Compressive fracture aspect of thick quasi-isotropic carbon fiber reinforced plastic laminates

• Published in: Composites science and technology 2019-09, Vol.181, p.107706, Article 107706
• Main Authors: Goto, Keita, Arai, Masahiro, Kano, Yuki, Hara, Eiichi, Ishikawa, Takashi
• Format: Article
• Language: English
• Subjects: Carbon fiber reinforced plastics; Carbon fibers; Carbon fibres; Compressive strength; Crack initiation; Crack propagation; Fiber reinforced plastics; Fracture; Fracture mechanics; Fracture toughness; Fractures; High speed cameras; High-speed images; Laminates; Layers; Polymer-matrix composites (PMCs); Shear stress; Strength
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2019.107706

The compressive fracture aspect for the thick quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates was investigated using a high-speed camera to clarify the progress of the brooming fracture. The compressive fracture types of the laminates could be classified into two groups, i.e., the fractures initiating from the innermost 0∘ ply and those initiating from the fixed sections of the specimen. The standard deviation of the compressive strength for the innermost 0∘ ply-initiated fracture type was larger than that for the fixed-section fracture type, although the average compressive strengths for each fracture mode were similar. The initial fracture in the innermost 0∘ ply was caused by the microbuckling of the fibers. The numerical results demonstrated a considerable out-of-plane shear stress around the free edges of the specimen, especially for the innermost 0∘ ply. Such a shear stress is thought to cause the microbuckling at the innermost 0∘ ply, with the crack subsequently propagating toward the outer plies of the specimen. The compressive strength of the innermost 0∘ ply was an important factor affecting the fracture behavior of the thick quasi-isotropic CFRP laminates.