The Truth Behind Composite Inspection Methods
(Room Conference Hall)
04 Apr 18
2:00 PM
-
3:30 PM
Composite pipe repair systems have become widespread repair choices throughout the pipeline, offshore, plant and refinery markets. This has increased interest in knowledge about composite repair inspection methods among end users. They want to know how they can monitor the health of a repair system and predict failure before it happens. There is a lot of confusion and misinformation in the industry on how to properly inspect a composite pipe repair via non-destructive inspection techniques, sometimes referred to as NDI or NDT. The governing standard in America, ASME PCC-2, has very little information to offer the end user about inspection techniques besides a rudimentary tap test. The standard defers the responsibility for NDI knowledge to the materials manufacturer, and some manufacturers have used this gap to spread potentially misleading information on the inspectability of composites. All composite repair systems are inspectable and a lot of the information on applicable methods has existed within the Aerospace Industry for decades. The most critical areas for defect inspection are: the underlying pipe wall, the bond line between the pipe wall and the composite, and inside the composite repair. Most NDI methods are limited in what kinds of defects they can detect, so examining a specific area requires the correct NDI method. Testing methods to be covered include: 1. Phased Array: This form of ultrasonic NDT uses dozens of independently pulsing transducers that can be swept at a variety of angles to locate defects. This method can be used to inspect both the bond line and in the pipe wall. 2. Guided Wave: Another form of ultrasonic testing, the guided wave method can detect, characterize and visually present delamination defects in a composite structure. 3. Pulse Eddy Current: This NDT method, based upon Faraday’s Law of Magnetic Induction, is an electromagnetic testing method that measures the strength of eddy currents to detect defects in conductive materials. This method can be used to inspect the underlying pipe wall through the composite. 4. Digital Radiography: Also known as X-ray, this method uses penetrating radiation to inspect delamination and disbonding within the materials being tested. This method can find defects in both the composite and in the pipe wall. 5. Microwave: This method is used to detect defects such as delamination and gouges in nonmetallic materials, making it possible to view surface defects of steel pipe underneath a composite repair. 6. Thermography: By detecting the change in thermal activity within a material, thermography can find defects by creating a heat map of the surface of a stressed object. This method can find defects within the composite.