Effect of pre-crack length on Mode I fracture toughness of 3-D angle-interlock woven composites from finite element analyses

Abstract

Fracture toughness is a key factor to design impact behaviors of composite materials. This paper reports the influence of pre-crack length on Mode I fracture toughness of 3-D angle-interlock woven composites. Double cantilever beam specimens with different pre-crack lengths were tested to obtain load-displacement curves and strain energy release rates. A finite element analysis model at microstructure level was established to reveal the fracture damage development and stress distribution in the specimens. We found that the fracture toughness decreases with increase in pre-crack length. The higher pre-crack length resulted in increased stress concentration at crack tip position and the enhanced crack propagation. The higher strength through-thickness yarns are recommended for improving fracture toughness.

Keywords:

• Fracture toughness
• double cantilever beam (DCB)
• pre-crack length
• energy release rate
• finite element analysis (FEA)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge the financial supports from National Science Foundation of China [grant Nos. 51875099 and 51675095]. The Fundamental Research Funds for the Central Universities of China [grant No. 2232018G-02] are also gratefully acknowledged.