Open Collections

Sourki, Reza

University of British Columbia

Forming simulation of woven fabrics has continually been employed over the years to help production designers optimize advanced composite manufacturing processes. In doing so, however, multiple deformation mechanisms such as tension, shear, bending, ply/ply interaction, along with resin-induced effects such as viscoelasticity, should be taken into consideration to achieve a reliable shape prediction of the formed parts. A comprehensive finite element model is realized in the present work to simulate the behavior of a plain weave prepreg during forming. Namely, a hybrid shell/membrane element is utilized to de-couple the in-plane and out-of-plane properties of the fabric ply. Viscous behavior, orientation- and pressure-dependent inter-ply frictional behavior, as well as the loading/unloading bending regime of the material, which was observed during forming experiments, were also characterized and implemented in the model. The latter regime has been particularly overlooked in the literature while being critical of the correct prediction of forming processes. To study the bending regimes, a custom-designed bending device was used to better understand and characterize the nonlinear behavior of textiles under out-of-plane deformations through the loading-unloading regimes. Furthermore, to incorporate the inter-ply frictional behavior, an empirical model was developed based on the response of the fabric under a wide range of processing conditions such as pressure and orientation. The numerical results for each deformation mode as well as the viscous and anisotropic frictional behavior were accurately modeled and compared with the experiments. Finally, all the developed models were integrated to provide a comprehensive mechanical tool to study forming processes. The results are shown to accurately predict the geometry of the formed test fabric along with the reaction forces of the tools, thus providing confidence in utilizing the tool to investigate forming processes and further use for optimization and minimization of major forming-induced defects such as wrinkling.

Text

2021-10-08

Attribution-NonCommercial-ShareAlike 4.0 International

http://hdl.handle.net/2429/79933

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-sa/4.0/