NDT of offshore composite wrap repairs – New technology available

Nelvik, Kristian; Optonor AS; Norway

Vikhagen, E.; Optonor AS; Norway
Nelvik, K.; Optonor AS; Norway

ID: ECNDT-0007-2018
Download: PDF
Session: Composite General 1
Room: G1
Date: 2018-06-11
Time: 13:50 - 14:10

By introducing new technology for quality control and monitoring of composite wrap repairs the achievements will be:
– Better assurance of quality to new repairs.
– The efficient and cost saving method of composite wrap repairs can be applied on more critical systems.
– Monitoring solutions for in-service inspection programs permits increased life-time.
– Improved product and operator qualification, verification and development.

Technology for fast and efficient testing of composite structures in challenging environments is now available. The object surface is illuminated by an expanded laser beam and the object is imaged by a zoom lens onto a CMOS sensor array. The system measures the spatial derivative of the dynamic surface deflections, as the deflection of each point on the surface is measured relative to a neighboring point. The distance between the optical head and the target surface can be up to 5 meters, or even further depending on surroundings, wind and thermal conditions.

The inspected object is exposed to vibration excitations. The excitation results in structural vibrations or surface waves that propagate across the object field, revealing surface or subsurface defects. Vibration amplitude contour maps can be displayed in real-time or as numerical recordings.

For simple and informative interpretation and evaluation the Defect Detection Scan functionality is developed.This algorithm performs a frequency scan to detect discontinuities in vibration pattern and modes and results are presented in figures and illustrations.

This inspection technology will be able to detect:
– Delamination
– Lack of bonding
– Impact damages
– Matrix and fiber cracking

The underlying algorithms and filtering techniques have been improved over time to produce a very robust measurement system. Inspections can be done in challenging conditions offshore and onshore. The complete inspection system is applicable to many types of inspection sites such as workshops, process plants, hangars and shipyards.