The Application of Modal Synthesis Method in the Processing Center Dynamics Analysis

2012 ◽  
Vol 163 ◽  
pp. 207-210
Author(s):  
Peng Liu ◽  
Chun Jie Wang ◽  
Ru Sun
Keyword(s):  
Computational Efficiency ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Vibration Mode ◽  
Synthesis Method ◽  
Component Mode Synthesis ◽  
Dynamics Analysis ◽  
Full Model ◽  
Modal Synthesis ◽  
Five Axis

Modal synthesis method is a method which can reduce structural degrees of freedom, it is applicable for analysis and calculations of Machining centers and other large-scale structure. In this paper, the dynamical performance of Five-axis boring and milling processing center was studied with component mode synthesis technology . Compared with full model FEM, component mode synthesis technology could meet the accuracy requirements and have higher computational efficiency. Modal characteristics of processing center in different positions was studied, the result showed that each frequency of processing center in different position was different while the vibration mode remained unchanged.

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.

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.

A Method for Substructural Sensitivity Synthesis

1991 ◽  
Vol 113 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Joo Ho Heo ◽  
K. F. Ehmann
Keyword(s):  
Dynamic Characteristics ◽  
Computational Efficiency ◽  
Synthesis Method ◽  
Simple Calculation ◽  
Component Mode Synthesis ◽  
New Method ◽  
Eigenvalues And Eigenvectors ◽  
Modal Data ◽  
Entire Structure ◽  
Design Variables

A new method, termed the substructural sensitivity synthesis method, which utilizes the computational merits of the component mode synthesis technique was proposed for the simple calculation of design sensitivities of the dynamic characteristics of substructurally combined structures. It has been shown that the modal sensitivities of the entire structure can be obtained by synthesizing the substructural modal data and the sensitivities of the modal data for the design variables of the modifiable substructure. For a truss structure, as an example, the sensitivities of the eigenvalues and eigenvectors obtained by the new method were compared with exact solutions in terms of accuracy and computational efficiency.

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.

scholarly journals A Combination of Modal Synthesis and Subspace Iteration for an Efficient Algorithm for Modal Analysis within a FE-Code

2003 ◽  
Vol 10 (1) ◽  
pp. 27-35 ◽  
Author(s):  
M.W. Zehn
Keyword(s):  
Eigenvalue Problem ◽  
Modal Analysis ◽  
Efficient Algorithm ◽  
Degrees Of Freedom ◽  
Synthesis Method ◽  
Problem Solver ◽  
Synthesis Methods ◽  
Combined Method ◽  
Subspace Iteration ◽  
Modal Synthesis

Various well-known modal synthesis methods exist in the literature, which are all based upon certain assumptions for the relation of generalised modal co-ordinates with internal modal co-ordinates. If employed in a dynamical FE substructure/superelement technique the generalised modal co-ordinates are represented by the master degrees of freedom (DOF) of the master nodes of the substructure. To conduct FE modal analysis the modal synthesis method can be integrated to reduce the number of necessary master nodes or to ease the process of defining additional master points within the structure. The paper presents such a combined method, which can be integrated very efficiently and seamless into a special subspace eigenvalue problem solver with no need to alter the FE system matrices within the FE code. Accordingly, the merits of using the new algorithm are the easy implementation into a FE code, the less effort to carry out modal synthesis, and the versatility in dealing with superelements. The paper presents examples to illustrate the proper work of the algorithm proposed.

Modeling of Flexible Robot-Payload Systems Through Component Synthesis

1998 ◽  
Vol 122 (2) ◽  
pp. 381-386 ◽  
Author(s):  
T. Zhou, ◽  
J. W. Zu, and ◽  
A. A. Goldenberg
Keyword(s):  
Degrees Of Freedom ◽  
Synthesis Method ◽  
Modeling Method ◽  
Component Mode Synthesis ◽  
Flexible Robot ◽  
Computationally Efficient ◽  
Efficient Manner ◽  
Robot Gripper ◽  
Coupling Dynamics ◽  
Rigid Body Motions

In this paper, a new modeling method is developed for analyzing the dynamic behavior of a system consisting of a rigid robotic manipulator and a flexible sheet metal payload. The component mode synthesis method is applied to reduce the degrees of freedom of the payload and to model the interfaces between the robot gripper and the payload. Using nonlinear compatibility functions, the method is modified to synthesize the dynamics of the entire robot-payload system. Exact models are developed capable of describing both large and small rigid-body motions. A modular form is derived and the coupling dynamics is formulated in a computationally efficient manner. Numerical examples are presented to demonstrate the effectiveness of the modeling method. [S0022-0434(00)01102-3]

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