Improving the prediction of tensile failure in unidirectional fibre composites by introducing matrix shear yielding

Hierarchical scaling law for the strength of composite fibre bundles

“…Most authors use a characteristic length independent of load and number of fibre breaks, although this is known not to be correct (Behzadi et al, 2009, Phoenix et al, 1988. Laffan et al (2010) and Pimenta et al (2010) reported self-similar or quasi-fractal fracture surfaces in thin (under 0.5 mm) UD laminas and fibre bundles; this provides experimental evidence that the length-scale of the failure process increases with the number of fibres involved.…”

“…Several authors (Behzadi et al, 2009, Landis et al, 2000, Mahesh et al, 2002, Phoenix et al, 1988 recognised that, although their models used a fixed characteristic length, this is not realistic nor accurate; Wisnom and Green (1995) considered the characteristic length to be additive regarding the number of broken fibres, but included no stress concentrations in their calculations. The present model uses a variable control length l…”

Synchrotron radiation computed tomography for experimental validation of a tensile strength model for unidirectional fibre-reinforced composites

“…Standard linear superposition would sum up the SCFs for single fibre breaks, even though it is known that the interactions between broken fibres in a cluster will cause an underestimation of the SCFs [19,51]. Another issue is that this approach neglects the SCFs exerted by the broken fibres onto each other, resulting in a loss of force equilibrium in the model.…”

“…Many theories exist to predict the tensile strength of UD composites [11][12][13][14][15][16][17][18][19][20][21][22][23], and most of these contain three key features. The first is the assumption of a Weibull distribution of fibre strength, which is determined by the random distribution of flaws in the fibre [23].…”

The role of matrix cracks and fibre/matrix debonding on the stress transfer between fibre and matrix in a single fibre fragmentation test

“…Thus the fibres do not reach their full load carrying potential [4]. Recently Behzadi et al [10] have studied the role of multiple fibre-breaks on the failure of a 0 o fibre composite. It has been reported that the formation of a matrix crack is influenced by cure temperature, matrix modulus, surface treatment of the fibres, and strain rate [3,4,[11][12][13]].…”