The effect on elastic modulus of rigid-matrix tubular composite braid radius and braid angle change under tensile loading

The objective of this paper is to assess changes in braid radius and braid angle of braided composite tubes under tensile loading using stereomicroscope digital image correlation (DIC) based optical measurement techniques. Using this approach, displacement fields were calculated and three dimensional surfaces were reconstructed. The radius of the tube and the braid angle were determined from the reconstructed surfaces and images. With this initial work showing the effects of tensile loading on the tube radius and braid angle also included development of approaches for deconstructing data. Results highlight that there is ∼10% difference between findings for elastic modulus between existing investigation techniques and the methods developed here for rigid-matrix composite braids.