Nondestructive Evaluation of Sandwich Structures: A Review of Some Inspection Techniques

This article is a summary of research and development conducted by the author's group at Iowa State University for the nondestructive evaluation (NDE) of sandwich structures in aviation, space, and marine applications. The targets of inspection include manufacture defects, in-service damage due to human and natural causes, and the inspection of repairs on sandwich structures. The emphases adopted in the development of NDE techniques and instruments for sandwich structures are imaging capability, quantitative inspection, and the ease of use in the field. This article describes the various NDE methods for sandwich structures, especially those techniques and instruments developed at Iowa State University that had gone through the research, development, and field test stages.