SEM fractography and failure analysis of nonmetallic materials

Abstract

This paper analyzes a collection of SEM fractographs compiled from 12 years of undergraduate and graduate level courses on fractography and failure analysis. Each nonmetallic material studied (glass, plastic, FRP, and wood) was fractured under controlled conditions so that the fracture was due mainly to one mode of loading such as tension, torsion, unidirectional bending, fatigue by reverse bending, and impact. With the aid of the stereomicroscope and the SEM, the fracture features of each sample were analyzed and fractographs obtained at a wide range of magnifications. The features and direction of crack propagation were correlated with the mode of loading which induced the fracture. From this study, correlations among the main fracture modes, micromechanisms, microfracture features, and loading conditions were compiled. Such correlations are invaluable for the proper interpretation of fracture features during failure analysis especially where little is known about the cause of the fracture.