The narrow waist makes the specimen yield and break in the middle rather than at the grips, giving clean values for yield and break strength and elongation. Sheet tensile and stress crack tests on polyethylene geomembranes use dumbbell shapes punched with a steel die. Seam coupons, by contrast, are usually straight strips.
Heard on the job
Punch five dogbones each way off the conformance sample for tensile, machine and cross direction.
Also heard as
- dumbbell
- dog bone
- dumbbell specimen
Related terms
Coupon
Narrow strip cut across a seam sample for peel or shear testing, usually one inch wide.
Stress cracking
Brittle cracking of polyethylene geomembranes under long-term tension well below their yield strength.
Conformance testing
Testing samples from rolls delivered to a site to confirm the material matches the specification.