NDT & E International

(1) Experimental measurements of the spatial distribution of zero-group-velocity Lamb mode resonance frequency as a function of loading cycles during the whole fatigue lifetime (fatigue loading in a two sides clamped compression configuration inducing buckling). (2) Examples of numerical calculations, to perform frequency-wavenumber (f-k) analyzes of the Lamb modes in a fatigued sample (Aluminum) realized using the finite element method, for both intact (loading cycles = 0) and damaged (loading cycles = 4000, 9500 and 10000) cases.

The data obtained from ultrasonic and quantitative metallography measurements on GH4169 samples, is used to built a an optimized multi-parameter ultrasonic evaluation model for grain diameter. The performance of the new model described in this study was benchmarked against three single parameter models (i.e. velocity, attenuation, and backscattering) using two test samples. The abstract are list follow. An evaluation model based on multiple ultrasonic parameters was developed to control mean absolute error between an actual measured value and a model calculation value. Superalloy GH4169 was used to validate the presented model. A multi-dimensional ultrasonic parameter set was built for each sample by ultrasonic and nonlinear ultrasonic test and parameter calculation. The feature scale of different parameters was restricted to the same range using normalization. The dimensionality of the parameter set was descended by a correlation metric with grain size. A new one-dimensional ultrasonic characteristic parameter was comprised of the select normalized set of ultrasonic parameters under application of a mapping function in the form of a quadratic polynomial with undetermined coefficients. The relationship between the new ultrasonic multiple eigenvalues mapping parameter and grain size was expressed using a linear fitting function. An optimization problem aimed at minimizing the mean absolute error between the mapping and fitting parameters was solved using evolutionary algorithms to obtain coefficients for the mapping and fitting functions. These calculations were used to generate the full multi-parameter ultrasonic evaluation model, which was benchmarked against three single parameter evaluation models (i.e. velocity, attenuation coefficient, and backscattering). The mean grain size evaluation value of GH4169 using this new multi-parameter model is sound and precise.

************************************************************************************************************* This folder contains 1 .xlsx file and 3 subfolders for the data used to carry out the probablity of detection (PoD) study in the following published paper: Performance analysis of single-frequency near electrical resonance signal enhancement (SF-NERSE) defect detection Robert R. Hughes and Steve Dixon Accepted ## Oct 2018 for publication in NDT&E International ------------------------------------------------------------------------------------------------------------- TYPE OF DATA: 2D eddy-current scan data (@ single frequency) DATES OF ACQUISITION: 21st May 2015 - 7th July 2015 DATA ACQUIRED BY: Robert R. Hughes CONTACT PERSON: Dr Robert R. Hughes, University of Bristol, e-mail: robert.hughes@bristol.ac.uk JOURNAL PUBLISHING THE DATA: NDT&E International TOTAL NUMBER OF FOLDERS: 03 TOTAL NUMBER OF FILES: 1 (.xlsx) and 03 x 36 (.mat) ------------------------------------------------------------------------------------------------------------- DESCRIPTION OF THE DATA ACQUISITION: The complex scan data was acquired using a 1.14mm outer diameter, ferrite cored and sheilded solenoid coil of 35 turns manufactured in-house. The data was aquired via in-house Labview software, and the data processed via Python and Matlab. Each folder contains 36 .mat (Matlab) format files holding the complex data matrix for each scan. The following additional information may be useful for interpreting the data: scan pitch: x = 0.25 mm, y = 0.25 mm Frequency: 3.25 MHz and 4 MHz This folder also contains an .xlsx spreadsheet summarising the peak defect signals, maximum background signal and rms background level. -------------------------------------------------------------------------------------------------------------

This data includes the measurements taken on the flat and curved aircraft panels referenced within the research paper, and shows the results of the two convergence studies completed and detailed within the paper.

This dataset contains the reconstructed simulation data, MCW surface point clouds, measurement results used for Fig 14 and Fig 16.

This dataset contains the reconstructed simulation data, MCW surface point clouds, measurement results used for Fig 14 and Fig 16.