scholarly journals Computationally efficient reduction of modal data from finite element models by nested sets of B-splines

2015 ◽  
Vol 134 ◽  
pp. 549-564
Author(s):  
Diego Cárdenas ◽  
Hugo Elizalde ◽  
Oliver Probst ◽  
Walter Lacarbonara ◽  
Pier Marzocca ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
B Splines ◽  
Modal Data ◽  
Efficient Reduction ◽  
Nested Sets

scholarly journals Correction of Finite Element Models Using Experimental Modal Data.

1991 ◽  
Vol 57 (537) ◽  
pp. 1591-1595 ◽  
Author(s):  
Kukil SOHN ◽  
Masaaki OKUMA ◽  
Akio NAGAMATSU
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Modal Data

Validating and Updating Finite Element Models Using Experimental Measurements of Dynamics

1990 ◽  
Vol 204 (1) ◽  
pp. 45-50
Author(s):  
C F McCulloch ◽  
P Vanhonacker ◽  
E Dascotte
Keyword(s):  
Finite Element ◽  
Structural Dynamics ◽  
Model Updating ◽  
Measured Data ◽  
Physical Parameters ◽  
Experimental Measurements ◽  
Finite Element Models ◽  
Data Sets ◽  
Modal Data ◽  
Modelling Assumptions

A method is proposed for updating finite element models of structural dynamics using the results of experimental modal analysis, based on the sensitivities to changes in physical parameters. The method avoids many of the problems of incompatibility and inconsistency between the experimental and analytical modal data sets and enables the user to express confidence in measured data and modelling assumptions, allowing flexible but automated model updating.

The Influence of Experimental Errors on the Correction Parameters of Finite Element Models

1997 ◽  
Author(s):  
Stefan Keye
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Element Model ◽  
Finite Element Models ◽  
Correction Factors ◽  
Modal Data ◽  
Experimental Errors ◽  
Measurement Uncertainties ◽  
The Impact

Abstract A simulation study has been performed on the influence of experimental errors on the accuracy of finite element model corrections. The impact of measurement uncertainties on the sub-structure correction factors, natural frequencies, and mode shape correlation is investigated using simulated modal data. Different numerical models are used to assess the effects of modelization error magnitudes and locations.

Towards the Design of Compliant Continuum Topologies With Geometric Nonlinearity

1999 ◽  
Author(s):  
A. Saxena ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Linear Models ◽  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
Mechanics Model ◽  
Nonlinear Design ◽  
Nonlinear Force ◽  
Synthesis Procedure

Abstract Optimal design methods that use continuum mechanics model for the deformation of the elastic body, are capable of generating suitable topology, shape, and dimensions of compliant mechanisms for desired specifications. Elastic analysis with linear finite element models employed in the synthesis procedures to date is not quantitatively accurate for large displacement situations. Also, the design specifications involving nonlinear force-deflection characteristics and generation of a curved path for the output port are difficult to realize with linear models. In this paper, the synthesis of compliant mechanisms is performed using geometrically nonlinear finite element models that appropriately account for large displacements. Frame elements are chosen for developing the synthesis procedure because of ease of implementation of the general approach and their ability to capture bending deformations. A computationally efficient method for computing the nonlinear design sensitivities is described. Examples are included to illustrate the usefulness of the synthesis method.

scholarly journals Finite Element Modeling of K-Monel Bolts under Static Loading and Dynamic Shock Loading

2013 ◽  
Vol 20 (3) ◽  
pp. 575-589 ◽  
Author(s):  
Kevin Behan ◽  
Emily Guzas ◽  
Jeffrey Milburn ◽  
Stacy Moss
Keyword(s):  
Finite Element ◽  
High Resolution ◽  
Shock Loading ◽  
Future Research ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
Bolted Connections ◽  
Bolted Connection ◽  
Physical Testing ◽  
Static Shear

The Naval Undersea Warfare Center has funded a project to investigate the accuracy of various bolt models used to represent actual shipboard bolted connections within an analytical shock survivability assessment. The ultimate goal within this project is to develop finite element bolt representations that are not only computationally efficient, but also accurate. A significant task within this effort involved the development of highly detailed finite element models of bolted connections under various load configurations. Accordingly, high-resolution bolt models were developed and incorporated into simulations of four bolted connection test arrangements: static shear, static tension, dynamic shear, and dynamic tension. These simulation results are validated against experimental data from physical testing of each configuration. Future research will focus on exploring simplified finite element bolt representations and comparing these against the high-resolution results.

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.

The Poly-SAFE method: A semi-analytical representation of finite element models via nested polynomial reduction of modal data

2014 ◽  
Vol 111 ◽  
pp. 301-316 ◽  
Author(s):  
Diego Cárdenas ◽  
Hugo Elizalde ◽  
Pier Marzocca ◽  
Oliver Probst ◽  
Ricardo Ramirez ◽  
...  
Keyword(s):  
Finite Element ◽  
Analytical Representation ◽  
Finite Element Models ◽  
Safe Method ◽  
Modal Data ◽  
Polynomial Reduction

Correlating and Updating Finite Element Models of Different Fidelity Using an Energy-Based Approach

2020 ◽  
Author(s):  
Alexander Hardenberg ◽  
Arnold Kühhorn ◽  
Maren Fanter
Keyword(s):  
Finite Element ◽  
Kinetic Energy ◽  
Finite Element Model ◽  
Model Updating ◽  
Three Dimensional ◽  
Element Model ◽  
Finite Element Models ◽  
Modal Data ◽  
Aero Engine ◽  
Turbine Casing

Abstract Building finite element models of complex structures requires the engineer to make various simplifying assumptions. While there exists no unique way of modeling, the resulting model depends to a level on experience and engineering judgment. The inherent model uncertainties can be subdivided into three categories: idealization errors, discretization errors and parameter errors. Understanding the effect of different modeling assumptions and minimizing these uncertainties is key for creating efficient and physical meaningful finite element models. In this paper the effects of different modeling assumptions are analyzed by comparing finite element models of an aero engine turbine casing. Various models of different fidelity are created reaching from simple shell element representations neglecting geometric features like bosses, fixings and holes, to higher fidelity mixed dimensional models using coupled shell and three-dimensional elements. To quantify their impact on the stiffness and mass properties, the different models are correlated with a high-fidelity three-dimensional finite element model using numerical modal data. A novel method is proposed based on the strain and kinetic energy distribution to assess the effect of different modeling assumptions on the model structure. This is done by splitting the discretized model into multiple sections of interest and calculating the deviation of energies within the related splits. The derived strain and kinetic energy deviations are then used in addition to other correlation criteria like the modal assurance criteria or the relative difference in eigenfrequencies to analyze the impact of the different modeling assumptions. Having quantified the differences, the difficulties of error localization using modal data are discussed in the context of the correlation results. Finally, the effectiveness of the derived deviation values are demonstrated by updating a finite element model of an aero engine turbine casing in the presence of structural simplifications using an evolutionary optimization algorithm and comparing the model updating strategy to the standard sensitivity-based updating approach. If the resulting updated model is used to predict structural modifications or untested loading conditions, the updated parameters might lose their physical meaning when altering regions of the model not in error. Therefore, it is important to examine the physical significance of the updated parameters. It is shown, how the energy-based model updating can help to address this problem. All in all, the proposed energy-based approach can be used to compare various modeling strategies in order to build efficient finite element models as well as assist in the choice of parameters for subsequent model updating to validate the numerical model against test data.

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