Radio Frequency IDentification (RFID) tag is a promising device for the management of products at a very low cost. Huge number of such low-cost sensors can be installed to the structure beforehand, after a disaster we can access to these sensors wirelessly and very easily. In this system, a printed sheet is applied to a part of structure in which crack will occur. Copper wire is connected to th...

This research studies the performance of a battery-free wireless antenna sensor for measuring crack propagation. In our previous work, a battery-free folded patch antenna was designed for wireless strain and crack sensing. When experiencing deformation, the antenna shape changes, causing shift in electromagnetic resonance frequency of the antenna. The wireless interrogation system utilizes the ...

The present paper deals with the concept of antiresonance in multiple cracked beams and application for multi-crack identification. First, governing equations antiresonant frequency are conducted used both computing frequencies versus crack parameters measuring-loading colocation identifying cracks by measured frequencies. Then, a procedure is proposed identification cantilever beam based on so...

Electrical Impedance Tomography (EIT) is an imaging modality which reconstructs the impedance distribution of a closed domain using the measured boundary voltage data when injecting current [1-6]. It has been applied to numerous industrial applications such as: process tomography [7], nondestructive testing [8], imaging biological cells [9], medical imaging equipment [4] etc. Among them, non-de...

A method for deriving apparent activation energies, Eapp, for fatigue crack growth (FCG) is presented. It is shown how these Eapp values can be used to analyse the main underlying mechanism causing the progression of the crack. The Eapp values for fatigue crack growth in air and vacuum, and with and without a dwell are obtained for a range of Ni based superalloys for turbine disc applications. ...

In this research, a slotted patch antenna sensor is designed for wireless strain and crack sensing. An offthe-shelf RFID (radiofrequency identification) chip is adopted in the antenna sensor design for signal modulation. The operation power of the RFID chip is captured from wireless reader interrogation signal, so the sensor operation is completely battery-free (passive) and wireless. For strai...

This research was initiated to investigate the capability of using lasers for crack detection in pavements. If such a capability could be developed it would be used to aid in obtaining and evaluating pavement distress and cracking information for the State's P.E.S. procedures, used for maintaining and evaluating pavements. The research effort has involved three stages. The first two stages were...

The output of real-time diagnostic systems based on the interpretation of signals from a sensor network is often affected by very large uncertainties if compared with local nondestructive testing methods. Sequential Importance Resampling (SIR) is used in this study to filter the output distribution from a committee of Artificial Neural Networks. The methodology is applied to a helicopter panel ...

Dynamic fracture in a wide class of materials reveals a "fracture energy" Gamma much larger than the expected nominal surface energy due to the formation of two fresh surfaces. Moreover, the fracture energy depends on the crack velocity, Gamma=Gamma(upsilon). We show that a simple dynamical theory of viscoplasticity coupled to asymptotic pure linear elasticity provides a possible explanation to...

Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and auto detection. The application of digital...