A fast crack profile reconstitution model in nondestructive testing is developed using an arrayed eddy current sensor. The inverse problem is based on an iterative solving of the direct problem using genetic algorithms. In the direct problem, assuming a current excitation, the incident field produced by all the coils of the arrayed sensor is obtained by the translation and superposition of the ...

Polymer Bonded Explosives (PBX) are well-known explosives for the weapons, especially for the parts of some important weapon. Generally, they first are modelled in cylinder. One of the most important issues in PBX cylinder properties is the detection of its flaw. Each PBX cylinder may have flaws that influence the security, machine-performance and other important physical or chemical performanc...

The pulse compression technique is successfully and widely used in many fields for improving the signal to noise ratio (SNR); which is especially useful when the environment is noisy and the SNR is poor. Since high frequency ultrasound is strongly attenuated in concrete, only low frequency ultrasound can be used in ultrasonic nondestructive testing (NDT) of concrete. In this study the pulse com...

Beamforming techniques based on sigma-delta modulation (SDM) have been proposed to reduce the hardware complexity of conventional multi-bit digital delay-sum beamformer, in which beamforming operation is performed upon over-sampled single bit sequences obtained by applying SDM to the received signals from each array elements. In conventional single bit SDM beamforming, the single bit sequence i...

Pulse-echo reflection techniques are used for ultrasonic flaw detection in most commercial instruments. As the measured pulse echo signal is assumed to be the result of linearly convolving the defect impulse response (IR) with the measurement system response, the objective is thus, to remove the effect of the measurement system through a deconvolution operation and extract the defect impulse re...

The goal of this research is to examine the potential of Raman spectroscopy as a method of condition assessment for carbon fiber composite materials. Carbon fiber composites are used in high performance situations such as overwrapping of composite over-wrapped pressure vessels (COPVs) in aerospace applications and hydrogen and natural-gas transportation systems. The composites will play a large...

Abstract. The aim of the topological sensitivity analysis is to determine an asymptotic expansion of a shape functional with respect to the variation of the topology of the domain. In this paper, we consider a state equation of the form div (A∇u) + ku = 0 in dimensions 2 and 3. For that problem, the topological asymptotic expansion is obtained for a large class of cost functions and two kinds o...

The work described here is an uHrasonies based experimental study which aims to address the lack of a reliable technique for detecting strength loss in adhesive joints after exposure to hot wet environments. This is manifested as a change in the failure mode of an adhesive system from a cohesive failure in the as-made condition, that is failure through the adhesive, to an adhesive failure, fail...