Chapter 5 - 3D Woven Composites

Abstract

This chapter discusses the in-plane mechanical properties, delamination resistance, and impact damage properties of three-dimensional (3D) woven composites. The microstructure of a 3D woven composite is determined largely by the fiber architecture to the woven preform and weaving process, and to a lesser extent by the consolidation process. Various types of microstructural defects are inadvertently produced during 3D weaving that can degrade the in-plane, through-thickness, and impact properties. When the interlaminar shear strength of various types of 3D woven composite are evaluated, it is generally found that the strength is the same or slightly higher than an equivalent two-dimensional (2D) material. The normalized shear strength is the interlaminar shear strength of the 3D woven composite divided by the interlaminar strength of a 2D woven laminate with nominally the same fiber content. The impact damage tolerance of 3D woven composites has been extensively evaluated because of their potential use in aircraft and rocket structures prone to impact loading. 3D woven composites have been impact tested under low- to medium-energy levels using light-weight, low-speed projectiles to evaluate their damage resistance for aircraft structures subject to hail and bird strikes during flight and to dropped tools during maintenance.