Three-point bending and four-point bending tester test method - Database & Sql Blog Articles

Applicable to mobile phone mirrors, plexiglass, fiberglass, fiberglass, liquid crystal glass, flat materials, etc.; generally three-point bending, but a small number of customers require four-point bending to test. Now let's distinguish the difference between three-point bending and four-point bending.
Generally, there are two kinds of loading stress modes, namely three-point bending and four-point bending. Different bending methods have different bending strengths. Both loading methods have advantages and disadvantages. The three-point bending loading mode is simple, and the loading mode is concentrated. The bending distribution is not uniform, the defects of a certain part may not be displayed, and the effect is not achieved. The bending moment is evenly distributed at the four-point bending, and the test result is more accurate, but the pressing structure is complicated and less used in industrial production.

Three-point bending definition:
A test method for measuring the bending properties of materials. The strip sample is placed flat in the bending test fixture to form a simple supported beam. The distance between the two lower support points of the support sample is adjustable depending on the length of the sample, and there is only one loading point above the sample.
Four-point bending definition:
A test method for measuring the bending properties of materials. The strip sample is placed flat in the bending test fixture to form a simple supported beam. The distance between the two lower support points of the supporting specimen is adjustable according to the length of the specimen, and there are two symmetrical loading points above the specimen.
Bending strength: The maximum bending force reached before the specimen is bent and fractured. According to the loading method and the shape of the specimen, the bending strength has different calculation methods. For a rectangular specimen with a width b and a height h, a three-point bending formula: S=3FL/2bh?2;
Four-point bending formula: S=FL/bh?2; (US standard)