A coupon cut across the seam is gripped by the top tail on one side and the bottom tail on the same side, so the weld is pried open from its edge. Results are judged on strength and on how the specimen breaks: tearing through the sheet beside the weld passes, while the weld separating cleanly, or separating past a set share of its width, fails. On dual-track welds both tracks are peeled.
Peel test on the inside track separated almost halfway through the weld, so that seam fails.
Peels give the earlier warning: a seam can pass shear comfortably while its peels are already separating.
Also heard as
- peel
- peel strength
- seam peel
Do not mix it up with
- Shear test: Shear pulls the sheets apart in their own plane across the seam, as service loads do, while peel pries the weld open from its edge.
Related terms
Shear test
Seam test that pulls the two sheets apart in their own plane, loading the whole weld in shear.
FTB
Film tear bond: a seam coupon that breaks in the sheet beside the weld rather than through the weld itself.
Tensiometer
Portable tensile tester used on site to pull geomembrane seam coupons in peel and shear.
Coupon
Narrow strip cut across a seam sample for peel or shear testing, usually one inch wide.