scholarly journals On the variability of permeability induced by reinforcement distortions and dual scale flow in liquid composite moulding: A review

2019 ◽  
Vol 120 ◽  
pp. 188-210 ◽  
Author(s):  
M. Bodaghi ◽  
S.V. Lomov ◽  
P. Simacek ◽  
N.C. Correia ◽  
S.G. Advani
Keyword(s):  
Liquid Composite Moulding ◽  
Dual Scale

Unsaturated flow characteristics in dual-scale fibre fabrics at one-dimensional constant flow rate

2016 ◽  
Vol 23 (6) ◽  
pp. 617-624
Author(s):  
Yan Shilin ◽  
Yan Fei ◽  
Li Dequan ◽  
Li Yongjing
Keyword(s):  
Flow Rate ◽  
Unsaturated Flow ◽  
Flow Characteristics ◽  
Constant Flow ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
Liquid Composite Moulding ◽  
Mould Filling ◽  
Set Up ◽  
Dual Scale

AbstractFibre fabrics in liquid composite moulding can be considered as dual-scale porous media. In different gap scales, an unsaturated flow is produced during the mould filling process. This particular flow behaviour deviates from the traditional Darcy’s law, which is used to calculate the filling pressure and will cause errors. To prove the mechanism of this unsaturated flow, an experimental device was set up with a one-dimensional constant flow rate. The influencing factors, such as injected media, flow velocity and fibre fabric, were investigated in this study. Based on the experimental data, several useful conclusions were drawn, providing good references for optimising the process parameters and controlling the product quality.

Modelling Tow Impregnation of Woven Fabric Reinforcements and Its Application in Liquid Composite Moulding Process Modelling

2008 ◽  
Author(s):  
Y. Wang ◽  
S. M. Grove ◽  
M. Moatamedi
Keyword(s):  
Woven Fabric ◽  
Scale Model ◽  
Flow Front ◽  
Moulding Process ◽  
Mathematical Algorithm ◽  
Model Liquid ◽  
Liquid Composite Moulding ◽  
Sink Term ◽  
Time Required ◽  
Dual Scale

This paper proposes a detail physical model for the micro-scale flow in plain woven reinforcements. The modelling results are formulated into a mathematical algorithm which is then directly incorporated into a continuum dual-scale model as a ‘sink’ term. When used to model liquid composite moulding (LCM) processes, this incorporated dual-scale model demonstrates the fact that the impregnation of fibre tows lags behind the resin front in macro pore spaces. The modelling results are in agreement with the experimental observations. It has been shown that the unsaturated region at the flow front could increase or have a fixed length under different circumstances. These differences are explained due to the variation in tow impregnation speed (or the time required for the tow to become fully impregnated) which is related to the weave infrastructure and the nesting and packing of plies. The modelling results have also demonstrated the drooping of the inlet pressure when the flow processes are carried out under constant injection rates.

scholarly journals A Numerical Analysis of Resin Flow in Woven Fabrics: Effect of Local Tow Curvature on Dual-Scale Permeability

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 405
Author(s):  
Hatim Alotaibi ◽  
Masoud Jabbari ◽  
Constantinos Soutis
Keyword(s):  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Void Formation ◽  
Fibre Volume ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Resin Flow ◽  
Liquid Composite Moulding ◽  
Proposed Model ◽  
Dual Scale

Permeability is a crucial flow parameter in liquid composite moulding (LCM), which is required to predict fibre impregnation, void formation and resin back flow. This work investigates the dual-scale (micro- and meso-) nature of permeability during resin infusion into woven fabric by incorporating the intra tow flow where the degree of local tow curvature (tow/yarn undulation) is taken into account. The mesoscopic permeability of a dual-scale porous media in a unit cell is estimated using Darcy’s law, where the Gebart analytical model is applied for the intra tow flow in longitudinal and transverse directions with respect to distinct fibre packing arrangements. The results suggest that for a low fibre volume fraction (≤42%), the degree of local curvature at the mesoscale can be neglected. However, for a high fibre volume fraction (>42%) and a higher fibre bundle curvature, the proposed model should be adopted, since the resin flow is affected by a mesoscopic tow curvature that could result in around 14% error in predicting permeability. It is shown that the permeability results of the current study are in good agreement with and in the range of the retrieved available experimental data from the literature.

scholarly journals A Review of Permeability and Flow Simulation for Liquid Composite Moulding of Plant Fibre Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4811
Author(s):  
Delphin Pantaloni ◽  
Alain Bourmaud ◽  
Christophe Baley ◽  
Mike J. Clifford ◽  
Michael H. Ramage ◽  
...  
Keyword(s):  
Flow Simulation ◽  
Fibre Reinforcement ◽  
Resin Impregnation ◽  
Liquid Composite Moulding ◽  
Mould Filling ◽  
Fibre Composites ◽  
Plant Fibre ◽  
Unsaturated Permeability ◽  
Specific Factors ◽  
Dual Scale

Liquid composite moulding (LCM) of plant fibre composites has gained much attention for the development of structural biobased composites. To produce quality composites, better understanding of the resin impregnation process and flow behaviour in plant fibre reinforcements is vital. By reviewing the literature, we aim to identify key plant fibre reinforcement-specific factors that influence, if not govern, the mould filling stage during LCM of plant fibre composites. In particular, the differences in structure (physical and biochemical) for plant and synthetic fibres, their semi-products (i.e., yarns and rovings), and their mats and textiles are shown to have a perceptible effect on their compaction, in-plane permeability, and processing via LCM. In addition to examining the effects of dual-scale flow, resin absorption, (subsequent) fibre swelling, capillarity, and time-dependent saturated and unsaturated permeability that are specific to plant fibre reinforcements, we also review the various models utilised to predict and simulate resin impregnation during LCM of plant fibre composites.

scholarly journals Spatial-Temporal Evolution and Relationship between Urbanization Level and Ecosystem Service from a Dual-Scale Perspective: A Case Study of the Pearl River Delta Urban Agglomeration

2021 ◽  
Vol 13 (15) ◽  
pp. 8537
Author(s):  
Yuanyuan Mao ◽  
Lingli Hou ◽  
Zhengdong Zhang
Keyword(s):  
Ecosystem Service ◽  
Pearl River Delta ◽  
Temporal Evolution ◽  
Pearl River ◽  
Ecosystem Service Value ◽  
Urbanization Level ◽  
Service Value ◽  
The Pearl River Delta ◽  
The Pearl River ◽  
Dual Scale

Since the beginning of the 21st century, urbanization has brought about dramatic changes in population, life, and economy, while having a significant impact on the distribution of ecosystem service. As research on the relationship between urbanization and ecosystem service has gradually specified, we decided to explore it at different scales. In this paper, we quantified and mapped the spatial–temporal evolution and relationship between urbanization and ecosystem service value in the Pearl River Delta Urban Agglomeration from 2000 to 2019 based on a dual-scale perspective of county and 3 km × 3 km raster. Our results show that the overall trend of urbanization level and ecosystem service value was increasing. Urbanization and ecosystem service value at the county scale showed a negative spatial correlation, while it was not significant at the raster scale. The “high–high” agglomeration was more concentrated, while the other three “low–low”, “low–high” and “high–low” agglomerations were more dispersed. Our findings suggest it is crucial to identify the key factors of small urban areas to grasp the development mechanism in the urbanization process and maintain the balance of the ecosystem.

Beyond Superwetting Surfaces: Dual-Scale Hyperporous Membrane with Rational Wettability for “Nonfouling” Emulsion Separation via Coalescence Demulsification

2021 ◽  
Vol 13 (3) ◽  
pp. 4731-4739
Author(s):  
Jianqiang Wang ◽  
Bing He ◽  
Yajie Ding ◽  
Tiantian Li ◽  
Weilin Zhang ◽  
...  
Keyword(s):  
Emulsion Separation ◽  
Dual Scale
Sign in / Sign up

Export Citation Format

Share Document