Continuous filament wound composite concepts for aircraft fuselage structures

Reddy, Ambur D.; Valisetty, R.; Rehfield, Lawrence W.

doi:10.2514/3.45115

Cited by 50 publications

(15 citation statements)

References 2 publications

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“…An orthogrid-stiffened composite circular cylinder with the diameter of 990 mm and the height of 1168 mm [6] is employed to investigate the critical buckling states of a cylinder under axial compression loading. The skin is made of AS4/3502 graphite/epoxy, while stiffeners are combinations of both AS4/3502 graphite/epoxy and filler.…”

Section: A Composite Circular Cylindermentioning

confidence: 99%

“…1, are used in practical applications. Many researchers have devoted themselves to studying grid-stiffened composite panels [5,6,7,8,9]. The discrete stiffener and the smeared stiffener methods are two main methods used to study behaviour of such structures.…”

Section: Introductionmentioning

confidence: 99%

“…Practically, global buckling loads of grid-stiffened panels are usually assessed using the smeared method, while local buckling loads are predicted approximately with boundary conditions properly assumed at the interface of skin and stiffeners. The global buckling load for a axial compressed cylinder was obtained in a closed form for classical simply supported ends, while for the case of a combined axial compression and torsion, the global buckling problem was formulated using the Galerkin approach [6]. Moreover, with the assumption of a simple support at the stiffener/skin attachment, the skin buckling was calculated with the skin cell simply supported along its edges and the stiffener crippling was calculated with a clamped fixity condition imposed at the nodes.…”

Section: Introductionmentioning

confidence: 99%

“…Both global and local buckling behaviours were considered in a weight-minimum design for grid-stiffened panels and cylinders using a genetic algorithm [19,20]. In the work, an improved smeared theory with the offset effect of stiffeners included [21] was employed for the global analysis, while the local skin buckling was assessed by the Rayleigh-Ritz method which accounts for material anisotropy and stiffener crippling was assessed using the method provided in Reddy's work [6]. Then, this method was applied to optimization design of grid-stiffened panels with variable curvature, which were modeled as assemblies of panels with constant curvature [22].…”

Section: Introductionmentioning

confidence: 99%

“…Buckling modes of grid-stiffened panels. [6] A different approach to calculate local instability in periodic media is furnished by Bloch's wave theory. In the Bloch wave theory, the displacement of a particle in a periodic medium could be represented as a product of a periodic component with the same periodicity as the medium and periodic function with an arbitrary wavelength.…”

Section: Introductionmentioning

confidence: 99%

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Buckling Analysis of Grid-Stiffened Composite Shells

Wang

Abdalla

2016

Design and Analysis of Reinforced Fiber Composites

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Abstract. There is a renewed interest in grid-stiffened composite structures; they are not only competitive with conventional stiffened constructions and sandwich shells in terms of weight but also enjoy superior damage tolerance properties. In this paper, both global and local structural instabilities are investigated for grid-stiffened composite panels using homogenization theory. Characteristic cell configurations with periodic boundary constraints are employed for orthogrid-and isogrid-stiffened shells in order to smear the stiffened panel into an equivalent unstiffened shell. Homogenized properties corresponding to classical lamination theory are obtained by matching the strain energy of the stiffened and equivalent cells. Global buckling analysis is carried out based on the homogenized shell properties. Bloch wave theory is adopted to calculate the local buckling load of grid-stiffened shells, where the interaction of adjacent cells is fully taken into account. Moreover, instead of considering skin buckling and stiffener crippling separately, as is commonly done, the skin and stiffeners are assembled together at the level of the characteristic cell. The critical instabilities can be captured whether they are related to the skin or stiffener or their interaction. The proposed combination of global/local models can also be used to predict the material failure of a structure. Numerical examples of orthogrid-and isogrid-stiffened isotropic panels show that the local buckling loads predicted by the proposed method match finite element calculations better than semi-analytical methods based on assumptions and idealisations. The proposed method is further validated using typical configurations of flat composite panels and circular composite cylinders.

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Section: A Composite Circular Cylindermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Buckling Analysis of Grid-Stiffened Composite Shells

Wang

Abdalla

2016

Design and Analysis of Reinforced Fiber Composites

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An improved multiscale finite element method for nonlinear bending analysis of stiffened composite structures

Ren

Cong

Wang

et al. 2019

Numerical Meth Engineering

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Stiffened composite structures are commonly composed of skins and stiffeners that are employed to transfer and carry load, respectively. An improved multiscale finite element method is presented for geometrically nonlinear bending analysis of composite grid stiffened laminates. In the developed method, two kinds of strategies for establishing stiffened multiscale models are presented, in which the stiffeners are modeled at different scale. By introducing a virtual degree of freedom and additional coupling terms, multiscale base functions are improved to consider the local effects of stiffeners and coupling effects of composites. To construct the multiscale base functions of stiffened multiscale models, an extended displacement boundary conditions are constructed, in which the displacements of stiffeners are imposed constraints based on the displacement continuous conditions between skin and stiffener. Incremental multiscale finite element formulations are derived based on Total-Lagrange description and von Karman's large deflection plate theory. The incremental displacement boundary conditions are constructed to consider the effect of microscopic unbalanced force on microscopic results. Numerical examples show high efficiency and applicability of the developed method for composite grid stiffened laminates. KEYWORDS displacement boundary conditions, geometrically nonlinear bending analysis, multiscale base functions, multiscale finite element method, stiffened composite structures, stiffened multiscale models Int J Numer Methods Eng. 2019;118:459-481.wileyonlinelibrary.com/journal/nme

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