scholarly journals Vibration Analysis and Dynamic Characterization of Structural Glass Elements with Different Restraints Based on Operational Modal Analysis

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Chiara Bedon ◽  
Marco Fasan ◽  
Claudio Amadio
Keyword(s):  
Modal Analysis ◽  
Video Tracking ◽  
Operational Modal Analysis ◽  
Analytical Models ◽  
Design Stage ◽  
Damping Capacity ◽  
Structural Glass ◽  
Dynamic Characterization ◽  
Analysis And Design

Given a series of intrinsic features of structural glass systems (i.e., material properties, type of restraints, operational conditions, etc.), special care should be spent at the design stage, to ensure appropriate fail-safe requirements, but also in the service life of these innovative building components and assemblies. In this paper, the dynamic characterization of simple monolithic glass elements is presented, based on non-destructive laboratory experiments and Operational Modal Analysis (OMA) techniques, including Finite Element (FE) numerical simulations, classical analytical models, and video-tracking approaches. It is shown, in particular, how the actual restraint condition (i.e., flexibility of supports, with respect to ideal boundaries) can affect the vibration parameters of a given glass member (frequency and damping capacity). This turns out in possible variations of its overall structural performance, including stress-strain-related effects, hence suggesting the need for even further dedicated studies and methods for the reliable analysis and design of structural glass assemblies and complex systems under dynamic loads.

Operational Modal Analysis for Dynamic Characterization of a Ro-Lo Ship

2014 ◽  
Vol 58 (04) ◽  
pp. 216-224 ◽  
Author(s):  
Esben Orlowitz ◽  
Anders Brandt
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Operating Conditions ◽  
Operational Modal Analysis ◽  
Mode Shapes ◽  
Dynamic Characterization ◽  
Sea Trial ◽  
Global Modes ◽  
Bending Modes

The dynamic characteristics of ship structures are becoming more important as the flexibility of modern ships increases, for example, to predict reliable design life. This requires an accurate dynamic model of the structure, which, because of complex vibration environment and complex boundary conditions, can only be validated by measurements. In the present paper the use of operational modal analysis (OMA) for dynamic characterization of a ship structure based on experimental data, from a full-scale measurement of a 210-m long Ro-Lo ship during sea trial, is presented. The measurements contain three different data sets obtained under different operating conditions of the ship: 10 knots cruising speed, 18 knots cruising speed, and at anchor. Natural frequencies, modal damping ratios, and mode shapes have been successfully estimated for the first 10 global modes. Damping ratios for the current ship were found within the range 0.9%–1.9% and natural frequencies were found to range from 0.8 to 4.1 Hz for the first 10 global modes of the ship at design speed (18 knots). The three different operating conditions showed, in addition, a speed dependency of the natural frequencies and damping ratios. The natural frequencies were found to be lower for the 18-knots condition compared with the two other conditions, most significantly for the vertical bending modes. Also, for the vertical bending modes, the damping ratios increased by 28%–288% when the speed increased from 10 to 18 knots. Other modes were not found to have the same strong speed dependency.

Modal-Model Applications for Large Energetic Machines

2007 ◽  
Vol 347 ◽  
pp. 221-226 ◽  
Author(s):  
Piotr Kurowski
Keyword(s):  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Operational Modal Analysis ◽  
Machine Condition ◽  
Research Practice ◽  
Dynamic Characterization ◽  
Applied Method ◽  
Modal Model ◽  
Theoretical Assumptions

Modal models are commonly encountered forms of dynamic characterization of mechanical structures. They are applied in machine-condition diagnosing as well as in monitoring processes. In research practice the most frequently applied method is Experimental Modal Analysis, and in exploitation - Operational Modal Analysis. Difficulties associated with the EMA and OMA have contributed to the increase of OMAX model applications, especially in case of energetic machines. Theoretical assumptions related with modal analysis are very strong. In reality when big and heavy structures are considered often those assumptions are not fulfilled. In the paper such situations are considered and practical solutions are showed.

scholarly journals Operational modal analysis for characterization of mechanical and thermal–hydraulic fluctuations in simulated neutron noise

2021 ◽  
Vol 373 ◽  
pp. 111017
Author(s):  
Luis Alejandro Torres Delgado ◽  
Vasudha Verma ◽  
Cristina Montalvo ◽  
Abdelhamid Dokhane ◽  
Agustín García-Berrocal
Keyword(s):  
Modal Analysis ◽  
Operational Modal Analysis ◽  
Neutron Noise

Simulation and Characterization of Particle Damping in Transient Vibrations

2004 ◽  
Vol 126 (2) ◽  
pp. 202-211 ◽  
Author(s):  
Kuanmin Mao ◽  
Michael Yu Wang ◽  
Zhiwei Xu ◽  
Tianning Chen
Keyword(s):  
Damping Capacity ◽  
Friction Damper ◽  
Dense Particle ◽  
Relative Significance ◽  
Analysis And Design ◽  
Damping Characteristics ◽  
Highly Nonlinear ◽  
Particle Damping ◽  
The Impact

Particle damping is a technique of providing damping with granular particles embedded within small holes in a vibrating structure. The particles absorb kinetic energy through particle-to-wall and particle-to-particle frictional collisions. While the concept of particle damping seems to be simple and it has been used successfully in many fields for vibration reduction, it is difficult to predict the damping characteristics due to complex collisions in the dense particle flow. In this paper, we utilize the 3D discrete element method (DEM) for computer simulation and characterization of particle damping. With the DEM modeling tool validated with experimental results, it is shown that the particle damping can achieve a very high value of specific damping capacity. Furthermore, simulations provide information of particle motions within the container hole during three different regions and help explain their associated damping characteristics. The particle damping is a combination of the impact and the friction damping. The damping is found to be highly nonlinear as the rate of energy dissipation depends on amplitude. Particularly, the damping effect results in a linear decay in amplitude over a finite period of time. These characteristics are examined with respect to a simple single-mass impact damper and a dry-friction damper. It is concluded that the particle damping is a mix of these two damping mechanisms. It is further shown that the relative significance of these damping mechanisms depends on a particular arrangement of the damper. This study represents an effort towards a deeper understanding of particle damping to provide a comprehensive methodology for its analysis and design.

scholarly journals Operational modal analysis for the characterization of ancient water towers in Pompeii

2017 ◽  
Vol 199 ◽  
pp. 3374-3379 ◽  
Author(s):  
F. Lorenzoni ◽  
M.R. Valluzzi ◽  
M. Salvalaggio ◽  
A. Minello ◽  
C. Modena
Keyword(s):  
Modal Analysis ◽  
Operational Modal Analysis
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