Mechanically coupled laminates with balanced plain weave

Shamsudin, Mohd Hafizi; York, Christopher

doi:10.1016/j.compstruct.2013.08.004

Cited by 12 publications

(15 citation statements)

References 20 publications

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“…6(b) reveal that when the laminate aspect ratio a/b > 1, 8-14 plies A F B 0 D S laminates with immunity to HTSD, except 13-ply A F B 0 D S laminates with immunity to HTSD, all fall on or below the buckling strength of the equivalent FIL. The buckling strengths for 8,9,10,11,12,14 plies A F B 0 D S laminates with immunity to HTSD are shown to be up to 27.7% lower than the equivalent FIL, while the buckling strength for13-ply A F B 0 D S laminates with immunity to HTSD is shown to be up to 18.3% higher than the equivalent FIL.…”

Section: Comparisonmentioning

confidence: 89%

“…It insures the laminate is immune to thermal warping distortion which occurs on cooling after the elevated temperature curing process used in the manufacture [8]. However, it is noted that the hygro-thermally curvature-stable laminates do not guarantee hygro-thermal curvature stability when the laminates are introduced into structure configuration.…”

Section: Introductionmentioning

confidence: 99%

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Extension-shear coupled laminates with immunity to hygro-thermal shearing distortion

Jin

2015

Composite Structures

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Section: Comparisonmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Extension-shear coupled laminates with immunity to hygro-thermal shearing distortion

Jin

2015

Composite Structures

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“…As seen in the UD laminate sequences of Fig Single ply terminations applied to NCF materials are equivalent to two adjacent ply terminations in traditional UD materials [21] and therefore introduce a constraint that reduces the design space substantially in contrast to a general two ply termination scheme [22], particularly in 'thin laminate' designs. However, this can be overcome by adopting 'thin-ply' or 'spread-tow' technology, which will allow an exponential increase in tailoring opportunities by bringing design flexibilities, found only in traditionally thick laminate construction, into the thin laminate domain.…”

Section: Bi-angle Non-crimp Fabric Hybrid Laminatesmentioning

confidence: 99%

On tapered warp-free laminates with single-ply terminations

York

2015

Composites Part A: Applied Science and Manufacturing

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Abstract:This article reviews the current state of the art in the design of traditional uni-directional fibre laminate construction; beyond the ubiquitous balanced and symmetric design. A ply termination algorithm is then employed to develop permissible tapered designs, with single-ply terminations and ply contiguity constraints, which are free from undesirable changes in mechanical coupling characteristics.More importantly however, is the fact that all tapered designs have immunity to thermal warping distortion; which include all combinations of anti-symmetric (or cross-symmetric), non-symmetric and symmetric angle-and cross-ply sub-sequence symmetries. Tapered designs are presented for laminates with fully uncoupled properties, and those possessing extension-shearing and/or bending-twisting coupling. Such designs represent typical fuselage skin thicknesses, i.e., with between (n =) 12 and 16 plies, but due consideration is also given to new fuselage design concepts with grid-stiffeners and/or geodesic stiffener arrangements, for which thinner designs (n e 8) are of interest.

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“…Ply terminations can also be applied to any layer without 3 changing the Extension-Shearing and Bending-Twisting dominant mechanical coupling, necessary for aero-elastic tailoring of wing-box structures. However, thermal warping distortions are eliminated only when the number of repeats (r) remain large.Recent research has however demonstrated that tailored Non-Crimp Fabric (NCF) designs, based on 0/45 and 0/-45 architectures, can produce fully uncoupled laminates or laminates with Extension-Shearing and/or Bending-Twisting coupling, and that all have immunity to thermal warping distortion [7]. The extent to which tapered laminate designs can be achieved, without introducing unwanted thermo-mechanical coupling, was also investigated through a layer termination algorithm to introduce single-layer [8] or, where necessary, multiple-layer terminations [4,7].…”

mentioning

confidence: 99%

“…However, thermal warping distortions are eliminated only when the number of repeats (r) remain large.Recent research has however demonstrated that tailored Non-Crimp Fabric (NCF) designs, based on 0/45 and 0/-45 architectures, can produce fully uncoupled laminates or laminates with Extension-Shearing and/or Bending-Twisting coupling, and that all have immunity to thermal warping distortion [7]. The extent to which tapered laminate designs can be achieved, without introducing unwanted thermo-mechanical coupling, was also investigated through a layer termination algorithm to introduce single-layer [8] or, where necessary, multiple-layer terminations [4,7]. This research followed related studies on laminate design for uni-directional (UD) fibre architectures for fully uncoupled laminates [9], and those with Extension-Shearing [10] and/or Bending-Twisting coupling [11,12].The results presented in this article investigate these four laminate classes constructed from the new NCF architectures, see Fig.…”

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confidence: 99%

Tapered laminate designs for new non-crimp fabric architectures

York

Almeida

2017

Composites Part A: Applied Science and Manufacturing

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Non-Crimp Fabric (NCF) materials are now available in a range of areal weights and layer architectures, including 0/45, 0/-45, 45/-45 and 0/90, which correspond to the standard ply orientations employed in traditional UD material lay-ups.The benefit of NCF material is generally associated with increased deposition rate, but this advantage may be offset by reduced design freedoms when a specific form of mechanical coupling behaviour is required, layer terminations must be introduced and/or thermal warping distortion eliminated.This article investigates the extent to which new NCF architectures can be tailored to achieve warp free tapered laminates with mechanical Extension-Shearing Bending-Twisting couplings, by single axis (longitudinal) deposition of all ply angles; thus avoiding ply discontinuities that may be introduce in large component manufacture.Lamination parameter design spaces are used to demonstrate the extent of the feasible solutions both before and after applying a laminate tapering scheme. 2 IntroductionDesign issues associated with tapered composite laminates have been comprehensively reviewed in a number of articles [1,2]. These reviews reveal an extensive literature, focussing primarily on delamination initiation and propagation in the region of ply terminations, but also reveal that little attention has been given to the extent to which plies may be dropped without introducing thermal warping distortion and associated changes in mechanical coupling characteristics. Indeed, current tapering schemes tend to consider only short ramps or pad-ups, and few [3] consider thermal warping and the associated locked in stresses. By contrast, tapering schemes for continuous wing or fuselage panel construction, in which only single ply terminations may be necessary between adjacent ribs or ring stiffeners, to satisfy strength and/or buckling constraints, are currently restricted to balanced and symmetric laminate designs. Hence, with few exceptions [4], such designs generally require a minimum of 4 ply terminations to avoid introducing thermal warping distortions; their inherent mechanical Bending-Twisting coupling characteristics can also lead to significant reductions in the compression buckling strength [5]. New joint requirements for aero-elastic tailoring and more efficient manufacturing of composite wing or winglet construction requires a more considered tapering scheme, which has resulted in the recent development of bi-angle non-crimp fabrics (NCF) architectures, consisting of two plies of UD material, one at 0° and the other at either a shallow angle,   20°, or the standard 45° angle, stitched together. The repeating biangle [/0]rT NCF concept [6] has the potential to reduce wet lay-up times by half, in comparison to traditional UD tape. In what follows, a layer (of NCF material) contains 2 plies (of UD material). Ply terminations can also be applied to any layer without 3 changing the Extension-Shearing and Bending-Twisting dominant mechanical coupling, necessary for aero-elastic tailoring of wi...

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Mechanically coupled laminates with balanced plain weave

Cited by 12 publications

References 20 publications

Extension-shear coupled laminates with immunity to hygro-thermal shearing distortion

Extension-shear coupled laminates with immunity to hygro-thermal shearing distortion

On tapered warp-free laminates with single-ply terminations

Tapered laminate designs for new non-crimp fabric architectures

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