ASTM D790 is commonly used in the plastics industry for measuring the flexural properties of unreinforced and reinforced plastics. This test can also be used on high-modulus composites and electrical insulating materials. The resulting data is often used to select materials for parts that will support loads without flexing.
ASTM D790
These test methods utilize a three-point loading system applied to a simply supported beam. ASTM D790 has two possible procedures. Procedure A is used for measuring flexural properties such as flexural modulus, and Procedure B can be used for measurement of flexural strength. Procedure A is typically for materials that can break at small deflections, where B is used for stronger specimens. Since most materials can vary in strength depending on their ambient temperature, it may be best to test the materials at their intended environmental temperature.
Testing Procedure
A test sample bar rests on two supports and is loaded by means of a loading nose midway between the supports. A support span-to-depth ratio of 16 to 1 is generally used. The specimen is deflected until a breaking point occurs in the outer surface of the test specimen or until a maximum strain of 5 per cent is reached.
We recommend using a versatile universal testing machine with a three point bend fixture to bend plastic test bar specimens. If temperature is a factor in your testing, consider an environmental chamber. By means of our testing expertise and modular product design, we will help find the testing solution that is right for you. Give one of our application engineers a call today for help with creating the best budget and testing plan according to ASTM D790.
Recommended Test Machines
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
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
Load ratings up to 250 kN (56,250 lbf)
Base lengths up to 1200 mm (48 in)
Various roller sizes available
Available in 3-point and 4-point configurations
Load ratings up to 10 kN (2,250 lbf)
Interchangeable roller diameters from 1 mm to 12.7 mm (0.04 in to 0.5 in)
Easily adjustable span
Base lengths of 150 mm (6 in) and 300 mm (12 in)
Available from a 1 mm (0.04 in) measurement range to a 25 mm (1.0 in) measurement range
May be used in a wide variety of tests
Includes a magnetic and adjustable mounting base
Standard units meet Class B-1 of ASTM E83, Class 0,5 of ISO 9513
Standard temperature range of -155°C to 620°C (-247°F to 1150°F)
Accompanied by a broad set of accessories that are capable of withstanding the heat or cold
PID controlled internal temperature
Mounts directly to the test frame
