New practical way to evaluate cracks and toughness in materials

A novel practical way of modelling cracking and toughening of fibre composite materials has been developed. The novel approach also revealed new insights on the fracture behaviour of fibres reinforcing a composite laminate during intralaminar cracking. The new way can be used to complement inspection of laminated structures that are used as primary structures in many industries.

Cracks in a material

A team led by Zhao Chang Fang from Nanjing University of Science and Technology has developed a practical way for studying the intralaminar crack propagation of unidirectional fiber reinforced polymer composite (GFRP) laminate. The novel approach was implemented by finite element analysis (FEA), and validated by tensile/compression experiment. The novel approach using FEA was conducted using a progressive damage model (PDM) -which was executed by using the implicit user material (UMAT), explicit user material (VUMAT), the extended finite element method (XFEM) subroutines completed by a microscale model of crack propagation that was implemented using a representative volume element (RVE) algorithm. The results from the predictions agreed very well with experimental results from mechanical testing and scanning electron microscopy (SEM). In conclusion, using a blended approach for FEA simulation, namely by combining the the PDM and RVE with XFEM subroutines, could be a step forward to simulating the intralaminar crack propagation phenomenon in order to gain deeper insights into the micro–macro failure mechanism.

The members of his team of international researchers are hailed from Nanjing University of Science and Technology (comprising Jianlin Zhong, Rui Ren, Kebin Zhang, Zhendong Zhang, Guigao Le), and Newcastle University (Kheng Lim Goh).

The work has been published in Structures ( For further details and enquiry on potential collaboration, please contact Changfang Zhao at [email protected], Jianlin Zhong at [email protected] or Kheng Lim Goh at [email protected].

Published: 07 Jul 2022

Contact details:

Dr Kheng Lim Goh

172A Ang Mo Kio Avenue 8 #05-01
SIT Building @ Nanyang Polytechnic
Singapore 567739

+65 6908 6073
Academic discipline: 
Content type: 

Intralaminar crack propagation of glass fiber reinforced composite laminate, Structures, Volume 41, July 2022, Pages 787-803;

Funding information:

The authors gratefully acknowledged the financial supports from the National Natural Science Foundation of China (12002169, 11902160), the Postgraduate Research & Practice Innovation Program of Jiangsu Province of China (KYCX21_0342), and the 2022 Excellent Doctor Training Fund of Nanjing University of Science and Technology. Especially, the China Scholarship Council (202106840033) was acknowledged, which sponsored the first author (Changfang Zhao) to Singapore for visiting study one year. Furthermore, the assistance in micro- morphology analysis from Nanjing YJCTEST Center and the assistance in experiments from Prof. Chen Tao in School of Science, Nanjing University of Science and Technology were acknowledged.