Continued advancements in the design and manufacture of engineered composites have allowed composite materials to work their way into the products we use every day. The most common modern advanced composites are fiber-matrix composites and they can be manufactured with polymer, carbon, metal, or ceramic matrix and an extremely wide range of reinforcement fiber including, carbon, boron, aramid, and glass. Since composites are anisotropic materials, care must be taken in setting up and conducting tensile tests to ensure proper specimen alignment and load application to the test sample. Specimen alignment and orientation may not be as crucial for non-aligned short fiber composites, as many exhibit quasi isotropic behavior. However, non-aligned short fiber composites should still be carefully aligned and tested in multiple orientations to ensure that manufacture processes do not induce undesired fiber alignment. All aligned fiber composites will exhibit different mechanical properties in different orientations.
Tensile tests of composite materials are commonly conducted using specially designed grips and clamps. These grips aid in the proper alignment of test samples, help ensure failure in the specific mode being tested, and prevent improper load application or clamping forces which could damage the composite microstructure and adversely impact test results. TestResources has many grip options, including mechanical wedge grips and wedge action grips. Composites test fixtures are also designed to be used in a wide variety of test conditions, which are necessary to recreate the real-life application environment of composite materials. The creation of these environments is achieved through the use of saline baths for testing composites used in marine, biological, and outdoor environments and high-temperature environmental chambers for composites used in the aviation, aerospace, and automotive industries. Check out the suggested options below for tensile testing your fiber composites. ASTM and ISO have developed standard test methods for testing composite materials in tension. Standards provide methods that can be recreated, ensuring materials are tested in the same manner and conditions and allowing test results validation between manufacturers and customers. Look below for common composite test methods. Fiber reinforced composites exhibit their greatest strength under tensile loading, so tensile testing of high strength modern composites requires high force machines. Depending on size, the force requirements can be met with either tabletop or floor standing machines. The machine families below can be matched to the wide range of composite materials being tested. Since grips for composites tend to be custom, many of the grips below are designed for specific ASTM or ISO test methods, and others are representative of grip families which have been used for composites tensile testing. Contact a TestResources application engineer to determine the best machine and grip combination for your exact testing needs.
Applicable Testing Standards
- ISO 527 - Tensile Test of Plastics Composites
- ASTM D638 Tension Testing for Plastics
- ASTM D3039 Tensile Testing for Advanced Composite Materials
- ASTM D4762 Polymer Matrix Fiber Reinforced Composites Test Equipment
- ASTM D5766 Open-Hole Tensile Strength of Polymer Matrix Composite Laminates
- ASTM D6742 Filled Hole Test Equipment for Polymer Matrix Composites
- ASTM D7205 Tensile Tests of GFRP Matrix Composite Bars
- ASTM D7291 Flatwise Tensile Strength Test Equipment for Fiber-Reinforced Polymer Matrix Composite
- ASTM D7337 Tensile Creep Rupture Equipment for Polymer Matrix Composites
Recommended Test Machine
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