COUPON GEOMETRIES THAT INDUCE FAILURE IN GAUGE AREA OF COMPOSITE FATIGUE TEST COUPONS

摘要

PROBLEM TO BE SOLVED: To provide a coupon geometry that reliably fails in a gauge area of a coupon during fatigue testing.SOLUTION: A test coupon 10 has a bow-tie-shaped profile with tapered sides 12a, 12b, 12c and 12d that converge as extending from opposing ends 44 and 50 of the coupon 10 to a gauge area 20, forming a pair of trapezoidal portions 16 and 18 connected by the gauge area 20. These trapezoidal portions 16 and 18 of the test coupon 10 include regions where similarly trapezoidal tabs will adhere to the front and back of the coupon 10. The test coupon 10 has a minimum width in the gauge area 20 and a constant thickness, and the height of the gauge area 20 is 3% or less of the height of the test coupon 10.