In-situ Nondestructive Evaluation for Horizontal Stabilator of T-50 Advanced Trainer using Mobile Pulse-echo Ultrasonic Propagation Imager

2019 ◽  
Vol 39 (5) ◽  
pp. 261-268
Author(s):  
Seung-Chan Hong ◽  
Jung-Ryul Lee ◽  
Jongwoon Park
Keyword(s):  
Nondestructive Evaluation ◽  
Ultrasonic Propagation ◽  
Pulse Echo

Real world application of angular scan pulse-echo ultrasonic propagation imager for damage tolerance evaluation of full-scale composite fuselage

2019 ◽  
Vol 18 (5-6) ◽  
pp. 1943-1952 ◽  
Author(s):  
WJ Lee ◽  
BH Seo ◽  
SC Hong ◽  
MS Won ◽  
JR Lee
Keyword(s):  
Composite Structures ◽  
Fatigue Testing ◽  
Damage Tolerance ◽  
Structural Characteristics ◽  
Full Scale ◽  
Inspection Method ◽  
Complex Test ◽  
Ultrasonic Propagation ◽  
Pulse Echo

Composite structures are assertively used for new airframe designs and manufacturing in military aircrafts because of superior strength-to-weight ratios and fatigue resistance. Because the composites have different fatigue failure characteristics compared with metals, it is necessary to develop different approaches for the composite fatigue design and testing. In this study, we propose an in situ damage evaluation technology with high spatial resolution during full-scale fatigue testing of composite aircraft structures. For real composite structure development considering composite fatigue characteristics, full-scale fatigue and damage tolerance tests of the composite fuselage structure were conducted to evaluate the structural characteristics. In the meantime, the laser ultrasonic nondestructive inspection method, called an angular scan pulse-echo ultrasonic propagation imager, which is fully noncontact, real-time, and portable to position it in between the complex test rigs, is used to observe in situ damage growth of the composite. Finally, the verification procedure assisted by the angular scan pulse-echo ultrasonic propagation imager assures no growth of the initial impact damages after lifetime operation and proves the damage tolerance capability of the developed composite fuselage structure.

Correlations Between Advanced Nondestructive Evaluation Methods and Fracture Mechanics Parameters

1980 ◽  
Vol 102 (1) ◽  
pp. 50-55 ◽  
Author(s):  
C. M. Teller ◽  
J. R. Barton ◽  
G. A. Matzkanin ◽  
F. N. Kusenberger ◽  
R. E. Beissner
Keyword(s):  
Surface Wave ◽  
Fracture Mechanics ◽  
Nondestructive Evaluation ◽  
Surface Waves ◽  
Fatigue Cracks ◽  
Small Surface ◽  
Magnetic Perturbation ◽  
Hinge Model ◽  
Pulse Echo ◽  
Aisi 4340

Investigations were conducted on surface entering fatigue cracks, 0.13 to 1.27 mm (0.005 to 0.05 in.) long, in rod-type tensile specimens of HY 180 and AISI 4340 steels using surface wave ultrasonics and magnetic perturbation. Pulse-echo, surface wave ultrasonic results indicate that at 10 MHz the minimum flaw size detectable in HY 180 specimens is two to three times larger than that in AISI 4340. Also, fatigue cracks as long as 0.76 mm (0.030 in.) in HY 180 specimens could not be reliably detected with 10 MHz surface waves unless load was applied to open the crack. Extensive magnetic perturbation measurements on AISI 4340 suggest a “hinge” model for the opening of small surface entering fatigue cracks.

Dual-energy wave subtraction imaging for evaluation of barely visible impact damage with an ultrasonic propagation imaging system

2017 ◽  
Vol 29 (17) ◽  
pp. 3411-3425 ◽  
Author(s):  
Yunshil Choi ◽  
Jung-Ryul Lee
Keyword(s):  
Laser Beam ◽  
Nondestructive Evaluation ◽  
Composite Structures ◽  
Imaging System ◽  
Impact Damage ◽  
Dual Energy ◽  
Ultrasonic Waves ◽  
Excitation Energies ◽  
Ultrasonic Signals ◽  
Ultrasonic Propagation

Barely visible impact damage from low-velocity impacts have been studied as critical design factors of composite structures. In this article, a dual-energy wave subtraction algorithm using an ultrasonic propagation imaging system is proposed to evaluate barely visible impact damage as a strategy of fast in situ nondestructive evaluation or structural health monitoring (SHM). The ultrasonic propagation imaging system is a type of nondestructive evaluation or SHM system and is based on scanning laser-induced guided ultrasound and fixed sensors. The amplitude of ultrasonic signals generated by the ultrasonic propagation imaging system increases with the increasing energy of the laser beam. Two ultrasonic signals generated by different excitation energies of the laser beam can be equalized by multiplying a constant factor to one of them. Therefore, the residuals after subtraction of two signals may be close to zero. However, the two different energy induced signals in the damaged area will be nonzero due to the change in material conditions regarding the laser ultrasonic generation mechanism. The dual-energy wave subtraction algorithm eliminates most of the incident ultrasonic waves and amplifies anomalous waves. A composite wing skin including two barely visible impact damages as well as a composite sandwich panel, including a single barely visible impact damage, were inspected to validate the proposed algorithm.

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