GB/T 8812-1988 Bending test method for rigid cellular plastics GB/T8812-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Rigid cellular plastics
Test method for bending of
rigid cellular plastics
This standard is equivalent to the international standard ISO1209-1976 "Bending test of rigid cellular plastics". 1 Subject content and scope of application
UDC678.5/7.074
: 620.174
GB 8812-88
ISO 1209--76
This standard specifies a test method for determining the bending properties of rigid cellular plastics, that is, determining the load or breaking load when the rigid cellular plastic specimen is subjected to three-point force to produce a specified deformation. Since the loading method used in this standard cannot cause pure bending deformation of the specimen, it cannot be used to calculate the bending strength and apparent bending modulus of the material. This test method is mainly used to evaluate the bending properties of foam plastics under laboratory conditions. 2 Reference standards
GB2918 Standard environment for state adjustment and testing of plastic specimens GB6342 Determination of linear dimensions of foam plastics and rubber 3 Principle
Place the specimen on a support, apply load to the specimen at a certain rate, and record the load value or breaking load value of the specimen at the specified deformation.
4 Test equipment
4.1 A compression tester or bending tester with a loading head and a support. 4.2 To avoid excessive indentation of the specimen, the top surface of the loading head and the support should be a cylindrical surface with an arc radius of 5 ± 0.2 mm, a span of 100 ± 1 mm between the two supports, and the loading head located in the center of the specimen. 5 Specimens and their preparation
5.1 Shape and size
The specimen is a rectangular parallelepiped with the following dimensions
Thickness (test height)
5.2 Specimen preparation
120±1.20 mm
25±0. 25 mm
20±0.20 mmWww.bzxZ.net
The cell structure of the specimen should not be deformed during specimen preparation. The specimen may be skinned on one or more sides. 5.3 Number of specimens
At least five specimens shall be tested for each type of sample. When the material to be tested is suspected to be anisotropic, two sets of specimens shall be prepared with their axes parallel and perpendicular to the direction of cell elongation, respectively.
5.4 Conditioning
GB8812-88
Test condition of the specimen is as specified in GB2918. The temperature is 23±2℃ and the relative viscosity is 45%~~55%. The size of the specimen is measured as specified in GB6342. 6 Test steps
Place the specimen in the middle of the support so that the height of the specimen is consistent with the loading direction. The pressure head contacts the specimen with the minimum pressure, and this position is recorded and used as the zero point of the specimen deformation. The loading pressure head applies load to the specimen at a rate of 10±2mm/min. Note and record the load value (in Newton) when the specimen is deformed by 20±0.2mm. If the specimen is broken before the deformation reaches 20mm, record the fracture force of the specimen and the deformation at the fracture point.
Results
Bending force (Newton);
Bending fracture force (Newton),
8Test report
The test report should include the following contents:
Load when 20mm deformation
Deformation at the fracture point (mm)
Material type and brand (including material density): Specimen surface condition:
The direction of applied load is perpendicular to the direction of cell elongation, each test result and arithmetic mean;
Test date;
Operation steps different from this standard.
Additional statement:
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the Plastics Processing and Application Research Institute of the Ministry of Light Industry. This standard was drafted by the Shanghai Plastic Products Research Institute. 417
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