A bi-directional damage model for matrix cracking evolution in composite laminates under fatigue loadings. (May 2020)

• Record Type: Journal Article
• Authors: Qi, Wenxuan; Yao, Weixing; Shen, Haojie
• Is Part Of: International journal of fatigue. Volume 134(2020)
• Publication Date: 2020-05
• Subjects: A laminates -- B fatigue -- B transverse cracking; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2019.105417
• Languages: English
• ISSNs: 0142-1123

Abstract

Graphical abstract: Highlights: The micromechanics based model was verified for composite laminates under fatigue loading in this paper, and mechanical behavior of composite laminates with transverse matrix cracks was modelled based on micromechanics theory. The initiation of matrix cracks in cracked plies was predicted with the definition of the initial matrix crack initiation life, which was considered as a fatigue property of composite materials in this paper, and the equation between the initial matrix crack initiation life and maximum load stress in cracked plies was deduced. The evolution of matrix crack density in cracked plies was predicted with the distribution of the initial matrix crack initiation life in cracked plies, and the distribution was obtained based on the distribution of critical energy release rate in quasi static model, which ensures the consistency in fatigue model and quasi static model. The experiment of cross-ply laminates under fatigue loading with four stress levels was conducted, several material parameters were determined based on the experimental results, and the prediction results were compared with the experimental results, including the degradation of normalized longitudinal modulus and evolution of matrix cracks density, and the comparison shows a good agreement. Abstract: An analytical model for prediction of transverse matrix cracks in composite laminates under fatigue loading was proposed. The micromechanics method was utilized to characterize the damaged behavior of composite laminates. The initial matrix crack initiation life was defined and deduced based on micromechanics method. Then the relation between initial matrix crack initiation life and critical energy release rate was established to obtain the distribution of initial matrix crack initiation life in cracked plies, and the evolution of matrix crack density and stiffness degradation were predicted. The prediction results were compared with experimental results and the comparison shows good agreement.