Identification of Defects in Products Made from Honeycomb Composite Materials Using Infrared Scanning Thermography

Abstract

Introduction. Recently, sandwich-structured composite materials based on honeycomb core and strong thin shells have become widespread. However, these materials are characterized by manufacturing and operational flaws such as “non-gluing” and “delamination” that is the breaking of the bonds between the shell and the honeycomb core that result in the deterioration in the mechanical, acoustic and thermal properties of the material. Aim of the Study. The study is aimed at developing effective methods for detecting flaws in gluing shell with comb core in honeycomb polymer materials. Materials and Methods. The article describes a method for detecting these flaws using scanning thermography with a linear heat source, based on the estimation and subsequent analysis of the distribution of local temperature field gradients on the product surface. Results. The experiments were carried out on a model polymer specimen with an embedded artificial flaw; there were shown the main sources of emerging noise, control errors, and the ways to reduce their influence; a numerical method for assessing the accuracy of the flaw measurement method was proposed. Discussion and Conclusion. Tests carried out on a control specimen showed that the proportion of errors in measuring a defect does not exceed 12%.