Processing and Probability Analysis of Pulsed Terahertz NDE of Corrosion under Shuttle Tile Data
This paper examines data processing and probability analysis of pulsed terahertz NDE scans of corrosion defects under a Shuttle tile. Pulsed terahertz data collected from an aluminum plate with fabricated corrosion defects and covered with a Shuttle tile is presented. The corrosion defects imaged were fabricated by electrochemically etching areas of various diameter and depth in the plate. In this work, the aluminum plate echo signal is located in the terahertz time-of-flight data and a threshold is applied to produce a binary image of sample features. Feature location and area are examined and identified as corrosion through comparison with the known defect layout. The results are tabulated with hit, miss, or false call information for a probability of detection analysis that is used to identify an optimal processing threshold.
Ultrasonic and advanced methods for nondestructive testing and material characterization
Ultrasonic Methods: Fundamentals Models and Measurements for Ultrasonic Nondestructive Evaluation Systems (L W Schmerr Jr.) Integrated and Flexible High Temperature Piezoelectric Ultrasonic Transducers (C-K Jen & M Kobayashi) Real-Time and In-Line Ultrasonic Diagnostics of Polymer Processes (C-K Jen et al.) Guided Wave Based Nondestructive Testing: A Reference-Free Pattern Recognition Approach (H Sohn et al.) Acoustic Nonlinear Imaging and Its Application in Tissue Characterization (D Zhang & X-F Gong) Advanced (Other) Methods: Electromagnetic NDE Techniques for Materials Characterization (B P C Rao et al.) Terahertz NDE for Aerospace Applications (R F Anastasi et al.) Large Area Time Domain Terahertz (T-Ray) Imaging Non-Destructive Evaluation for Security and Aerospace (D Zimdars et al.) Active Infrared Thermography Techniques for the Nondestructive Testing of Materials (C Ibarra-Castanedo et al.) Quantitative Evaluation of Emerging Infrared Thermography Technologies for Aerospace Applications (J DiMambro) Signal and Image Processing in NDE: Computational Intelligence Methodologies for Non-Destructive Testing/Evaluation Applications (M Cacciola et al.) Split Spectrum Processing and Automatic Flaw Detection (K D Donohue) Homomorphic Deconvolution of Ultrasonic Images (R Jirik & T Taxt) and other papers.
Concept definition: retirement for cause of F100 rotor components. Final report June 1977-March 1980
Historically, gas turbine engine disks are retired when they accrue an analytically determined lifetime where the first fatigue crack per 1000 disks could be expected. By definition then, 99.9% of these components are being retired prematurely. Retirement-for-cause (RFC) is a procedure, based on Fracture Mechanics, which would allow safe utilization of the full life capacities of each individual disk. Since gas turbine disks are among the most costly of engine components, adopting a RFC philosophy could result in substantial systems life cycle cost savings. These would accrue from reduced replacement costs, conservation of strategic materials such as cobalt, and energy savings. This study addresses the application of this concept to the USAF F100 engine.