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Articles 1 - 12 of 12
Full-Text Articles in Structural Engineering
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Simon Laflamme
A structural health monitoring system is provided to diagnose and localize crack damage on structural elements. The system uses one or more capacitive sensor assemblies that employ a soft dielectric material. The system can be applied over a large area as a sensing skin, allowing the presence of cracks to be localized.
Modified Friction Device For Control Of Large-Scale Systems, Simon Laflamme, Douglas Taylor, Mohamed Abdellaoui Maane, Jerome J. Connor
Modified Friction Device For Control Of Large-Scale Systems, Simon Laflamme, Douglas Taylor, Mohamed Abdellaoui Maane, Jerome J. Connor
Simon Laflamme
Semi-active control of civil structures has shown to be promising at mitigating vibrations. Those systems typically perform significantly better than passive systems, and only necessitate small power to operate. Nevertheless, semi-active control devices are not yet accepted by the construction and structural engineering communities. Among impeding factors, semi-active devices are not perceived as sufficiently reliable or robust. In this paper, a new semi-active damping device based on existing reliable technology is proposed. It is composed of a stiffness element, a viscous damper, and a braking mechanism in parallel. The device, termed the modified friction device (MFD), is essentially a variable …
Soft Capacitive Sensor For Structural Health Monitoring Of Large-Scale Systems, Simon Laflamme, M. Kollosche, J. J. Connor, G. Kofod
Soft Capacitive Sensor For Structural Health Monitoring Of Large-Scale Systems, Simon Laflamme, M. Kollosche, J. J. Connor, G. Kofod
Simon Laflamme
Structural integrity of infrastructures can be preserved if damage is diagnosed, localized, and repaired in time. During the past decade, there has been a considerable effort to automate the process of structural health monitoring, which is complicated by the inherent large size of civil structures. Hence, a need has arisen to develop new approaches that enable more effective health monitoring.In this paper, a new sensing technique for damage localization on large civil structures is proposed. Specifically, changes in strain are detected using a capacitance sensor built with a soft, stretchable dielectric polymer with attached stretchable metal film electrodes. A change …
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Simon Laflamme
A structural health monitoring system is provided to diagnose and localize crack damage on structural elements. The system uses one or more capacitive sensor assemblies that employ a soft dielectric material. The system can be applied over a large area as a sensing skin, allowing the presence of cracks to be localized.
Quasi-Static Analysis Of Rocking Wall Systems, Douglas Seymour, Simon Laflamme
Quasi-Static Analysis Of Rocking Wall Systems, Douglas Seymour, Simon Laflamme
Simon Laflamme
Rocking wall systems consist of shear walls that are free to rotate at their base. Their purpose is to mitigate seismic structural damage by constraining the structure primarily to its first mode. This constraint prevents weak story failure, and maximizes energy dissipation by activating plastic hinges throughout the structure. The purpose of this paper is to present a methodology for the design of rocking wall systems. A quasi-static analysis model is used for predicting the seismic mitigation performance of rocking walls. The stiffness matrix is generalized for an N-story simplified structure equipped with this structural system. The model presented enables …
Control Of Large-Scale Structures With Large Uncertainties, Simon Laflamme
Control Of Large-Scale Structures With Large Uncertainties, Simon Laflamme
Simon Laflamme
Performance-based design is a design approach that satisfies motion constraints as its primary goal, and then verifies for strength. The approach is traditionally executed by appropriately sizing stiffnesses, but recently, passive energy dissipation systems have gained popularity. Semi-active and active energy dissipation systems have been shown to outperform purely passive systems, but they are not yet widely accepted in the construction and structural engineering fields. Several factors are impeding the application of semi-active and active damping systems, such as large modeling uncertainties that are inherent to large-scale structures, limited state measurements, lack of mechanically reliable control devices, large power requirements, …
Wavelet Network For Semi-Active Control, Simon Laflamme, J.J.E. Slotine, J.J. Connor
Wavelet Network For Semi-Active Control, Simon Laflamme, J.J.E. Slotine, J.J. Connor
Simon Laflamme
This paper proposes a wavelet neurocontroller capable of self-adaptation and self-organization for uncertain systems controlled with semi-active devices, ideal candidates for control of large-scale civil structures. A condition on the sliding surface for cantilever-like structures is defined. The issue of applicability of the control solution to largescale civil structures is made the central theme throughout the text, as this topic has not been extensively discussed in the literature. Stability and convergence of the proposed neurocontroller is assessed through various numerical simulations for harmonic, earthquake, and wind excitations. The simulations consist of semi-active dampers installed as a replacement to the current …
Strongly Enhanced Sensitivity In Elastic Capacitive Strain Sensors, Matthias Kollosche, Hristiyan Stoyanov, Simon Laflamme, Guggi Kofod
Strongly Enhanced Sensitivity In Elastic Capacitive Strain Sensors, Matthias Kollosche, Hristiyan Stoyanov, Simon Laflamme, Guggi Kofod
Simon Laflamme
Strain sensors based on dielectric elastomer capacitors function by the direct coupling of mechanical deformations with the capacitance. The coupling can be improved by enhancing the relative permittivity of the dielectric elastomer. Here, this is carried out through the grafting of conducting polymer (poly-aniline) to the elastomer backbone, leading to molecular composites. An enhancement in capacitance response of 46 times is observed. This could help to extend the possible range of miniaturization towards even smaller device features.
Large-Scale Capacitance Sensor For Health Monitoring Of Civil Structures, Simon Laflamme, Matthias Kollosche, Jerome J. Connor, Guggi Kofod
Large-Scale Capacitance Sensor For Health Monitoring Of Civil Structures, Simon Laflamme, Matthias Kollosche, Jerome J. Connor, Guggi Kofod
Simon Laflamme
In this paper, a new type of sensing technique for damage localization on large civil structures is proposed. Specifically, changes in strain are detected using a capacitance sensor built with a soft-stretchable dielectric polymer with attached stretchable metal film electrodes. This sensor is sensitive to a change in strain that causes a change in its capacitance. Fixed to a structure, small changes in the strain can be monitored directly by measuring the change in the capacitance of the unit. This technology allows for simple yet highly accurate measurements of cracks occurring due to deformation, aging, or other structural failures. The …
Intelligent Controller For Smart Base Isolation Of Masonry Structures, Simon Laflamme, T.Y. Yu, Jerome J. Connor
Intelligent Controller For Smart Base Isolation Of Masonry Structures, Simon Laflamme, T.Y. Yu, Jerome J. Connor
Simon Laflamme
In this paper, an intelligent controller to control a smart base-isolated masonry structure is proposed. The smart base isolation consists of rubber bearings and a magnetorheological damper. This semi-active scheme takes advantage of the low power requirement of magnetorheological devices to achieve structural control. The controller is capable of mapping the behaviour of the controlled structure sequentially, using a self-organizing neural network which has time-varying learning rates. This neurocontroller is augmented by a sliding mode controller to account for the uncertainty on the semi-active damping forces. Wavelets are used as functions in the single hidden layer for their capability of …
Application Of Self-Tuning Gaussian Networks For Control Of Civil Structures Equipped With Magnetorheological Dampers, Simon Laflamme, Jerome J. Connor
Application Of Self-Tuning Gaussian Networks For Control Of Civil Structures Equipped With Magnetorheological Dampers, Simon Laflamme, Jerome J. Connor
Simon Laflamme
This paper proposes an adaptive neural network composed of Gaussian radial functions for mapping the behavior of civil structures controlled with magnetorheological dampers. The online adaptation takes into account the limited force output of the semi-active dampers using a sliding mode controller, as their reaction forces are state dependent. The structural response and the actual forces from the dampers are used to adapt the Gaussian network by tuning the radial function widths, centers, and weights. In order to accelerate convergence of the Gaussian radial function network during extraordinary external excitations, the learning rates are also adaptive. The proposed controller is …
Online Learning Algorithm For Structural Control Using Magnetorheological Actuators, Simon Laflamme
Online Learning Algorithm For Structural Control Using Magnetorheological Actuators, Simon Laflamme
Simon Laflamme
Magnetorheological actuators are promising devices for mitigating vibrations because they only require a fraction of energy for a similar performance to active control. Conversely, these semi-active devices have limited maximum forces and are hard to model due to the rheological properties of their fluid. When considering structural control, classical theories necessitate full knowledge of the structural dynamic states and properties most of which can only be estimated when considering large-scale control, which may be difficult or inaccurate for complicated geometries due to the non-linear behaviour of structures. Additionally, most of these theories do not take into account the response delay …