Search results for "structural health"
showing 10 items of 52 documents
WSNs for structural health monitoring of historical buildings
2009
Monitoring structural health of historical heritage buildings may be a daunting task for civil engineers due to the lack of a pre-existing model for the building stability, and to the presence of strict constraints on monitoring device deployment. This paper reports on the experience maturated during a project regarding the design and implementation of an innovative technological framework for monitoring critical structures in Sicily, Italy. The usage of wireless sensor networks allows for a pervasive observation over the sites of interest in order to minimize the potential damages that natural phenomena may cause to architectural or engineering works. Moreover, the system provides real-tim…
Lock-In Signal Post-Processing Techniques in Infra-Red Thermography for Materials Structural Evaluation
2013
This paper describes the potential of off-line thermographic signal processing by means of Lock-In Correlation algorithms, in order to implement structural health monitoring and stress analysis techniques. Thermal datasets acquired by infrared thermocameras are locked-in and correlated numerically with opportune reference signals, and amplitude and phase values of various harmonics retrieved by means of a Fast Fourier Transform and time averaging based filtering. This information is then processed for NDT defect probing and for evaluating the Thermoelastic Effect induced temperature changes. Two case studies in particular are discussed, implementing the proposed signal lock-in processing: a…
Artificial neural network comparison for a SHM procedure applied to composite structures.
2013
In this paper different architectures of Artificial Neural Networks (ANNs) for structural damage detection are studied. The main objective is to create an ANN able to detect and localize damage without any prior knowledge on its characteristics so as to serve as a realtime data processor for SHM systems. Two different architectures are studied: the standard feed-forward Multi Layer Perceptron (MLP) and the Radial Basis Function (RBF) ANNs. The training data are given, in terms of a Damage Index ℑD, properly defined using the piezoelectric sensor signal output to obtain suitable information on the damage position and dimensions. The electromechanical response of the assembled structure has b…
Systematic comparison of Artificial Neural Networks for a SHM procedure applied to Composite Structure
2014
The problems related to damage detection represents a primary concern, particularly in the framework of composite structure. In fact, for this kind of structures barely visible damage can occur. Moreover, one of the major in-service damage of composite aircraft strcutures is represented by disbonds between the stiffeners and the skin undergoing dynamic or post-buckling loads. The effective implementation of a SHM system relies on the synthesis of non-destructive technique (NDT), fracture mechanics, sensors technology, data manipulation and signal processing, and it can receive a great improvement through the use of an Artificial Neural Networks. Different architectures of Artificial Neural …
Structures with Surface-Bonded PZT Piezoelectric Patches: a BEM Investigation into the Strain-transfer Mechanism for SHM applications
2009
In this work a three-dimensional BEM model is used for the analysis of structures with cracks and surface bonded piezoelectric PZT patches used as strain sensors. The cracked structure is modelled by the dual boundary element method, which allows for accurate and reliable crack analysis, while the piezoelectric patch is analyzed by a finite element state-space approach, that embodies both the full electro-mechanical coupling and the suitable sensor’s boundary conditions. The model is used to investigate the strain-transfer mechanism from an host elastic structure to the piezoelectric layer, taking into account the effect of the adhesive layer, as well as the mechanical interaction between t…
Validation of a Novel Sensing Approach for Continuous Pavement Monitoring Using Full-Scale APT Testing
2023
The objective of this paper is to present a novel approach for the continuous monitoring of pavement condition through the use of combined piezoelectric sensing and novel condition-based interpretation methods. The performance of the developed approach is validated for the detection of bottom-up fatigue cracking through full-scale accelerated pavement testing (APT). The innovative piezoelectric sensors are installed at the bottom of a thin 102 mm (4 in.) asphalt layer. The structure is then loaded until failure (up to 1 million loading cycles in this study). The condition-based approach, used in this work, does not rely on stain measurements and allows users to bypass the need for any struc…
Materials Communicating with the BIM: Aims and First Results of the McBIM Project
2019
This paper introduces McBIM, a French national research project working on on-line monitoring on concrete structure. This project gathers 3 french laboratories (the CRAN, LAAS and LIB) associated with one company (360SmartConnect/FINAO SAS) that are working together from 2018 to 2021. It proposes 1) to design a “communicating concrete”, made of concrete equipped with embedded low-energy wireless microsensor network, able to manage and exchange data using BIM standards, and 2) to demonstrate the usefulness of this approach across several building lifecycle phases, namely the manufacturing, construction and exploitation phases for structural health monitoring. The paper will first start by in…
The role of evanescent modes in Global-Local analysis of UGW in plates with varying local zone-scatterer relations
2023
In order to provide a reliable and robust SHM performance, Ultrasonic Guided Waves (UGWs) need to be analyzed and understood. Numerical modeling of UGW propagation and scattering by hybrid methods offers the possibility of simulating UGW interaction with waveguides of arbitrary cross-sections and discontinuities. Maximizing the accuracy of such methods is important to perform quantitative SHM, while maintaining minimum computational cost. This work investigates the role of evanescent modes in the numerical analysis of UGWs in aluminum and composite plates with defects, by the hybrid Global-Local method. The complex solutions to the UGW eigenvalue problem are found and the scattering spectra…
BEM analysis of a piezoelectric structural health monitoring system for delamination detection
2013
In the present work a piezoelectric based structural health monitoring (SHM) system is analyzed with the aim of assessing the ability of the piezoelectric patch to detect both edge and embedded delaminations proper of flange-skin composite laminated structures. he boundary element model is developed for piezoelectric solids and is implemented by taking advantage of the multidomain technique to model laminated and cracked configurations. A non-linear spring model interface is then implemented in conjunction with an iterative procedure allowing for the simulation of the finite stiffness of the bonding layers as well as of the non-penetration condition of the delamination surfaces. he dynamic …
On the use of the EMI for the health monitoring of bonded elements
2014
The low weight, robustness and fatigue resistance of adhesive joints make them suitable for structural joints. A fully developed nondestructive evaluation technique however is needed to monitor and assess the quality of bonded joints. In the present paper the application of the electromechanical impedance (EMI) technique is proposed. In the EMI method a piezoelectric transducer (PZT) is attached to the structure of interest. The high sensitivity and low power consumption make the EMI method feasible for real time structural health monitoring. In this study we investigated the sensitivity of the electromechanical response of a PZT to the curing and the quality of the adhesive used for bonded…