Method for manufacturing composite structure and method for manufacturing integrated composite structure

1. A method for manufacturing a composite structure in which a first member and a structure material as a second member are integrated, the method comprising:

an arrangement step of arranging a structure precursor comprising a resin and reinforced fibers in a mold comprising the first member;

a heating step of heating the structure precursor to equal to or higher than a temperature at which a storage elastic modulus (G′) of the structure precursor is less than 1.2×10 8 Pa;

a shaping step of expanding the structure precursor during the heating step to form a structure material as a second member, and bringing the structure material into close contact with the first member to obtain a composite structure; and

a cooling step of cooling the composite structure,

the first member having a bending modulus of 5 GPa or more at a temperature of the heating step,

the structure material as the second member comprising a resin, reinforced fibers and voids.

2. The method for manufacturing a composite structure according to claim 1 , which further comprises a molding step of molding the composite structure by pressurization, after the shaping step.

3. The method for manufacturing a composite structure according to claim 1 , which further comprises a deformation step of locally applying pressure to deform the composite structure, after the shaping step.

4. The method for manufacturing a composite structure according to claim 3 , wherein at least a part of a portion to be deformed is heated in the deformation step.

5. The method for manufacturing a composite structure according to claim 1 , wherein a linear expansion coefficient of the first member is 50×10 −6 /° C. or less.

6. The method for manufacturing a composite structure according to claim 1 , wherein the first member is a member selected from the group consisting of a fiber reinforced thermosetting resin member, a fiber reinforced thermoplastic resin member, a metal member, and a ceramic member.

7. The method for manufacturing a composite structure according to claim 1 , wherein a thickness of the first member is 0.1 mm or more.

8. The method for manufacturing a composite structure according to claim 1 , wherein the structure material as the second member satisfies the following (1) to (3):

(1) a volume content of the resin is 2.5 to 85% by volume;

(2) a volume content of the reinforced fibers is 0.5 to 55% by volume; and

(3) a volume content of the voids is 10 to 97% by volume.

9. The method for manufacturing a composite structure according to claim 1 , wherein the structure precursor satisfies the following (4) to (6):

(4) a volume content of the resin is 2.5 to 95% by volume;

(5) a volume content of the reinforced fibers is 0.5 to 85% by volume; and

(6) a volume content of the voids is 0 to 30% by volume.

10. The method for manufacturing a composite structure according to claim 1 , wherein a density (ρ) of the structure material as the second member is 0.9 g/cm 3 or less.

11. The method for manufacturing a composite structure according to claim 1 , wherein the reinforced fibers in the structure material as the second member are discontinuous, and dispersed in a nearly monofilament form and in a random manner.

12. A method for manufacturing an integrated composite structure, the method comprising further integrating another member with at least a part of a surface of the composite structure obtained by the method according to claim 1 .