A modified equation for the stress concentration factor in countersunk holes

Darwish, Feras H.; Gharaibeh, Mohammad A.; Tashtoush, Ghassan

doi:10.1016/j.euromechsol.2012.02.014

Cited by 26 publications

(18 citation statements)

References 8 publications

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“…As noted earlier, the amount of work on understanding stress/strain concentrations in scarfed composite laminates is very limited. As described previously, Darawish et al (28,29) is one of a few researchers to study stress concentrations ( Figure 1a). Darawish et al concluded that a stress concentration factor in an orthotropic composite laminate may be expressed using…”

Section: Existing Methodsmentioning

confidence: 93%

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Understanding the influence of laminate stacking sequence on strain/stress concentrations in thin laminates at repair holes with large scarf angles

Damghani

Bakunowicz

Murphy³

2019

Journal of Composite Materials

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Scarf repair is widely used in the restoration of structural performance of damaged aircraft secondary structures. Such repairs result in reduced thickness sections which are significantly larger than those associated with typical fastener holes. Significant literature exists on the distribution of strain/stress concentration in fastener hole geometries, both straight sided and countersunk, but is lacking for the geometries associated with shallow scarf angles and thin laminates. Hence, herein three-dimensional finite element models are developed to understand the influence of stacking sequence and scarf angle on strain/stress concentrations. The results demonstrate and quantify for the first time that strain concentrations are not only dependant on the laminate membrane stiffness but also on laminate bending stiffness, due to the anisotropy created as a result of scarfing angle, hole geometry and laminate thickness. Scarfing is demonstrated, for typical repair geometry associated with foreign object damage (hole diameter 20 mm, scarf angles 3° to 7°), to elevate strains by up to 2.5 times when compared to equivalent diameter straight-sided holes in laminates of thickness ≈1 mm.

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Section: Existing Methodsmentioning

confidence: 93%

“…Darwish et al (28,29) carried out numerous FEA studies on orthotropic plates having countersunk holes. In the investigation the effect of countersunk size, plate thickness, and plate dimensions were investigated.…”

Section: Introductionmentioning

confidence: 99%

Understanding the influence of laminate stacking sequence on strain/stress concentrations in thin laminates at repair holes with large scarf angles

Damghani

Bakunowicz

Murphy³

2019

Journal of Composite Materials

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“…Their simulation results showed that the stress concentration is commonly located at the sinking edge of the hole and they further used the numerical data to formulate an empirical formulas to mathematically compute t K in countersunk holes based on the geometry of the hole. Later, Gharaibeh et al [15] and Darwish et al [16,17] provided improved formulas for the SCF in countersunk holes in isotropic and orthotropic plates subjected to uniaxial tensile loadings. Hayajneh et al [18] and Bhargava et al [19] investigated the strain concentration factor (SeCF) in countersunk holes under uniaxial tension.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Stress Concentration Factor Induced in Double Countersunk Holes Due to Uniaxial Tension

Gharaibeh

2020

International Journal of Applied Mechanics and Engineering

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Finite element and response surface methods were utilized to investigate the stress concentration factor induced in isotropic rectangular plates with two identical countersunk rivet holes due to uniaxial tension. In this investigation, the finite element model was constructed using ANSYS software and used to produce stress concentration factor (SCF) data. Additionally, the response surface method (RSM) was implemented to characterize the influence of the problem geometric parameters on the SCF. Besides, RSM combined with least squares regression methods were employed to formulate a simple and effective equation to mathematically compute the stress concentration factor (Kt) value. This equation was consequently verified with finite element analysis (FEA) results. Lastly, an optimum plate and holes configuration that minimizes the SCF was suggested and hence recommended.

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“…Othman et al 24 used FEA and the concept of defence hole system (DHS) to reduce stress concentration in holes of composite bolted joints. Darwish et al 25,26 used three-dimensional FEA to formulate stress concentration around circular countersunk holes in composite orthotropic plates under uniaxial loading.…”

Section: Introductionmentioning

confidence: 99%

“…Darwish et al. 25,26 used three-dimensional FEA to formulate stress concentration around circular countersunk holes in composite orthotropic plates under uniaxial loading.…”

Section: Introductionmentioning

confidence: 99%

The effects of composite laminate stiffness and loading on stress resultant concentration factor around a hole

Damghani

Harrison

Kennedy

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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An analytical tool is developed using conformal mapping and the complex variable method for determining the stress resultant concentration factor in an infinite plate with a circular or elliptical hole. This tool is validated against finite element analysis. A population space of 305 laminates is generated by stacking unidirectional carbon fibre reinforced polymer material at various orientations covering a wide spectrum of homogenised stiffness values. The analytical approach is then used to study the effect(s) of loading conditions, stacking sequences and laminate homogenised stiffness values on the stress resultant concentration factor at the edge of a circular hole.

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A modified equation for the stress concentration factor in countersunk holes

Cited by 26 publications

References 8 publications

Understanding the influence of laminate stacking sequence on strain/stress concentrations in thin laminates at repair holes with large scarf angles

Understanding the influence of laminate stacking sequence on strain/stress concentrations in thin laminates at repair holes with large scarf angles

A Study on the Stress Concentration Factor Induced in Double Countersunk Holes Due to Uniaxial Tension

The effects of composite laminate stiffness and loading on stress resultant concentration factor around a hole

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