Abstract:

By using Fiber Hexprismyarn Diagonal Brick Cell(FHDBC) and experimental methods, the thermal expansion and conductivity of 3 D braided fiber composites were investigated and the results were compared with those from tests. The investigation shows that FHDBC can reflect the real structure of 3 D braided fiber composites. The geometric models and boundary conditions of the unit cell can be conveniently simulated by FEM. The effective thermal expansion in the braided cross sectional area decreases as fiber volume fractions and braided angle increase; the effective thermal conductivity in the braided cross sectional area increase as fiber volume fractions and braided angle increase.

Key words: 3-D 4-step braided, fiber hexprismyarn diagonal brick cell, fiber yarn, effective thermal expansioncoefficient, effective thermal conductivity coefficient, finite element method