Preform figuring method, composite material shaping method, composite material, and aircraft structural part

A preform figuring method comprising:

• mounting and stacking a plurality of sheet-shape fibrous preparations that are yet to be impregnated with a thermosetting resin or that have been impregnated with the thermosetting resin on a figuring die, wherein the figuring die comprises a shape that is formed by a flat plate and a protrusion formed on the flat plate, the protrusion has a first figuring surface that is a flat top surface, a second figuring surface that is a concave curved surface of the protrusion on its radially inner side, and a third figuring surface that is a convex curved surface of the protrusion on its radially outer side;
• and
• making a preform for a composite material, the preform having a curved inner flange formed by bending the plurality of sheet-shape fibrous preparations mounted on the first figuring surface onto the second figuring surface, a curved outer flange formed by bending the plurality of sheet-shape fibrous preparations mounted on the first figuring surface onto the third figuring surface, and a flat planar web that is coupled with the curved inner flange and the curved outer flange, wherein
• the preform is formed as a stack of the plurality of sheet-shape fibrous preparations which has a plurality of layers,
• a layer of the stack of the plurality of sheet-shapes fibrous preparations has a first sheet-shape fibrous preparation, a second sheet-shape fibrous preparation and a third sheet-shape fibrous preparation,
• the first sheet-shape fibrous preparation is configured to form:
• an entirety of the curved outer flange that forms a side having a smaller curvature of the preform;
• a portion of the flat planar web that includes a central portion of the flat planar web;
• and
• a portion of the curved inner flange that forms a side having a larger curvature of the preform, the portion of the curved inner flange including a central portion of the curved inner flange,
• the second sheet-shape fibrous preparation is configured to form:
• a portion of the flat planar web that includes a side end portion of the flat planar web;
• and
• a portion of the curved inner flange that includes a side end portion of the curved inner flange,
• the third sheet-shape fibrous preparation is configured to form:
• a portion of the flat planar web that includes another side end portion of the flat planar web;
• and
• a portion of the curved inner flange that includes another side end portion of the curved inner flange, and
• at least a fraction of the layers that constitute the stack are formed by mounting the plurality of sheet-shape fibrous preparations on the first figuring surface or on the sheet-shape fibrous preparation adjacent in a stacking direction so that the plurality of sheet-shape fibrous preparations partly overlap each other and bending portions of the plurality of sheet-shape fibrous preparations mounted so as to overlap onto the second figuring surface, and
• wherein a fiber length direction is varied among at least the fraction of the layers included in the stack.