1、 FORD LABORATORY TEST METHOD EU-BS 005-01 Date Action Revisions 2000 11 10 Revised Editorial no technical change A. Cockman 1994 09 21 Printed copies are uncontrolled Page 1 of 3 Copyright 2000, Ford Global Technologies, Inc. DETERMINATION OF FLEXURAL STRENGTH AND THE ELASTICITY MODULUS Application
2、This procedure is used to determine the flexural strength, before and after water immersion and the modulus of elasticity of cellulose fibre boards. Apparatus Required Flexural Loading Device (see sketch) The support cylinders and the flexing mandrel must be of a width greater than the test specimen
3、 The diameter of the flexing mandrel and that of the support cylinders must be 12.5 mm for a test specimen up to 6 mm thick, and i t must be 25 mm for a test specimen 6 - 10 mm thick. Recording Device This shall be used to set up the load/deflection diagram. Micrometer Gauge Conditioning and Test C
4、onditions All test values indicated herein are based on material conditioned in a c ontrolled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure A. Original Flexural Strength 1
5、 Cut six test specimens from the mat erial under test, three in the longitudinal and three in the transverse direction. Note: The thickness of the specimen “a“ (see sketch) must be measured in the centre of the cellulose fibre board. The width of the specimen “b“ must be 50 mm and it must b e measu
6、red accurately to 0.1 mm. The edges of the specimen must be clean cut and must be parallel to each other within +/ -0.4 mm. The length of the specimen “Lg“ must be approximately 50 mm greater than the distance between the lines of support “Ls“. Th e latter must be 24 x the specimen thickness “a“. FO
7、RD LABORATORY TEST METHOD EU-BS 005-01 Page 2 of 3 Copyright 2000, Ford Global Technologies, Inc. 2. Adjust the supports of the loading fixture to the correct span for the thickness of the boards “Ls“ and place the specimen on the support cylinders midway between the supports. The smooth side must f
8、a ce the flexing mandrel. 3. Apply the load at a uniform rate in the middle of the supported span, until fracture takes place. Record the breaking - load (P) in Kilogram force. The break must occur within 30 - 45 seconds. Evaluation The flexural strength in MN/m cm is then computed according to the
9、following formula: Flexural Strength in MN/m cm = P x 3L s_ 9.81 2B x a Where: P = Breaking Load in Kgf. L s = Supported Span in cm. a = Thickness of the test specimen in cm, measured in the middle of the supported span. b = Width of the test specimen in cm. B. Flexural Strength After Water Immersio
10、n The specimens shall be immersed for 24 hours in distilled water at 20 +/ - 1 C and must be tested immediately afterwards as described under p aragraphs 1 to 3. Note: Measure thickness before water immersion. C. Determination of the Elasticity Modulus When each test is completed, the force/deflecti
11、on diagram must be recorded. For this purpose the deflection “f“ must be measured in the middle of the supported span, if possible until the moment of fracture, using a suitable micrometer gauge to an accuracy of 0.01 mm. The force (load) must be applied gradually in steps, such that at least six re
12、adings are taken before one third of the total (bre aking) load is applied. FORD LABORATORY TEST METHOD EU-BS 005-01 Page 3 of 3 Copyright 2000, Ford Global Technologies, Inc. Evaluation The modulus of elasticity is related to the gradient of the straight section of the force/deflection curve and it
13、 shall be computed as follows: E = Modulus in MN/m cm = P x L S 9.81d 4b x a P = Force (Load) in Kg as indicated in the straight section of the force/deflection curve. d = The deflection (expressed in cm) which corresponds to the Force P. Sketch Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities.
