Feature Selection of Surface Topography Parameters for Fatigue Damage
Detection Using Pearson Correlation Method and Neural Network Analysis
Abstract
The global objective of this study was to investigate the best features
of the surface topography for fatigue damage detection and
classification. The presence of the stress concentration in valleys of
the surface topography causes a grain slip and a crack initiation at the
surface of the machined structure and finally leads to fatigue failures.
Therefore, the surface topography has a major influence on the fatigue
strength of the machined structure. An optical confocal measurement
system (Alicona) was applied to measure the surface topography
parameters. These parameters are the arithmetical mean height S a , the
root-mean-square height S q , the maximum peak height S p , the maximum
valley depth S v , the maximum height S z , and ten-points height S z 1
0 . In this paper, feature selection using the Pearson correlation
method was adopted to select the best surface textures that provide best
the neural network (NN) model performance.The proposed NN models have
been trained using the scaled conjugate-gradient back-propagation
method. Results showed that the best surface topography parameters were
S a , S v , S 1 0 Z , S z , where the NN model can detect and classify
the damage with an accuracy of up to ∼94 .4%.