Selection of Dynamic Testing Measurement Locations for Integrally Bladed Disks

2018 ◽  
Author(s):  
Joseph A. Beck ◽  
Alex A. Kaszynski ◽  
Jeffrey M. Brown ◽  
Daniel L. Gillaugh ◽  
Onome E. Scott-Emuakpor
Keyword(s):  
Finite Element ◽  
Point Cloud ◽  
Dynamic Testing ◽  
Experimental Testing ◽  
Mode Shapes ◽  
Cyclic Symmetry ◽  
Bladed Disks ◽  
Fine Mesh ◽  
Mesh Density ◽  
Selection Of

The selection of sensor locations during dynamic testing of integrally bladed disks (Blisks) is discussed for measuring experimental mode shapes. As-manufactured geometries of the experimental Blisk are obtained in point-cloud form via a structured light optical measurement system. The nominal finite element mesh of the Blisk is then “morphed” to the average sector of as-measured, point-cloud geometry through a mesh metamorphosis algorithm. A ray-tracing algorithm is developed for selecting observable degrees of freedom (DOFs) of the morphed mesh to an overhead laser scanning vibrometer. This set of DOFs is then down-selected since measuring tens-of-thousands of points is in-feasible during experimental testing. This selection is carried out using a Cyclic Effective Independence Method that exploits a Blisk’s cyclic symmetry to greatly reduce computational expenses. Furthermore, the approach allows for selecting points belonging to specific engine order excitations typical in engine operating environments that can be excited during bench top traveling wave testing. Measurement point locations are compared for three cyclic symmetry finite element models: a nominal coarse mesh density, a nominal fine mesh density, and a fine mesh density morphed to average sector geometries.

scholarly journals High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2018 ◽  
Author(s):  
Adam Koscso ◽  
Guido Dhondt ◽  
E. P. Petrov
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Coordinate Systems ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Material Orientation

A new method has been developed for sensitivity calculations of modal characteristics of bladed disks made of anisotropic materials. The method allows the determination of the sensitivity of the natural frequencies and mode shapes of mistuned bladed disks with respect to anisotropy angles that define the crystal orientation of the monocrystalline blades using full-scale finite element models. An enhanced method is proposed to provide high accuracy for the sensitivity analysis of mode shapes. An approach has also been developed for transforming the modal sensitivities to coordinate systems used in industry for description of the blade anisotropy orientations. The capabilities of the developed methods are demonstrated on examples of a single blade and a mistuned realistic bladed disk finite element models. The modal sensitivity of mistuned bladed disks to anisotropic material orientation is thoroughly studied.

scholarly journals Effect of Mesh Density on Finite Element Analysis Simulation of a Support Bracket

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Nicholas S Gukop ◽  
Peter M Kamtu ◽  
Bildad D Lengs ◽  
Alkali Babawuya ◽  
Adesanmi Adegoke
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computation Time ◽  
Mesh Size ◽  
High Quality ◽  
Element Analysis ◽  
Fine Mesh ◽  
Finite Element Analysis Simulation ◽  
Mesh Analysis ◽  
Mesh Density

Investigation on the effect of mesh density on the analysis of simple support bracket was conducted using Finite element analysis simulation. Multiple analyses were carried out with mesh refinement from coarse mesh of 3.5 mm to a high-quality fine mesh with element size of 0.35 mm under 15 kN loading. Controlled mesh analysis was also conducted for the same loading. At the mesh size of 0.35 mm, it has a maximum stress value of 42.7 MPa. As the element size was reduced, it was observed that below 1.5 mm (higher mesh density) there was no significant increase in the peak stress value; the stress at this level increased by 0.028 % only. Further decreased of mesh size shows insignificant effect on the stresses and displacements for the high-quality fine mesh analysis. The application of High-quality mesh control analysis showed a significant reduction in the computation time by more than 90%. Regardless of the reduction in computation time, the controlled mesh analysis achieved more than 99% accuracy as compared to high-quality fine mesh analysis. Keywords— Computation time, Finite Element Analysis, Mesh density, Support Bracket.

Identification of printed circuit boards mechanical properties using response surface methods

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammad Gharaibeh
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Material Properties ◽  
Printed Circuit Boards ◽  
Dynamic Testing ◽  
Mode Shapes ◽  
Fe Model ◽  
Circuit Boards ◽  
Content Type ◽  
Printed Circuit

Purpose This study aims to discuss the determination of the unknown in-plane mechanical material properties of printed circuit boards (PCBs) by correlating the results from dynamic testing and finite element (FE) models using the response surface method (RSM). Design/methodology/approach The first 10 resonant frequencies and vibratory mode shapes are measured using modal analysis with hammer testing experiment, and hence, systematically compared with finite element analysis (FEA) results. The RSM is consequently used to minimize the cumulative error between dynamic testing and FEA results by continuously modifying the FE model, to acquire material properties of PCBs. Findings Great agreement is shown when comparing FEA to measurements, the optimum in-plane material properties were identified, and hence, verified. Originality/value This paper used FEA and RSMs along with modal measurements to obtain in-plane material properties of PCBs. The methodology presented here can be easily generalized and repeated for different board designs and configurations.

scholarly journals Numerical Assessment of Factors Affecting Waveform Based on Low Strain Testing of Piles

2014 ◽  
Vol 8 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Zegen Wang ◽  
Yifeng Wu ◽  
Zuocheng Xiao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Testing ◽  
Element Model ◽  
Numerical Analyses ◽  
Factors Affecting ◽  
The Real ◽  
Numerical Assessment ◽  
Strain Testing ◽  
Mesh Density

In this paper dynamic testing of piles using the low strain method is performed by means of numerical analyses based on solid finite element model. To this end, velocity-time curves are presented investigating the influence of various parameters such as mesh density, impulse width, receiving point, and soil modulus on the waveform characteristics. Then, find regularity of waveform affected by different parameters to provide reference of the real project detection.

scholarly journals High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Adam Koscso ◽  
Guido Dhondt ◽  
E. P. Petrov
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Coordinate Systems ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Material Orientation

A new method has been developed for sensitivity calculations of modal characteristics of bladed disks made of anisotropic materials. The method allows the determination of the sensitivity of the natural frequencies and mode shapes of mistuned bladed disks with respect to anisotropy angles that define the crystal orientation of the monocrystalline blades using full-scale finite element models. An enhanced method is proposed to provide high accuracy for the sensitivity analysis of mode shapes. An approach has also been developed for transforming the modal sensitivities to coordinate systems (CS) used in industry for description of the blade anisotropy orientations. The capabilities of the developed methods are demonstrated on examples of a single blade and a mistuned realistic bladed disk finite element models. The modal sensitivity of mistuned bladed disks to anisotropic material orientation is thoroughly studied.

A Comparison of Two Finite Element Reduction Techniques for Mistuned Bladed-Disks

2000 ◽  
Author(s):  
François Moyroud ◽  
Torsten Fransson ◽  
Georges Jacquet-Richardet
Keyword(s):  
Finite Element ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
Bladed Disks ◽  
Mode Localization ◽  
Reduced Order ◽  
Bladed Disk ◽  
Reduction Techniques ◽  
Modal Reduction

The high performance bladed-disks used in today’s turbomachines must meet strict standards in terms of aeroelastic stability and resonant response level. One structural characteristic that can significantly impact on both these area is that of bladed-disk mistuning. To predict the effects of mistuning, computationally efficient methods are necessary to make it feasible, especially in an industrial environment, to perform free vibration and forced response analyses of full assembly finite element models. Due to the size of typical finite element models of industrial bladed-disks, efficient reduction techniques must be used to systematically produce reduced order models. The objective of this paper is to compare two prevalent reduction methods on representative test rotors, including a modern design industrial shrouded bladed-disk, in terms of accuracy (for frequencies and mode shapes), reduction order, computational efficiency, sensitivity to inter-sector elastic coupling, and ability to capture the phenomenon of mode localization. The first reduction technique employs a modal reduction approach with a modal basis consisting of mode shapes of the tuned bladed-disk which can be obtained from a classical cyclic symmetric modal analysis. The second reduction technique is based on a Craig and Bampton substructuring and reduction approach. The results show a perfect agreement between the two reduced order models and the non-reduced finite element model. It is found that the phenomena of mode localization is equally well predicted by the two reduction models. In terms of computational cost, reductions from 1 to 2 orders of magnitude are obtained for the industrial bladed-disk, with the modal reduction method being the most computationally efficient approach.

Reduced Order Model for a Two Stage Gas Turbine Including Mistuned Bladed Disks and Shaft Interaction

2009 ◽  
Author(s):  
Luis A. Boulton ◽  
Euro Casanova
Keyword(s):  
Finite Element ◽  
Gas Turbine ◽  
Reduced Order Model ◽  
Mode Shapes ◽  
Order Model ◽  
Two Stage ◽  
Bladed Disks ◽  
Reduced Order ◽  
Bladed Disk ◽  
The Impact

A number of previous works have suggested that in some cases the interaction between shaft and bladed disk modes could significantly modify the dynamics of the whole assembly i.e. the bladed disks mounted on a flexible shaft. This paper presents the application of a previously published reduced-order modeling technique to the dynamical modeling of a real two stage gas turbine, including the bladed disks and the shaft. In the resulting reduce order model, mistuning is included in the bladed disk models and the shaft is modeled using beam finite elements according to the classical rotordynamic approach. Generation of finite element parent model for the real turbine is presented and discussed as well as simplifications used in order to generate the reduced order model. Comparisons are made between the reduced model and the full finite element solution for free response frequencies and mode shapes in order to assess the methodology and to evaluate the impact of simplifying hypothesis considered in model generation. Finally, this work also shows interaction between shaft modes and bladed disk modes, therefore confirming that stage independent analysis might not be adequate for predicting the global dynamic response of some turbomachinery rotors.

scholarly journals Modal Verification and Strength Analysis of Rotor Bladed Disks of Turbine in Rated Working Conditions

2021 ◽  
Vol 11 (14) ◽  
pp. 6306
Author(s):  
Chang-Sheng Lin ◽  
Hung-Tse Chiang ◽  
Chuan-Hsing Hsu ◽  
Ming-Hsien Lin ◽  
Jui-Kai Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Blast Furnace ◽  
Stress Distribution ◽  
Modal Analysis ◽  
Centrifugal Force ◽  
Working Conditions ◽  
Maximum Stress ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Bladed Disks

The Top-pressure Recovery Turbine (TRT) uses the blast furnace gas generated in the iron and steel manufacturing process to push the turbine which drives the generator to generate electricity, and the generated electric energy is supplied to in-plant equipment. In this paper, we investigate the aerodynamic force, centrifugal force, and maximum stress on the structure of the TRT rotor in rated working conditions and the positions of occurrence using the Finite Element Method (FEM), as well as discuss the dynamic characteristics of bladed disks during TRT operation through Campbell and SAFE diagrams. To confirm the effectiveness of the finite element models, the mode shapes and natural frequencies in the FEA-based modal analysis of the TRT rotor will be captured and compared with those of the practical structures through the Experimented Modal Analysis (EMA). To verify the agreement between the mode shapes of the finite element analysis and those of the actual structure, the Modal Assurance Criterion (MAC) is introduced here to confirm the reliability of the finite element model. The stress distribution on the structure in the rotation is obtained by centrifugal force analysis. The TRT rotor is driven as the blast furnace top pressure pushes the moving blade; when the rotor rotates, the moving blade bears centrifugal and periodic aerodynamic forces. The stress distribution is investigated on the structure when these forces act simultaneously using aerodynamic analysis. To discuss whether the bladed disks will resonate with the external force under the operating conditions, Campbell and SAFE diagrams are used for evaluation, and the modal parameters obtained from the EMA are used to estimate the strength and durability of the blades. According to the analysis results when the TRT rotor is in working conditions, the fatigue failure may occur at the maximum stress existing on the dovetail slot.

Reduction of Multistage Rotor Models Using Cyclic Modeshapes

2007 ◽  
Author(s):  
Arnaud Sternchu¨ss ◽  
Etienne Balme`s
Keyword(s):  
Representative Sample ◽  
Mode Shapes ◽  
Cyclic Symmetry ◽  
Bladed Disks ◽  
Cyclic Mode

This study deals with the reduction of models of bladed disks assemblies through the use of mono-harmonic cyclic mode-shapes. The first part of this paper describes how the classical substructuring technique in cyclic symmetry can be extended to rotors in the case of non compatible meshes to compute mono-harmonic eigenvectors. The second part of the paper then presents the method employed by the authors to seek the full modes of the rotor in a subspace generated from a set of such modeshapes. All the concepts developed here are illustrated on a representative sample.

Automated Meshing Algorithm for Generating As-Manufactured Finite Element Models Directly From As-Measured Fan Blades and Integrally Bladed Disks

2018 ◽  
Author(s):  
Alex A. Kaszynski ◽  
Joseph A. Beck ◽  
Jeffrey M. Brown
Keyword(s):  
Finite Element ◽  
Human Interaction ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Element Analysis ◽  
Tetrahedral Meshes ◽  
Volumetric Representation ◽  
Mesh Density ◽  
Scan Data ◽  
Mesh Convergence

Automated tetrahedral meshing from manifold tessellated optical scan data is investigated to determine its viability as an approach for finite element analysis. This approach avoids the costs of constructing a volumetric representation of the scan data that can be meshed with conventional grid generation approaches. This paper demonstrates an auto-meshing algorithm for inserted airfoil and integrally bladed rotor hardware. These automatically generated models are compared to experimentally obtained frequencies and mode shapes for validation. In an effort to compare the fidelity as well as the effect of mesh density on analytical convergence rate, manually generated all-hexahedral models are compared against the auto-meshed tetrahedral finite element models. CPU time, solution accuracy, and mesh convergence are evaluated to determine the viability of automatically generated tetrahedral meshes versus the standard approach of manually generating hex-dominant meshes. This paper demonstrates that given the power of modern CPUs, automatically generated all-tetrahedral meshes can serve as a viable alternative to manually generated hex-dominant finite element models, especially when these meshes can be refined for solution convergence within the auto-mesher. This new approach effectively solves both the mesh convergence problem while demonstrating that models based on as-measured geometry can be rapidly built with virtually no human interaction.

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