Thermal Nondestructive Testing of Fiberglass Using Liquid Crystals: A Two-Part Report

摘要

Thermal nondestructive testing is a technique for obtaining surface temperature profiles on a structure and subsequently relating this information to some imperfection within the structure. This two-part report details research to investigate cholesteric liquid crystals as the thermal medium for identifying fiberglass flaws. Increasingly fiberglass, a composite material, is replacing wood, steel and aluminum in boat manufacture and an easy to use, inexpensive but effective testing method to detect manufacturing defects or accident damage is needed. Part 1 describes a one-dimensional heat transfer model through a laminate with various kinds of interlaminar flaws. The effects of flaw thickness, depths, and heat flow characteristics have been plotted for a range of variables that model most practical situations. Part 2 of the report focuses on studies of a fiberglass laminate containing simulated flaws or orthogonal to the surface. Various plots on the sensitivity and effectiveness of liquid crystal thermal testing are put forth.