Recovery of the resonance frequency of buildings following strong seismic deformation as a proxy for structural health

2019 ◽  
Vol 18 (5-6) ◽  
pp. 1966-1981 ◽  
Author(s):  
Ariana Lucia Astorga ◽  
Philippe Guéguen ◽  
Jacques Rivière ◽  
Toshihide Kashima ◽  
Paul Allan Johnson
Keyword(s):  
Structural State ◽  
Relaxation Times ◽  
Mechanical Damage ◽  
Recovery Process ◽  
Frequency Variation ◽  
Slow Recovery ◽  
Engineering Structures ◽  
Structural Health ◽  
Real Earthquake ◽  
Seismic Deformation

Elastic properties of civil engineering structures change when subjected to a dynamic excitation. The modal frequencies show a rapid decrease followed by a relaxation, or slow recovery, that is dependent on the level of damage. In this article, we analyze the slow recovery process applying three relaxation models to fit real earthquake data recorded in a Japanese building that shows variant structural state over 20 years. Despite the differences in conditions, the different scales and the complexity of a real-scale problem, the models originally developed for laboratory experiments are well adapted to real building data. The relaxation parameters (i.e. frequency variation, recovery slope, characteristic times and their amplitudes, and range of relaxation times) are able to characterize the structural state, given their clear connection to the degree of fracturing and mechanical damage to the building. The recovery process following strong seismic deformation, could, therefore, be a suitable proxy to monitor structural health.

scholarly journals Multiscale Post-Seismic Deformation Based on cGNSS Time Series Following the 2015 Lefkas (W. Greece) Mw6.5 Earthquake

2021 ◽  
Vol 11 (11) ◽  
pp. 4817
Author(s):  
Filippos Vallianatos ◽  
Vassilis Sakkas
Keyword(s):  
Time Series ◽  
Relaxation Time ◽  
Relaxation Times ◽  
Relaxation Mechanism ◽  
Mesoscopic Scale ◽  
Macroscopic Scale ◽  
Epicentral Area ◽  
Arrhenius Dependence ◽  
Seismic Deformation ◽  
Logarithmic Type

In the present work, a multiscale post-seismic relaxation mechanism, based on the existence of a distribution in relaxation time, is presented. Assuming an Arrhenius dependence of the relaxation time with uniform distributed activation energy in a mesoscopic scale, a generic logarithmic-type relaxation in a macroscopic scale results. The model was applied in the case of the strong 2015 Lefkas Mw6.5 (W. Greece) earthquake, where continuous GNSS (cGNSS) time series were recorded in a station located in the near vicinity of the epicentral area. The application of the present approach to the Lefkas event fits the observed displacements implied by a distribution of relaxation times in the range τmin ≈3.5 days to τmax ≈350 days.

Study and Application of Health Monitoring by Fiber Optic Sensors in Civil Engineering

2003 ◽  
Author(s):  
Hong-Nan Li ◽  
Dong-Sheng Li ◽  
Su-Yan Wang
Keyword(s):  
Health Monitoring ◽  
Fiber Optic ◽  
Civil Engineering ◽  
Fiber Optic Sensor ◽  
Current Status ◽  
Fibre Optic ◽  
Engineering Structures ◽  
Monitoring Method ◽  
Structural Health ◽  
Potential Damage

In civil engineering, the smart health monitoring method by use of fiber optic sensor is a new approach that evaluates the structural health situation. The current status in applications of fibre optic structural health monitoring in civil engineering structures with a brief introduction of the advantages, basic principles of fibre optic sensors is described in this paper. Leakage detection and potential damage to pipelines are emphasized. Finally, existing problems for packing and implementing fibre optic sensors in structures are discussed.

scholarly journals Analysis of Guided Wave Propagation in a Multi-Layered Structure in View of Structural Health Monitoring

2019 ◽  
Vol 9 (21) ◽  
pp. 4600 ◽  
Author(s):  
Yevgeniya Lugovtsova ◽  
Jannis Bulling ◽  
Christian Boller ◽  
Jens Prager
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Guided Waves ◽  
Oil And Gas ◽  
Numerical Approach ◽  
Guided Wave ◽  
Mode Shapes ◽  
Engineering Structures ◽  
Structural Health

Guided waves (GW) are of great interest for non-destructive testing (NDT) and structural health monitoring (SHM) of engineering structures such as for oil and gas pipelines, rails, aircraft components, adhesive bonds and possibly much more. Development of a technique based on GWs requires careful understanding obtained through modelling and analysis of wave propagation and mode-damage interaction due to the dispersion and multimodal character of GWs. The Scaled Boundary Finite Element Method (SBFEM) is a suitable numerical approach for this purpose allowing calculation of dispersion curves, mode shapes and GW propagation analysis. In this article, the SBFEM is used to analyse wave propagation in a plate consisting of an isotropic aluminium layer bonded as a hybrid to an anisotropic carbon fibre reinforced plastics layer. This hybrid composite corresponds to one of those considered in a Type III composite pressure vessel used for storing gases, e.g., hydrogen in automotive and aerospace applications. The results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and by that damage present in this layer can be detected. The results obtained help to understand the wave propagation in multi-layered structures and are important for further development of NDT and SHM for engineering structures consisting of multiple layers.

scholarly journals Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
M. Sun ◽  
W. J. Staszewski ◽  
R. N. Swamy
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Smart Materials ◽  
Civil Engineering ◽  
Piezoelectric Sensors ◽  
Sensors And Actuators ◽  
Engineering Structures ◽  
Structural Health ◽  
Civil Engineering Structures ◽  
Smart Sensing

Structural Health Monitoring (SHM) aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement. The first step to set up a SHM system is to incorporate a level of structural sensing capability that is reliable and possesses long term stability. Smart sensing technologies including the applications of fibre optic sensors, piezoelectric sensors, magnetostrictive sensors and self-diagnosing fibre reinforced composites, possess very important capabilities of monitoring various physical or chemical parameters related to the health and therefore, durable service life of structures. In particular, piezoelectric sensors and magnetorestrictive sensors can serve as both sensors and actuators, which make SHM to be an active monitoring system. Thus, smart sensing technologies are now currently available, and can be utilized to the SHM of civil engineering structures. In this paper, the application of smart materials/sensors for the SHM of civil engineering structures is critically reviewed. The major focus is on the evaluations of laboratory and field studies of smart materials/sensors in civil engineering structures.

Restoration and structural health monitoring of Manitoba's Golden Boy

2003 ◽  
Vol 30 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
Aftab A Mufti
Keyword(s):  
Structural Health Monitoring ◽  
Knowledge Base ◽  
Health Monitoring ◽  
Civil Engineering ◽  
Paper Briefly ◽  
Engineering Applications ◽  
Engineering Structures ◽  
Structural Health ◽  
Existing Structures ◽  
History Of

Although bridges were among the first civil engineering structures to use structural health monitoring (SHM) technologies, research is now expanding to explore other types of applications, including Manitoba's famous Golden Boy statue. Global research is identifying the value of using SHM technologies for civil engineering applications. Structural health monitoring uses a variety of sensors to gather information about the behaviour of a structure. The information creates a valuable knowledge base that can be analyzed to help identify potential structural risks, develop safer and more efficient new structures, and determine more effective ways to rehabilitate existing structures. This paper briefly describes the history of the Manitoba Legislative Building and the Golden Boy and also the use of SHM technologies to help preserve the Golden Boy statue, an icon of provincial heritage.Key words: history, Golden Boy, statue, sculptors, architects, engineers, shaft, corrosion, sensors, monitoring.

UV-Activated Frequency Control of Beams and Plates Based on Isogeometric Analysis

2017 ◽  
Author(s):  
Yujie Guo ◽  
Hornsen Tzou
Keyword(s):  
Isogeometric Analysis ◽  
Uv Light ◽  
Frequency Control ◽  
Dynamic Stiffness ◽  
Frequency Variation ◽  
Frequency Change ◽  
Engineering Structures ◽  
Plate Structures ◽  
C1 Continuity ◽  
Euler Bernoulli Beam

A new LaSMP smart material exhibits shape memory behaviors and stiffness variation via UV light exposures. This dynamic stiffness provides a new noncontact actuation mechanism for engineering structures. Isogeometric analysis utilizes high order and high continuity NURBS as basis functions which naturally fulfills C1-continuity requirement of Euler-Bernoulli beam and Kirchhoff plate theories. The UV light-activated frequency control of LaSMP laminated beam and plate structures based on the isogeometric analysis is presented in this study. The accuracy and efficiency of the proposed isogeometric approach are demonstrated via several numerical examples in frequency control. The results show that, with LaSMPs, broadband frequency control of beam and plate structures can be realized. Furthermore, the length of LaSMP patches on beams is varied, which further broadens its frequency variation ranges. Studies suggest that 1) the newly developed IGA is an effective numerical tool and 2) the maximum frequency change ratio of beam and plate structures respectively reach 24.30% and 6.37%, which demonstrates the feasibility of LaSMPs induced vibration control of structures.

scholarly journals Resistance of Geosynthetics against the Isolated and Combined Effect of Mechanical Damage under Repeated Loading and Abrasion

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3558
Author(s):  
Filipe Almeida ◽  
David Miranda Carlos ◽  
José Ricardo Carneiro ◽  
Maria de Lurdes Lopes
Keyword(s):  
Hydraulic Properties ◽  
Construction Materials ◽  
Mechanical Damage ◽  
Tensile Tests ◽  
Repeated Loading ◽  
Short Term ◽  
Engineering Structures ◽  
Wide Range ◽  
Materials Used ◽  
Reduction Factors

The behaviour of materials used for developing engineering structures should be properly foreseen during the design phase. Regarding geosynthetics, which are construction materials used in a wide range of engineering structures, the installation on site and the action of many degradation agents during service life may promote changes in their properties, endangering the structures in which they are applied. The evaluation of the damage suffered by geosynthetics, like installation damage or abrasion, is often carried out through laboratory tests. This work studied the behaviour of five geosynthetics (three geotextiles and two geogrids) after being individually and successively exposed to two degradation tests: mechanical damage under repeated loading and abrasion. The short-term mechanical and hydraulic behaviours of the geosynthetics were analysed by performing tensile tests and water permeability normal to the plane tests. Reduction factors were determined based on the changes occurred in the tensile strength of the geosynthetics. Findings showed that mechanical damage under repeated loading and abrasion tended to affect the mechanical and hydraulic properties of the geosynthetics and that the reduction factors calculated according to the traditional method may not be able to represent accurately the damage suffered by the materials when exposed successively to the degradation mechanisms.

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