GB/T 3356-1999 Test method for bending properties of unidirectional fiber reinforced plastics

This standard specifies the test method for the bending properties of unidirectional fiber reinforced plastics. This standard is applicable to the determination of the bending strength, bending modulus and load-deflection curve of unidirectional fiber reinforced plastic laminates. Symmetrical laminates can also be used as a reference. GB/T 3356-1999 Test method for bending properties of unidirectional fiber reinforced plastics GB/T3356-1999 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
GB/T3356-1999
Implementation of the test method for flexural properties of unidirectional fiber reinforced plastics
1999—08—01
National Bureau of Standards
Page 1
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Data compilation of the test method for flexural properties of unidirectional fiber reinforced plastics
3356-1999
2 Test conditions
3 Test steps.
4 Calculation
5 Test results
6 Test report
Additional notes:
Test method for bending properties of unidirectional fiber reinforced plastics"《Single-directional fiber reinforced plastics》356-1999
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This standard is applicable to the determination of flexural strength, flexural elastic modulus and load-deflection bending properties of unidirectional fiber reinforced plastics. This standard adopts three-point loading of simply supported beams and is mostly used for material selection and quality control.
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Strong plastic bending strength
Wei Zengma
Flexibility
3356-1999
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1 Specimen
1.1 The geometry of the specimen is shown in Figure 1 (Figure omitted). Span 1 is calculated according to the span-to-thickness ratio 1/h. The span-to-thickness ratio should be selected to ensure that the failure of the specimen under bending span occurs in the outermost inoaec.com
layer of fiber. The recommended span-to-thickness ratio 1/h values ​​are 16, 32 and 40. The specimen width is 10-15mm.
1.2 Standard specimen size
Thickness h=2.0±0.2mm;
Width b=12.5±0.5mm;
Span-to-thickness ratio, glass fiber reinforced plastic is 1/h=16±1, carbon fiber reinforced plastic is 1/h=32±1.1.3 The number of specimens in each group should be not less than 5. "Single
Dimensional
Flexibility 1
356-1999
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2 Test conditions
2.1 The standard environment for specimen state adjustment and testing shall comply with the provisions of GB1446 "General Principles for Test Methods for Properties of Fiber Reinforced Plastics". In general, the storage and test conditions of the specimens should be recorded. 2.2 The test equipment shall comply with the provisions of GB1446.
2.3 The schematic diagram of the test device is shown in Figure 2 (Figure omitted). The loading head and the support shall be cylindrical surfaces. The radius of the head R=5±0
When the radius of the support corner is h≤3mm, r=0.5±0.2mm; when h>3mm, r=2±0.2mm.
For carbon fiber reinforced plastics, r=2±0.2mm is suitable. 2.4 Loading speed:
2.4.1 When determining the bending strength, the loading speed is calculated according to formula 2): 1[2]
Where: V——loading speed, mm/min; 1span, mm;
h——specimen thickness, mm;
The strain rate of the outer fiber at the midpoint of the span is 1%/min. Z
When 1/h=16, the loading speed v=---; 2
When 1/h=32, the loading speed v=2h. In general tests, the loading speed v=5~10mm/min can also be taken. (2
2.4.2 When determining the bending elastic modulus and load-deflection curve, the loading speed is 1~2mm/min or manual speed. Page 5
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Test method for bending properties of strong plastics》
856-1999
3.1 Prepare the specimen according to the provisions of GB1446.
3 Test steps
3.2 Check the appearance of the specimen according to the provisions of GB1446. 3.3 Adjust the state of the specimen according to the provisions of GB1446. 3.4 Number the specimen, draw lines and measure the width and thickness of any three points of the working section, and take Arithmetic mean. The measurement accuracy shall be in accordance with the provisions of GB1446.
3.5 Adjust the span to an accuracy of 0.5mm. The axis of the loading head is located in the middle of the support and is parallel to the support. 3.6 Place the specimen at the center of the two supports, and make the length direction of the specimen perpendicular to the supports and the loading head. 3.7 Place the instrument for measuring deformation at the midpoint of the span, in contact with the lower surface of the specimen, apply an initial load (approximately 5% of the breaking load), check and adjust the instrument, and put the entire system in a normal state. 3.8 When measuring the bending elastic modulus or the load-deflection curve, use graded loading with a step difference of 510% of the breaking load until the deflection reaches the value to be measured. Record the load and the corresponding deflection value at each level. The automatic recording device can load continuously.
3.9 When measuring the bending strength, continue to load until the specimen fails and record the failure load. 3.10 Draw the load-deflection curve.
3.11 Specimens that fail in interlayer shear or fail within the middle 1/3 of the span should be discarded. If there are less than 5 valid specimens, the test should be repeated.
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Flexural Properties Test Method
3356-1999
4.1 Flexural strength is calculated according to formula (3):
Where: af-
4 Calculation
3Pb·1||tt| |2b·h[2]
-bending strength, kgf/cm[2] (MPa); Note: 1MPa=1N/mm[2]～10
2kgf/cm[2].
Maximum load when the specimen is damaged, kgf(N); 1-span, cm(mm);
b-specimen width, cm(mm);
specimen thickness, cm(mm). bZxz.net
When the bending deflection moment of the specimen at failure is 10% of f/1, if accuracy is required, the bending strength can be calculated according to formula (4): 3Pb·1
(1+4(f/1)[2D..
2b· h[2]
where: f is the deflection at the midpoint of the span when the specimen fails, cm (mm). 4.2 The bending elastic modulus is calculated according to formula (5): AP·1
4b·h[3]·Af
where: Ef is the bending elastic modulus, kgf/cm[2] (MPa); △P is the load increment corresponding to the straight line segment on the load-deflection curve, kgf (N); △f is the deflection at the midpoint of the span corresponding to △P, cm (mm). (4)
· (5)
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Test method for flexural properties of fiber reinforced plastics" Material Code
856-1999
5 Test results
According to the provisions of GB1446
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Flexural properties of fiber reinforced plastics
Test method
3356-1999
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Test Report
According to the provisions of GB1446
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Reinforced Plastics Bending
Fiber Reinforced Plastics
Bending Performance
Test Method
3356-1999
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Additional Notes:
This standard was proposed by the Ministry of Aviation Industry of the People's Republic of China and the State Building Materials Industry Bureau, and is under the jurisdiction of the Fiber Reinforced Plastics Branch of the National Plastics Standardization Technical Committee. inoaec.com
This standard was jointly drafted by the Institute of Aeronautical Materials, Beijing University of Aeronautics and the Beijing Glass Fiber Reinforced Plastics Research Institute of the State Building Materials Industry Bureau.
The main drafters of this standard are Yang Naibin, Sun Yijuan, Wang Binru and Wu Youying. Single
Wei Zengma
Flexibility 1
Test Method#
3356-1999
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