Abnormalities in Ultrasonic (C-Scan) Images of Composite Structures: Impact Damaged Versus Hole Damaged

Mahmoud Zaki Iskandarani

doi:10.3844/jcssp.2019.972.982

Abstract

This paper is about applying image processing to detect different types and levels of damage in composite structures using in C-scan images produced by ultrasonic testing. This method plays an important role as it can detect any discontinuities or flaws in the specimen. To analyze such critical image in an, automated inspection environment an image processing method that correlates Threshold values to Gradient Field values is used to extract important information from the c-scan images in order to detect abnormalities that may exist. The paper presents an improved approach to composite damage characterization using Threshold Level Variation as an input variable to Gradient Fields. Furthermore, the detailed results showed an important dependency between what can be detected and the used threshold level. At each level certain abnormalities appeared. Setting threshold value is proved to be a function of image type and quality, purpose and application.

Highlights

Composite laminated has a marked impact on engineering as many industries are attempting to produce lightweight material with best quality
The nature of wave-material interaction is complicated as one kind of incident wave can result in the generation of other types within a structure. These types of waves tend to get modified by the encountered boundaries, by the material itself and the presence of defects, which in non-uniform composite structures and/or damaged composites will most of the time result in the creation of edges within the fibermatrix system
Impact Damaged Case: Impact Damage Case: Table 1 show the effect of varying the threshold level on the pixel distribution of the C-Scan image of impact damaged Woven Glass composite structure

Summary

Introduction

Composite laminated has a marked impact on engineering as many industries are attempting to produce lightweight material with best quality. The nature of wave-material interaction is complicated as one kind of incident wave can result in the generation of other types within a structure These types of waves tend to get modified by the encountered boundaries, by the material itself and the presence of defects, which in non-uniform composite structures and/or damaged composites will most of the time result in the creation of edges within the fibermatrix system. The segmented image is a function of both discontinuity and uniformity Both factors can be used to establish similarity and level of damage as a result of abrupt change or edges (Murat and Rahman, 2017; Putkis et al, 2016; Murat et al, 2016; Murat and Fromme, 2016)

Methods

Discussion

Conclusion