Abstract: As the application of composites has been broaden from the secondary structures to the primary structures of aircrafts, the stiffeners such as stringers and frames are made of composites rather than metals. To develop the primary structure of the pylon of civil aircrafts, a stiffener with A shape is experimentally studied using the RTM processing. The mold design, the layup design, the choice of the inlet and outlet, and the injection parameters optimization are studied, based on which the A stiffener is machined successfully.

Key words: RTM, stiffener, injection simulation, mold design