The interaction of an ultrasonic guided Lamb wave mode with delamination type defects in a quasi-isotropic laminated composite plate has been studied, using both simulations and experiments. In symmetric delamination, when the primary anti-symmetric mode, Ao, is incident at entrance exit it generates new So, that confined only to sub-laminates undergoes multiple reflections delaminated region. It was observed mode-converted Ao modes propagate main laminate. two reverberate between ends...

Propagation of the primary anti-symmetric Lamb mode (Ao) in an asymmetrically delaminated cross-ply laminate has been studied through both numerical simulations and experiments employing air coupled ultrasonic technique. When Ao interacts with entrance exit located delamination, addition to Ao, a converted symmetric (So) also propagates each two sub-laminates as well main laminate. These modes propagate independently sub-laminates. In addition, turning (i.e. propagating one sub-laminate...

Lamb wave tomography offers a new dimension to the challenging field of in situ health monitoring structures. The possibility constructing tomograms from network sensors generating and sensing waves thin, multi-layered, anisotropic composite plates is explored present study. It shown that improved result when attenuative characteristics are accounted for by (a) using newly identified energy earliest signals as reconstruction parameter, (b) modifying sensor configuration conventional...

A new compact sensor configuration comprising a single transmitter and multi-receivers (STMR) is presented for the in situ structural health monitoring (SHM) of large plate-like isotropic structures. The STMR exploits long-range propagation characteristics ultrasonic guided Lamb waves phase reconstruction algorithm to provide defect detection location capability under non-dispersive as well dispersive regimes waves. Simulations are performed on defect-free defective finite plates aluminum...

Platelike structures, made of composites, are being increasingly used for fabricating aircraft wings and other substructures. Continuous monitoring the health these structures would aid reliable operation aircrafts. This paper considers use a Lamb wave based structural (SHM) system to identify locate defects in large multilayered composite plates. The SHM comprises single transmitter multiple receivers, coupled one side plate that send receive waves. proposed algorithm processes data...

The reconstruction of all nine unknown elastic moduli orthotropic plate structures has been achieved using a single-transmitter-multiple-receiver (STMR) compact structural health monitoring (SHM) array. This method uses the velocity measurement fundamental guided Lamb wave modes (S0 and A0), generated from central transmitter, received by sparse array receivers that encircle transmitter. measured velocities are then used in an inversion algorithm based on genetic algorithms. A prototype STMR...

A higher order cylindrically guided ultrasonic wave was used for the detection and sizing of hidden pitting-type corrosion in crevice regions (between pipe supports) without lifting or disturbing structural layout arrangement pipelines. The circumferential waves were generated using a piezoelectric crystal based transducer, located at accessible top region pipes, pulse-echo mode. By studying experimental parameters such as dispersion, particle displacement, wavelength modes, an appropriate...

In this article an attempt has been made to quantitatively assess the extent of delamination in composite laminates, using time-of-flight fundamental Lamb wave modes, without recourse baseline data from a healthy structure. An expression derived determine size, group velocities primary modes sub-laminates and transmitted A o signal mode converted signal, which is generated when propagates through delamination. The effectiveness expression, main laminate were used, verified numerical...

Customization of substrates for the design metamaterial absorbers gives user a wide choice parameters like flexibility, thickness, dielectric constant, etc. Polymer composites are attractive in this regard as they provide variety options to fabricate with desirable properties depending on matrix and filler materials. In work, flexible polymer nanocomposites different weight percentages graphene nanoplatelets (GnP) epoxy were fabricated characterization was performed. The presence GnP...