Abstract: The composite aero-engine bypass duct manufactured by autoclave molding technology is a large-size tubular structure with flanged edge. Due to its complex structure and the adverse factors such as high temperature, high pressure and long curing time, it is difficult to guarantee the structure quality for the selected polyimide BMP370 resin matrix composite material. In this study, the molding qualities of the simulation parts of the case were better controlled by packaging technology, molding design and manufacturing technology and process techniques. The results of non-destructive testing, mechanical properties of furnace pieces, T_g test and 370 ℃ static strength test show that the case is qualified in non-destructive testing with porosity under 2% and mechanical properties at high temperature above 50% of that at room temperature. The T_g of 430.2 ℃ and 370 ℃ damage intensity also meets the design requirements.

Key words: composite bypass duct casing model, high temperature resistance, flanging barrel structure, autoclave curing process