Original text - Engels - four point bending tests

stressing is accomplished by bending using a stressing jig and by restraining the bend in a specimen holder to prevent spring-back.Both the specimen and the specimen holder are exposed to test environment.
four point bending tests are cheap and easy to prepare but their reproducibility is somewhat weak.They are suitable for multiple testing and for atmospheric stress corrosion tests.
The pretension of for point bending specimens is performed using a special pretension tool.