Optical Methods For Non Contact Measurements Of Membranes

Paper number

IAC-07-C2.2.01

Author

Prof. Pierre Rochus, Centre Spatial de Liège, Belgium

Coauthor

Dr. Stéphane Roose, Centre Spatial de Liège, Belgium

Coauthor

Dr. Yvan Stockman, Centre Spatial de Liège, Belgium

Coauthor

Mr. Thomas Kuhn, Germany

Coauthor

Mr. Michael Lang, Germany

Coauthor

Dr. Horst Baier, Germany

Coauthor

Mr. Stéphane Langlois, European Space Agency (ESA)/ESTEC, The Netherlands

Coauthor

Mr. GianLuca Casarosa, The Netherlands

Year

2007

Abstract

Structures for space applications very often suffer stringent mass constraints. Therefore, lightweight structures are developed for this purpose, through the use of deployable and/or inflatable beams. The mass of the support for the active surface (solar cells, antenna patches, etc) shall also be reduced. Therefore, thin-film membranes are investigated for this purpose.
However, their inherent properties (low mass and small thickness) preclude the use of conventional measurement methods (accelerometers and displacement transducers for example) during on-ground testing. In this context, innovative non-contact measurement methods need to be developed for these stretched membranes.
The exact measurement requirements obviously depend upon the specific application: sun shield, solar array, antenna or others, with sizes ranging from one to several dozens of meters.
Furthermore, the surface nature of the reflector can be specular reflective, diffusing or transparent.
Many applications dealing with the mechanical behavior of materials require the measurement of displacement fields or deformation fields. In order to attain these measurements, optical methods have become unavoidable due to their non-intrusive approach, their high spatial resolution, their high sensitivity, the large size of their measured field, and the increasing power of the computers that now allow the processing of huge quantities of data.
The object of the presented project is to perform a review of existing measurement systems able to fulfill the requirements: dot-projection videogrammetry (static measurements), stereo-correlation (dynamic and static measurements), fringe projection (wrinkles) and 3D laser scanning vibrometry (dynamic measurements).
Therefore, minimum requirements were given for the study in order to have a representative test articles covering a wide range of applications. In the study we have emphasized the problem of measurement accuracy.
We present test results obtained with the different methods on our test articles.

Abstract document

IAC-07-C2.2.01.pdf

Manuscript document

IAC-07-C2.2.01.pdf (🔒 authorized access only).

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