Each destructive or trial sample is cut into a set of coupons, commonly five for peel and five for shear, and each one is pulled on the tensiometer. Coupons are cut with a die or template so widths are exact, since a ragged edge can start a tear and fail a good seam. The pass rule is usually a set number of coupons, often four of five, meeting strength and break-type requirements.
Cut ten coupons off the trial weld, five peel and five shear, and keep them in order.
Also heard as
- specimen
- seam coupon
Related terms
Tensiometer
Portable tensile tester used on site to pull geomembrane seam coupons in peel and shear.
Peel test
Seam test that pulls the top sheet away from the bottom sheet across the weld to check how well they fused.
Shear test
Seam test that pulls the two sheets apart in their own plane, loading the whole weld in shear.
Dogbone
Dumbbell-shaped specimen punched from geomembrane sheet for tensile and stress crack tests.
Destruct
Installer shorthand for a destructive seam sample, and for the job of cutting one out.
Same word, different worlds
A small test piece sprayed alongside production parts to stand in for them in destructive tests.
AdhesivesA small standard test piece, usually a metal or plastic strip, bonded to check adhesive strength or prep.
Printed Circuit BoardsSmall test pattern built on the production panel and measured or sectioned to prove the boards meet spec.