The compressive properties of polymeric materials vary widely based on chemical composition, molecular structure, fillers, and service environment to name a few. Plastics are being increasingly used for structural applications due to their low density, corrosion resistance, electrical insulation, and formability/molding characteristics. Knowledge of the compressive properties of plastics is important for most structural applications. Compression testing plastic composites involves a specimen experiencing opposing forces that push inward upon the specimen. The plastic sample is generally placed in between two flat plates that evenly distribute the applied load across the entire surface area of the test sample. In contrast to a tensile test, as the compressive stress increases the cross-sectional area of the material becomes larger and the sides of the specimen bow out due to the friction between the compression platens and the material. Ultimate stresses measured during compression are oftentimes significantly higher than when in tension.
Compression tests of plastic composites require specific test machine accessories including special platens, extensometers and fixtures. Compression Test standards (ISO, ASTM, etc) provide detailed test machine setup and operational requirements and define the test equipment requirements for TestResources test machines. For example, when testing materials under 3.2mm thick in accordance with ASTM standard D695, use a TestResources ASTM D695 Compression Anti-Buckling Fixture. This fixture meets ASTM D695 requirements at forces up to 89 kN (20,000 lbs) and prevents specimen bucking. For testing to Boeing Specification BSS 7260, a TestResources BSS Boeing Compression Anti-Buckling Fixture is required. This fixture prevents buckling for high strength steel construction and is manufactured to test in accordance with BSS 7260. TestResources has a vast range of specified test fixtures and accessories for compression testing plastics and composites. For more information view the tabs below, or call today to speak directly with a TestResources compression test engineer.
Applicable Testing Standards
- ISO 604 Compressive Plastics Testing Equipment
- ASTM D695 Compression Testing for Rigid Plastics
- ASTM D1621 Compression Testing of Expanded Plastics and Foams
Recommended Test Machine
Forces up to 5 kN (1,125 lbf)
Low force tabletop systems
Tests at speeds up to 2,500 mm/min (100 in/min)
Best for high travel or high elongation test requirements
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
Designed in accordance to ASTM D695, Figure 2
Rated to 50 kN (11,250 lbf)
Maximum specimen footprint of 12.7 mm x 12.7 mm (0.50 in x 0.50 in)
Designed in accordance to ASTM D695, Figure 3
Rated to 100 kN (22,500 lbf)
For specimen thicknesses of 0.76 mm to 6.35 mm (0.030 in to 0.250 in)
Designed in accordance to BSS-7260
Rated to 89 kN (22,000 lbf)
