A Lamb wave-based crack detection method for aluminum plates health monitoring is developed in this paper. Piezoelectric disks are employed to actuate and capture the Lamb wave signals. The position of crack is assumed to be aligned with the sensor and actuator.  Extraction of high quality experimental results of lamb wave propagation in a plate-like structure is considerably complicated due to...

Pavement crack detection from images is a challenging problem due to intensity inhomogeneity, topology complexity, low contrast, and noisy texture background. Traditional learningbased approach has difficulty in obtain representative training samples. We propose a new unsupervised multi-scale fusion crack detection (MFCD) algorithm that does not require training data. First, we develop a window...

Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD), a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decom...

Crack propagation along one of the interfaces between a thin ductile adhesive layer and the elastic substrates it joins is considered. The layer is taken as being elastic-plastic, and the fracture process of the interface is modeled by a traction-separation law, characterized by the peak separation stress 6 and the work of separation per unit area To. Crack growth resistance curves for mode I l...

SOMMARIO La misura di vibrazioni é frequentemente adottata per individuare cricche di fatica nelle strutture. In questo lavoro é presentata una metodologia, basata sull'analisi bispettrale, al fine di rilevare la presenza di una cricca in una trave a sezione costante; la tecnica di analisi del segnale è applicata alla risposta del sistema sottoposto ad eccitazione random mediante shaker. ABSTRA...

In piping the defects play a key role for determining the life of component. Also the risk for pipe failure combined to the defects has to be taken into account. In this study thermal dynamic load has been applied to austenitic material (Aisi 304) in order to introduce dynamic behaviour into the crack. The studied crack (~20 mm ! 7 mm) has been produced by thermal fatigue in advance. Different ...

In order to overcome the high computational complexity of beamlet tree-structure algorithm, the paper proposes an improved algorithm and applies it to pavement crack detection, thereby; solving the problem of pavement crack detection which has the disadvantages of poor noise immunity and inaccurate test results. First, the pavement crack image is rectified by multiplicative factors to eliminate...

A high temperature cured self-healing epoxy is demonstrated by incorporating microcapsules of poly (dimethylsiloxane) (PDMS) resin and separate microcapsules containing an organotin catalyst. Healing is triggered by crack propagation through the embedded microcapsules in the epoxy matrix, which releases the healing agents into the crack plane initiating crosslinking reactions. A series of taper...

Denda and Marante [1] have developed the boundary element method for the mixed mode fracture analysis of multiple curvilinear cracks in the general anisotropic solids in two dimensions for which in-plane Mode I, II, and out-of-plane Mode III, of fracture are coupled. They have developed the crack tip singular element (CTSE) to model any curvilinear cracks, including center and edge cracks. The ...

A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat Σ99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hy...