Fatigue Properties of the Cell 3D Composite Structure

A novel type of hybrid cell composite structure has been developed, experimentally investigated and used for many practical applications. The cell system can fill relatively thick parts of cross sections of beams with lower risk of shear stress damage and cracks between uniaxial oriented fibres. Typical macroscopic sub-cells in the cross section structure are formed by the stamping process of partially cured and axially-oriented high modulus carbon fibre bundles (about 4-6 mm in the diameter), which are wrapped around by a thin layer of high strength fibres (oriented in ±45 or 89 degrees). An advantage of this final 3D cell composite structure is its higher static and fatigue strength and shear stiffness in comparison with thick unidirectional composite parts. Static, fatigue and residual static strength was experimentally investigated for 1D unidirectional as well as for 3D cell structure under four point bending loading on specimens with the rectangular cross section. The 3D structure shows much better static and fatigue properties as the thick 1D unidirectional structure.