NDTsi 2001 Session: Advances in Non-Ultrasonic NDE Methods
Use of Real-Time Shearography for the Integrity Inspection of Filamentary Wounded Pressure Vessels
M.A. De Smet, F. Santos, NDT-Expert, France
ABSTRACT
An experimental procedure based on a laser interferometric technique - Shearography - has been implemented to verify the integrity of filamentary wounded pressure vessels when submitted to impact and ageing. The reservoir of the pressure vessels is constituted by a liner of aluminium and glass-fibre filamentary wounded. Shearography is a laser based interferometric technique that is sensitive to the out-of-plane deformation of a surface. Under the action of a small load, the structure is deformed and the presence of defects is revealed by local strain singularities. It has the advantages of the global methods, the absence of contact, the high-resolution (sensitivity) and the capability to do quasi real-time inspections. Also there is no major influence by environmental noises, because it is sensitive to gradient displacement information. Tests were made using a very low pressure (6 bar) compared with the in-service pressure (350 bar). Some results are presented and discussed regarding the blow-up pressure. The results show that the method is very effective in the detection of delaminations (internal or external), at very low pressure (less than 6 bar). Also a discussion is opened about the possibility to investigate the ageing of the structure by observation of the laxity of the fibres. The reasoning process, references and results are presented.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
