Effects of layer waviness on the compression fatigue performance of thermoplastic composite laminates

Adams, Daniel O.; Hyert, M. W.

doi:10.1016/0142-1123(94)90450-2

Cited by 43 publications

(30 citation statements)

References 12 publications

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“…Understanding how wrinkles form during these manufacturing processes is important because, depending on their severity, they may compromise the structural integrity of the final part, leading in some cases to expensive wholesale rejection. The formation of wrinkles not only disrupts the even distribution of fibre and resin, but most significantly can increase through-thickness stresses triggering failure at significantly reduced loads [1].…”

Section: Wrinkling Of Carbon Fibre Composites During Consolidationmentioning

confidence: 99%

Out-of-plane ply wrinkling defects during consolidation over an external radius

Dodwell

Butler

Hunt

2014

Composites Science and Technology

104

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a b s t r a c tIf carbon fibre layers are prevented from slipping over one another as they consolidate onto a non-trivial geometry, they can be particularly susceptible to wrinkling/buckling instabilities. A one dimensional model for out-of-plane ply wrinkling during consolidation over an external radius is presented. Critical conditions for the appearance of wrinkles provide manufacturing strategies to eliminate such defects. Predicted wrinkle wavelengths and critical wrinkling conditions show good agreement with wrinkle defects observed in a spar demonstrator.

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Section: Wrinkling Of Carbon Fibre Composites During Consolidationmentioning

confidence: 99%

Out-of-plane ply wrinkling defects during consolidation over an external radius

Dodwell

Butler

Hunt

2014

Composites Science and Technology

104

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“…Unfortunately, many works have shown in practice that fi bre undulation or waviness characteristics (wavelength and amplitude) have a negative influence on the stiffness and strength of fibrereinforced composites (Mrse & Pigott, 1990;Pigott & Lam, 1991;Pigott, 1995;Adams & Hyer, 1994;Hsiao & Daniel, 1996;Stecenko & Pigott, 1997;De Morais & Marques, 1997;Drapier et al, 2001). Figure 4 displays strong fi bre waviness effects on ply failure strain that can be three times less in comparison with a theoretical perfect straight fi bres ply.…”

Section: Figurementioning

confidence: 93%

Thick laminates quality for ship design

Jochum

Grandidier

2007

Australian Journal of Mechanical Engineering

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This paper draws attention to the quality problems encountered during the curing of thick structural thermosetting composites for naval use. For example, during curing thermal gradients and internal stresses are generated, leading to several imperfections (bubbles, fi bre waviness, etc) and, therefore, decreasing the quality of the composite. The fi rst part of the paper presents experimental results about material quality description. In particular, gradients of properties (degree of cure, cure shrinkage, elastic modulus) are clearly established within the composite and their dependency to the cure is presented. In the second part, a numerical tool that couples mechanical, physical and chemical phenomena, and devoted to industrial software, is proposed for cure simulation. The fi rst fi nite element modelling (FEM) results are presented and compared with experimental data of the cure. Thermal load is an important factor for thick thermosetting laminates quality, since the coupling effect between the thermo-activated and exothermal behaviour for thermosets becomes more pronounced with mass effect. Finally, while waiting for complete developments of such simulation tools of the curing process, the best advice for thick laminates manufacturers in order to improve the quality is to slow the cure cycle as the thickness increases.

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“…[10] There is a large volume of literature confirming the large amounts of mechanical property reductions due to these defects [11][12][13][14] . Some have attributed the causes of fiber waviness in composites to the relationships between the mandrel and pressure considerations during cure [15,16] .…”

Section: Introductionmentioning

confidence: 99%

An Infrared Thermoelastic Stress Analysis Investigation for Detecting Fiber Waviness in Composite Structures

Elhajjar

Haj-Ali

Wei

2014

Polymer-Plastics Technology and Engineering

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A full-field thermoelastic stress analysis infrared (TSA-IR) method is used to investigate the possibility of inspecting for out of plane fiber waviness in composite structures. Two different waviness profiles are generated and compared to control specimen having no anomalies. Tension and compression loading schemes are investigated and the TSA-IR emissions are compared to cross-sectional investigations. A subset of the specimens is also notched to investigate the thermal emissions from holes when compared to the waviness. The interaction of the hole and waviness shows the errors that can be introduced when using TSA-IR for quantitative analysis.

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Effects of layer waviness on the compression fatigue performance of thermoplastic composite laminates

Cited by 43 publications

References 12 publications

Out-of-plane ply wrinkling defects during consolidation over an external radius

Out-of-plane ply wrinkling defects during consolidation over an external radius

Thick laminates quality for ship design

An Infrared Thermoelastic Stress Analysis Investigation for Detecting Fiber Waviness in Composite Structures

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