Guide to using the fixture of the four point bending tester

Guide to using the fixture of the four point bending tester

Guide to using the fixture of the four point bending tester

Four point bending tester fixture---GB30367-2025

GB 30367-2025The four point bending tester fixture specified in the standard is used for mechanical property testing of dental ceramic materials, and its design must comply with the technical requirements in the standard appendix to ensure the accuracy and repeatability of the test results.

According to this standard, the core parameters of the four point bending fixture are as follows:

Supporting roller rod diameter:1.5 mm～5 mm（±0.2 mm）, used to support the specimen;

Center span of supporting roller rod（L）‌：‌16.0 mm～40.0 mm（±0.5 mm）, can be adjusted according to the sample size;

Loading method: Using1/4Point loading structure, where two inner loading rollers are located at the total span of the outer support rollers（Lof1/4Place, make the middle1/2Uniform distribution of bending moments within the span area;

Loading roller rod diameter: the same as the supporting roller rod, is1.5 mm～5 mm（±0.2 mm）‌；

Material requirements: The roller bar should have a hardness greater than40 HRCMade of hard steel or other hard materials, with a smooth surface and roughnessRaLess than0.5 Mm‌；

Measurement accuracy: The center to center distance of the support roller rod needs to be measured to0.1 mmEnsure accurate loading position within.

This fixture is suitable for universal mechanical testing machines, with a crosshead speed set to(1±0.5) mm/minTesting can accurately determine the bending strength and fracture toughness of ceramic materials. Due to the uniform stress zone generated in the middle of the specimen by four point bending loading, it can more accurately reflect the properties of the material body and avoid the problem of stress concentration at the loading point during three-point bending.