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

1994 ◽  
Vol 21 (1) ◽  
pp. 167-168
Author(s):  
Mohamed Abdel-Mooty
Keyword(s):  
Vibration Analysis ◽  
Synthesis Method ◽  
Flexural Vibration ◽  
Stiffened Plates ◽  
Free Interface ◽  
Modal Synthesis

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.

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

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.

Torsional Vibration Analysis of Complicated Multi-Branched Shafting Systems by Modal Synthesis Method

2003 ◽  
Vol 125 (3) ◽  
pp. 317-323 ◽  
Author(s):  
Chun-Ping Zou ◽  
Duan-Shi Chen ◽  
Hong-Xing Hua
Keyword(s):  
Torsional Vibration ◽  
Vibration Analysis ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Elastic Coupling ◽  
Improved Method ◽  
Modal Synthesis ◽  
Rigid Connection ◽  
Flexible Connections ◽  
Fixed Interface

The torsional vibration calculations of the complicated multi-branched system with rigid connection and flexible connections made up of elastic-coupling parts are very difficult to perform using conventional methods. In this paper, a modal synthesis method of torsional vibration analysis for the system is proposed. This approach is an improved method of Hurty’s fixed-interface and Hou’s free-interface modal synthesis methods. Because of the introduction of flexible substructure, the improved modal synthesis method can effectively treat the complicated system in which there exists a rigid connection and a flexible connection that is formed by an elastic-coupling part. When the calculation is performed, the complicated multi-branched system is divided into several substructures that are analyzed by FEM (finite element method) except the special elastic-coupling part that is defined as flexible substructure and treated individually. The efficiency of modal synthesis is improved by choosing suitable number of lower-frequency modes in modal synthesis. As an example of an application of this method, the analysis of torsional vibration of a cam-type engine shafting system is carried out both numerically and experimentally. The results show that the above kind of multi-branched shafting system can be analyzed effectively by the proposed method.

A Novel Gap Element for the Coupling of Incompatible Interface in Component Mode Synthesis Method

2019 ◽  
Vol 17 (07) ◽  
pp. 1950033
Author(s):  
Ruoyu Li ◽  
Jianyao Yao ◽  
Linlin Wang ◽  
Chen Jiang ◽  
Fei Wu ◽  
...  
Keyword(s):  
Vibration Analysis ◽  
Natural Frequencies ◽  
Synthesis Method ◽  
Component Mode Synthesis ◽  
Complex Structures ◽  
Compatibility Conditions ◽  
Free Interface ◽  
Numerical Errors ◽  
Gap Element ◽  
Finite Elements Model

The component mode synthesis (CMS) methods are often utilized for modal analysis to investigate the vibration characteristics of the complex structures which are commonly divided into several substructures. However, non-matching finite element meshes may occur at the interfaces between components and virtual gaps are easily produced along the curved interfaces, which limit the application of CMS and lead to larger numerical errors for vibration analysis. To overcome the problem, a novel gap element method (GEM) is employed into a free-interface CMS method in this paper, where both displacements and forces of the nodes on the incompatible interfaces are introduced by two independent Lagrange multipliers to enforce the compatibility conditions. Two-dimensional numerical examples are given to validate the effectiveness of the proposed method. The results of natural frequencies and modal shapes obtained using the proposed method agree very well with the ones obtained using full finite elements model, no matter the gaps along the interface exist or not. The influence of the number of nodes on the non-matching interfaces on the accuracy of frequencies is also discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document