Structural monitoring of a wind turbine steel tower - Part I: system description and calibration

Rebelo, C.,Veljkovic, M.,da Silva, L. Simoes,Simoes, R.,Henriques, J. Techno-Press 2012 Wind and Structures, An International Journal (WAS Vol.15 No.4

This paper describes the development and calibration of a structural monitoring system installed in a 80 meters high steel wind tower supporting a 2.1 MW turbine Wind Class III IEC2a erected in the central part of Portugal. The several signals are measured at four different levels and include accelerations, strains on the tower wall and inside the connection bolts, inclinations and temperature. In order to correlate measurements with the wind velocity and direction and with the turbine operational parameters the corresponding signals are obtained directly from the turbine own monitoring system and are incorporated in the developed system. Results from the system calibration, the structural identification and the initial period of data acquisition are presented in this paper.

Structural monitoring of a wind turbine steel tower - Part II: monitoring results

Rebelo, C.,Veljkovic, M.,Matos, R.,Silva, L. Simoes Da Techno-Press 2012 Wind and Structures, An International Journal (WAS Vol.15 No.4

This paper presents results from the structural monitoring of a steel wind tower characterized and presented in Part I of the paper. Monitoring period corresponds to about fifteen months of measurements. Results presented refer to stress distribution on shell and in bolts at different heights, stress fatigue spectra, section forces along height evaluated from the stress measurements and comparison with design forces, dynamic response in terms of accelerations, stresses, deflections and rotations.

Structural monitoring of a wind turbine steel tower – Part I: system description and calibration

C. Rebelo,M. Veljkovic,L. Simões da Silva,R. Simões,J. Henriques 한국풍공학회 2012 Wind and Structures, An International Journal (WAS Vol.15 No.4

This paper describes the development and calibration of a structural monitoring system installed in a 80 meters high steel wind tower supporting a 2.1 MW turbine Wind Class III IEC2a erected in the central part of Portugal. The several signals are measured at four different levels and include accelerations, strains on the tower wall and inside the connection bolts, inclinations and temperature. In order to correlate measurements with the wind velocity and direction and with the turbine operational parameters the corresponding signals are obtained directly from the turbine own monitoring system and are incorporated in the developed system. Results from the system calibration, the structural identification and the initial period of data acquisition are presented in this paper.

Structural monitoring of a wind turbine steel tower – Part II: monitoring results

C. Rebelo,M. Veljkovic,R. Matos,L. Simões da Silva 한국풍공학회 2012 Wind and Structures, An International Journal (WAS Vol.15 No.4

This paper presents results from the structural monitoring of a steel wind tower characterized and presented in Part I of the paper. Monitoring period corresponds to about fifteen months of measurements. Results presented refer to stress distribution on shell and in bolts at different heights, stress fatigue spectra, section forces along height evaluated from the stress measurements and comparison with design forces, dynamic response in terms of accelerations, stresses, deflections and rotations.

Recent Approaches on Signal Transduction and Transmission in Acupuncture: A Biophysical Overview for Medical Sciences

Lı´gia Rebelo Gomes,Pedro Leão 사단법인약침학회 2020 Journal of Acupuncture & Meridian Studies Vol.13 No.1

Acupuncture is one of the areas among the alternative therapies that arise high curiosity in the biomedical scientific community. It is particularly popular for treatment of chronic diseases and addictions. However, contrasting with its evidence-based effectiveness, the lack of reasonable explanations for its mode of action divides that scientific community. Difficulties also arise to those responsible for providing information for clinicians and professionals who wish to acquire competencies leading to the acupuncture practice and have a background based on biochemistry and physiology. The classic theories of nerve conduction do not fully explain how information is read and transmitted during the acupuncture treatment. Other theories have been proposed, but they are based on concepts such as biophotonic waves and quantum biochemistry that are difficult to read and understand by those who do not have knowledge in physics. It is the main objective of this review to provide a summary of the main theories and explanatory approaches to the signal transduction and conduction in acupuncture and to describe them in terms of their explanatory hypotheses, limitations, and weaknesses. The most of the literature found support theories for neural conduction, including gate control. They explain the effects of acupuncture in pain relief; few studies have been conducted concerning the conduction based on biophotons. The primo vascular system has been referred as a possible anatomic support for conduction of information during an acupuncture treatment, which could be connected to biophoton transmission.

Master-slave mapping and slave base placement optimization for intuitive and kinematically robust direct teleoperation

Jo?o Rebelo,Andre Schiele 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

This paper presents a technique to map two dissimilar master-slave devices with similar, human-like workspaces for telemanipulation. The mapping focuses on achieving full geometric pose correspondence between the operator and the slave device while avoiding reaching into areas close to singularities and joint limits. The approach followed can be divided in 4 steps, namely: master workspace offset and scaling adjustment to ensure that the operator always controls the manipulator within reachable areas; optimized mounting of the slave end-effector to eliminate manipulator wrist singularities; redundancy mapping using the arm angle criteria for geometric pose correspondence; slave manipulator base placement optimization to place the task-space area in the zone of highest manipulability. A setup using the EXARM exoskeleton and a virtual model of the Kuka 7-DOF Lightweight Robot is used to show that the proposed method generates geometric correspondence and places the operation within areas far from joint limits and singularities for the human arm workspace, thus ensuring robust tracking of human operators in real-time for arbitrary trajectories inside the task-space.

Mutations in <i>ATP1A1</i> Cause Dominant Charcot-Marie-Tooth Type 2

Lassuthova, Petra,Rebelo, Adriana P.,Ravenscroft, Gianina,Lamont, Phillipa J.,Davis, Mark R.,Manganelli, Fiore,Feely, Shawna M.,Bacon, Chelsea,Brož,ková,, Dana Š,afka,Haberlova, Jana,M University of Chicago Press [etc.] 2018 American journal of human genetics Vol.102 No.3

<P>Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way—by combining data from seven countries on four continents—we were able to define mutations in <I>ATP1A1</I>, which encodes the alpha1 subunit of the Na<SUP>+</SUP>,K<SUP>+</SUP>-ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c.143T>G (p.Leu48Arg), c.1775T>C (p.Ile592Thr), c.1789G>A (p.Ala597Thr), c.1801_1802delinsTT (p.Asp601Phe), c.1798C>G (p.Pro600Ala), c.1798C>A (p.Pro600Thr), and c.2432A>C (p.Asp811Ala). Immunostaining peripheral nerve axons localized ATP1A1 to the axolemma of myelinated sensory and motor axons and to Schmidt-Lanterman incisures of myelin sheaths. Two-electrode voltage clamp measurements on <I>Xenopus</I> oocytes demonstrated significant reduction in Na<SUP>+</SUP> current activity in some, but not all, ouabain-insensitive ATP1A1 mutants, suggesting a loss-of-function defect of the Na<SUP>+</SUP>,K<SUP>+</SUP> pump. Five mutants fall into a remarkably narrow motif within the helical linker region that couples the nucleotide-binding and phosphorylation domains. These findings identify a CMT pathway and a potential target for therapy development in degenerative diseases of peripheral nerve axons.</P>

Rayleigh-Ritz procedure for determination of the critical load of tapered columns

Liliana Marques,Luís Simões da Silva,Carlos Rebelo 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.1

EC3 provides several methodologies for the stability verification of members and frames. However, when dealing with the verification of non-uniform members in general, with tapered cross-section, irregular distribution of restraints, non-linear axis, castellated, etc., several difficulties are noted. Because there are yet no guidelines to overcome any of these issues, safety verification is conservative. In recent research from the authors of this paper, an Ayrton-Perry based procedure was proposed for the flexural buckling verification of web-tapered columns. However, in order to apply this procedure, Linear Buckling Analysis (LBA) of the tapered column must be performed for determination of the critical load. Because tapered members should lead to efficient structural solutions, it is therefore of major importance to provide simple and accurate formula for determination of the critical axial force of tapered columns. In this paper, firstly, the fourth order differential equation for non-uniform columns is derived. For the particular case of simply supported web-tapered columns subject to in-plane buckling, the Rayleigh-Ritz method is applied. Finally, and followed by a numerical parametric study, a formula for determination of the critical axial force of simply supported linearly web-tapered columns buckling in plane is proposed leading to differences up to 8% relatively to the LBA model.

Seismic behaviour of gravity load designed flush end-plate joints

David Cassiano,Mario D’Aniello,Carlos Rebelo 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.5

Flush end-plate (FEP) beam-to-column joints are commonly used for gravity load resisting parts in steel multistorey buildings. However, in seismic resisting structures FEP joints should also provide rotation capacity consistent with the global structural displacements. The current version of EN1993-1-8 recommends a criterion aiming at controlling the thickness of the end-plate in order to avoid brittle failure of the connection, which has been developed for monotonic loading conditions assuming elastic-perfectly plastic behaviour of the connection's components in line with the theory of the component method. Hence, contrary to the design philosophy of the hierarchy of resistances implemented in EN1998-1, the over strength and the hardening of the plastic components are not directly accounted for. In light of these considerations, this paper describes and discusses the results obtained from parametric finite element simulations aiming at investigating the moment-rotation response of FEP joints under cyclic actions. The influence of bolt diameter, thickness of end-plate, number of bolt rows and shape of beam profile on the joint response is discussed and design requirements are proposed to enhance the ductility of the joints.

Influence of seismic design rules on the robustness of steel moment resisting frames

David Cassiano,Mario D’Aniello,Carlos Rebelo,Raffaele Landolfo,Luís S. da Silva 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.3

Seismic design criteria allow enhancing the structural ductility and controlling the damage distribution. Therefore, detailing rules and design requirements given by current seismic codes might be also beneficial to improve the structural robustness. In this paper a comprehensive parametric study devoted to quantifying the effectiveness of seismic detailing for steel Moment Resisting Frames (MRF) in limiting the progressive collapse under column loss scenarios is presented and discussed. The overall structural performance was analysed through nonlinear static and dynamic analyses. With this regard the following cases were examined: (i) MRF structures designed for wind actions according to Eurocode 1; (ii) MRF structures designed for seismic actions according to Eurocode 8. The investigated parameters were (i) the number of storeys; (ii) the interstorey height; (iii) the span length; (iv) the building plan layout; and (v) the column loss scenario. Results show that structures designed according to capacity design principles are less robust than wind designed ones, provided that the connections have the same capacity threshold in both cases. In addition, the numerical outcomes show that both the number of elements above the removed column and stiffness of beams are the key parameters in arresting progressive collapse.