ISO 3348-1975 pdf free.Wood — Determination of impact bending strength.
1.SCOPE AND FIELD OF APPLICATION
This International Standardspecifies a methodfordetermination of the impact bending strength of woodusing a pendulum impact testing machine.
2.REFERENCES:
ISo 3129,Wood – Sampling methodsand generalrequircments for physical and mechanical tcsts.1 )
ISo 3130，Wood – Determination of moisture content inphysical and mechanical tests.1 )
3.PRINCIPLE
Determination of the impact strength by testing a test piecefor cross-sectional bending under dynamic load application.
4.APPARATUS
4.1Pendulum impact machine with a range of energythree to five times more than the work used for the impactbreak of the test piece and allowing the measurement of thecnergy to an accuracy of 1J.Thc pcndulum tup and testpiece supports shall have a radius of curvature of 15 mm.The height of the supports shall be greater than 20 mm.The distance between the centres of the supports shall be240± 1 mm.
4.2Measuringinstrumentfordeterminingthecross-sectional dimensions of test pieces to an accuracy of0,1 mm.
4.3 Equipment for the determination of moisture contentin accordance with ISO 3130.
5.PREPARATION OF TEST PIECES
5.1 Test pieces shall be made in the form of right prismshaving a square cross-section 20 mm × 20 mm and lengthalong the grain 300 mm.One face of the test piece shall liein a radial plane and thc other in a tangential plane.
5.2The preparation,moisture content and number of testpieces shall be in accordance with ISO 3129.
6.PROCEDURE
6.1Carry out the determination of impact strength by animpact,usually, on a radial surface (a tangential bending).lt is permitted to carry out the determination by an impacton a tangential surface (a radial bending).
6.2Before the test, measure the cross-sectional dimensionsin the middle of the test piece to an accuracy of 0,1 mm.6.3The test piece,placed symmetrically on the supports,shall be broken by one impact. Measure the work absorbedby the test piece to the accuracy specified in 4.1.The formof fracture (conchoidal or chipped) shall be recorded in thetest report.A conchoidal fracture shall be considered as onewith projecting fibres of not more than 3 mm long.
6.4After the test has been completed,determine themoisture content of the test pieces according to lSO 3130.Take a portion 20 to 30 mm long,cut from near thefracture,as the sample for dctcrmination of moisturecontent. To determine the mean moisture content,it ispermissible tc use only some of the test pieces. Theminimum number oftest pieces for moisture contentdetermination shall be determined in accordance withlSo 3129.ISO 3348 pdf download.