A twofold strength and toughness criterion for the onset of free-edge shear delamination in angle-ply laminates

Abstract

a b s t r a c tFree edge delamination in composite structures results from very localised stress fields which induce a stress concentration promoting the nucleation of an interfacial crack. To predict such a delamination onset at the free edge of a ðAEhÞ s laminate in traction, use is made of a strength and toughness criterion which combines a stress condition with an energy analysis. A generalised plane strain model allows to determine the stress distribution near the free edge and the energy released by the nucleation of an interfacial crack. The results show that this approach can predict the delamination onset for ððAE10Þ s ; ðAE20Þ s Þ laminates provided the interfacial fracture energy and interlaminar shear strength are known. These characteristic values can be identified with the help of traction tests performed on samples with different thicknesses.

Finite fracture mechanics analysis of crack onset at a stress concentration in a UD glass/epoxy composite in off-axis tension

“…FFM has thus been shown to provide a reasonably accurate, conservative estimate of the effect of stress concentration on the strength of a UD composite, using material characteristics determined by separate tests. FFM approach has also been successfully applied to delamination modeling in composite laminates [54]. The results obtained suggest that FFM merits further development and validation as it may provide an alternative method to damage mechanics and cohesive zone models for failure analysis of laminated composites.…”

The Interaction of Failure Modes in the Compression Response and Failure of Laminated Composites

“…The first laminate is a [0 0 /90 0 ]s laminate from Zhang et al 30 and the second is a [+10 0 / − 10 0 ]s laminate from Martin et al 29 The current implementation is compared against the results presented by Zhang et al 30 and Martin et al, 29 and the stresses along the interfaces are found to match well. Further, the above formulation is also implemented for an 8-ply (stacking of [-45/+45/90/0]s)laminate to determine the weak interfaces.…”

“…Based on the formulation given in Pipes and Pagano, 28 and Martin et al, 29 a laminate of length 2L, width of 2b and lamina thickness equal to h is considered. The geometry of the laminate along with its boundaries is shown in Fig.…”

A finite fracture model for the analysis of multi-cracking in woven ceramic matrix composites

“…Many applications of the CC can be found in the literature with a wide range of structural applications including free-edge delamination, transverse cracking and notched strength of composite laminates [36][37][38][39][40][41], adhesive and brazed joints [42][43][44][45][46][47][48], crack onset at Vnotches [49][50][51], cracking in ceramic laminates [52][53][54]. An overview of applications and an extensive list of references can be found in review papers [55][56].…”