Aging of current commercial and military aircraft has become a major concern as many older aircraft are reaching their original design life. Service failures due to inaccurate characterization of aging responses might result in costly repair, premature component replacement, and loss of human lives. The properties of aluminum alloys, titanium alloys, and nickel-based superalloys used in aircraft structures and engines might degrade with service conditions associated with the operation of the aircraft. Important aspects of environmental conditions encountered in service cannot be accurately simulated. Thus, it will be a great advantage that the in-situ mechanical properties can be obtained nondestructively. A novel portable/in-situ stress-strain microprobe (SSM) system was developed to use an automated ball indentation technique to measure, yield strength, true- stress versus true-plastic-strain curve, strength coefficient, strain-hardening-exponent, and to estimate fracture toughness. Example test results on metallic structural components and samples are given in this paper and a video demonstration will be presented at the conference. Furthermore, potential applications of the SSM technology to assess the integrity of aging aircraft are briefly discussed.

Date Published: 14 November 1996
PDF: 12 pages
Proc. SPIE 2945, Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware, (14 November 1996); doi: 10.1117/12.259096

Published in SPIE Proceedings Vol. 2945:
Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware
Raymond D. Rempt; Alfred L. Broz, Editor(s)