Vacuum assisted resin transfer molding (VARTM) in polymer matrix composites

Manufacturing processes for composite materials and components for aerospace applications

“…Two of the most popular of these processes are CRTM which is reviewed by Bickerton and Kelly (2012) [22] and VARTM which is discussed by Hsiao and Heider (2012) [23]. The use of vacuum to develop resin-infusion processes has been one of the most successful developments in reducing the problem of voidage as well as speeding up the process.…”

Experimental and Numerical Study of Vacuum Resin Infusion for Thin Walled Composite Parts

“…A process of vacuum assisted composite fabrication is widely used for producing large components with good quality, and widely applying in aircraft [1][2][3], shipbuilding [1, 4 -7], automotive [8], wind energy [4,7,9,10] and defense industries [5,10], due to its low cost, timeconsuming, simplicity of the required equipment and better ecology conditions at the manufacturing.…”

“…Meanwhile, some modifications of the VARTM processes have been developed to improve its quality, versatility and performance that allowed to significantly expand the scope of the process in the practice of composites manufacturing. Among these contrivances, which were able to overcome the difficulties associated with low permeability of the preforms, are a high permeability (HPM) and flow distribution media [5,15], air-permeable membrane [5], use of multiple injection lines and vents with independent control of resin and vacuum pressure [5,6,[16][17][18][19][20][21]. A distributed thermal control sometimes is used to reduce the resin viscosity while ensuring a low degree of the resin cure at the end of the preform filling [20,[22][23][24][25][26][27][28].…”

“…In the dry region, where the low air pressure vac p is supplied due to connection to the vacuum vent, the compressive pressure exerting a compression effect on the preform is equal to [14]. This phenomenon, which significantly changes the permeability of the preform for the moving liquid resin, as well as the fact that the pressure of the infusible resin during the vacuum process is much lower than with the traditional RTM, when the vacuum is deficient before the start of preform's filling [10], can contribute to the creation of incompletely saturated zones and dry spots [4,5,19,[29][30][31]. The presence of differently oriented layers in laminated preform leads to the appearance of undesirable phenomena: the impregnation of the layers depends on their permeability in the direction of the resin front propagation, as well as leads to the layers deformation that disrupt their packing [13,23].…”

“…depends on the geometry of the reinforcement. Combining equations (4) and (5), it is easy to obtain the dependence of permeability on compacting pressure. Using the relation between porosity ϕ and Vf, the dependence of permeability can also be expressed in terms of the porosity…”