The Evolving NDT Method of 3D Laser Scanning for Inspection

Transcription

1 The Evolving NDT Method of 3D Laser Scanning for Inspection David Mackintosh, Bryan Cornforth, Tom Taylor, Kerry Blevins, Samuel Langdon

2 Outline 1. Introduction to 3D scanning 2. Case example 3. 3D Scanning as an NDT method

3 Part 1 Introduction to 3D Scanning

4 Some Applications of 3D Scanning Inspection and damage assessment Measurement and verification Reverse engineering ( scan to CAD ) Plants, facilities, and tanks (mid range)

5 Mid Range Laser Scanning Typical specs: Range up to 150 m (500 ft) Completes 360 scan in about 15 min.

6 Overview of Mid Range Scanning Documentation and measurement of component damaged in explosion Tank deformation strain analysis Coke burner floor warpage Surge bin fill volume

7 Close-Range Laser Scanning Close range means a few inches from the surface Creaform3D.com The rest of this presentation will focus on close range LaserScan3D

8 A Surface Scan Gives Information Compare this surface to a cylinder Highlights: Corrosion Mechanical Manufacturing imperfections

9 Example: Dent Assessment Software Designed for on-site analysis by Level 2 technician Post-processing for strain analysis:

10 Laser Scanning for Inspection Strengths Non-contact: no part wear or damage High resolution (tens of thousands of points per square foot) High accuracy available: some metrologygrade scanners rated 1 in 10,000 (0.1 mm over 1 m, or inch over 1 foot) Scan data can be imported for finite element analysis

11 Laser Scanning for Inspection Limitations Surface method only; needs reference surface for analysis. Shiny or dark-coloured surfaces usually require preparation (matte white) Bright ambient light can blind scanner; shading may be needed Cannot scan into sharp cracks Analysis often software-intensive

12 Ultrasonic Testing (UT) as a Partner Technology to Laser Scanning Laser scanning and UT can be used together to estimate depth of corrosion. Automated (scanning) UT has difficulty on heavily corroded surfaces Spot UT (pencil probe) can provide check points Laser scanner can cover entire surface at high resolution, with verification from UT points.

13 Depth of Metal Loss on a Curve In software, a reference curve can be used to measure depth With extensive corrosion, estimating the reference curve is more difficult?

14 Ultrasonic Thickness (UT) for More Accurate Reference Surface UT1 UT2 UT3 UT4 UT5 Estimated reference surface

15 Part 2 Case Example

16 A Sample Scanning Job, from Start to Finish Fitness for service assessment of support legs on storage sphere Scan data was used to estimate corrosion depth Job in Edmonton, Canada, -9 C (16 F)

17 Surface at First Sight Before scanning, surface was sandblasted to remove coating and heavy rust.

18 Additional Debris (Ice) was Removed from Surface Meanwhile, the scanner is in open air being cooled to ambient temperature

19 Calibrate. Scan.

20 Ultrasonic Thickness (UT) Readings UT readings used for reference on extensive corrosion. Position of each reading is marked with an optical target

21 Scan Data

22 Analysis Scan data Reference surface

23 Report: Deviation plot

24 Report: Spreadsheet Grid of Depths 24

25 Part 3 3D Scanning as an NDT Method

26 Challenges of a New Technology Few codes and standards [MacKinnon, 2014] Advanced analysis software can be expensive and complex Common perception of the technology as: easy automatic gives you all the info you need laser = accurate

27 Elements of a Quality Program Training course Written requirements for certification Scanning reference blocks Benchmarking

28 Training and Certification Syllabus Multi-choice exams Practical exams (scan, analyze, report) Written requirements for experience hours

29 Training Course Outline 3D scanning: purpose, benefits, & limitations Laser safety (most laser scanners are eye-safe) Theory: Scanner principle of operation Optical properties of surfaces Field Practices Suitability of scanner for a given job Optimizing scan settings Sources of noise and inaccuracy Software analysis tools

30 Scanning Reference Block Example: Portable verification coupon for pipeline corrosion scanning Coupon is scanned to verify that the system produces the correct ASME B31G burst pressure

31 Benchmarking Example: pit sizing test block Block is used to measure and verify scanner performance on a range of pit sizes

32 Benchmarking Example What is the narrowest pit (aspect ratio) that a scanner can measure? Typical scanner viewing angles range from 15 to 30.

33 Conclusion

34 3D Scanning 3D scanning: a powerful and rapidly-evolving NDT method As with other methods, requires training, experience, development, and an effective quality program.

35 Thank you! Questions?

36 References and Sources ANSI/ASNT CP , Standard Topical Outlines for Qualification of Nondestructive Testing Personnel, The American Society for Nondestructive Testing, Columbus, OH, ASME B31G-2012, Manual for Determining the Remaining Strength of Corroded Pipelines, The American Society of Mechanical Engineers, New York, ASNT, Laser Based Profilometry Using Point Triangulation, Nondestructive Testing Handbook, Second Edition: Volume 9, Special Methods, the American Society for Nondestructive Testing, Columbus, OH, ASNT, Recommended Practice No. SNT-TC-1A: Personnel Qualification and Certification in Nondestructive Testing, The American Society for Nondestructive Testing, Columbus, OH, Harding, K. "3D profilometry: next requests from the industrial viewpoint", Proc. SPIE 7855, Optical Metrology and Inspection for Industrial Applications, (November 11, 2010). Kainat, M., Samer, A., Cheng, J.J.R., Ferguson, J., and Martens, M., Identifying Initial Imperfection Patterns of Energy Pipes Using a 3D Laser Scanner, Proceedings of the 9th International Pipeline Conference IPC2012, Calgary, Canada, September 24 28, MacKinnon. D., Roe, G., "3D Imaging Standards: Where are we now?" 2014 SPAR International Conference, Colorado Springs, CO, April 17, Mackintosh, D., Taylor, T., Bryant, G. "Field Experience and Best Practices for Laser Assessment of Pipeline Damage," NDT in Canada 2013 Conference, Calgary, Alberta, October 7-10, Pfeffer, C., The State of 3-D Imaging Standards, Quality Digest, November 9,

37 Authors Acuren Group, Inc. David Mackintosh, Edmonton, Alberta Bryan Cornforth, Calgary, Alberta Tom Taylor, Acuren Group Inc., Calgary, Alberta Acuren Inspection, Inc. Samuel Langdon, Acuren Inspection, Inc., Cincinnati, OH Kerry Blevins, Acuren Inspection, Inc., Cincinnati, OH