In this paper we summarize the hardware and software issues of impedance-based structural health moni- toring based on piezoelectric materials. The basic concept method is to use high-frequency excitations monitor local area a structure for changes in impedance that would indicate imminent damage. A brief overview research work experimental theoretical stud- ies various structures considered several papers these topics are cited. This concludes with discussion future areas path forward....

A novel time series analysis is presented to locate damage sources in a mechanical system, which running various operational environments. The source of located by solely analyzing the acceleration histories recorded from structure interest. First, data normalization procedure proposed. This selects reference signal that `closest' newly obtained an ensemble signals when undamaged. Second, two-stage prediction model (combining auto-regressive (AR) and with exogenous inputs (ARX) techniques)...

This paper casts structural health monitoring in the context of a statistical pattern recognition paradigm. Two techniques based on time series analysis are applied to fiber optic strain gauge data obtained from two different conditions surface-effect fast patrol boat. The first technique is two-stage combining Auto-Regressive (AR) and with eXogenous inputs (ARX) prediction models. second employs an outlier Mahalanobis distance measure. main objective extract features construct model that...

This paper poses the process of structural health monitoring in context a statistical pattern recognition paradigm. particularly focuses on applying control (SPC) technique known as an "X-bar chart" to vibration-based damage diagnosis. A chart provides framework for future measurements and identifying new data that are inconsistent with past data. First, autoregressive (AR) model is fit measured time histories from undamaged structure. Coefficients AR selected damage-sensitive features...

Damage detection techniques have been proposed to exploit changes in modal parameters and identify the extent location of damage large structures. Most such techniques, however, generally neglect environmental effects on parameters. Such include loads, boundary conditions, temperature, humidity. In fact, due can often mask more subtle structural caused by damage. This paper examines a linear adaptive model discriminate temperature from those or other effects. Data Alamosa Canyon Bridge state...

In this paper a signal processing technique is developed to detect delamination on composite structures. particular, wavelet-based and combined with an active sensing system produce near-real-time, online monitoring for A layer of piezoelectric patches used generate input specific wavelet waveform measure response signals. Then, the signals are processed by transform extract damage-sensitive features from original The applicability proposed method identification has been demonstrated...

Stated in its most basic form, the objective of damage diagnosis is to ascertain simply if present or not based on measured dynamic characteristics a system be monitored. In reality, structures are subject changing environmental and operational conditions that affect signals, variations can often mask subtle changes system’s vibration signal caused by damage. this paper, unique combination time series analysis, neural networks, statistical inference techniques developed for classification...

A Bayesian probabilistic approach is presented for the damage detection of multistorey frame structures. In this paper, a applied to identify multiple locations using estimated modal parameters when (1) measurement data are potentially corrupted with noise, (2) only small number degrees freedom measured, and (3) few fundamental modes estimated. To reduce intensive computational cost proposed method, branch-and-bound search scheme simplified modelling structures employed. six-storey shear...

This paper presents an automated crack visualization technique using ultrasonic wavefield images obtained by a complete noncontact laser scanning system. First, the system is built integrating and synchronizing Q-switched Nd:YAG for generation, Doppler vibrometer measurement galvanometers scanning. Then, four different schemes are compared to find most effective practical strategy presented application. Second, novel image processing developed isolate visualize crack-induced standing wave...

A damage detection technique, which does not rely on any past baseline signals, is proposed to assess in composite plates by using an enhanced time reversal method. concept of modern acoustics has been adapted guided-wave propagation improve the detectability local defects structures. In particular, wavelet-based signal processing techniques have developed enhance reversibility Lamb waves thin laminates. method, input at excitation point can be reconstructed if a response measured another...

The paper presents signal and image processing algorithms to automatically detect delamination disbond in composite plates from wavefield images obtained using a scanning laser Doppler vibrometer (LDV). Lamb waves are excited by lead zirconate titanate transducer (PZT) mounted on the surface of plate, out-of-plane velocity field is measured an LDV. From scanned time signals, constructed processed study interaction with hidden delaminations disbonds. In particular, frequency–wavenumber (f–k)...

A new methodology of guided-wave-based nondestructive testing (NDT) is developed to detect crack damage in a thin metal structure without using prior baseline data or predetermined decision boundary. In conventional techniques, often identified by comparing the 'current' obtained from potentially damaged condition with 'past' collected at pristine structure. However, it has been reported that this type pattern comparison can lead increased false alarms due its susceptibility varying...