is clear that, the coupled beam-piezoelectric material is affected by the hysteresis of the piezoelectric material and the natural frequencies of the beam structure. This characteristic is important for the piezoelectric actuator manufacturer and by providing the correction algorithm, it can improve the performance of the piezoelectric actuator for many applications.

scholarly journals Aerodynamics and Modal Analysis for the Combined Vane type Vertical Axis Wind Turbine

2018 ◽  
Vol 7 (4.38) ◽  
pp. 1395 ◽  
Author(s):  
Kadhim H. Suffer ◽  
Yassr Y. Kahtan ◽  
Zuradzman M. Razlan
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Mode Shapes ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Starting Torque

The present global energy economy suggests the use of renewable sources such as solar, wind, and biomass to produce the required power. The vertical axis wind turbine is one of wind power applications. Usually, when the vertical axis wind turbine blades are designed from the airfoil, the starting torque problem begins. The main objective of this research is to numerically simulate the combination of movable vanes of a flat plate with the airfoil in a single blade configuration to solve the starting torque problem. CFD analysis in ANSYS-FLUENT and structural analysis in ANSYS of combined blade vertical axis wind turbine rotor has been undertaken. The first simulation is carried out to investigations the aerodynamic characteristic of the turbine by using the finite volume method. While the second simulation is carried out with finite element method for the modal analysis to find the natural frequencies and the mode shape in order to avoid extreme vibration and turbine failure, the natural frequencies, and their corresponding mode shapes are studied and the results were presented with damping and without damping for four selected cases. The predicted results show that the static pressure drop across the blade increase in the active blade side because of the vanes are fully closed and decrease in the negative side because of the all the vanes are fully open. The combined blade helps to increase turbine rotation and so, thus, the power of the turbine increases. While the modal results show that until the 5th natural frequency the effect of damping can be neglected. The predicted results show agreement with those reported in the literature for VAWT with different blade designs.   

Modal Analysis of Magnetic Resonance Imaging (MRI) Scanner Support Structure

2018 ◽  
Author(s):  
Geneviève Rodrigue ◽  
Chris K. Mechefske
Keyword(s):  
Modal Analysis ◽  
Vibration Isolation ◽  
Natural Frequencies ◽  
Design Tool ◽  
Mode Shapes ◽  
Resonance Imaging ◽  
Support Structure ◽  
Analysis And Design ◽  
Passive Vibration Isolation ◽  
Magnetic Resonance Imaging Mri

Experimental and computational modal analysis has been completed as part of a larger project with the ultimate goal of understanding MRI vibration and implementing passive vibration isolation in the MRI machine support structure. The specific purpose of the modal analysis is to extract natural frequencies (eigenvalues) and mode shapes (eigenvectors) of the MRI support structure in order to validate the computational model of the base against the experimental results so that the former may be used as an analysis and design tool. From the model, the resonance points of the MRI support structure are determined within the expected frequency ranges of excitation.

Modal Analysis of Flexible Assembling Fixture for Aircraft Panel Component

2010 ◽  
Vol 97-101 ◽  
pp. 3392-3396
Author(s):  
Li Gang Qu ◽  
Ke Qiang Pan ◽  
Xin Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Characteristic ◽  
Natural Frequencies ◽  
Great Influence ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Dynamic Vibration ◽  
Structural Weakness ◽  
Modal Vibration

The dynamic characteristic of flexible assembling fixture (FAF) for aircraft panel component is analysed by the method of finite element modal analysis. Consequently, the every order of natural frequencies and mode shapes of given different postures of the FAF are obtained. It structural weakness were pointed out through the analysis results of the modal vibration characteristics. The properties of mass and stiffness of the FAF's components are concurrently calculated, whose optimal matching and harmonizing with each other have great influence on the dynamic vibration characteristics of the FAF. As the results of these analysis, the design improving suggestion for the FAF is put forward.

Effect of Weight on the Experimental Modal Analysis of Slender Cantilever Beams

2009 ◽  
Author(s):  
Lawrence Virgin ◽  
David Holland
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Vertical Direction ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Lateral Stiffness ◽  
Axial Loads ◽  
Horizontal Orientation ◽  
Beam System ◽  
Tensile Forces

It is relatively well known that axial loads tend to influence lateral stiffness and hence natural frequencies of slender structural components. Tensile forces tend to increase the lateral stiffness and compressive forces tend to reduce lateral stiffness, bringing with it the possibility of buckling. In many practical situations this is a negligible effect. But for very slender structures it can be important, including the effect of self-weight. This paper will focus attention on a form of double cantilever beam system, i.e., two cantilevers sharing a common hub. A differential axial load can be applied to this system via orientation in a gravitational field. We shall neglect the effect of gravity when the beams are in their horizontal orientation from a limited theoretical standpoint. It is of course present in the experiments but the cantilevers are much stiffer in one direction than the other, and the beams are clamped with their stiffer resistance in the vertical direction. The focus of the current paper is on the natural frequencies and mode shapes of a two-beam system from an experimental modal analysis perspective.

Vibration Modal Analysis of Involve Gear with Asymmetric Tooth Profile and Double Pressure Angles

2011 ◽  
Vol 418-420 ◽  
pp. 1748-1751
Author(s):  
Wei Li ◽  
Ning Liu ◽  
Ning Li ◽  
Yan Jun Liu ◽  
Liang Ma
Keyword(s):  
Modal Analysis ◽  
3D Model ◽  
Natural Frequencies ◽  
Reference Value ◽  
Tooth Profile ◽  
Mode Shapes ◽  
Ansys Software ◽  
Dynamic Design ◽  
Dynamic Performances ◽  
Vibration Modal

The 3D model of gear with asymmetric profile and double pressure angles is built by the autodesk inventor software. It is imported and analyzed by the ANSYS software. Then each order natural frequencies and mode shapes are obtained. So resonance and harmful mode shapes can be avoided, and dynamic performances of gear with asymmetric profile and double pressure angles is improved. This paper has a certain reference value for the dynamic design of other types of gears.

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