Methods of making a specimen with a predetermined wrinkle defect
In an aspect, there is a method of determining allowable defects for a composite component comprising identifying at least one wrinkle characteristic of a composite component wrinkle defect; making a first plurality of specimens each having a predetermined wrinkle defect representative of the composite component wrinkle defect; measuring each of the predetermined wrinkle defects in the first plurality of specimens for at least one performance metric to generate performance data; and generating an allowable wrinkle defect profile based on the performance data from the first plurality of specimens. In other aspects, there are methods of making a specimen with a predetermined wrinkle defect.
1. A method of making a specimen with a predetermined wrinkle defect, the steps comprising:
orienting a composite material around a layup tool at a wrap angle to form a closed loop;
generating at least one wrinkle with a predetermined characteristic in a portion of the dosed loop to form the specimen with a stretcher including an actuating mechanism in mechanical communication with a first arm and a second arm; the step of generating at least one wrinkle including positioning the first arm and the second arm in the closed loop; and moving at least one of the first arm and the second arm sufficient to form at least one wrinkle in the closed loop;
prior to a curing step, removing the first arm and the second arm from the closed loop; and
after the steps of generating the at least one wrinkle and removing the first arm and the second arm from the closed loop, curing the specimen;
wherein 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.
2. The method according to claim 1 , wherein the closed loop has a generally flat oval cross-sectional shape, the closed loop includes a top arcuate portion, a bottom arcuate portion, and a hollow portion between the top and bottom arcuate portions.
3. The method according to claim 2 , wherein the first arm is disposed in the top arcuate portion and the second arm is disposed in the bottom arcuate portion.
4. The method according to claim 1 , wherein the first arm and the second arm comprise a portion of a frame.
5. The method according to claim 1 , wherein the stretcher comprises a tensile test machine or a tension load frame.
6. The method according to claim 1 , wherein after the generating at least one wrinkle step, the specimen includes an unwrinkled portion adjacent to the wrinkled portion.
7. The method according to claim 1 , wherein the layup tool has a rectangular cross-sectional shape.
8. The method according to claim 1 , further comprising:
after the step of curing the specimen, cutting at least one coupon from the specimen.