Methods of making a tubular specimen with a predetermined wrinkle defect
There is a method of making a tubular specimen with a predetermined wrinkle defect including providing a layup tool with a cavity forming member having a cavity which resembles a desired shape of the at least one wrinkle; orienting a composite material around the mandrel at a wrap angle to form a closed loop; positioning a wrinkle tool on the closed loop; and/or generating at least one wrinkle with a predetermined characteristic in a portion of the closed loop to form a tubular specimen. The predetermined characteristic is at least one of the following: wrinkle location, an outward wrinkle, an inward wrinkle, a wrinkle width, a wrinkle height, and a wrinkle length. In another aspect, there is a method of offset load testing a tubular composite specimen. In a third aspect, there is a method of determining allowable defects for a composite component.
1. A method of making a tubular specimen with a predetermined wrinkle defect comprising:
providing a layup tool with a cavity forming member having a cavity which is complementary with a desired shape of at least one primitive wrinkle;
orienting a composite material around the layup tool at a wrap angle to form a closed loop, the wrap angle comprising at least one of the following: 45 degrees and −45 degrees;
generating at least one primitive wrinkle;
curing the closed loop after generating the at least one primitive wrinkle to form a tubular specimen, the tubular specimen including a top portion, a bottom portion, and a center portion disposed between the top portion and the bottom portion; the at least one wrinkle with a predetermined characteristic disposed only in the center portion of the tubular specimen; and
providing a plurality of reinforcement layers on the exterior surface at the top portion and the bottom portion of the tubular specimen to prevent bending in the top portion and bottom portion during offset load testing;
wherein the predetermined characteristic is at least one of the following: a wrinkle location, an outward wrinkle, an inward wrinkle, a wrinkle width, a wrinkle height, and a wrinkle length.
2. The method according to claim 1 , wherein the cavity forming member comprises a slot in a forming surface of the layup tool.
3. The method according to claim 1 , wherein the layup tool is a mandrel.
4. The method according to claim 3 , wherein the cavity forming member comprises a slot that extends around the mandrel.
5. The method according to claim 1 , further comprising:
positioning a wrinkle tool on the closed loop to form the primitive wrinkle;
wherein the generating at least one primitive wrinkle step includes deforming a portion of the closed loop around the wrinkle tool to create a primitive wrinkle.
6. The method according to claim 5 , wherein the wrinkle tool mates with the cavity in the cavity forming member.
7. The method according to claim 1 , wherein after the generating at least one primitive wrinkle step, the tubular specimen includes an unwrinkled portion adjacent to a wrinkled portion.
8. A method of making a tubular specimen with a predetermined wrinkle defect comprising:
providing a mandrel;
orienting a composite material around the mandrel at a wrap angle to form a closed loop;
positioning a wrinkle tool on the closed loop;
generating at least one primitive wrinkle by deforming a portion of the closed loop around the wrinkle tool to form the primitive wrinkle in the closed loop, the at least one primitive wrinkle is oriented essentially perpendicular to the longitudinal axis of the closed loop; and
curing the closed loop after generating the at least one primitive wrinkle to form a tubular specimen including at least one wrinkle with a predetermined characteristic, the tubular specimen including a top portion, a bottom portion, and a center portion disposed between the top portion and the bottom portion; the at least one wrinkle with a predetermined characteristic disposed only in the center portion of the tubular specimen; and
providing a plurality of reinforcement layers on the exterior surface at the top portion and the bottom portion of the tubular specimen to prevent bending in the top portion and bottom portion during offset load testing;
wherein the predetermined characteristic is at least one of the following: a wrinkle location, an outward wrinkle, an inward wrinkle, a wrinkle width, a wrinkle height, and a wrinkle length.
9. The method according to claim 1 , wherein the plurality of reinforcement layers comprises woven fiberglass plies wrapped around the exterior surface of the tubular specimen.
10. The method according to claim 1 , wherein the top portion and bottom portion each include a pair of aligned holes.
11. The method according to claim 5 , wherein the wrinkle tool comprises at least one of the following: a piece of wire, a punch device, a screw driver, a paper clip, a piece of rope, a piece of plastic string, one or more strings of yarn, round cross-sectional shaped objects, and bell cross-sectional shaped objects.
12. The method according to claim 8 , wherein the wrinkle tool comprises at least one of the following: a piece of wire, a punch device, a screw driver, a paper clip, a piece of rope, a piece of plastic string, one or more strings of yarn, round cross-sectional shaped objects, and bell cross-sectional shaped objects.
13. The method according to claim 8 , further comprising:
positioning a cavity forming member on the mandrel, the cavity forming member including a cavity which is complementary with a desired shape of at least one primitive wrinkle;
wherein the generating at least one primitive wrinkle step includes deforming a portion of the closed loop around the cavity forming member to create a primitive wrinkle.
14. The method according to claim 13 , wherein the wrinkle tool mates with the cavity in the cavity forming member.
15. The method according to claim 13 , wherein the cavity forming member comprises a slot that extends around the mandrel.
16. The method according to claim 8 , wherein after the generating at least one primitive wrinkle step, the tubular specimen includes an unwrinkled portion adjacent to a wrinkled portion.
17. The method according to claim 8 , wherein the plurality of reinforcement layers comprises woven fiberglass plies wrapped around the exterior surface of the tubular specimen.
18. The method according to claim 8 , wherein the top portion and bottom portion each include a pair of aligned holes.