A methodology to determine permeability distribution of a preform in resin transfer molding process

Abstract

This article presents a scheme that directly calculates permeability distribution of a preform during the RTM process. The measured filling front locations as well as the corresponding inlet conditions are used in the proposed scheme to calculate the permeability distribution that also takes into account race-tracking phenomenon. The proposed scheme employs a numerical optimization algorithm to minimize a cost function that leads to the permeability field of the preform. Time-step-independent RTM filling algorithm is utilized as a computational kernel to generate the cost function for the subsequent minimization. Numerical development of the proposed scheme is discussed in this article. In addition, the proposed scheme is applied to several test problems involving a variety of spatial permeability distribution of the preform including a situation that involves race-tracking phenomena.

Thermoplastic matrix‐based composites produced by resin transfer molding: A review

“…[ 29 ] Minaie et al studied the permeability distribution for the edge injection strategy in anisotropic and isotropic textiles, and a numerical algorithm was proposed to predict the flow front. [ 30 ] In this study, an elliptical shape of the flow front for anisotropic textiles could clearly be established (Figure 5). The methodology used to predict the permeability distribution during the RTM process using numerical simulations can also be useful for enhancing the mold filling.…”

“…Flow front position in a 0.1 m × 0.2 m × 0.01 m resin transfer molding (RTM) mold for (a) isotropic and (B) anisotropic permeability distributions [ 30 ] …”

“…To produce thermoplastic composites with good mechanical properties using reactive thermoplastic systems in TP-RTM, the following are required: (i) a high conversion rate of the monomers/oligomers, (ii) a high molecular weight of the resulting polymer matrix, and (iii) no unwanted by-products. [35] F I G U R E 5 Flow front position in a 0.1 m  0.2 m  0.01 m resin transfer molding (RTM) mold for (a) isotropic and (B) anisotropic permeability distributions [30] Certain important industrial polymers are produced via ROP, such as polyethylene oxide, polyphosphazene, and polyamides like Nylon ® 6 (poly(ε-CL)), the most significant in terms of volume. [36] Nowadays, some biobased and biodegradable polymers are industrially produced via ROP, such as Ingeo TM (polylactide) commercialized by NatureWorks, and Capromer TM PCL from BASF.…”

Non-uniform capillary model for unidirectional fiber bundles considering pore size distribution

“…It is well known that these fiber reinforcements are regarded as double scale porous media; therefore, there are two scales of flow during LCM: (1) a viscous flow between fiber tows; and (2) a capillary flow inside each fiber bundle. [1][2][3][4][5] A direct result from this flow competition is entrapment of voids within the preform, [6][7][8] especially micro voids formed due to the microscopic capillary effects and low permeability of the fiber tows. 9,10 Hence, it is of great significance to analyze the capillary flow within fiber bundles in order to improve the process and product quality.…”

Transversal flow-induced deformation of fibres during composites manufacturing and the effect on permeability

“…The flow takes place on two scales within the fibre bundles and between them. 1–15 The aim is to reveal how transversal flow-induced deformations of different initial arrangements of the fibres influence the detailed permeability. This is especially important in composites manufacturing with liquid moulding processes such as Resin Transfer Moulding and Vacuum Infusion where relatively high pressure gradients drive the fluid flow and the properties of the final composite are crucially dependent on the orientation and distribution of the fibres.…”