A new finite element approach applied to the free edge effect on composite materials

Esquej, R.; Castejón, Luis; Lizaranzu, M.; Carrera, Marco; Miravete, Antonio; Buil, Ramón Miralbés

doi:10.1016/j.compstruct.2012.09.043

Cited by 18 publications

(7 citation statements)

References 20 publications

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“…The fibrous layers are modelled with 6 elements through thickness, graded such that the outer elements are smaller than those in the middle of the layers. Modelling undertaken in [23] produced satisfactory results with 5 elements per layer (through thickness), also with element size near the interface reduced. The interface layers are modelled with 2 elements through thickness, which is believed sufficient since bending of the interface layers is not important to the modelling.…”

Section: Mesh Refinement and Model Parametersmentioning

confidence: 95%

“…Stresses change most rapidly in the vicinity of the free edge and this is also the key area of interest for failure initiation. Therefore, the FE mesh is graded, such that there is higher fidelity near the edge than towards the mid-width, which has been shown to significantly reduce modelling errors [23]. The fibrous layers are modelled with 6 elements through thickness, graded such that the outer elements are smaller than those in the middle of the layers.…”

Section: Mesh Refinement and Model Parametersmentioning

confidence: 99%

“…The stress field in the vicinity of the free edge is highly complex, as is the way in which the resin edge treatment interacts with it. Interlaminar stresses 13 and 33 have been identified as critical components contributing towards failure near the free edge [23]. Comparisons between untreated and treated laminates of global interlaminar direct stress ( 33 ) and…”

Section: Effect Of Resin Edge On Near-edge Interlaminar Stressesmentioning

confidence: 99%

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Resin treatment of free edges to aid certification of through thickness laminate strength

Fletcher

Kim

Dodwell

et al. 2016

Composite Structures

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Large aerospace parts are typically certified by testing narrow specimens, such as curved laminates, which have exposed free edges. These edges (not present in the production part) have been found to reduce the 3D strength of curved laminates by over 20%, showing this certification method is unreasonably conservative. The free edges also create a singularity, such that Finite Element (FE) modelling is challenging, which is typically approximated using non-linear analysis of cohesive interlaminar zones. A new treatment process is developed whereby a layer of resin is applied to the free edges of curved laminates. This significantly reduces the edge effect and delays failure. The resin edge treatment increases the strength of the curved laminate test specimens by 16%. The treatment also simplifies FE modelling by allowing for non-zero stresses normal to the laminate edge, removing the singularity. This enables use of linear FE models, which converge at the laminate edge. A linear FE method developed in this paper is conservative and predicts the strength of treated curved laminates to within 5% of the average test value. Hence it is shown that the resin edge treatment can be used to improve reliability of both certification tests and FE models.

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Section: Mesh Refinement and Model Parametersmentioning

confidence: 95%

Section: Mesh Refinement and Model Parametersmentioning

confidence: 99%

Section: Effect Of Resin Edge On Near-edge Interlaminar Stressesmentioning

confidence: 99%

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Resin treatment of free edges to aid certification of through thickness laminate strength

Fletcher

Kim

Dodwell

et al. 2016

Composite Structures

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“…21 In fact, there exists a prominent stress concentration with high stress gratitude in the free boundary of bearings known as the free-edge effect, 22 which has been extensively studied in the field of composite laminates. 23,24 It is found that the stress concentration coefficient depends strongly on the clearance of bearings and loadings, increasing almost linearly with the difference of spherical radius. 25…”

Section: Introductionmentioning

confidence: 97%

Distribution of conformal contact pressure in spherical plain bearings considering friction and free-edge effects

Han

Yao

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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The pressure distribution of conformal contact in spherical plain bearings is studied adopting both theoretical methods and finite element simulations. The effects of normal loads and friction coefficients on the distribution of both axial and circumferential contact stress are investigated. The results show that the circumferential stress can be exactly described with the complete spherical conformal contact theory while the axial one presents strong free-edge effects, mainly caused by the compressive strain. In addition, the distribution of contact stress tends to be uniform with the increase of the load and the friction coefficient, referring to a decrease of contact pressure in the central region and a rise on both edges of the outer ring, which can be attributed to the obstruction effects of friction on the deformation of bearings and the corresponding alteration of contact area.

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“…In the resolution of three-dimensional equations the use of the Finite Element Method is very common [21][22][23], though it requires a high level of mesh refinement in order to be able to analyse the stress concentration phenomenon and presents some problems due to the singularity that appears at the free edge [14]. Other methodologies used in this problem are the Boundary Element Method [24] and the Finite Differences Method [25].…”

Section: Introductionmentioning

confidence: 99%

Influence of ply orientation on free-edge effects in laminates subjected to in-plane loads

Solis

Sánchez-Sáez

Barbero

2018

Composites Part B: Engineering

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A new finite element approach applied to the free edge effect on composite materials

Cited by 18 publications

References 20 publications

Resin treatment of free edges to aid certification of through thickness laminate strength

Resin treatment of free edges to aid certification of through thickness laminate strength

Distribution of conformal contact pressure in spherical plain bearings considering friction and free-edge effects

Influence of ply orientation on free-edge effects in laminates subjected to in-plane loads

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