Online prognosis of fatigue crack at welded joints using nonlinear ultrasonic modulation

Hyung Jin Lim; Hoon Sohn

doi:10.1117/12.2513830

27 March 2019 Online prognosis of fatigue crack at welded joints using nonlinear ultrasonic modulation

Hyung Jin Lim, Hoon Sohn

Proceedings Volume 10970, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2019; 109701H (2019) https://doi.org/10.1117/12.2513830
Event: SPIE Smart Structures + Nondestructive Evaluation, 2019, Denver, Colorado, United States

Abstract

In this study, an online residual fatigue life estimation (prognosis) technique based on nonlinear ultrasonic modulation is developed for a welded joint. When two ultrasonic input signals are applied to a structure at two distinct frequencies, resulting crack opening-and-closing generates modulation components at the summation and difference of the two input frequencies. For prognosis, a fatigue index is defined and extracted from nonlinear ultrasonic modulation components obtained from a target structure. Based on Nazarov-Sutin and Paris-Erdogan theories, the fatigue index is formulated as a simple power function of the loading cycles applied to the target structure. Next, a residual fatigue life is estimated by fitting a power function to the ultrasonic modulation data obtained up to the current loading cycles and extrapolating the fitted power function to the failure point. Finally, the proposed prognosis technique is validated using test data obtained from aluminum (6061-T6) plate specimens with a welded joint. The uniqueness of this paper lies in (1) definition of a fatigue index based on nonlinear ultrasonic modulation components, (2) theoretical formulation of the fatigue index as a power function of loading cycles, (3) online fatigue crack prognosis based on nonlinear ultrasonic measurements, and (4) experimental validation using welded aluminum plates under cyclic loading.

Conference Presentation

Citation Download Citation

Hyung Jin Lim and Hoon Sohn "Online prognosis of fatigue crack at welded joints using nonlinear ultrasonic modulation", Proc. SPIE 10970, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2019, 109701H (27 March 2019); https://doi.org/10.1117/12.2513830

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available