ASTM D695 Compression Testing of Rigid Plastics

0 1
ASTM D695 Compression Testing of Rigid Plastics

ASTM D695 is used to determine the compressive strength of rigid unreinforced and reinforced plastic. The specification was put in place to ensure that consumers are getting what they pay for when they purchase a product. Whether it be for food, beauty products, toys, or anything else, this test helps ensure the quality of the product. 

What Does ASTM D695 Measure?

ASTM D695 measures the compressive properties of rigid plastics including high modulus composites. It is a companion plastics test method to its tensile test standard equivalent, ASTM D638.

Key ASTM D695 test measurements include:

  • Compressive modulus of elasticity
  • Yield stress
  • Deformation beyond yield point
  • Compressive strength

ASTM D695 Test Systems

Test samples are end loaded in compression using low test speeds. A universal test machine with constant rate of crosshead displacement is commonly configured with ASTM D695 test fixtures. Depending on the maximum expected forces, either a single column or dual column universal testing machine works. Complete system includes controller software, load frame and fixtures specifically configured for your test requirements. Our ASTM D695 fixtures are compatible with any brand of test machine. We offer adapters that allow the grips and fixtures to be used on test machines from TestResources, Instron®, MTS®, Tinius Olsen® and every other brand of machine.

What Are the Fixture Requirements for Rigid Unreinforced Plastics per ASTM D695?

For rigid unreinforced plastics, the test samples for strength measurements are based on right cylinder or prism sample geometries whose length is twice its principle width or diameter. To test this material type and this geometry, the ASTM D695 standard defines the need for a special test fixture,“FIG. 2 Compression Tool”, which corresponds to FIG2 compression fixture GD695-813.

What Are the Fixture Requirements for Rigid Reinforced Plastics per ASTM D695?

For reinforced plastics and thin materials (3.2 mm or less), you need an anti-buckling fixture that consists of a set of inserts matching "D695 FIG. 4".

OurG793 plastics compression test fixture has been created for these applications and it offers a modular design that serves multiple applications including the ASTM D695. In fact it can be configured to serve a broad range of polymer matrix composite applications and international test methods involving plastics.

Each G793 fixture configuration is matched to your exact test requirements using different inserts that are compatible with a common carrier. The G793 carrier was developed in support of Boeing’s needs as defined by their Boeing standard BSS 7260, “Advanced Composite Compression Tests”, Boeing document D888-10026. The carrier is now known as a "Modified ASTM D695" which is an improvement over the original D695 “I shaped” lateral support plate. It meets both the ASTM D695 standard and Boeing BSS 7260.