Date of Award
Master of Science (MS)
Francisco Lopez Jimenez
Soft ber reinforced composites are very suitable materials for space deployable structures.
These materials are characterized by a very compliant matrix that allows the bers
to highly deform so microbuckling under bending can appear without failure. This mechanism
acts as a stress-reliever, so the material can be folded to very high curvatures without
damage. However, the existing models are not able to accurately capture the mechanical
behavior of these materials.
A new micromechanical model is proposed for this materials under bending. The
model considers both the pre and post buckling regimes using a large strain formulation.
The strain energy is calculated as the sum of the energy in the matrix and the bers. The
energy of the matrix is calculated using homogenization methods and the energy of the bers
is approximated using classical beam theory. The obtained energy model is a function of
the position of the neutral axis, the buckling wavelength and a function that denes where
buckling appears through the thickness. These parameters are calculated by minimizing the
The results obtained from the theoretical model are compared with numerical simulations.
The comparison shows good agreement for the pre-buckling regime but it does not
predict well the curvature when buckling appears. The in
uence of some problem parameters
such as the volume fraction and the shear modulus of the materials is also studied.
Brachthauser Balcells, Savina, "Modeling of Fiber Microbuckling in Soft Composites Under Bending" (2018). Aerospace Engineering Sciences Graduate Theses & Dissertations. 199.