Development of a Helicopter Landing Gear Prototype using Resin Infusion Molding

Abstract

Because of the advances in material and technology, resin transfer molding is used for fabricating advanced polymer composites. It has the advantage of simple, potential automation, and low cost. The process involves injecting reactive resin into a closed mold with preplaced fiber preform. Resin infusion process applies a vacuum to draw resin into the mold cavity for mold filling. In this study, a low cost mold of a helicopter landing gear with a bow shape was constructed. A vacuum-assisted resin infusion process was used to fabricate the landing gear. A preheater is constructed and integrated in the process to heat the resin to a specified temperature before flowing into the mold while the mold is kept at room temperature. Numerical simulation of the resin infusion process was used to study the effect of the heated resin on the filling result. An adiabatic boundary condition was used to simulate the heat transfer condition at the foam core side of the part during the filling process. During the resin infusion process, the filling pressure is lower than the atmospheric pressure and the resulting filling flow is very slow in this case. Temperature of the resin will decrease quickly on entering the mold to meet the cool preplaced fiber reinforcements. However, increase of the resin temperature can reduce the viscosity and reduce the filling time. A critical temperature is identified in the simulation below by which the heated resin can fill the mold without any gelation.