ISO 1922 pdf download.Rigid cellular plastics — Determination of shear strength
1 Scope
This International Standard specifies a method of determining the shear strength of rigid cellular plastics. It also provides for the optional determination of shear modulus.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 291 :1 997, Plastics — Standardatmospheres forconditioning andtesting. ISO 1 923:1 981 , Cellularplastics andrubbers — Determination oflineardimensions.
3 Principle
A shear stress is applied to a test specimen of defined shape by means of metal supports bonded to the specimen.
4 Apparatus
4.1 Test machine The test machine (see Figure 1 ) shall be such that: a) a test specimen having the form and dimensions specified in clause 5 is held vertically between two fixing devices each comprising a metal support, one of these devices being fixed and the other movable, and the stress being transmitted along the longitudinal axis of the specimen; b) the movable grip will be moved away from the fixed grip at a constant rate of (1 + 0,5) mm per minute in a direction parallel to the longitudinal axis of the specimen; c) the force exerted on the specimen shall be known with a maximum error of 1 %, and the distance between the grips shall be known with a maximum error of 0,01 mm, by means of recording devices. 4.2 Metal supports These shall consist of flat, rectangular-sectioned, mild-steel plates, machined on one side, with a thickness of (1 6 + 1 ) mm and a width of 1 0 50 + mm. The thickness of the adaptors that connect the metal supports to the test machine grips shall be equal to the thickness of the test specimen. 4.3 Adhesive The adhesive used to fix the metal supports to the test specimen shall be such that the shear strength and modulus of the adhesive film are significantly greater than that of the cellular material under test, so as to ensure ultimate failure in the cellular material rather than at the adhesive interface. The adhesive shall also be compatible with the material under test. Details of a suitable adhesive and the method of application are given in annex A.
6 Number of test specimens
Test a set of five specimens. When testing materials suspected of being anisotropic, prepare sets of specimens having their major axes parallel with and normal to the suspected directions of anisotropy. Reject specimens that fail at the adhesive interface before failure of the cellular material and test additional specimens so that the number of significant results is not less than five.
7 Conditioning and test temperature
Condition specimens immediately before testing for a period of not less than 1 6 h at a temperature of (23 2) °C and at (50 5) % relative humidity, in accordance with ISO 291 . Conduct the test at a temperature of (23 2) °C. 8 Procedure Attach a test specimen to the grips of the test machine and apply a force by separating the movable grip from the fixed grip at a rate of (1 0,5) mm per minute, with a variation not greater than 1 0 % during the test. Record the force-deflection diagram.