scholarly journals Free-Interface Modal Synthesis Based Substructural Damage Detection Method

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Shanghong Chen ◽  
Wei Lin ◽  
Jiexin Yu ◽  
Ai Qi
Keyword(s):  
Detection Method ◽  
Synthesis Method ◽  
Eigenvalues And Eigenvectors ◽  
Sensitivity Matrix ◽  
Free Interface ◽  
Global Sensitivity ◽  
Modal Synthesis ◽  
Sensitivity Method ◽  
Derivatives Of ◽  
Storey Building

Free-interface modal synthesis method is applied to civil structure, and a substructure method is proposed by introducing the method into global sensitivity method. The substructure expression of the derivatives of eigenvalues and eigenvectors with respect to elemental parameters is obtained. The accuracy of the application of free-interface modal synthesis method is evaluated with different retained modes in substructure, and then the effectiveness of the proposed substructure sensitivity method is illustrated through an 11-storey building under both single- and multidamage cases. Both the damage locations and the extent can be effectively identified. By comparing it with the identical results of global sensitivity method, the proposed method can be faster in detecting the damage location and more stable under multidamage cases. Since this substructure sensitivity method only needs to update sensitivity matrix in the substructure with relative small number of DOFs, it may save much computation effort and become more efficient.

A Modal Synthesis Technique Based on the Force Derivative Method

1992 ◽  
Vol 114 (2) ◽  
pp. 209-216 ◽  
Author(s):  
L. E. Suarez ◽  
E. E. Matheu
Keyword(s):  
Finite Element Method ◽  
Synthesis Method ◽  
The Finite Element Method ◽  
Free Interface ◽  
Combination Methods ◽  
Modal Synthesis ◽  
Elastic Forces ◽  
Derivative Method ◽  
Modes Of Vibration ◽  
Combined Structure

In this paper a new free interface modal synthesis method for the dynamic analysis of linear structures by the finite element method is developed. The technique is based on the so called higher order modal combination methods. In particular, the second force derivative method is used to accurately include the effect of the higher truncated modes in the representation of the substructures’ response. It is shown that the method is capable of providing very accurate estimates of the nature frequencies of the combined structure as well as the associated modes of vibration and elastic forces.

Free flexural vibration analysis of one-way stiffened plates by the free interface modal synthesis method

1993 ◽  
Vol 20 (6) ◽  
pp. 885-894 ◽  
Author(s):  
Ian Smith ◽  
Lin J. Hu ◽  
Allison B. Schriver
Keyword(s):  
Natural Frequencies ◽  
Synthesis Method ◽  
Flexural Vibration ◽  
Mode Shapes ◽  
Stiffened Plates ◽  
Shear Rigidity ◽  
Rotatory Inertia ◽  
Inertia Effects ◽  
Free Interface ◽  
Modal Synthesis

A numerical model is presented for predicting the natural frequencies of one-way stiffened plates with ribs having high ratios of flexural to shear rigidity. The model is based on the free interface modal synthesis method. Experimental validation using floors with wood I-joists and wood-based sheathing showed that the model has good numerical accuracy in the predictions of natural frequencies and mode shapes if analyses include shear deformation and rotatory inertia effects in ribs. Neglect of these effects can lead to large errors in the predicted natural frequencies for plates with ribs having high ratios of flexural to shear rigidity. Large errors can also be encountered in natural frequency prediction for plates with fairly low ratios of flexural to shear rigidity. This occurs with mode shapes that have multiple curvature along ribs if shear deformation and rotatory inertia effects are neglected. Key words: free flexural vibration, natural frequencies, ribbed plates, flexural rigidity, shear rigidity, modal synthesis.

Global Sensitivity Matrix for Vehicle Development

ATZ worldwide ◽  
2021 ◽  
Vol 123 (3) ◽  
pp. 26-31
Author(s):  
Jana Büttner ◽  
Stefan Schwarz ◽  
Axel Schumacher ◽  
Thomas Bäck
Keyword(s):  
Sensitivity Matrix ◽  
Vehicle Development ◽  
Global Sensitivity

Modal synthesis method of lateral vibration analysis for rotor-bearing system

2002 ◽  
Vol 80 (32) ◽  
pp. 2537-2549 ◽  
Author(s):  
Chun-Ping Zou ◽  
Hong-Xing Hua ◽  
Duan-Shi Chen
Keyword(s):  
Vibration Analysis ◽  
Synthesis Method ◽  
Lateral Vibration ◽  
Modal Synthesis ◽  
Rotor Bearing ◽  
Bearing System

Contact Modeling Technique of a Flexible Piston and Cylinder Using Modal Synthesis Method

2005 ◽  
Author(s):  
W. K. Kim ◽  
S. H. Sohn ◽  
H. J. Cho ◽  
D. S. Bae ◽  
J. H. Choi
Keyword(s):  
Contact Force ◽  
Synthesis Method ◽  
Normal Modes ◽  
Modeling Technique ◽  
Mode Shapes ◽  
Dynamics Analysis ◽  
Contact Modeling ◽  
Static Correction ◽  
Modal Synthesis ◽  
Contact Surfaces

In this paper, contact modeling technique and dynamics analysis of piston and cylinder system are presented by using modal synthesis method. It is very important to select mode shapes representing a global or local behavior of a flexible body due to a specified loading condition. This paper proposes a technique to generate the static correction modes which are nicely representing a motion by a contact force between a piston and cylinder. First normal modes of piston and cylinder under a boundary condition are computed, and then static correction modes due to a contact force applied at contacted nodes are added to the normal modes. Also, this paper proposes an efficient dynamics analysis process while changing the shape of the piston and cylinder. In optimization process or design study, their geometric data can be changed a bit. The slight changes of their contact surfaces make a high variation of the magnitude of a contact force, and it can yield the different dynamic behavior of an engine system. But, since the variations of the normal and correction modes are very small, the re-computation of their normal and correction modes due to the change of contact surfaces can be useless. Until now, whenever their contact surfaces are changed at a design cycle, the modes have been recomputed. Thus, most engineers in industries have been spent many times in very tedious and inefficient design process. In this paper, the normal and correction modes from the basic geometry of the piston and cylinder are computed. If the geometry shape is changed, nodal positions of the original modal model are newly calculated from an interpolation method and changed geometry data. And then the updated nodes are used to compute a precise contact force. The proposed methods illustrated in this investigation have good agreement with results of a nodal synthesis technique and proved that it is very efficient design method.

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