Contact:
Melody Verges
University of New Orleans
Dept. of Mechanical Engineering
New Orleans, LA 70148
Tel: (504) 280-5472
mverges@uno.edu

To achieve the performance requirements objectives of future single stage, reusable launch vehicles, significant effort is being expended towards the development of composite aerospace structures. Important issues that must be addressed before completely embracing this technology include the improvement in the manufacturing process of composite structures and the capability of detecting and monitoring flaws in these structures that occur in service and/or in the manufacturing process. Particular damage of interest for aerospace applications includes microcracking and debonding.

In recent years, the Non-Destructive Evaluation (NDE) of structures has proven beneficial in the improvement of manufacturing processes as well as in the assessment of the integrity of structures. While many of the available NDE techniques are capable of assessing a homogeneous component on a qualitative level, research is still underway in the area of NDE for improving the capability of quantifying subsurface flaws in terms of orientation and size.

The University of New Orleans has initiated "NDE Techniques for Application in Composite Manufacturing" in order to develop procedures for the analysis of the quality of a composite part on a quantitative scale. While the focus of this technique will be the assurance of the quality of the fabricated composite part for aerospace structures, this technique will also be useful for the monitoring of the integrity of the structure in field conditions. The three year, three phase objectives of this work are summarized as follows:

• The initial phase of the project will involve the exploration of computed x-ray microtomography (micro-CT) as an NDE technique for composite materials. The objectives of this exploration will be to (1) investigate the use of micro-CT for direct detection of micro-cracking and debonding in composite structures, and (2) develop micro-CT as a research tool in the development of a coupled experimental and computational nondestructive testing methodology for assessing subsurface fractures within structures.
• The next phase of the project has the objective of developing an analytical model relating surface displacements to subsurface flaw size and shape in composite structures. This would be an extension of current work that concentrates on using such methods for characterizing embedded flaws in homogeneous materials.
• The objective of the final phase of this project is to combine these tools into a non-destructive evaluation technique capable of assessing the integrity of composite structures and improve health monitoring in composites manufacturing.