A new modeling method to predict the mechanical properties of braided composites

Abstract

The present research signifies a new modeling method for calculating the stiffness of braided composites. In previous works, the modeling approach has been related to repetitive unit cells for analysis of braided composites based on a single area or a few added areas. Also, no confirmed modeling method has recently been available for braided composites because of different fibers’ configuration considerations. Therefore, there is no preferred one, and fiber bundle arrangements are complex in practicality; it is unclear whether their shape is straight or curved. Also, the previously proposed mesoscale repetitive unit cell models have many elements and nodes in the finite element analysis phase, so applying periodic boundary and mesh conditions can mislead the results when they are used. So current research proposes a multi-cell multi-domain strategy and verifies it for modeling and computation of mechanical properties while showing the significance of braiding path and manufacturing process. The currently proposed method is tested with selected sections’ configuration and shown for actual braided composites’ scenario. So, according to the literature, the section is modeled as a complex shape with a squeezing effect. Then, that model is analyzed, and calculated properties are verified by the existing methods and found results with a maximum and minimum difference of 2.7% and 0.25%, respectively. Afterward, it is divided into cells, which are then analyzed and checked to determine which number of simplistic division stages can represent a section. It is found that a minimum of 15 divisions can be defined with a maximum 2% difference, and over that has approximately the same results as of the current considered section model. Additionally, the study examines how the elastic constants of 2D braided composites are influenced by the braiding angle and fiber volume fractions.