Effect of micro in-plane fiber waviness on compressive properties of unidirectional fabric composites

In this paper, a combination of experimentation and analysis is used to study the effect of micro in-plane fiber waviness on the compressive properties of unidirectional fabric composites. The experimental part includes a measurement of the micro in-plane fiber waviness in two types of unidirectional fabrics, manufacturing composites with each unidirectional fabric via VaRTM process and tests for establishing the compressive modulus and strengths of the composites. The compressive strengths were confirmed to be affected by the micro in-plane fiber waviness, but the compressive modulus was not. Furthermore, a two-dimensional numerical model is proposed to explain our experimental results. The numerical results indicate that the tensile stress (owing to the micro in-plane fiber waviness) and compressive stress along the weft and warp directions, respectively, of the composite lead to reductions in the compressive strength.