Dominant vibration modes for broadband frequency analysis of multiscale structures with numerous local vibration modes

Ezvan, Olivier; Zeng, Xiaobo; Ghanem, Roger; Gencturk, Bora

doi:10.1002/nme.5971

Cited by 8 publications

(3 citation statements)

References 21 publications

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“…The fuel assembly considered in this paper has 92 fuel rods. More illustrations of the fuel assembly can be found in Sections 3 and 4 and a detailed description of it can be found in [73]. The overall structure presents three distinct structural levels and is characterized by a pseudo-periodicity (see Fig.…”

Section: Problem Statement and Fundamental Toolsmentioning

confidence: 99%

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Multiscale modal analysis of fully-loaded spent nuclear fuel canisters

Ezvan

Zeng

Ghanem

et al. 2020

Computer Methods in Applied Mechanics and Engineering

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In this paper, an efficient numerical procedure is proposed, adapted to the modal analysis of a fully-loaded spent nuclear fuel canister, which exhibits distinct structural levels associated with a hierarchy of components. On the one hand, the fully-loaded spent nuclear fuel canister is constituted of the repetition of identical components, resulting in a pseudo-periodicity; and the components of a given level are separated from each other and only connected to their upper level through localized attachments, which gives rise to an advantageous structural connectivity that can be exploited for efficiency. On the other hand, the necessary fine mesh resolution of the small levels leads to a high-dimensional computational model and, in addition, the independent resonant vibrations of each of the components produce a very large number of vibration eigenmodes. The aforementioned opportunities and difficulties are respectively leveraged and tackled by an adapted method that combines domain decomposition, shift-invert Lanczos eigenvalue solver, and Craig-Bampton substructuring technique. A parallel eigensolution via spectrum slicing is facilitated by an efficient block factorization by Schur complement that is enabled by the sparsity of the Craig-Bampton matrices. A computational gain of four orders of magnitude is obtained, at the expense of negligible errors that are exactly characterized. The proposed methodology enables a high-fidelity vibration analysis of the sealed fully-loaded spent nuclear fuel canister, useful for non-intrusive inverse identification of the structural integrity of the internal structural levels holding the nuclear material.

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Section: Problem Statement and Fundamental Toolsmentioning

confidence: 99%

“…The necessity to compute the exact modes contradicts the purpose of the construction of the CB model. To circumvent this difficulty, the proposed approach consists in performing the FRF comparison within a reduced subspace, spanned by a reduced set of dominant modes [73], i.e., the modes with greatest contribution.…”

Section: Frf Errormentioning

confidence: 99%

Multiscale modal analysis of fully-loaded spent nuclear fuel canisters

Ezvan

Zeng

Ghanem

et al. 2020

Computer Methods in Applied Mechanics and Engineering

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“…The admissible set is the support of the prior probability distribution of the uncertain control parameter. This situation, which we have just described, is that of the fully-loaded spent nuclear fuel canisters studied in [1,2,3] and depicted in Fig. 1.…”

Section: Introduction (I) Objectives Of the Papermentioning

confidence: 96%

Updating an uncertain and expensive computational model in structural dynamics based on one single target FRF using a probabilistic learning tool

et al. 2023

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The paper presents an appropriate and efficient methodology for updating the control parameters of very large uncertain computational models, which are used for analyzing the linear vibrations in the frequency domain of highly complex structures for which there are an enormous number of intertwined local and global elastic structural modes in the broad frequency band of analysis. Moreover, the numerical cost of a single evaluation of the frequency response functions with the computational model is assumed to be very high and only one experimental frequency response function is available as a target. For decreasing the numerical cost of this challenging problem, a parameterized reduced-order model is constructed. Nevertheless, this reduction is not sufficient to be able to solve the non-convex optimization problem related to the updating. Consequently, for avoiding the call to the computational model, the probabilistic learning on manifolds is used for generating a learned set from a training set, which, coupled with conditional statistics, allows the evaluation of the cost function without calling the computational model. A numerical illustration is presented for validating the proposed methodology.

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Dominant substructural vibration modes for fully-loaded spent nuclear fuel canisters

et al. 2020

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This paper investigates the dynamic characteristics of a multilevel structure for the transportation and storage of spent nuclear fuel (SNF) from commercial power plants. The nuclear fuel is stored in slender rods that are grouped together into fuel assemblies (FA). In a sealed cylindrical container called "canister", the FA are inserted into a honeycomb basket. The objective of this paper is to develop a computational model that accurately describes the structural dynamics of the canister, based on measurements collected from its external surface. Based on these measurements, the computational model is intended to capture the signature of the structural integrity of the internal components (FA and fuel rods). The numerous components lead to a large finite element (FE) model and numerous vibration modes and eigenfrequencies. Nevertheless, the localized connections between components enable an efficient domain decomposition with few interface coordinates. Craig-Bampton (CB) substructuring is thus used to perform the modal analysis. However, the high modal density yields a large-scale CB eigenvalue problem that necessitates a sparse solver. A block factorization by Schur complement that exploits the sparsity of the CB matrices allows an efficient calculation of the numerous eigenpairs. Many local vibration modes contribute little to the dynamics of the SNF canister. The main contribution of this paper is the development of an efficient methodology for determining the importance of each of

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Dominant vibration modes for broadband frequency analysis of multiscale structures with numerous local vibration modes

Cited by 8 publications

References 21 publications

Multiscale modal analysis of fully-loaded spent nuclear fuel canisters

Multiscale modal analysis of fully-loaded spent nuclear fuel canisters

Updating an uncertain and expensive computational model in structural dynamics based on one single target FRF using a probabilistic learning tool

Dominant substructural vibration modes for fully-loaded spent nuclear fuel canisters

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