System and method of measuring defects in ferromagnetic materials

US9651471B2 · kind B2 · utility

Assignee

• The Charles Stark Draper Laboratory, Inc. · US

Inventors

• Almir Davis · Quincy, US
• William Joseph Trinkle · Cambridge, US
• Donald E. Gustafson · Lexington, US
• Philip S. Babcock, IV · Westford, US
• Richard Berthold · Binningen, CH

Key dates

• Filing date: May 15, 2015
• Grant date: May 16, 2017
• Expiry date: Jul 1, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/8864
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Defects in ferromagnetic materials are detected and characterized by analyzing the items' magnetic fields to find portions of the magnetic fields that differ in characteristic ways from residual magnetic fields generated by non-defective portions of the items. The portions of the magnetic fields that differ in the characteristic ways correspond to locations of the defects. The residual magnetic fields correspond to portions of the items distant from the defects. The defect characterization may include volume of material lost due to each defect and/or width and/or depth of each defect.