Khaled F. Aljanaideh, Dennis S. Bernstein,
... 1356 0888-3270 CrossrefGoogle Scholar[11] Maia N., Urgueira A. and Almeida R., "Whys and Wherefores of ... Croatia, 2011, pp. 197–216. Google Scholar[12] Urgueira A., Almeida R. and Maia N., "On the ...
Tópico(s): Structural Health Monitoring Techniques
2015 - American Institute of Aeronautics and Astronautics | Journal of Guidance Control and Dynamics
Júlio M. Montalvão e Silva, António P.V. Urgueira,
An analytical model for the vibration response of a curved beam is developed and presented. The model is based on the solution (closed solution) of the dynamic differential equations of equilibrium for an infinitesimal element vibrating out of its initial plane of curvature and allows for inclusion of the effects of rotary inertia and or shear deformation. Final solutions are presented under the form of elements of the tip dynamic stiffness matrix for a free-free beam. The validity of the model is ...
Tópico(s): Structural Analysis and Optimization
1988 - Elsevier BV | International Journal of Solids and Structures
Raquel Almeida, António P.V. Urgueira, N. M. M. Maia,
The evaluation of the rigid body properties of a structure is a very important issue for the study of its dynamic behaviour when the influence of the rigid body modes is considerably significant. Various approaches exist for this purpose. In the present work the authors explore a particular group of methods where ten rigid body properties are estimated from modal information extracted from Frequency Response Data (FRF) measured on structures. This kind of methods, usually known as modal methods, ...
Tópico(s): Acoustic Wave Phenomena Research
2009 - Elsevier BV | Mechanical Systems and Signal Processing
António P.V. Urgueira, Raquel Almeida, N. M. M. Maia,
The dynamic characteristics of a structure are often derived from a set of measured frequency response functions (FRFs). However, it may happen that the measurement of certain FRFs is impossible, as they are related to some points of interest that may become physically inaccessible in operational conditions. In this circumstance, it is useful to have some tools that can provide the prediction of such dynamic information. The transmissibility concept can play an important role to circumvent these ...
Tópico(s): Seismic Performance and Analysis
2010 - Elsevier BV | Mechanical Systems and Signal Processing
N. M. M. Maia, Raquel Almeida, António P.V. Urgueira, R.P.C. Sampaio,
Structures experience various types of loads along their lifetime, which can be either static or dynamic and may be associated to phenomena of corrosion and chemical attack, among others. As a consequence, different types of structural damage can be produced; the deteriorated structure may have its capacity affected, leading to excessive vibration problems or even possible failure. It is very important to develop methods that are able to simultaneously detect the existence of damage and to quantify ...
Tópico(s): Concrete Corrosion and Durability
2011 - Elsevier BV | Mechanical Systems and Signal Processing
Raquel Almeida, António P.V. Urgueira, N. M. M. Maia,
A knowledge of the rigid body properties of a structure can be important in vibration analysis, control, optimisation and structural dynamic problems in general. Whenever a system has a complicated shape and the location of its centre of mass and inertia tensor cannot be easily determined by purely theoretical tools, it may be convenient to use measured experimental dynamic data and to apply appropriate methods to evaluate those properties. In the present work a parametric modal identification method ...
Tópico(s): Hydraulic and Pneumatic Systems
2006 - Elsevier BV | Journal of Sound and Vibration
Raquel Almeida, Daniel Cardoso Vaz, António P.V. Urgueira, A.R. Janeiro Borges,
The paper deals with the use of strain-gage based ring-sensors to measure the dynamic forces involved in wind-tunnel testing for research of aeroelastic instabilities. In these experiments, the model has to be supported by an elastic suspension system that allows it to move in response to the flow. The motivation for the work here reported was the assessment of the possibility of occurrence of aeroelastic instabilities in a sectional model of a bridge deck under the action of lateral wind. The model ...
Tópico(s): Tribology and Lubrication Engineering
2012 - Elsevier BV | Sensors and Actuators A Physical
R.P.C. Sampaio, N. M. M. Maia, Raquel Almeida, António P.V. Urgueira,
Catastrophic structural failure of aircrafts, bridges, buildings and other structures in modern societies has always been of primary concern because of the loss of human lifes and of negative economic impact. The aging of the structures, the growing dependency on their role in our networks of transportation, energy and comunications, the smaller construction tolerances, the bigger power demanded and the media and society awardness to catastrophic events are sufficient motivations for the growing ...
Tópico(s): Infrastructure Maintenance and Monitoring
2015 - Elsevier BV | Mechanical Systems and Signal Processing
Daniel Cardoso Vaz, Raquel Almeida, Éric Didier, António P.V. Urgueira, A.R. Janeiro Borges,
The susceptibility of bridge decks to vortex induced oscillations can be addressed through wind-tunnel testing. This paper considers the case of the Vila-Real Bridge, in the north of Portugal, which has the highest deck above ground (230 m), among concrete-deck bridges cable-stayed in the central plane. It has a single-cell rectangular box girder with a wide top flange supported by regularly spaced inclined struts. Aeroelastic studies of this precise type of deck seem nonexistent in the literature. ...
Tópico(s): Wind and Air Flow Studies
2016 - Elsevier BV | Journal of Wind Engineering and Industrial Aerodynamics
Raquel Almeida, António P.V. Urgueira, N. M. M. Maia,
The identification of the rigid body properties of a structure is an important matter in various structural dynamic applications, namely in structural modification (coupling/uncoupling), optimization and vibration control. In most situations, the experimental route is the only via to obtain the desired dynamic properties. This goal is achieved by an inverse process which starts from the measurement of Frequency Response Functions (FRFs) and ends on matrices describing the mass distribution of a rigid ...
Tópico(s): Effects of Vibration on Health
2008 - Hindawi Publishing Corporation | Shock and Vibration
N. M. M. Maia, António P.V. Urgueira, Raquel Almeida,
The notion of transmissibility, in what mechanical vibrations are concerned, may lead to various potential applications. Depending on the related quantities, responses or forces, it is possible to use different formulations and to deduce important properties. All these aspects are overviewed in the present article, where transmissibility can be oriented to the evaluation of unmeasured frequency response functions, to the estimation of reaction forces and, with special focus here, to the detection ...
Tópico(s): Structural Response to Dynamic Loads
2012 - Springer Nature | Conference proceedings of the Society for Experimental Mechanics
Raquel Almeida, António P.V. Urgueira, N. M. M. Maia,
When deriving an experimental model from Frequency Response Functions (FRFs), it may happen that the measurement of certain FRFs is impossible. This may be an important issue, mainly in the field of condition monitoring and damage detection, since some points of interest may become inaccessible in operational conditions. In this circumstance, it is useful to have some tools that can provide the prediction of such dynamic information. The transmissibility concept, extended to a general multiple degree- ...
Tópico(s): Acoustic Wave Phenomena Research
2010 - Hindawi Publishing Corporation | Shock and Vibration
António P.V. Urgueira, Nuno Venâncio, Pedro Riscado, Raquel Almeida, Tiago A. N. Silva,
The development of new sensors that are available at more accessible prices may lead to the spread of their use on common studies in structural dynamics. One of areas of interest is the experimental determination of rigid body properties that are mandatory when the vibration response is to be calculated at low frequency ranges. In this work, a comparison of the experimental determination of rigid body properties is carried out to evaluate the performance of the commonly used tri-axial piezoelectric ...
Tópico(s): Effects of Vibration on Health
2018 - EDP Sciences | MATEC Web of Conferences
Tiago A. N. Silva, Raquel Almeida, António P.V. Urgueira,
Testing is a very important task in structural dynamics and on its applications, namely on the characterization of the dynamic behaviour of structures or on the use of the structural responses to indirectly determine dynamic properties or parameters. The increasing availability of sensors, capable of measuring rotational responses, leads to the improvement of existing methods and to the development of new ones in several fields of application. In this work, an evaluation of the applicability and ...
Tópico(s): Bladed Disk Vibration Dynamics
2018 - IOP Publishing | Journal of Physics Conference Series
J.M.Montalvão e Silva, A.P.V. Urgueira,
Tópico(s): Biomedical Text Mining and Ontologies
1989 - Elsevier BV | International Journal of Solids and Structures