INTRA-YARN PERMEABILITY ASSESSMENT WITH A NEW DEDICATED SET-UP AND CHARACTERISATION OF THE ASSOCIATED CAPILLARY PRESSURE
Topic(s) : Manufacturing
Co-authors :
Romain RAVEL (FRANCE), Morgan CATALDI , Yanneck WIELHORSKI (FRANCE), Nicolas MOULIN (FRANCE), Monica PUCCI (FRANCE), Pierre-Jacques LIOTIER (FRANCE)Abstract :
Manufacturing of high quality composites reinforced by complex fibrous preforms such as 3D interlocks by Resin Transfer Moulding (RTM) requires impregnation simulations in order to prevent the formation of defects. The multiscale structure of reinforcements involves dual-scale flows of a liquid resin within the fibres of the yarn and between the yarns. To conduct those simulations [1-2], experimental data on the intra-yarn behaviour are required.
Most of the studies on this topic consider yarns as non-permeable [3], which can be understandable for quasi-unidirectional flows and large inter-yarn channels. However, in the context of complex 3D interlocks compacted during RTM, intra-yarn permeability has to be estimated. Another aspect that is usually neglected in studies from literature is the effect induced by the surface energy of fibres i.e. capillary effects. There is currently a lack of data on the intra-yarn capillary pressure.
The main aim of the present study is to introduce a new device designed for assessing intra-yarn permeability and to describe results obtained on different yarns size (12k, 24k and 48k) provided by SAFRAN Aircraft Engines. In addition to this intra-yarn permeability characterization, wicking experiments on single yarns were conducted using an adapted sample holder, inspirated by previous work [4]. The combination of all those data will thus allow to calculate the intra-yarn capillary stress at different fibre volume fractions. Those results will be compared to evolutions of capillary pressure against fibre volume fraction from previous studies [6] and included into simulations at higher scales [2].
Most of the studies on this topic consider yarns as non-permeable [3], which can be understandable for quasi-unidirectional flows and large inter-yarn channels. However, in the context of complex 3D interlocks compacted during RTM, intra-yarn permeability has to be estimated. Another aspect that is usually neglected in studies from literature is the effect induced by the surface energy of fibres i.e. capillary effects. There is currently a lack of data on the intra-yarn capillary pressure.
The main aim of the present study is to introduce a new device designed for assessing intra-yarn permeability and to describe results obtained on different yarns size (12k, 24k and 48k) provided by SAFRAN Aircraft Engines. In addition to this intra-yarn permeability characterization, wicking experiments on single yarns were conducted using an adapted sample holder, inspirated by previous work [4]. The combination of all those data will thus allow to calculate the intra-yarn capillary stress at different fibre volume fractions. Those results will be compared to evolutions of capillary pressure against fibre volume fraction from previous studies [6] and included into simulations at higher scales [2].