Flexural bend testing method measures the behavior of materials subjected to simple bending loads. Similar to elastic modulus in tensile testing, flexural modulus (stiffness) is the slope as determined by stress over strain in the elastic region of the force vs. deflection curve.
An ASTM bend test is commonly used on brittle materials such as ceramics, stone, masonry, some metals and glasses. It can also be used to examine the behavior of materials which are intended to bend during their useful life, such as wire insulation, plastic tray materials and other elastomeric products.
Our team can carry out flexural bend testing to accepted industry standards, assist with the creation of custom protocols and create custom fixturing for special case needs.
ASTM D790 Flexural Test of Plastics & Composites
ASTM D790 is commonly used to evaluate reinforced and unreinforced plastics, thermoplastics and thermosets, electrical insulation materials, and high modulus composites. This test measures the flexural properties of a material while under a bending strain or deflection to help determine the stiffness of materials needed to support the loads required for your application. ASTM D790 testing is used to determine the following mechanical properties:
- Tangent modulus – Also known as flexural modulus, this is the slope of the initial linear portion of the load deflection curve and is a measurement of the material’s stiffness
- Secant modulus – The slope between the origin and a predefined point on the load deflection curve
- Chord modulus – The slope between two predefined points on the load deflection curve
- Flexural strength – The maximum flexural stress obtained during a bend test
- Flexural Stress at Break – The flexural stress at which a specimen breaks during a bend test. For some materials, the specimen breaks before a yield point, in which cases the flexural strength equals the flexural stress at break.
A few of the standards that employ flexural testing include:
- ASTM C393 – Flexural Properties of Sandwich Constructions
- ASTM C1161 – Flexural Strength of Advanced Ceramics at Ambient Temperature
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