The critical point setting for low-temperature bending test needs to be scientifically determined based on material characteristics, application scenarios, and international standards to determine the test temperature and bending angle, as follows:

Test temperature setting

Conventional testing range: Depending on the difference in material category, the conventional testing temperature range covers -60 ℃ to 20 ℃. For example, building waterproofing membranes are usually tested at -15 ℃ to -30 ℃ to simulate actual usage environments in cold climates; Rubber parts for automobiles may be tested at temperatures of -40 ℃ or even lower depending on the usage scenario.

Customization of special materials: For special materials or application scenarios, a -196 ℃ ultra-low temperature testing scheme can be customized to evaluate the bending performance of materials in liquid nitrogen and other environments.

Temperature fluctuation control: During the experiment, it is necessary to strictly control the temperature fluctuation to ensure that it is within ± 0.5 ℃, in order to eliminate the influence of temperature fluctuations on the test results.

Bending angle setting

Standard angle: The bending angle is usually set to 180 ° to simulate the maximum degree of bending that the material may encounter in actual use. For example, the low-temperature bending test of materials such as polymer waterproofing membranes and rubber coated fabrics adopts a 180 ° bending angle.

Angle adjustment basis: The bending angle can be adjusted appropriately according to the material characteristics and application requirements. For example, for certain flexible electronic materials, it may be necessary to use smaller bending angles (such as 90 °) to evaluate their bending resistance performance in daily use.

Bending radius control: The bending radius is usually 3-5 times the thickness of the sample to simulate the bending stress during actual construction or use. For example, the bending radius of waterproofing membrane is usually set to 5 times the thickness of the sample.