Modeling of dynamic mode I crack growth in glass fiber-reinforced polymer composites: fracture energy and failure mechanism

• Published in: Engineering fracture mechanics Vol. 243; p. 107522
• Main Authors: Liu, Y., van der Meer, F.P., Sluys, L.J., Ke, L.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 15.02.2021; Elsevier BV
• Subjects: Composites; Crack propagation; Ductile fracture; Dynamic crack propagation; Dynamic loads; Embedded cell; Energy release rate; Failure mechanisms; Fiber composites; Fiber reinforced polymers; Fracture energy; Fracture mechanics; Fracture toughness; Glass fiber reinforced plastics; Inertia; J integral; Loading rate; Microcracks; Polymer matrix composites; Strain rate; Composites; Fracture energy; Dynamic crack propagation; Embedded cell
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2020.107522

The mode-I dynamic fracture energy and failure mechanisms of glass fiber-reinforced polymer composites are investigated with an embedded cell model of the single-edge-notched-tension (SENT) geometry. Under an applied dynamic loading, a crack may propagate in the embedded microstructure, accompanied by the development of a fracture process zone in which fiber/matrix debonding, matrix cracking and ductile matrix tearing are observed. Reaching a maximum nominal strain rate of 250/s, a series of SENT tests are performed for different loading velocities and specimen sizes while the dynamic energy release rate is evaluated using the dynamic version of the J-integral. The influence and interaction of loading rate, time-dependent material nonlinearity, structural inertia and matrix ligament bridging on the fracture toughness and failure mechanisms of composites are evaluated. It is found that with the given material parameters and studied loading rate range, the failure type is brittle with many microcracks but limited plasticity in the fracture process zone and a trend of increasing brittleness for larger strain rates is observed. The inertia effect is evident for larger strain rates but it is not dominating. An R-curve in the average sense is found to be strain-rate independent before the fracture process zone is fully developed and afterwards a velocity–toughness mechanism is dictating the crack growth. •An embedded cell model is introduced to simulate dynamic crack growth in composites.•A implicit dynamics solution scheme is adopted instead of explicit dynamics.•Crack speed versus dynamic J-integral is extracted for different loading rates.•Contribution of plasticity, microcracking and inertia on fracture energy is analyzed.