Contract for Scientific Visual Analysis and Multimedia

Principle Investigator: David H. Mollenhauer

Title: Comparison of Moire Interferometry and SVELT Strain Data

Description & Progress

Spline Variational Elastic Laminate Technology (SVELT) is a technique under development for the United States Air Force that performs a 3-D analysis of a composite laminates with holes. It is in the development stage and thus requires validation. One of the techniques chosen to aid in validation is moire' interferometry. Moire' interferometry is an experimental technique that measures inplane surface displacements over a relatively large field of view. Inplane strains may be determined through numerical differentiation of the displacement data. Unfortunately, numerical differentiation is a noise enhancing process. For a good comparison, the moire' data must be smoothed. Unfortunately, this may be quite a subjective process. The use of visual tools may aid in making a better, yet still subjective, choice on the level of smoothing necessary.

I currently have moire' displacement data from one test on a 28-ply composite which was tested a little less than a year ago. I also have the corresponding strain data obtained by using the SVELT computer model. I have already determined the procedures necessary for smoothing and manipulating the displacement data, but have arbitrarily arrived at a proper level of smoothing (I did not examine very many different levels of smoothing before making this choice).

Objectives:

Use scientific visualization tools to visually (qualitatively) compare surface strain fields with those obtained using a new analysis technique (SVELT) under development for the U.S. Air Force.

Due to noise present in the moire' displacement data (many causes) and the noise enhancing tendency of numerical differentiation, the data must be smoothed or fitted. Smoothing is currently being examined, but how much smoothing is necessary. Hopefully, some insight into this problem will be gained from using the visual tools available.

Use the multimedia aspect of the course project to create a tool that will allow people to more fully and easily understand the ramifications of the data manipulation.

The first two objectives are mostly research oriented (although the first one can also be considered as an educational tool also). The last objective is essentially an educational tool designed to allow colleagues to better understand the problem.

Tools:

Image generation and manipulation will primarily be accomplished using Spyglass Transform and Adobe Photoshop. Auxiliary figures will be generated on any of the following: MacDraw Pro, Adobe Photoshop, and/or Kaleidagraph. problem.