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Thesis
Analysis of acoustic emission data detected from a full-scale curved composite PRSEUS fuselage panel subjected to combined loading
Master of Science (M.S.), Drexel University
Jun 2013
DOI:
https://doi.org/10.17918/00010648
Abstract
A test program was conducted to evaluate the damage-containment capability of a full-scale Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) carbon/epoxy fuselage panel. The tests were conducted at the Full-Scale Airframe Structural Test Evaluation and Research (FASTER) facility, located at the Federal Aviation Administration William J. Hughes Technical Center, in partnership with NASA Langley Research Center and Boeing Research and Technology. The test section of the fuselage-like PRSEUS panel contained a two-bay through-the-thickness notch, severing the central stringer, and was subjected to combined internal pressure and axial tensile loading. Notch tip damage initiation and progression were monitored visually (via interior and exterior cameras). The PRSEUS panel was successfully arrested damage along the stringer stitch-rows within the two-bay test section, up to loads exceeding the design limit requirements. The panel failed in a catastrophic manner well above ultimate load requirements. Detailed post-test nondestructive and destructive examinations were conducted to determine the extent of damage and the primary modes of failure in the composite skin of the panel. As part of this study, a comprehensive investigation involving the use of the acoustic emission (AE) technique to detect and locate notch tip damage initiation and accumulation was conducted. Particular attention was given to tracking damage progression during loading was performed. The primary objective of using the AE technique during the combined loading of the PRSEUS panel was to: i) determine the point of damage initiation in terms of applied load; ii) track the progression of damage in real-time, and provide an indication of incipient catastrophic failure of the panel; and iii) determine the severity and extent of damage in terms of the size of the damage. Detailed post-test AE data analyses were conducted to characterize the AE signals recorded during loading. Special attention was given to distinguishing between the emission generated by damage growth at the notch tip and the voluminous emission generated by macro and micro damages throughout the AE gage section, including delamination, disbanding, matrix cracking, stitch failures, and the corresponding fretting among the numerous newly formed fracture surfaces as well as extraneous emission from the loading mechanisms. Two-dimensional location scatter plots of AE events and three-dimensional AE event and event-energy histograms were used to track damage progression as a function of applied load. The location of AE events in the test section was correlated with the visually observed notch-tip damage on the exterior and interior surfaces of the panel. The intensity of the generated emission was used as a basis of distinguishing between damage-related emission from that generated from extraneous sources. Pattern recognition algorithms were employed to cluster the voluminous data set of AE signals into legitimate 'burst'-type AE signals, noisy signals, and 'trains of hits'. The results indicated that AE was able to detect damage initiation at early stages of loading, locate the notch tip damage site, and monitor and track damage progression. AE data analyses indicated that the high intensity events, located by at least five sensors, provide the best agreement between AE results and the visually measured extent of notch tip damage. The intensity distribution histograms of the recorded AE events aided in distinguishing extraneous emission from damage-related emission in terms of AE signal features such as amplitude, duration, counts and energy. Power Law fitting of the amplitude distributions demonstrated the effect of attenuation of stress waves as they propagated in the panel. The pattern recognition technique successfully separated emission associated with notch-tip damage from that generated from extraneous sources. This study thus demonstrates the potential of the AE technique in monitoring damage propagation in large structures in real-time.
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Details
- Title
- Analysis of acoustic emission data detected from a full-scale curved composite PRSEUS fuselage panel subjected to combined loading
- Creators
- Amey Rajendra Khanolkar
- Contributors
- Jonathan Awerbuch (Advisor) - Drexel University, Mechanical Engineering and MechanicsDidem Ozevin (Advisor)Tein-Min Tan (Advisor) - Drexel University, Mechanical Engineering and Mechanics
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xxxi, 668 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- College of Engineering (1970-2026); Mechanical Engineering (and Mechanics) [Historical]; Drexel University
- Other Identifier
- 991021930810104721