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).
- 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
- 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.
- 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.