Outil 44. Le local technique de site

2015 ◽  
pp. 136-137
Author(s):  
Jean-Michel Lathiere ◽  
Jérôme Moreau
Keyword(s):  
Local Technique

Building Stiffness Estimation by Wave Traveling Times

2014 ◽  
Author(s):  
Jesús Morales-Valdez ◽  
Luis Alvarez-Icaza
Keyword(s):  
Wave Propagation ◽  
Modal Analysis ◽  
Single Layer ◽  
Original Formulation ◽  
Arrival Times ◽  
Identification Methods ◽  
Novel Technique ◽  
Wave Propagation Method ◽  
Local Technique ◽  
Interesting Alternative

A novel technique to estimate stiffness in buildings is presented. In contrast with most of the available work in the literature that resorts to diverse forms of modal analysis, this local technique is based on the propagation of a Ricker pulse through the structure and on measuring the wave arrival times at each story of the building, represented as a single layer in a multiple stratum model. These arrival times are later used to recuperate building stiffness at each story. Wave propagation is based on the Thomson-Haskell method, that allows to generalize the wave propagation method to multi-story buildings without significant changes to the original formulation. The number of calculated parameters is small in comparison with methods based on modal analysis. This technique provides and quick and easy methodology to assess building integrity and is an interesting alternative to verify results obtained by other identification methods. Simulation results for building with heterogeneous characteristics across the stories confirm the feasibility of the proposal.

An accurate double-superposition global–local theory for vibration and bending analyses of cylindrical composite and sandwich shells subjected to thermo-mechanical loads

2011 ◽  
Vol 225 (8) ◽  
pp. 1816-1832 ◽  
Author(s):  
M Shariyat
Keyword(s):  
Vibration Analysis ◽  
Cylindrical Shells ◽  
High Order ◽  
Computational Time ◽  
Local Theory ◽  
Transverse Stress ◽  
Mechanical Loads ◽  
Local Technique ◽  
Sandwich Shells ◽  
First Time

Based on the idea of double superposition, an accurate high-order global–local theoryis proposed for bending and vibration analysis of cylindrical shells subjected to thermo-mechanical loads, for the first time. The theory has many novelties, among them: (1) less computational time due to the use of the global–local technique and matrix formulations; (2) satisfaction of the complete kinematic and transverse stress continuity conditions at the layer interfaces under thermo-mechanical loads; (3) consideration of the transverse flexibility; (4) release of Love–Timoshenko assumption; and (5) capability of investigating the local phenomena. Various comparative examples are included to validate the theory and to examine its accuracy and efficiency.

scholarly journals Established Numerical Techniques for the Structural Analysis of a Regional Aircraft Landing Gear

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
F. Caputo ◽  
A. De Luca ◽  
A. Greco ◽  
A. Marro ◽  
A. Apicella ◽  
...  
Keyword(s):  
Finite Elements ◽  
Numerical Models ◽  
Three Dimensional ◽  
Landing Gear ◽  
Point Of View ◽  
Fe Model ◽  
One Dimensional ◽  
Reaction Forces ◽  
Local Technique ◽  
Stick Model

Usually during the design of landing gear, simplified Finite Element (FE) models, based on one-dimensional finite elements (stick model), are used to investigate the in-service reaction forces involving each subcomponent. After that, the design of such subcomponent is carried out through detailed Global/Local FE analyses where, once at time, each component, modelled with three-dimensional finite elements, is assembled into a one-dimensional finite elements based FE model, representing the whole landing gear under the investigated loading conditions. Moreover, the landing gears are usually investigated also under a kinematic point of view, through the multibody (MB) methods, which allow achieving the reaction forces involving each subcomponent in a very short time. However, simplified stick (FE) and MB models introduce several approximations, providing results far from the real behaviour of the landing gear. Therefore, the first goal of this paper consists of assessing the effectiveness of such approaches against a 3D full-FE model. Three numerical models of the main landing gear of a regional airliner have been developed, according to MB, “stick,” and 3D full-FE methods, respectively. The former has been developed by means of ADAMS® software, the other two by means of NASTRAN® software. Once this assessment phase has been carried out, also the Global/Local technique has verified with regard to the results achieved by the 3D full-FE model. Finally, the dynamic behaviour of the landing gear has been investigated both numerically and experimentally. In particular, Magnaghi Aeronautica S.p.A. Company performed the experimental test, consisting of a drop test according to EASA CS 25 regulations. Concerning the 3D full-FE investigation, the analysis has been simulated by means of Ls-Dyna® software. A good level of accuracy has been achieved by all the developed numerical methods.

A local technique based on vectorized surfaces for craniofacial reconstruction

2010 ◽  
Vol 200 (1-3) ◽  
pp. 50-59 ◽  
Author(s):  
Françoise M. Tilotta ◽  
Joan A. Glaunès ◽  
Frédéric J.P. Richard ◽  
Yves Rozenholc
Keyword(s):  
Craniofacial Reconstruction ◽  
Local Technique

Anesthetic Choice for Functional Endoscopic Sinus Surgery

1992 ◽  
Vol 6 (1) ◽  
pp. 1-4 ◽  
Author(s):  
John A. Fornadley ◽  
Kevin S. Kennedy ◽  
Joseph F. Wilson ◽  
Peter T. Galantich ◽  
Gregg S. Parker
Keyword(s):  
General Anesthesia ◽  
Endoscopic Sinus Surgery ◽  
Functional Endoscopic Sinus Surgery ◽  
Sinus Surgery ◽  
Patient Comfort ◽  
Anesthetic Technique ◽  
Anesthetic Techniques ◽  
Local Infiltration ◽  
Local Technique ◽  
Local Anesthetic Injection

Controversy continues concerning the optimal anesthetic technique when completing endoscopic sinus surgery. To attempt to investigate the results using different anesthetic techniques, experience with endoscopic sinus surgery over 12 months (233 cases) was retrospectively reviewed. The use of local anesthetic injection with or without regional blocks (specifically ethmoid and greater palatine) was evaluated, as was the choice of general anesthesia versus local technique in a context of blood loss, patient comfort, and complications. Regional block technique appears to add morbidity for little additional benefit. Endoscopic sinus surgery may be performed safely in appropriately selected patients using either general anesthesia or local infiltration with sedation.

Serum lidocaine and bupivacaine levels in local technique knee arthroscopy

1991 ◽  
Vol 19 (5) ◽  
pp. 499-502 ◽  
Author(s):  
Garron G. Weiker ◽  
Thomas E. Kuivila ◽  
Charles E. Pippinger
Keyword(s):  
Knee Arthroscopy ◽  
Local Technique

scholarly journals Local and Global Approaches for Damage Detection in Composite Structures by Fiber Optic Sensors

2018 ◽  
Author(s):  
Alfredo Guemes ◽  
Antonio Fernandez- Lopez ◽  
Patricia F. Diaz-Maroto ◽  
Angel Lozano ◽  
Julián Sierra-Pérez
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Fiber Optic ◽  
A Priori ◽  
Fiber Optic Sensors ◽  
Network Density ◽  
Strain Measurements ◽  
Damage Location ◽  
Local Technique ◽  
External Loads

Fiber optic sensors cannot measure damage; for getting information about damage from strain measurements, additional strategies are needed, and several alternatives have been proposed. This paper discuss two independent concepts: the first one is based on detecting the new strains appearing around a damage spot; the structure does not need to be under loads; the technique is very robust, damage detectability is high, but it requires sensors to be located very close to the damage, so it is a local technique. The second approach offers a wider coverage of the structure, it is based on identifying the changes caused by the damage on the strains field in the whole structure for similar external loads. Damage location does not need to be known a priori, detectability is dependent upon the sensors network density, damage size and the external loads. Examples of application to real structures are given.

scholarly journals Influence of Heat Treatment on the Microstructure and Corrosion Behavior of Thixo-cast Mg-Y-Nd-Zr

2020 ◽  
Vol 29 (9) ◽  
pp. 6181-6195
Author(s):  
Z. Szklarz ◽  
Ł. Rogal
Keyword(s):  
Heat Treatment ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Eutectic Mixture ◽  
Linear Sweep Voltammetry ◽  
The Matrix ◽  
Local Technique ◽  
Polarization Resistances ◽  
Global And Local ◽  
Cast Microstructure

Abstract The influence of semisolid metal processing (SSM, also called thixoforming) and T6 heat treatment (HT) on the microstructure and corrosion behavior in chlorides of Mg-Y-Nd-Zr (WE43B) magnesium alloy was investigated. The as-cast microstructure is composed of α-Mg grains with the size of 52.8 ± 1.9 μm surrounded by eutectic precipitations enriched in rare-earth elements (Y, Nd). The thixo-cast microstructure contained α-Mg globular grains with the size of 65.5 ± 2.1 μm surrounded by a fine eutectic mixture in the volume of 26.6%. The T6 HT (heat treatment and saturation at 525°C/5 h, cooling in H2O and aging at 190°C/48 h) caused an increase of yield strength to 180 MPa and tensile strength to 280 MPa at the hardness 105 ± 4 HV5. Next, the electrochemical response was investigated in 0.1 M NaCl using the global and local LSV (linear sweep voltammetry) and EIS (electrochemical impedance spectroscopy) methods. The EIS method suggests the same mechanism for the processes occurring at the electrode/electrolyte interface and shows higher values of the polarization resistances of treated samples after 24-h immersion tests. In particular, better corrosion resistance in chlorides is observed in the alloy after SSM compared to the SSM/HT specimen, which has also been confirmed by the LSV tests performed after 24-h immersion. By using a local technique, a higher susceptibility of the matrix of SSM and SSM/HT samples to pitting corrosion has been revealed.

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