B-Scan image analysis for position and shape defect definition in plates
- Autori: Cerniglia, D.; Ingrassia, T.; Nigrelli, V.; Scafidi, M.
- Anno di pubblicazione: 2017
- Tipologia: Capitolo o Saggio (Capitolo o saggio)
- Parole Chiave: B-scan image analysis; defect definition; NDE; Laser Ultrasonic
- OA Link: http://hdl.handle.net/10447/221361
Definition of size, shape and location of defects into a mechanical component is of extreme importance in the manufacturing industry in general and particularly in high-tech applications, and in applications that can become dangerous due to the structural failure of mechanical components. In this paper, a laser-UT system has been used to define position and shape of internal defects in aluminum plates. An infrared pulsed laser is used to generate ultrasonic waves in a point of the plate and a CW laser interferometer is used as receiver to acquire the out-of-plane displacements due to the ultrasonic waves in another point of the plate. The method consists of acquiring a B-Scan map on which some information on the defects in the mechanical component are visible. Storing the characteristics of the wave reflected by the defect and acquired in the B-Scan, the detection and the drawing of the defect is possible. The acquisition of the times of arrival of the waves reflected by the defect from the B-scan allows defining large parts of the shape of the defect. The times of arrival are acquired from the B-scan by analyzing the colour variations due to the wave reflected by the defect. The experiments operated from both sides of the plate allow drawing the defect in a virtual image of the plate section, from which the definition of defect shape and position can be determined.