Pulsed eddy current (PEC) stimulated thermography is proposed as a powerful non-destructive evaluation (NDE) technique, allowing the operator to observe the heating developed from the eddy current distribution in a structure using infrared imaging, detecting defects over a relatively wide area within a short time. Some defects (impact, delamination, disbond or crack) commonly occur in aerospace...

From all bridge components, concrete bridge decks in most cases deteriorate the fastest. Theretransportation agency budgets for bridges. The current practice of bridge deck inspection typically provides information when the deterioration is already in its latest stage. Main reductions in the expenditures can be achieved through their monitoring and assessment using nondestructive evaluation (ND...

In the present work, the interaction of Rayleigh waves with a delamination in a fiber reinforced composite plate was analyzed. Rayleigh waves, upon interacting with delamination mode, convert into Lamb waves in the delamination zone. These guided Lamb modes have the capability to mode convert back into Rayleigh modes when they interact with the edge of the delamination. A unidirectional glass/e...

Drilling-induced delamination often occurs both at the entrance and the exit of the workpiece during drilling of composite material. Investigators have studied analytically and experimentally that delamination in drilling can be correlated to the thrust force of the drill. With a pre-drilled pilot hole, the delamination can be reduced significantly. Early reference reported models of drilling-i...

A study was undertaken using electrochemical impedance spectroscopy to measure delamination and compare that measurement, which can be performed on the sample repeatedly, with the accepted method of cathodic disbondment (CD) testing, the major drawback of which is that this measurement can only be done once on the sample; in reaching this goal, EIS could be used to predict delamination based on...

The susceptibility of QFN package to delamination, particularly in the area between the Ni/Pd/Au leadframe die pad and mold compound, has been a major concern to many IC manufacturers. The presence of a Ni/Pd/Au oxide layer on the leadframe of QFN packages was found to cause delamination at the die pad or mold compound interface. Delamination refers to the disbonding between a surface of the mo...

Time reversal active sensing using Lamb waves is investigated for health monitoring of a composite structure. In the present work experiments were conducted on a glass/epoxy composite plates to study the time reversal behavior of A0 and S0 Lamb wave modes. PZT wafer sensors were surface bonded to the structure for generation and reception of the Lamb wave modes. Time reversal experiments were f...

in this research, b4c-ni cermet coating was sprayed on the surface of 4130 steel from b4c and ni feed-stockpowders using high velocity oxy-fuel (hvof) method. in order to characterize the tribological behavior of thecoating, ball on disk wear tests were done at the ambient temperature and under the loads of 1, 3 and 5 n.phase analysis of the coating after spraying was studied by x-ray diffracto...