Bending test

Test setup for the four-point bending test

The Bending test is a destructive Material test method.

Various test structures are available. They differ according to the number of load applications and the way test pieces are supported.

• In the two-point bending test, one side of a sample is held in place and an indenter applies a load to the other (free) side.
• In a three-point bending test, the sample is supported at both ends and the indenter subjects it to a load in the middle. It is important to minimise the frictional and torsional loads on the samples.
• In the four-point bending test, an indenter with two pressure points applies a load to a sample that is supported at two points. A constant Bending moment is created between the two points of support.

The bending Force and deflection are recorded. These values can be depicted graphically in a sample-specific stress-strain curve from which material characteristics such as flexural Strength and fracture Toughness can be read off. The flexural strength is the maximum outer fibre stress that a material supports when subjected to an elastic bending stress.