BS EN 15930:2010 pdf free download Fibres — Elasticity of fibres — Test methods
1 Scope
This test method covers the determination of the elasticity of fibres and may lead to classification of the fibreas elastic fibre (see Annex A).
lt is applicable to single man-made crimped and uncrimped fibres.
2Normative references
The following referenced documents are indispensable for the application of this document. For datedreferences,only the edition cited applies. For undated references,the latest edition of the referenceddocument (including any amendments) applies.
EN 12751,Textiles — Sampling of fibres, yarns and fabrics for testing
EN ISO 139,Textiles — Standard atmospheres for conditioning and testing (ISo 139:2005)
EN ISO 1973,Textile fibres —Determination of linear density —Gravimetric method and vibroscope method(lso 1973:1995)
EN ISO 7500-1,Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines – Verification and calibration of the force-measuring system (Iso7500-1:2004)
3Terms and definitions
For the purposes of this document, the following terms and definitions apply.3.1
elasticity
property of a fibre by virtue of which it tends to recover its original size and shape immediately after theremoval of the force causing deformation
3.2
linear density
mass per unit length of an essentially linear structure
3.3
constant-rate-of-extension(CRE) testing machine
tensile testing machine provided with one clamp,which is virtually stationary,and another clamp,whichmoves with a constant speed throughout the test, the entire testing system being virtually free from deflection
3.4
gauge length
distance between the two effective clamping or holding points of a testing device
3.5
initial length
length of the test specimen between the two effective clamping or holding points at the required pretension,hoforo toctinc
3.6
extension
increase in length of a test specimen expressed in units of length e.g. millimetres
3.7
elongation
ratio of the extension of the test specimen to its initial length, expressed as a percentage
3.8
maximum force
force recorded in Newton at the position when a test specimen is taken to a fixed extension
3.9
cycle
process whereby a fibre is taken from the gauge length to fixed extension or elongation and returned to gauge length
3.10
elastic recovery
recovered elongation expressed as a percentage of the specified elongation
3.11
permanent deformation
ratio of un-recovered extension of the test specimen after cycling to its initial length, expressed as a percentage
3.12
force decay
loss of force measured over time when a test specimen is stretched to a specified elongation or extension and held at this position for a given time period
4 Principle
The measurements are performed on an individual fibre.
A fibre is cycled between the gauge length and a specified elongation at a constant rate for an agreed number of cycles. The fibre can be maintained at the specified elongation or at the gauge length – for a specific period of time. Its elasticity is determined by measuring certain physical characteristics.
5 Apparatus
5.1 Pretension device
Pretension device able to apply (0,01 0 ± 0,005) cN/tex on the individual test specimen.
NOTE Pretension may be applied using masses with discontinuous values (e.g. adhesive paper or clips) or using a high-resolution load cells.
5.2 Tensile testing machine
The constant-rate-of-extension (CRE) testing machine shall conform to the following.
a) The tensile testing machine shall be provided with the means for indicating or recording the force and elongation values when cycling between gauge length and either a fixed load or fixed extension. Under conditions of use, the accuracy of the apparatus shall be at least class 1 of EN ISO 7500-1 . The error of the indicated or recorded maximum force at any point in the range in which the machine is used shall notexceed 1 %, and the error of the indicated or recorded jaw separation shall not exceed 1 mm.
b)lf recording of force or elongation is obtained by means of data acquisition boards and software,thefrequency of data collection shall be at least eight per second.
c)The machine shall be capable of constant rates of extension from (20,0 ± 0,5) mm/min to
(50,0± 0,5) mm/min.
d)The machine shall be capable of variable gauge length settings from (20,0 ± 0,5) mm to (50,0± 0,5) mm.
e)The clamping or holding devices shall be positioned with the centre in line with the applied force.
The jaws shall be capable of holding the test specimen without allowing it to slip and designed so that they donot cut or otherwise weaken the test specimen.
6 Atmosphere of conditioning and testing
Samples shall be conditioned in a tension free state for at least 16 h in the standard atmosphere according toEN ISO 139.
Testing shall be performed in this standard atmosphere.
7 Sampling
The sampling of the fibres to be tested from staple fibres,from yarns or from fabrics shall be according toEN 12751.
8Preparation of the test specimens
8.1 Preparation from staples
ln order to isolate one fibre first open very carefully the sample in a direction perpendicular to the local fibreorientation,taking care to apply the force at two points sufficiently distant to allow free fibre movementsnecessary to disentangle the fibre mass.