Phase field predictions of microscopic fracture and R-curve behaviour of fibre-reinforced composites

Abstract

We present a computational framework to explore the effect of microstructure and constituent properties upon the fracture toughness of fibre-reinforced polymer composites. To capture microscopic matrix cracking and fibre-matrix debonding, the framework couples the phase field fracture method and a cohesive zone model in the context of the finite element method. Virtual single-notched three point bending tests are conducted. The actual microstructure of the composite is simulated by an embedded cell in the fracture process zone, while the remaining area is homogenised to be an anisotropic elastic solid. A detailed comparison of the predicted results with experimental observations reveals that it is possible to accurately capture the crack path, interface debonding and load versus displacement response. The sensitivity of the crack growth resistance curve (R-curve) to the matrix fracture toughness and the fibre-matrix interface properties is determined. The influence of porosity upon the R-curve of fibre-reinforced composites is also explored, revealing a stabler response with increasing void volume fraction. These results shed light into microscopic fracture mechanisms and set the basis for efficient design of high fracture toughness composites.

Applications of phase field fracture in modelling hydrogen assisted failures

“…in Refs. [30,31] [32,33] and the use of strain gradient plasticity models reveals: (i) the existence of an elastic core surrounding the crack tip [34,35], and (ii) a crack tip stress distribution over the fracture process zone that is closer to that of linear elasticity [36,37]. Thus, linear elasticity provides a conservative, less computationally demanding alternative to multi-scale plasticity models.…”

An assessment of phase field fracture: crack initiation and growth

“…[12–15] and references therein). These capabilities are of increasing importance in advanced structural integrity assessment and the applications of phase field fracture have soared; examples include composite materials [16,17], shape memory alloys [18], rock-like materials [19], hydrogen embrittlement [20,21], functionally graded materials [22,23], dynamic fracture [9,24], fatigue damage [25,26], ductile damage [27,28] and Li-ion batteries [29,30]. On the occasion of the fracture mechanics meeting organized at the Royal Society, and the associated Special Issue, we review the fundamentals of phase field fracture and gain new insight into its ability to deliver predictions in agreement with the classical fracture mechanics theory laid out by Griffith and his contemporaries.…”

A Unified Abaqus Implementation of the Phase Field Fracture Method Using Only a User Material Subroutine

“…Variational phase field methods for fracture are enjoying a notable success [ 1 , 2 ]. Among many others, applications include shape memory alloys [ 3 ], glass laminates [ 4 , 5 ], hydrogen-embrittled alloys [ 6 , 7 ], dynamic fracture [ 8 , 9 ], fiber-reinforced composites [ 10 , 11 , 12 , 13 ], functionally graded materials [ 14 , 15 , 16 ], fatigue crack growth [ 17 , 18 ], and masonry structures [ 19 ]. The key to the success of the phase field paradigm in fracture mechanics is arguably three-fold.…”