A simulation of the non‐isothermal resin transfer molding process

Abstract

A simulation of the non‐isothermal resin transfer molding manufacturing process accounting for both the filling and the consolidation stage has been developed. The flow of an exothermally reactive resin through a porous medium has been analyzed with reference to the Darcy law, allowing for the chemorheological properties of the reacting resin. Thermal profile calculations have been extended to a three phase domain, namely the mold, the dry preform and the filled preform. The mold has been included in order to evaluate the thermal inertial effects. The energy balance equation includes the reaction term together with the conductive and convective terms, and particular attention has been devoted to setting the thermal boundary condition at the flow front surface. The moving boundary condition has been derived by a jump equation. The simulation performance has been tested by comparing the predicted temperature profiles with experimental data from literature. Further numerical analysis assessed the relevance of using the jump equation at the flow front position for both filling time and thermal profile determination.

Flow enhancement in liquid composite molding processes by online microwave resin preheating

“…In the LCM process, the resin cure and impregnation progress with different timescales; therefore, usually one can ignore the cure during the filling and considers the flowing resin as an isothermal fluid. [28,29,55,62] However higher temperatures initiate and accelerate the cure, the viscosity, hence, increases exponentially as the number of the crosslinks between polymeric chains raises, nullifying the previous reduction due to preheating. The power cycle was set before the beginning of the test and tuned according to the expected behavior of the resin.…”

“…[26,27] This occurrence is usually neglected in conventional LCM processes because the temperature of resin varies within a range where a significant amount of reaction is prevented. [3,10,28,29] Recently, two different approaches have been explored: offline or batch heating and online heating. Batch heating exhibits remarkable benefits concerning the reduction of fabric impregnation and cycle times; however, it is not feasible for high-volume production.…”

A process performance index based on gate-distance and incubation time for the optimization of gate locations in liquid composite molding processes

“…Several computer simulations, including some which address the thermal and curing problems, have been developed in RTM process in [16][17][18][19][20].…”

Vacuum infusion manufacturing and experimental characterization of Kevlar/epoxy composites

“…In addition, the impregnation of the dry fiber reinforcement by a thermoset liquid resin is carried out by vacuum application. Besides the several advantages of these processes, some limitations can be observed during the conventional VARTM process [1][2][3][4][5][6][7][8], such significant through-the-thickness impregnation gradients and local variation of compaction pressure that can determine not uniform thickness for the final composite part. A viable alternative to the conventional VIP is a new vacuum-assisted technology "Pulse Infusion" [9] that is based on the use of a proper designed pressure distributor.…”