A simple closed-form model for fracture of CFRP panel with shallow surface scratch confirmed by comprehensive flexural/tensile tests. (April 2021)

• Record Type: Journal Article
• Authors: Hu, Yunsen; Chen, Yi; Yuan, Bingyan; Hu, Xiaozhi
• Is Part Of: Mechanics of materials. Volume 155(2021)
• Publication Date: 2021-04
• Subjects: Composite fracture -- Shallow surface scratch -- Non-LEFM modelling -- Reliability for structural integrity; Strength of materials -- Periodicals; Mechanics, Applied -- Periodicals; Résistance des matériaux -- Périodiques; Mécanique appliquée -- Périodiques; Mechanics, Applied; Strength of materials; Periodicals; Electronic journals; 620.11
• DOI: 10.1016/j.mechmat.2020.103725
• Languages: English
• ISSNs: 0167-6636

Abstract

Abstract: Comprehensive tests using more than 200 CFRP laminate specimens with and without shallow surface scratches (20 μm - 3 mm) have been performed under three-point-bending (3-p-b) and direct tensile conditions. Critical flexural loads of scratched 3-p-b specimens have been linked to the tensile strength f t of CFRPs by a simple closed-form solution of a non-Linear Elastic Fracture Mechanics (non-LEFM) model for composite failures, which models the crack tip damage using the characteristic composite microstructure C ch (ply thickness of CFRP). The average f t measured from 30 direct tensile tests is virtually identical to that from 170 different 3-p-b tests with only 2% relative error, indicating potential applications of the simple closed-form solution in structural integrity analysis for scratched CFRP components. The statistical reliability has been combined into the predictive model, which can be important when not only the mean strength but also the prediction interval is required. Highlights: A non-Linear Elastic Fracture Mechanics model is applied to study quasi-brittle bending fracture of CFRPs. 185 three-point-bending specimens with different thicknesses and notch depths were tested and analysed. The tensile strength f t evaluated from three-point-bending specimens was compared to the value from tensile tests. A normal distribution method was used to analyse experimental scatters.