School of Mechanical Engineering Seminar
Wednesday, December 12, 2012 at 15:00
Wolfson Building of Mechanical Engineering, Room 206

MICROMECHANICAL ANALYSIS OF 3D WOVEN COMPOSITES USING THE FINITE ELEMENT METHOD

Yevgeny Yujelevski

MSc Student of Prof. Rami Haj-Ali

Refined micromechanical models are a preferred alternative for investigating the mechanical response of composite materials. Simplified micromechanical models were developed in the past mainly to predict effective elastic properties of media reinforced with different types of inclusions including fabrics. However, the development of refined nonlinear micromechanical models is currently needed as complex 3D woven composites requires more sophisticated modeling to predict their linear and damage mechanical behavior. The finite element method (FEM) is a good approach for detailed modeling of complex geometry and particularly effective in calculating local stress fields, including progressive damage and failure modeling.

The main objective of this study was to develop a finite element based micromechanical model for predicting both the effective elastic and strength properties of a new class of 3D woven composites. A new technique based on the local orientation of the tows in relation to the global coordinate system is proposed in order to account for the waviness of the tows. Periodic boundary conditions were imposed using the "Average Field Theory" and allow imposing general load combinations. Two damage models are included in the proposed FE micro-model for simulating damage propagation in the matrix and the tows. The proposed approach was implemented on a composite material system fabricated from a unique 2D woven 3D fabric. Predictions of the model were compared with select experimental results for composite coupons to illustrate the effectiveness of the proposed model.