Non-Destructive Detection of Defects in Composite Boat Hulls

Abstract

This paper demonstrates use of thermal imaging for nondestructive defect detection in a composite boat hull which covers a large area. There is a strong demand in the boat industry for a non-destructive method that can detect defects such as delamination, voids of air or fluid, cracks, acid, dry mat, and carbon fiber. These defects are always difficult to detect as they occur inside the walls of the boat. Currently, ultrasound and manual inspection methods are used to identify these defects. The manual checking technique is unscientific; furthermore the ultrasound method is not acceptable due to unsatisfactory results. Thermal imaging involves detecting infra-red radiation from a hot body; this is captured by a thermal imaging camera. A thermal heat gun is used to heat the walls of the boat hull. After heating for a specific time period, the walls of the boat start emitting radiation. Dry void attains the highest peak intensity value for short time heating followed by Acid. Other defects like carbon fiber, delamination, and dry mat took longer time to attain higher intensity value. The decay of radiations is also different for various types of defects. The maximum intensity decay occurs for dry void as compared to other defects. From the results obtained so far, it can be inferred that thermal imaging can distinctly differentiate the different kinds of defects, as well as the unaffected areas of the boat wall.