Comparison of frequency- and time-domain analyses for guyed masts in turbulent winds

2006 ◽  
Vol 33 (2) ◽  
pp. 169-182 ◽  
Author(s):  
B F Sparling ◽  
L D Wegner
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Analysis ◽  
Frequency Domain ◽  
Time Domain ◽  
Element Model ◽  
Mode Shapes ◽  
Nonlinear Behaviour ◽  
Element Analysis ◽  
Guyed Mast

Both frequency- and time-domain methods have been employed in the dynamic analysis of guyed telecommunication masts subjected to turbulent winds. Although the probabilistic frequency-domain approach offers some advantages in terms of its relative ease of implementation and in the statistical reliability of wind load descriptions, the deterministic time-domain method permits a more realistic treatment of system nonlinearities. In this study, a numerical investigation was undertaken to compare frequency- and time-domain dynamic response predictions for a selected guyed mast in gusty winds. Two different analysis techniques were employed, with the frequency-domain calculations performed using response influence lines and the time-domain analyses carried out using a stiffness-based finite element model. Good agreement was observed in root-mean-square and peak dynamic response estimates after compensation was included for differences in turbulence intensity levels assumed in the two models. In general, natural frequencies and mode shapes were also similar.Key words: guyed mast, dynamic analysis, wind, turbulence, nonlinear behaviour, finite element analysis, cables, frequency domain, time domain.

Numerical Study for Global Detection of Cracks Embedded in Beams

1999 ◽  
Author(s):  
S. A. Lipsey ◽  
Y. W. Kwon
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Natural Frequency ◽  
Mode Shape ◽  
Numerical Study ◽  
Element Model ◽  
Mode Shapes ◽  
Linear Effect ◽  
Modes Of Vibration ◽  
Damage Simulation

Abstract Damage reduces the flexural stiffness of a structure, thereby altering its dynamic response, specifically the natural frequency, damping values, and the mode shapes associated with each natural frequency. Considerable effort has been put into obtaining a correlation between the changes in these parameters and the location and amount of the damage in beam structures. Most numerical research employed elements with reduced beam dimensions or material properties such as modulus of elasticity to simulate damage in the beam. This approach to damage simulation neglects the non-linear effect that a crack has on the different modes of vibration and their corresponding natural frequencies. In this paper, finite element modeling techniques are utilized to directly represent an embedded crack. The results of the dynamic analysis are then compared to the results of the dynamic analysis of the reduced modulus finite element model. Different modal parameters including both mode shape displacement and mode shape curvature are investigated to determine the most sensitive indicator of damage and its location.

Dynamic Characteristics and Finite Element Model Updating of Micromachined Torsion Structures

2013 ◽  
Vol 284-287 ◽  
pp. 1831-1835
Author(s):  
Wei Hsin Gau ◽  
Kun Nan Chen ◽  
Yunn Lin Hwang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Speckle Pattern ◽  
Element Model ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Finite Element Model Updating ◽  
Element Analysis

In this paper, two experimental techniques, Electronic Speckle Pattern Interferometry and Stroboscopic Interferometry, and two different finite element analysis packages are used to measure or to analyze the frequencies and mode shapes of a micromachined, cross-shaped torsion structure. Four sets of modal data are compared and shown having a significant discrepancy in their frequency values, although their mode shapes are quite consistent. Inconsistency in the frequency results due to erroneous inputs of geometrical and material parameters to the finite element analysis can be salvaged by applying the finite element model updating procedure. Two updating cases show that the optimization sequences converge quickly and significant improvements in frequency prediction are achieved. With the inclusion of the thickness parameter, the second case yields a maximum of under 0.4% in frequency difference, and all parameters attain more reliable updated values.

Time Domain Computational Analysis for Shock Characteristics of Elastic Support Gearbox

2011 ◽  
Vol 86 ◽  
pp. 323-326
Author(s):  
Guang Hao Dai ◽  
Chang Wei Gao ◽  
Yong Heng Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Time Domain ◽  
Computational Study ◽  
Element Model ◽  
Elastic Support ◽  
Shock Load ◽  
Load Spectrum ◽  
Element Analysis ◽  
Load Effect

Shock load spectrum of elastic support gearbox is confirmed by Federation Wehrmacht vessel construction rules BV0430/85 standard, and convert into equivalent double-triangular wave acceleration shock load. We take one elastic support gearbox which used in a vessel as computational study subject. With the help of ABAQUS software, we establish finite element model of elastic support gearbox and put double-triangular shock load into finite element model. Taking finite element analysis method do time domain response characteristics numerical simulation research of elastic support gearbox with limited bit and unlimited bit design, respectively, under shock load effect.

Instantaneous Dynamic Analysis of the New Stirring Kneader Shaft

2011 ◽  
Vol 221 ◽  
pp. 472-477
Author(s):  
Zhi Min Fan ◽  
Guang Ting Zhou ◽  
Jian Ping Liu
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Dynamic Response ◽  
Finite Element Model ◽  
Dynamic Analysis ◽  
Structural Parameters ◽  
Element Model ◽  
Fatigue Analysis ◽  
Exciting Force ◽  
The Finite Element Model

The finite element model of the stirring kneader shaft was built by PRO/E software, which was inserted into ANSYS. Next, the instantaneous dynamic analysis of the new stirring kneader shaft was carried out. The instantaneous dynamic response of stirring shaft about the exciting force of fluid was obtained, which was to optimize the structural parameters of the stirring shaft. The foundation for the next fatigue analysis was laid based on the instantaneous dynamic response; the fatigue life of stirring kneader shaft can be predicted.

Identification of Bolt Connection Parameters for Vertical Grinding Machine in CAD/CAE Environment

2011 ◽  
Vol 697-698 ◽  
pp. 97-101
Author(s):  
Chao Hao Wang ◽  
Yong Liang Chen ◽  
Jin Ping Pang ◽  
Da Wei Zhang ◽  
G.X. Pan
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Element Model ◽  
Joint Surface ◽  
Element Analysis ◽  
Modal Test ◽  
Integrated Environment ◽  
Grinding Machine ◽  
Bolt Connection ◽  
The Mathematical Model

Dynamic analysis and modal test were conducted on a vertical grinding machine. The mathematical model of joint surface parameter identification between the bed and the column was established in CAD/CAE integrated environment. Based on the results of dynamic analysis and modal test, the parameters of joint surface were identified and the finite element model was accurately created. Then, the weak bodies of the original machine were improved. According to the finite element analysis of the improved machine, the performances of the new machine were better than the original machine.

Modal Analysis of the Cabinet of a Drum Washing Machine

2011 ◽  
Vol 199-200 ◽  
pp. 1126-1129
Author(s):  
Su Fang Fu ◽  
Han Gao ◽  
Jia Xi Du ◽  
Qiu Ju Zhang ◽  
Xue Ming Zhang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Ansys Software ◽  
Washing Machine ◽  
Element Analysis ◽  
The Finite Element Model ◽  
Good Agreement

In this paper, the finite element model for the cabinet of a drum washing machine and the model for testing vibration of the cabinet were developed in ANSYS software and PULSE™, respectively. A series of tests were conducted. The natural frequencies and mode shapes were obtained by finite element analysis and modal experiment, which revealed weak parts of the cabinet. Meanwhile, the computational modes were in good agreement with experimental ones and this could provide an available method by which it was convenient to improve the design of the cabinet.

Nonlinear FEA Simulation of Thorax Dynamic Response Under Blast Load

2012 ◽  
Author(s):  
Yahia M. Al-Smadi ◽  
Nedal Sumrein ◽  
Omar Awad ◽  
Oruba Rabie
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Element Model ◽  
Severe Injuries ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Blast Overpressure ◽  
Explicit Finite Element Analysis ◽  
New Material ◽  
Fea Simulation

Blast overpressure can cause severe injuries of several organs ranging from local injury to collapse or rapture of vital organs rapidly and death. This paper will investigate the thorax dynamic response for blast loading. The presented numerical blast tests will accompany the introduction of new material modeling details. Reliable and robust analysis explicit finite element analysis software (ANSYS and LS-DYNA) will be used to complete 3D finite element model and conduct numerical testing.

Transient Dynamic Analysis of Maglev Linear Feed Unit

2011 ◽  
Vol 317-319 ◽  
pp. 405-409
Author(s):  
An Dong Jiang ◽  
Jiang Jin ◽  
Su Yang Ma ◽  
Zheng Peng Xia ◽  
Ping Liao
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Magnetic Levitation ◽  
Element Model ◽  
Design Stage ◽  
Transient Dynamic Analysis ◽  
Element Analysis ◽  
Forecast Performance ◽  
Transient Dynamic ◽  
Feed Unit

Abstract. The magnetic levitation linear feed unit is a new type of machine features. In machining, the tool and workpiece interaction force will be delivered to the table and make the deformation, resulting in processing errors of machine tools, machining of precision and surface quality. In this paper we established three-dimensional finite element model of the table of feed unit, use the finite element analysis software ANSYS to analysis of the transient dynamic analysis of the pre-designed table and improve the structure of the table at the design stage and forecast performance of the table and provide a theoretical basis for structure optimization.

scholarly journals Post-buckling Analysis of Cold-form Steel Column

2020 ◽  
Vol 26 (4) ◽  
pp. 173-187
Author(s):  
Tuka Mohammed Qasim ◽  
Salah Rohaima Al-Zaidee
Keyword(s):  
Finite Element ◽  
Shell Element ◽  
Element Model ◽  
Mode Shapes ◽  
Local Mode ◽  
Local Market ◽  
Postbuckling Behavior ◽  
Element Analysis ◽  
Practical Applications ◽  
Post Buckling

For the time being, the cold-formed sections are widely used due to their simple manufacturing and construction processes. To be feasible, the strength of cold-formed columns should be determined based on their post-buckling behavior. Post-buckling relations are cumbersome and need design aids similar to those of American Iron and Steel Institute (AISI) to be applicable. These design aids have been developed to sections and materials other than those available in the local market. Therefore, this paper tries to develop a general finite element model to simulate the postbuckling behavior of cold-formed steel columns. Shell element has been used to discretize the web, flanges, and lips of the column. A linear bucking analysis with subspace Eigen value scheme has been achieved to determine the global, distortional, and local mode shapes. Subsequently, these modes have been used to generate the correspond imperfections. Finally, the modified Riks method has been used to solve the nonlinear equations of equilibrium and to a void the possible snap through phenomenon. Comparing with the traditional analyses using the effective width method and the direct strength method indicates that the finite element analysis is adequate and can be used for practical applications when dealing with local sections and materials. Finally, different case studies with different column spans have been considered to show the behavior of the column for different slenderness ratios.

DYNAMIC ANALYSIS OF POROUS MEDIA IN TIME DOMAIN USING A FINITE ELEMENT MODEL

2010 ◽  
Vol 13 (10) ◽  
pp. 895-910
Author(s):  
M. Pasbani Khiavi ◽  
A. R. M. Gharabaghi ◽  
K. Abedi
Keyword(s):  
Finite Element ◽  
Porous Media ◽  
Finite Element Model ◽  
Dynamic Analysis ◽  
Time Domain ◽  
Element Model
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