Approximate Determination of Eigen-Values of Classically Damped System with Added Viscous Damper

2016 ◽  
Vol 821 ◽  
pp. 221-228 ◽  
Author(s):  
Stanislav Hračov
Keyword(s):  
Perturbation Technique ◽  
Approximate Determination ◽  
Viscous Damper ◽  
State Space Approach ◽  
Damped System ◽  
Eigen Values ◽  
The Difference ◽  
Damped Systems ◽  
Space Approach

In this paper, an approximate method for determining the complex eigen-values of non-classically damped linear system is presented. Only the systems consisting of a linear classically damped system to which one viscous damper is attached are assumed. The proposed method reflects the difference in the eigen-values of classically and non-classically damped systems using the first-order perturbation technique. The procedure is easy to code and avoids using a numerically demanding state-space approach. It operates in the original dimension of the physical problem and requires only the knowledge of eigen-modes and eigen-values of the classically damped and undamped systems. Numerical example is given to demonstrate application and accuracy of the method.

scholarly journals State space approach with FEM for the determination of structural behaviour of composite plates

2017 ◽  
Vol 8 (4) ◽  
pp. 468-483
Author(s):  
Asad Shukri Albostami ◽  
Zhangjian Wu ◽  
Zhenmin Zou
Keyword(s):  
Plate Thickness ◽  
Composite Plates ◽  
Thickness Direction ◽  
Middle Plane ◽  
Structural Behaviour ◽  
State Space Approach ◽  
Content Type ◽  
Simply Supported ◽  
Space Approach

Purpose An analytical investigation has been carried out for a simply supported rectangular plate with two different loading conditions by using 3D state space approach (SSA). Also, the accurate location of the neutral plane (N.P.) through the thickness of the plate can be identified: the N.P. is shifted away from the middle plane according to the loading condition. The paper aims to discuss these issues. Design/methodology/approach SSA and finite element method are used for the determination of structural behaviour of simply supported orthotropic composite plates under different types of loading. The numerical results from a finite element model developed in ABAQUS. Findings The effect of the plate thickness on displacements and stresses is described quantitatively. It is found that the N.P. of the plate, identified according to the values of the in-plane stresses through the thickness direction, is shifted away from the middle plane. Further investigation shows that the position of the N.P. is loading dependant. Originality/value This paper describe the effect of the plate thickness on displacements and stresses quantitatively by using an exact solution called SSA. Also, it is found that the N.P. of the plate, identified according to the values of the in-plane stresses through the thickness direction, is shifted away from the middle plane. Further investigation shows that the position of the N.P. is loading dependant.

Analytic solution of angle-ply laminated plates under extension, bending, and torsion

2019 ◽  
Vol 54 (8) ◽  
pp. 1093-1106
Author(s):  
Shen-Haw Ju ◽  
Wen-Yu Liang ◽  
Hsin-Hsiang Hsu ◽  
Jiann-Quo Tarn
Keyword(s):  
Numerical Solutions ◽  
Anisotropic Elasticity ◽  
Laminated Plates ◽  
Rectangular Section ◽  
State Space Approach ◽  
Present Solution ◽  
End Conditions ◽  
Combined Action ◽  
Space Approach

This paper develops a Hamiltonian state space approach for analytic determination of deformation and stress fields in multilayered monoclinic angle-ply laminates under the combined action of extension, bending, and torsion. The present solution satisfies the equations of anisotropic elasticity, the end conditions, the traction-free boundary conditions on the four edge surfaces of the rectangular section, and the interfacial continuity conditions in multilayered laminates. The proposed method only requires the solutions of matrix and eigen equations, regardless of the number or lamination of the layers. The finite element analyses are used to validate the accuracy of the analysis. The analytical solution and the numerical solutions are in excellent agreement.

A Dual Craig-Bampton State-Space Approach for Model Reduction of Damped Systems

PAMM ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 303-304 ◽  
Author(s):  
Fabian M. Gruber ◽  
Daniel J. Rixen
Keyword(s):  
Model Reduction ◽  
State Space ◽  
State Space Approach ◽  
Damped Systems ◽  
Space Approach

scholarly journals Historic photos and TLS data fusion for the 3D reconstruction of a monastery altar ensemble

2015 ◽  
Vol XL-5/W7 ◽  
pp. 201-206 ◽  
Author(s):  
K. Hanke ◽  
M. Moser ◽  
R. Rampold
Keyword(s):  
Laser Scanning ◽  
Approximate Determination ◽  
Geometric Information ◽  
Exterior Orientation ◽  
Reconstruction Process ◽  
Starting Point ◽  
The Difference ◽  
The Church

The basis of the photogrammetric reconstruction of the altar at the monastery / church are 2 historic photos from around 1920’s as well as a 3D documentation of the church from terrestrial laser scanning. The point cloud from the laser scan was the starting point for an approximate computation of the interior and exterior orientation of that image that also contains parts of the altar area that still do exist. <br> <br> Using a projection of the recent geometry into the image allowed the analysis of changes of the altar ensemble since the time of image acquisition. Those parts that are still in situ are the origin for further action. Whether fragments and parts should be used further or newly positioned was decided in the next phase of reconstruction process. The focus of the first step of the workflow was at the outlines of the parts in the center of the altar. Using a monoplotting approach and assuming that the profiles are vertical and parallel to each other these object could be definitely compiled. Theses outlines also allowed an approximate determination of the interior and exterior orientation of the second historic photograph in which otherwise the complete connection to the recent altar area was missing. <br> <br> The side parts of the altar showed to be more complicated for reconstruction. The difference in depth of the varying edges could not be distinguished any more in the images. Such, the sequence and form of the different edges was adopted, scaled and transferred from the central part of the altar to the peripheral ones. Using this geometric information it was possible to define the necessary projection planes for the monoplotting restitution of the visible outlines. A concluding rigorous control was accomplished by back projection of the geometry into both historical images.

Analysis of Asymmetric Nonviscously Damped Linear Dynamic Systems

2003 ◽  
Vol 70 (6) ◽  
pp. 885-893 ◽  
Author(s):  
S. Adhikari ◽  
N. Wagner
Keyword(s):  
State Space ◽  
Past History ◽  
Kernel Functions ◽  
Extended State ◽  
State Space Approach ◽  
Linear Dynamic Systems ◽  
Convolution Integrals ◽  
History Of ◽  
Damped Systems ◽  
Space Approach

Multiple-degree-of-freedom linear asymmetric nonviscously damped systems are considered. It is assumed that the nonviscous damping forces depend on the past history of velocities via convolution integrals over exponentially decaying kernel functions. An extended state-space approach involving a single asymmetric matrix is proposed. The nature of the eigensolutions in the extended state space has been explored. Some useful results relating the modal matrix in the extended state space and the modal matrix in the original space has been derived. Numerical examples are provided to illustrate the results.

Ab initio structure determination of cytochrome c6 by combined reciprocal space-real space approach

2003 ◽  
Vol 218 (1) ◽  
Author(s):  
K. Chowdhury ◽  
S. Ghosh ◽  
M. Mukherjee
Keyword(s):  
Cytochrome C ◽  
Ab Initio ◽  
Structure Determination ◽  
Direct Method ◽  
Real Space ◽  
Reciprocal Space ◽  
Cytochrome C6 ◽  
Ab Initio Structure ◽  
Space Approach

AbstractThe direct method program SAYTAN has been applied successfully to redetermine the structure of cytochrome c

FRACTIONAL DETERMINATIONS OF URINARY 17-KETOSTEROIDS IN HYPEREMESIS GRAVIDARUM

1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen
Keyword(s):  
Hyperemesis Gravidarum ◽  
First Trimester ◽  
Control Group ◽  
Before And After ◽  
Daily Urine ◽  
First Trimester Of Pregnancy ◽  
The Difference

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.

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