Soft urethane foams are not commonly used in structural applications to support a tensile load, however their ability to withstand tensile loading is important for determining the material quality. Foam tensile properties are oftentimes an indicator of lot-specific process variability. Additionally, foams with low tensile strength pose significant handling issues during manufacturing. Tensile testing of foam and flexible cellular materials is conducted using a traditional dogbone-shaped specimen. For these applications consider your Grip selection carefully. Make sure your grips are able to clamp the foam without slipping, by applying a uniform pressure across the contact surface. To aid in slip prevention, air or spring-operated grips that automatically tighten with increasing applied tensile load are helpful. High accuracy elongation/strain measurements require an extensometer. Extensometers measure changes in the length of an object and are especially useful for tensile testing. Due to the low modulus characteristics of flexible foams, non-contact extensometers are the most accurate measurement of strain and strain rate for foams. Contact extensometers will cause changes in the specimen geometry and often cause premature breakage. Although grip separation measurement will not give a completely accurate characterization of the foam strain properties, it is the most economical method to measure elongation and is useful when comparing multiple specimens of the same materials with identical geometries and clamping conditions. For help choosing the right foam testing equipment for your testing needs, give one of our application engineers a call today at 800.430.6536.
Applicable Testing Standards
Recommended Test Machine
Forces up to 10 kN (2,250 lbf)
Low force tabletop systems
Modular series of five frame options with adjustable test space
Affordable testing option for tension, compression, bend, peel and much more
Force range of 5 kN to 600 kN (1,125 lbf to 135,000 lbf)
Adjustable test space
The most popular choice for static tension and compression tests
These dual column testers are available in both tabletop and floor standing models
Recommended Testing Accessories
Load ratings from 1 kN to 10 kN (225 lbf to 2,250 lbf)
Maximum specimen thicknesses of 7 mm or 8 mm (0.28 in. or 0.31 in.)
Works very well with flat, thin specimens
Eccentric design increases gripping force with tension
Rated to 500 N (112 lbf)
Maximum specimen thickness of 6 mm (0.23 in)
Pneumatic design allows for quick specimen setup
Consistent clamping force between tests
Rated to 0.6 kN (135 lbf)
Maximum specimen thicknesses from 8 mm to 50 mm (0.3 in. to 2.0 in.)
Clamp force up to 1.2 kN (270 lbf)
Quick and simple specimen setup for a wide variety of applications