Change search
ReferencesLink to record
Permanent link

Direct link
A numerical study of the influence from architecture on the permeability of 3D-woven fibre reinforcement
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. (Lättkonstruktioner)ORCID iD: 0000-0002-6616-2964
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.ORCID iD: 0000-0002-9207-3404
2015 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 74, 18-25 p.Article in journal (Refereed) Published
Abstract [en]

Various modelling aspects of the permeability of three-dimensional (3D) woven textile preforms are studied using computational fluid dynamics (CFD). The models are built using a recently developed technique able to generate close to authentic representations of 3D textile arrangements. One objective of the study is to investigate how parameters such as the tow architecture and the level of detail in the CFD models influence the results. A second objective is to investigate how the inter and intra-tow porosity affect the permeability. They are varied in a way that somewhat resembles how they would change during compaction, although compaction as such is not modelled. It is concluded that the intra-tow porosity has little effect on the overall permeability of a 3D-woven preform. Detailed modelling of local variation of the intra-tow porosity is thus redundant, which is also demonstrated. The inter-tow porosity, on the other hand, has a prominent influence on the overall permeability. The overall permeability is inherently anisotropic but when the inter-tow porosity is increased the permeability does not increase uniformly but becomes more isotropic. Good agreement is obtained between the numerical simulations and experiments performed in a parallel study.

Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 74, 18-25 p.
National Category
Vehicle Engineering
URN: urn:nbn:se:kth:diva-145996DOI: 10.1016/j.compositesa.2015.02.019ISI: 000356553600003ScopusID: 2-s2.0-84926615195OAI: diva2:721450
XPRES - Initiative for excellence in production research

Updated from manuscript to article in journal. QC 20150602

Available from: 2014-06-04 Created: 2014-06-04 Last updated: 2016-01-22Bibliographically approved
In thesis
1. Dual Scale Porosity and Interlaminar Properties of Composite Materials
Open this publication in new window or tab >>Dual Scale Porosity and Interlaminar Properties of Composite Materials
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In the strive towards reduced fuel consumption and lower emissions, low structural weight is becoming a key factor in the design of advanced vehicle and aerospace structures. Whereas most traditional construction materials are seemingly reaching their limitations, composite materials with their high specific properties offer possibilities to further reduce weight. In high demand structural applications, the quality of the composite material is of utmost importance, requiring the material to be void free and the matrix well distributed as a binder for the load carrying reinforcement. To achieve proper wetting of the fibres, knowledge of the flow resistance of the porous fibre reinforcement is required. It is normally expressed in terms of permeability.

Fibre reinforcements in composite materials are normally regarded as a heterogeneous porous media since both fabric and tows are porous but at different length scales. In order to numerically compute the permeability of such media, one of following two approaches can be used. Either filaments are added one-by-one into the modelled geometry (resolved model) or the tows are considered as porous homogenised media. In the latter case expression for the intra-tow permeability is needed.

In this thesis, a porous homogenised tow model is benchmarked with a resolved model to the level of refinement possible without being too expensive computationally. Based on this approach, the permeability of complex three- dimensional (3D) textiles is computed utilizing computational fluid dynamics (CFD) analysis. The effect of inter- and intra-tow porosity on the overall permeability of 2D and 3D structures is analysed and discussed in relation to contradictions found in past studies. A clearer picture of the problem is presented, which will be helpful in future modelling and understanding of the permeability of complex structures. In an experimental study, the overall fibre volume fraction as well as the tow compaction are varied and their influence on the permeability is measured. Experimental studies show good agreement with numerical simulations.

The interlaminar shear strength of thermoplastic composite materials is studied and the influence of specimen size is examined. Using finite element (FE) analysis it is shown that size effects may be partly due to statistical effects and partly due to the higher number of composite layers in thicker specimens.

The effect of processing on the interlaminar delamination toughness of car-bon/polyamide 12 (C/PA12) is studied. It is observed that processing conditions have vital effect on the interlaminar delamination of thermoplastic composites. The mode I crack energy release rate (GIc) of C/PA12 is found to be 15 times higher than for conventional thermoset based composites and 1.5 times higher than for a thermoset composite with stitched reinforcement through the thickness. The best performing C/PA12 composite is manufactured in a hydraulic press equipped with a cold tool, thereby showing potential for both cost and time efficient manufacturing.





Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. xiii, 39 p.
TRITA-AVE, ISSN 1651-7660 ; 2014:15
National Category
Aerospace Engineering
urn:nbn:se:kth:diva-145718 (URN)798-91-7595-185-0 (ISBN)
Public defence
2014-06-17, Kollegiesalen, Brinellvägen 8, KTH, Stockholm, 10:15 (English)

QC 20150602

Available from: 2014-06-04 Created: 2014-05-27 Last updated: 2015-06-23Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Tahir, Mohammad WaseemStig, FredrikÅkermo, MalinHallström, Stefan
By organisation
Lightweight Structures
In the same journal
Composites. Part A, Applied science and manufacturing
Vehicle Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 95 hits
ReferencesLink to record
Permanent link

Direct link