NDE of Non-metallic Components Using Microwave Based NDE Methods and Techniques

Abstract

The capability to inspect complex, non-metallic components is being developed.  The use of these non-metallic components has grown exponentially in recent years, due to advantages over metallic components more traditionally used.  Use of these components is limited to a significant extent by an inability to perform meaningful inspections for quality both during manufacture of these components and during their service life.  The establishment of accepted inspection methods for these components has expanded their use enabling technological progress to be made that would otherwise be impossible.  Future developments in NDE will enable further progress in material science. Inspection of non-metallic materials is often not practical, or even possible, using traditionally accepted inspection methods.  Specifically, eddy current methods, magnetic particle methods and other methods which rely on either bulk electrical conductivity or magnetism are entirely ineffective on many non-metallic materials.  Additionally, many such materials are reinforced using fibers or fabric which reflect and scatter ultrasonic beams, rendering that method ineffective.

What is needed is a method which can be used to penetrate and provide volumetric information for these non-metallic components.  One such method is microwave NDE. Microwave NDE has been in development since the last quarter of the last century.  Advances were made in the 1980’s which proved that inspection of industrial components was possible, leading to further advancements in the 1990’s making practical microwave NDE a reality. Challenges to application of microwave NDE are many, including a general lack of standardization of the materials and processes used in the manufacture of the non-metallic components in need of inspection.

This paper will provide the technical details of the challenges to implementation of microwave NDE, the history of how many of these challenges have been overcome and the current state of remaining challenges and the paths to their elimination.