A Prediction Method for In-Plane Permeability and Manufacturing Applications in the VARTM Process

Abstract

VARTM (Vacuum Assisted Resin Transfer Molding) is a popular method for manufacturing large-scaled, single-sided mold composite structures, such as wind turbine blades and yachts. Simulation to find the proper infusion scenario before manufacturing is essential to avoid dry spots as well as incomplete saturation and various fiber weaves with different permeability affect numerical simulation tremendously. This study focused on deriving the in-plane permeability prediction method for FRP (Fiber Reinforced Plastics) laminates in the VARTM process by experimental measurements and numerical analysis. The method provided an efficient way to determine the permeability of laminates without conducting lots of experiments in the future. In-plane permeability imported into the software, RTM-Worx, to simulate resin flowing pattern before the infusion experiments of a 3D ship hull with two different infusion scenarios. The close agreement between experiments and simulations proved the correctness and applicability of the prediction method for the in-plane permeability.

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.…”

“…Due to the above mentioned improvements in vacuum infusion processes, they were successfully implemented in the manufacture of aircraft structures (usually, shell type) [1][2][3], blades of wind turbines [1,9,10,27], ship's hulls [1,4,6,27,29], large-sized parts of cars bodies [30], details of spacecraft etc. [1,29].…”

“…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].…”

“…Historically, the first such system was the LIMS software [11,16,19,35], the theoretical foundations of which were presented in the 90s of the 20th century and presented in [36]. Late the kind of the similar systems has been developed and used by some scientists: PAM-RTM [16,20,22,37]; RTM-WORKS [4,6,9]; 3DINFIL [38]; RTMSim [39]; Moldex3D RTM [40] and the ANSYS Fluent module [3,7]. All of these systems are based on the use of the so-called Finite Element / Control Volume (FE / CV) method, which uses special means of monitoring the front movement of the resin to eliminate the need to work with the moving boundaries and the deformed finite element mesh.…”

“…An influence of the heating rates and isothermal holds on the uniformity of the temperature and degree of cure fields during resin impregnation were studied in [28] using the finite element software ABAQUS. In order to provide a resin flowing profile uniformity and make infusion time less than resin gel time the authors of [4,6] used RTM-Worx software at the optimization the manufacturing process of the boat hulls by manual changing injection gate position, length, and spacing of minor pipes for parallel and fish-bone arrangements of the pipes for the resin infusion.…”