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ISO 899-1:2017 pdf free

ISO 899-1:2017 pdf free.Plastics一Determination of creep behaviour
It is recommended that grips be used that will allow the specimen to be fixed in place, correctly aligned,prior to applying the load. Self-locking grips which allow the specimen to move as the load increases are not suitable for this test.
Loading system, capable of ensuring that the load is applied smoothly, without causing transient overloading, and that the load is maintained to within±1 % of the desired load. In creep-to-rupture tests,provision shall be made to prevent any shocks which occur at the moment of rupture being transmitted to adjacent loading systems. The loading mechanism shall allow rapid, smooth and reproducible loading.
Extension-measuring device, comprising any contactless or contact device capable of measuring the extension of the specimen gauge length or the increase in the distance between the clamp grips under load without influencing the specimen behaviour by mechanical effects (e.g. undesirable deformations,notches), other physical effects (e.g. heating of the specimen) or chemical effects.
In the case of contactless (optical) measurement of the strain, the longitudinal axis of the specimen shall be perpendicular to the optical axis of the measuring device. To determine the increase in length of the test specimen, an extensometer shall be used which records the increase in the distance between the clamp grips. The accuracy of the extension-measuring device shall be better than±0,01 mm.
For creep-to-rupture tests, it is recommended that the extension be measured by means of a contactless optical system operating on the cathetometer principle. Automatic indication of time to rupture is highly desirable. The gauge length shall be marked on the specimen, either by attaching (metal) clips with scratched-on gauge marks, or by ruling the gauge marks with an inert, thermally stable paint.
Electrical-resistance strain gauges are suitable only if the material tested is of such a nature as to permit such strain gauges to be attached to the specimen by means of adhesive and only if the adhesion quality is constant during the duration of the test. The modulus of the strain gauge when bonded to the specimen shall be such that the specimen is not reinforced.ISO 899-1 pdf download.

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