Event Title
Quantitative analysis of a class of subsurface cracks using shearography and finite element modeling
Location
La Jolla, CA
Start Date
1-1-1993 12:00 PM
Description
The application of a full field non-contacting measurement system for nondestructively evaluating (NDE) subsurface flaws in structures has been conducted using Electronic Shearography. Shearography has primarily been used as a qualitative tool for locating areas of stress concentration caused by anomalies in materials[1–4]. NASA has been applying optical techniques such as these to NDE inspection of aircraft lap joint integrity, composite material defects, and pressure vessel quality assurance. This paper examines a special class of defects manufactured in thin metal panels and serves as a testbed for interpreting the displacement gradients produced on a simple well-characterized sample with known defects. Electrode discharge machining (EDM) notches were cut into panels to simulate subsurface cracks. Shearography was used to determine the detectability of subsurface cracks ranging in size from 0.8 mm to 25.4 mm fabricated in both steel and aluminum test panels. Finite element modeling was used to verify and quantify experimental results obtained in these tests. Very good agreement existed between both the experimental and predicted displacement models.
Book Title
Review of Progress in Quantitative Nondestructive Evaluation
Volume
12A
Chapter
Chapter 1: Development of Standard Techniques
Section
Optical Techniques
Pages
403-410
DOI
10.1007/978-1-4615-2848-7_52
Copyright Owner
Springer-Verlag US
Copyright Date
January 1993
Language
en
File Format
application/pdf
Included in
Atomic, Molecular and Optical Physics Commons, Optics Commons, Semiconductor and Optical Materials Commons, Structures and Materials Commons
Quantitative analysis of a class of subsurface cracks using shearography and finite element modeling
La Jolla, CA
The application of a full field non-contacting measurement system for nondestructively evaluating (NDE) subsurface flaws in structures has been conducted using Electronic Shearography. Shearography has primarily been used as a qualitative tool for locating areas of stress concentration caused by anomalies in materials[1–4]. NASA has been applying optical techniques such as these to NDE inspection of aircraft lap joint integrity, composite material defects, and pressure vessel quality assurance. This paper examines a special class of defects manufactured in thin metal panels and serves as a testbed for interpreting the displacement gradients produced on a simple well-characterized sample with known defects. Electrode discharge machining (EDM) notches were cut into panels to simulate subsurface cracks. Shearography was used to determine the detectability of subsurface cracks ranging in size from 0.8 mm to 25.4 mm fabricated in both steel and aluminum test panels. Finite element modeling was used to verify and quantify experimental results obtained in these tests. Very good agreement existed between both the experimental and predicted displacement models.
