DESIGN OF MTB FRAME USING THREE DIMENSIONAL BRAIDED COMPOSITE

摘要

The mechanical behavior of 3D multi-layered braided composite was analyzed using a multi-scale modelling approach. Considering the braiding parameters and the fiber volume fraction of the composite, firstly a unit-cell inside the braided composites was modelled considering the motion of yarn carriers. The unit-cell was imported into finite element software to calculate its meso-scale material properties. In this calculation the yarns in the unit-cell were assumed to be solid constituents without considering each filament in them, i.e., a meso-scale approach was adopted for the yarn modelling. As for the material law, the linear elastic constitutive equation was used for both yarn and matrix, from which the orthotropic material properties of the unit-cell were obtained. Then, the calculated properties of the unit-cell were imported to analyze the macroscopic deformation behaviour of the 3D braided composite using a finite element shell model. The validity of the current meso- and macro-scale analysis was investigated using experimental results, concluding that the linear elastic assumption for the yarn and matrix was too restrict to predict the deformation behaviour of the composites beyond the small deformation regions and thus a nonlinear constitutive equation is required for the matrix or yarns. Finally a case study, an optimum design of mountain bike (MTB) frames using 3D multi-layed braided composites, is in progress to validate the current modelling approach and will be presented at the conference.