Model based Inverse Methods for Sizing Cracks of Varying Shape and Location in Bolt hole Eddy Current (BHEC) Inspections (Postprint)
Abstract
A comprehensive approach is presented to perform model-based inversion of crack characteristics using bolt hole eddy current (BHEC) techniques. Data was acquired for a wide range of crack sizes and shapes, including mid-bore, corner and through-thickness crack types, and from both standard eddy current hardware and a prototype BHEC system with z-axis position encoding. Signal processing algorithms were developed to process and extract features from the 2D data sets, and inversion algorithms using VIC-3D generated surrogate models were used for inverting crack size. New model results are presented, which now address the effect of having a corner crack at an edge and a through crack adjacent to two edges. A two-step inversion process was implemented that first evaluates the material layer thickness, crack type and location, in order to select the most appropriate VIC-3D surrogate model for subsequent crack sizing inversion step. Inversion results for select mid-bore, through and corner crack specimens are presented where sizing performance was found to be satisfactory in general, but also depend on the size and location of the flaw.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 10, 2016
- Accession Number
- AD1030928
Entities
People
- David Forsyth
- Doyle Motes
- Elias Sabbagh
- Eric A. Lindgren
- Harold A. Sabbagh
- Jennifer Flores-lamb
- John C. Aldrin
- Liming Zhao
- Mark Keiser
- R. K. Murphy
- Ryan Mooers
Organizations
- Air Force Research Laboratory Materials and Manufacturing Directorate