Analysis of vibration levels of large structural system with recursive component mode synthesis method: Theory and convergence

2006 ◽  
Vol 220 (9) ◽  
pp. 1339-1345 ◽  
Author(s):  
C W Kim
Keyword(s):  
Finite Element ◽  
Eigenvalue Problem ◽  
Large Scale ◽  
Synthesis Method ◽  
Lanczos Method ◽  
Component Mode Synthesis ◽  
Structural System ◽  
Accurate Analysis ◽  
Satisfactory Performance ◽  
And Performance

The component mode synthesis (CMS) method has been extensively used in industries. However, industry finite-element (FE) models need a more efficient CMS method for satisfactory performance since the size of FE models needs to be increased for a more accurate analysis. Recently, the recursive component mode synthesis (RCMS) method was introduced to solve large-scale eigenvalue problem efficiently. This article focuses on the convergence of the RCMS method with respect to different parameters, and evaluates the accuracy and performance compared with the Lanczos method.

Dynamic response of large structural system including non-proportional damping with recursive component mode synthesis method

2006 ◽  
Vol 220 (9) ◽  
pp. 1347-1351
Author(s):  
C W Kim
Keyword(s):  
Frequency Response ◽  
Large Scale ◽  
Synthesis Method ◽  
Element Model ◽  
Component Mode Synthesis ◽  
Structural System ◽  
Modal Frequency ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Block Lanczos Method

The modal frequency response problem including non-proportional damping is solved with the recursive component mode synthesis (RCMS) method. For large-scale structures, the RCMS method is used not only for computing the eigensolution, but also for forming the modal frequency response problem. The efficiency and accuracy of this approach are verified with examples of structural Finite-element model compared with the conventional industry approach that uses the block Lanczos method.

Rule-based Shape Optimization of Disks Subjected to Transient Thermoelastic Loading

1994 ◽  
Vol 116 (2) ◽  
pp. 419-422 ◽  
Author(s):  
J. Ke ◽  
A. Elbella
Keyword(s):  
Finite Element ◽  
Geometric Approach ◽  
Function Technique ◽  
Accurate Analysis ◽  
Rule Based ◽  
Component Shape ◽  
And Performance ◽  
Conventional Optimization ◽  
Rule Based Approach ◽  
Element Algorithm

This study introduces a rule-based geometric approach to the form optimization of axisymmetric components subjected to transient thermoelastic loading. A finite element algorithm is used for structural analysis and the computation of objective function and design constraints values. To satisfy a prescribed design objective, programmed geometric rules are used to iteratively modify the shape. The posed optimization problem is the minimization of the component’s weight while maintaining the stresses in the structure within allowable limits. A conventional optimization, the penalty function technique, coupled with the finite element algorithm is carried out for comparison. The effects of different loading conditions on component shape and performance are also investigated. A weight reduction of up to 57 percent is obtained for the casting shape of the disk. The results show the superiority of the rule-based approach to mathematical programming techniques. These results are obtained at lower computational costs and with accurate analysis.

scholarly journals Numerical Algorithms for Computing an Arbitrary Singular Value of a Tensor Sum

Axioms ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 211
Author(s):  
Asuka Ohashi ◽  
Tomohiro Sogabe
Keyword(s):  
Eigenvalue Problem ◽  
Large Scale ◽  
Numerical Algorithms ◽  
Direct Methods ◽  
Coefficient Matrix ◽  
Lanczos Method ◽  
Singular Value ◽  
Preconditioned Conjugate Gradient ◽  
Schur Decomposition ◽  
Pcg Method

We consider computing an arbitrary singular value of a tensor sum: T:=In⊗Im⊗A+In⊗B⊗Iℓ+C⊗Im⊗Iℓ∈Rℓmn×ℓmn, where A∈Rℓ×ℓ, B∈Rm×m, C∈Rn×n. We focus on the shift-and-invert Lanczos method, which solves a shift-and-invert eigenvalue problem of (TTT−σ˜2Iℓmn)−1, where σ˜ is set to a scalar value close to the desired singular value. The desired singular value is computed by the maximum eigenvalue of the eigenvalue problem. This shift-and-invert Lanczos method needs to solve large-scale linear systems with the coefficient matrix TTT−σ˜2Iℓmn. The preconditioned conjugate gradient (PCG) method is applied since the direct methods cannot be applied due to the nonzero structure of the coefficient matrix. However, it is difficult in terms of memory requirements to simply implement the shift-and-invert Lanczos and the PCG methods since the size of T grows rapidly by the sizes of A, B, and C. In this paper, we present the following two techniques: (1) efficient implementations of the shift-and-invert Lanczos method for the eigenvalue problem of TTT and the PCG method for TTT−σ˜2Iℓmn using three-dimensional arrays (third-order tensors) and the n-mode products, and (2) preconditioning matrices of the PCG method based on the eigenvalue and the Schur decomposition of T. Finally, we show the effectiveness of the proposed methods through numerical experiments.

scholarly journals Sharing Pandemic Vaccination Certificates through Blockchain: Case Study and Performance Evaluation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
José L. Hernández-Ramos ◽  
Georgios Karopoulos ◽  
Dimitris Geneiatakis ◽  
Tania Martin ◽  
Georgios Kambourakis ◽  
...  
Keyword(s):  
European Union ◽  
Performance Evaluation ◽  
Large Scale ◽  
Evaluation Criteria ◽  
Use Case ◽  
The European Union ◽  
Satisfactory Performance ◽  
And Performance ◽  
Network Response Time

During 2021, different worldwide initiatives have been established for the development of digital vaccination certificates to alleviate the restrictions associated with the COVID-19 pandemic to vaccinated individuals. Although diverse technologies can be considered for the deployment of such certificates, the use of blockchain has been suggested as a promising approach due to its decentralization and transparency features. However, the proposed solutions often lack realistic experimental evaluation that could help to determine possible practical challenges for the deployment of a blockchain platform for this purpose. To fill this gap, this work introduces a scalable, blockchain-based platform for the secure sharing of COVID-19 or other disease vaccination certificates. As an indicative use case, we emulate a large-scale deployment by considering the countries of the European Union. The platform is evaluated through extensive experiments measuring computing resource usage, network response time, and bandwidth. Based on the results, the proposed scheme shows satisfactory performance across all major evaluation criteria, suggesting that it can set the pace for real implementations. Vis-à-vis the related work, the proposed platform is novel, especially through the prism of a large-scale, full-fledged implementation and its assessment.

Component Mode Synthesis Order-Reduction for Dynamic Analysis of Structure Modeled With NURBS Finite Element

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
K. Zhou ◽  
G. Liang ◽  
J. Tang
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Large Scale ◽  
Order Reduction ◽  
Reduction Technique ◽  
Component Mode Synthesis ◽  
Original Structure ◽  
Surface Geometry ◽  
Compatibility Conditions ◽  
B Splines

Nonuniform rational B-splines (NURBS) finite element has advantages in analyzing the structure with curved surface geometry. In this research, we develop a component mode synthesis (CMS) based order-reduction technique which can be applied to large-scale NURBS finite element dynamic analysis. In particular, we establish a new substructure division scheme. The underlying idea is to optimally construct interface between adjacent substructures that can maximize the geometry consistency between the original structure and the divided substructures and at the meantime facilitate the compatibility conditions needed in mode synthesis. Case studies are carried out to validate the performance of the order-reduction formulation.

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