Dimensional stability of a thick composite panel submitted to temperature loading

MOLIMARD, J.; DOLINKO, A. E.; KAUFMANN, G. H.

Antwerp, Belgium

Congreso; 4th International Conference on Optical Measurement Techniques for Structures and Systems; 2009

Antwerp University

Under the impulsion of aircraft manufacturers, Carbon Fibre Reinforced Polymers have became thicker. But the manufacturing process still implies the development of important residual stresses, either due to moisture effects or thermal effects [1]. If the symmetry of the composite part is broken, the global part shape will be affected by any moisture/temperature variation. In this communication, a simple L thick composite shell is studied under moderate temperature changes. Displacements are recorded on the shell front and on its side using a mixed in-plane and out-of-plane DSPI set-up [2]. Complementary tests have been performed using digital image correlation and fringe projection. The zone of interest is limited here to the central part of the L shape i.e. where the curvature is significant. Even if the stacking sequence is symmetric, the L-shape varies with temperature, and typical flexure strain effects are outlined. This test allowed for a direct comparison of different optical full field techniques. Out-of-plane and in-plane displacements obtained by DSPI have been compared to fringe projection and digital image correlation results respectively. For these given conditions, geometric methods had a very low signal-to-noise ratio, implying a necessary low-pass filter. On the opposite, DSPI showed very convincing results, with the outline of a local behaviour related to the stacking sequence.