Mechanical performance of carbon fibre-reinforced composites based on stitched preforms

Beier, Uwe; Fischer, Franz; Sandler, Jan K.W.; Altstädt, Volker; Weimer, Christian; Buchs, Wolfgang

doi:10.1016/j.compositesa.2007.02.007

Cited by 90 publications

(51 citation statements)

References 18 publications

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“…-a benefit of the stitching is an improvement of the delamination resistance increasing the interlaminar fracture toughness under mode I and II loading conditions [4]; -stitching improves the impact resistance and the post-impact mechanical properties [1]; -the stiffness and strength of laminates loaded in quasi-static tension can be unaffected, increased or more common reduced by the stitching [6,7]; -the influence of stitching on fatigue life of laminates was examined mainly under cyclic compression loads [1] and only few study appeared for tensile fatigue (see e.g. [7,8,9] for CFRP and [10,11] for GFRP).…”

Section: Introductionmentioning

confidence: 99%

Fatigue and post-fatigue tensile behaviour of non-crimp stitched and unstitched carbon/epoxy composites

Carvelli

Tomaselli

Lomov

et al. 2010

Composites Science and Technology

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.submitted to Composites Science and Technology 1 FATIGUE AND POST-FATIGUE TENSILE BEHAVIOUR OF NON-CRIMP STITCHED AND UNSTITCHED CARBON/EPOXY COMPOSITES ABSTRACTAn experimental study is described in this paper dealing with the tensile-tensile fatigue and the quasistatic post-fatigue tensile behavior of a structurally stitched multi-ply carbon composite and the unstitched counterpart. The influence of the stitching on the fatigue life and on the residual post-fatigue quasi-static properties in two principal direction is investigated. The fatigue behavior of both composites is represented by Wöhler-like diagrams. The damage imparted during fatigue is studied by X-ray analyses. The present work aims to provide a contribution to understanding of tensile fatigue and post-fatigue behavior of a structurally stitched multi-ply carbon composite. To assess the influence of the structural stitching on the mechanical response of the stitched composite the experimental data are compared to the ones of the unstitched carbon composite counterpart. The term 'structural' means that the stitching yarn does not only consolidate the plies (as the non-structural one does) but forms also a through the thickness reinforcement. The quasi-static mechanical response of the considered stitched carbon composite, produced in a different batch, were experimentally investigated in [12].The first part of the paper presents the characteristics of the two composites and the description of the experimental techniques applied. In the second part, the tensile-tensile fatigue life is presented and compared by Wöhler-like diagrams. Pictures obtained by X-ray device are used to investigate the damage patterns produced during fatigue after different number of cycles for a stress amplitude. The last part of the paper is dedicated to the post-fatigue residual mechanical properties of composites undergone different number of cycles. During the post-fatigue quasi-static tensile tests, the techniques described in detail in [13] (acoustic emission registrations and optic full-field surface strain measurements) were used to investigate the damage onset and development. MATERIALSThe stitched and unstitched preforms (see Figure 1 and Figure 2) are laminated using two Seartex / 23Each NCF has a polyester sewing thread (8.3 tex, 2.6 x 5 mm tricot + chain knitting pattern, 6 g/m 2 )that knits together the carbon plies. The fabrics are stacked to form a symmetric laminate [45/-45/0/90/45/-45] S and has a total thickness of about 4.2 mm before impregnation. 90º direction corresponds to the non-structural sewi...

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Section: Introductionmentioning

confidence: 99%

Fatigue and post-fatigue tensile behaviour of non-crimp stitched and unstitched carbon/epoxy composites

Carvelli

Tomaselli

Lomov

et al. 2010

Composites Science and Technology

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“…Other approaches to the manufacture of preforms have been developed over the years including the use of a variety of stitching techniques, for example to attach stiffening stringers to skins. These methods can be aimed at simply providing a handleable preform [34,35] or at developing an element of 3D reinforcement using stitching or tufting with a structural thread [36].…”

Section: Resin Transfer Mouldingmentioning

confidence: 99%

“…Acting rigorously on a knowledge of the fundamental quality drivers can deliver reliable production in many 500mm 300mm 200mm cases, although process modelling can certainly help it is not always critical; understanding the fundamental quality drivers is however always critical. Recent work taking into account stochastic effects to handle in-process variability does, however, offer real promise (34). It can also be noted that BMW's i3 body shell mouldings are made in essentially the same way as the parts described here, from a number of relatively simple pressed preforms assembled in the tool and infused with resin to deliver a complex moulding.…”

Section: Resin Transfer Mouldingmentioning

confidence: 99%

‘But How Can We Make Something Useful Out of Black String?’ The Development of Carbon Fibre Composites Manufacturing (1965–2015)

Potter

2016

The Structural Integrity of Carbon Fiber Composites

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Abstract.This chapter looks at how the manufacturing community responded to the invention of carbon fibres, the first practical, high-modulus, reinforcement to be available as continuous fibres; largely through the lens of the author's personal experience. Whilst it seems axiomatic to us today that we use continuous fibres, most of the composites applications in 1965 used short fibres, for example chopped glass, asbestos, whiskers or linen fibres. To a large extent the narrative of carbon fibre composites manufacturing is the story of how to manipulate continuous fibres into complex geometries; and how to do that cost-effectively without introducing strength reducing defects. Until very recently, when the manufacturing and structural integrity communities have started to interact much more, there has tended to be an almost complete disconnect between the materials, design and manufacturing worlds. This has been the case as much in industry as it has in academia and seems to have been the norm since the very beginnings of the application of carbon fibre composites. The difficulties inherent in manufacturing geometrically complex parts were identified very early in the history of carbon fibre composites. However, it has proven to be very challenging to go beyond identifying problem issues to actually solving them, and that process is by no means complete. There are signs that the composites community may finally be on the right track, with some recent successes pointing towards research directions where design and manufacturing approaches can be unified to deliver reliable and cost-effective parts -only 50 years after the process started.

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“…For intermediate materials, Non-Crimp Fabric (NCF), which consists of unidirectional fiber plies that are kept together by stitching yarns arranged in a number of different orientations relative to the fabric production direction, has attracted much attention [1][2][3]. The use of NCF has simplified the laminating process compared to that of pre-impregnated unidirectional tapes (UD) by changing the arrangement and direction of the fiber tows, so the molding cost is expected to be reduced.…”

Section: Introductionmentioning

confidence: 99%

Formability evaluation of carbon fiber NCF by a non-contact 3D strain measurement system and the effects of blank folder force on its formability

Tanaka

Ushiyama

Katayama

et al. 2014

WIT Transactions on the Built Environment

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Non-Crimp Fabric (NCF) consists of unidirectional plies, which are kept together by stitching yarns arranged in a number of different orientations relative to the fabric production direction. Since NCF has no crimp, NCF can take full advantage of the continuous carbon fibers.As NCF is deformed mainly due to shear deformation, it is difficult to form 3D shapes from it. Therefore, formability improvement of NCF by slitting a textile preform has been attempted; however, problems such as strength degradation at a notch and cost increase due to the increase of working process have occurred. So, it is necessary to improve formability of NCF without slitting. One of the methods of formability improvement is to use blank holder force. In previous studies, though the influence of blank holder force on formability of woven fabrics has been clarified, that on formability of NCF is uncertain.In this study, the hemisphere geometry punch drape test was conducted to evaluate the influence of blank holder force on the formability of NCF. Meanwhile, deformation of NCF during the drape test was measured by a non-contact 3D strain measurement system.

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Mechanical performance of carbon fibre-reinforced composites based on stitched preforms

Cited by 90 publications

References 18 publications

Fatigue and post-fatigue tensile behaviour of non-crimp stitched and unstitched carbon/epoxy composites

Fatigue and post-fatigue tensile behaviour of non-crimp stitched and unstitched carbon/epoxy composites

‘But How Can We Make Something Useful Out of Black String?’ The Development of Carbon Fibre Composites Manufacturing (1965–2015)

Formability evaluation of carbon fiber NCF by a non-contact 3D strain measurement system and the effects of blank folder force on its formability

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