Issue 42

A. De Santis et alii, Frattura ed Integrità Strutturale, 42 (2017) 231-238; DOI: 10.3221/IGF-ESIS.42.25 231 Classification of ductile cast iron specimens: a machine learning approach Alberto De Santis, Daniela Iacoviello Department of Computer, Control and Management Engineering Antonio Ruberti, Sapienza University of Rome, via Ariosto 25, 00185, Rome, Italy desantis@dis.uniroma1.it, orcid.org/0000-0001-5175-4951 iacoviello@dis.uniroma1.it , orcid.org/0000-0003-3506-1455 Vittorio Di Cocco, Francesco Iacoviello Department of Civil and Mechanical Engineering, Università di Cassino e del Lazio Meridionale, via G. Di Blasio 43, 03043 Cassino (Fr), Italy v.dicocco@unicas.it iacoviello@unicas.it, orcid.org/0000-0002-9382-6092 A BSTRACT . In this paper an automatic procedure based on a machine learning approach is proposed to classify ductile cast iron specimens according to the American Society for Testing and Materials guidelines. The mechanical properties of a specimen are strongly influenced by the peculiar morphology of their graphite elements and useful characteristics, the features, are extracted from the specimens’ images; these characteristics examine the shape, the distribution and the size of the graphite particle in the specimen, the nodularity and the nodule count. The principal components analysis are used to provide a more efficient representation of these data. Support vector machines are trained to obtain a classification of the data by yielding sequential binary classification steps. Numerical analysis is performed on a significant number of images providing robust results, also in presence of dust, scratches and measurement noise. K EYWORDS . Ductile cast irons; Graphite nodules; Machine learning approach. Citation: De Santis, A., Iacoviello, D., Di Cocco, V. Iacoviello, F., Classification of ductile cast iron specimens: a machine learning approach, Frattura ed Integrità Strutturale, 42 (2017) 231-238. Received: 25.06.2017 Accepted: 15.08.2017 Published: 01.10.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION iscovered in the years 1943-48, ductile cast irons (DCIs) offer a really interesting combination of cast irons peculiarities (first of all, castability) and of carbon steels mechanical properties (e.g., toughness), [1]. Small additions of elements like Mg or Ce allow to modify the graphite elements shapes, from lamellae (extremely D