Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Full Notch Creep Test (FNCT)}} {{PSM_Infobox}} Full notch creep test (FNCT) FORCETOC ==Experimental Method== For a long time, the Full Notch Creep Test (FNCT) ('''Fig. 1'''), standardized in ISO 16770 [1], has extensively been used in Europe for the accelerated characterization of slow crack growth (SCG). ==Test specimen and characteristic parameter== The..."

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Created page with "{{Language_sel|LANG=ger|ARTIKEL=Full Notch Creep Test (FNCT)}} {{PSM_Infobox}} <span style="font-size:1.2em;font-weight:bold;">Full notch creep test (FNCT)</span> __FORCETOC__ ==Experimental Method== For a long time, the Full Notch Creep Test (FNCT) ('''Fig. 1'''), standardized in ISO 16770 [1], has extensively been used in Europe for the accelerated characterization of slow crack growth (SCG). ==Test specimen and characteristic parameter== The..."

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{{Language_sel|LANG=ger|ARTIKEL=Full Notch Creep Test (FNCT)}}
{{PSM_Infobox}}
<span style="font-size:1.2em;font-weight:bold;">Full notch creep test (FNCT)</span>
__FORCETOC__

==Experimental Method==

For a long time, the Full Notch Creep Test (FNCT) ('''Fig. 1'''), standardized in ISO 16770 [1], has extensively been used in Europe for the accelerated characterization of [[Slow Crack Growth|slow crack growth]] (SCG).

==Test specimen and characteristic parameter==

The test [[Specimen|specimen]] is a prismatic bar (machined from tubes or compression-moulded plates) having a size of 10 × 10 × 100 mm3 with a 1.5 mm-deep circumferential [[Notch|notch]], where a nominal [[Stress|stress]] of 4–5 MPa in a surface-active aqueous medium (temperature: 80–95 °C) is applied. Only the [[Failure Anasysis Basics|failure]] time is analysed. The failure time in the FNCT ranges from about ten hours for mono-modal PE types to about a thousand hours for bimodal PE 100 types and in some cases more than a year for new PE 100-RC types (RC – Resistant to Cracking). The high resistance of modern PE materials to [[Slow Crack Growth|SCG]] requires a modification of the FNCT or the development of completely new tests, such as the Crack Round Bar (CRB) test or the [[Strain Hardening Test (SHT)]].

==Comparison with other methods for describing slow crack growth==

Compared to other [[Slow Crack Growth|SCG]] tests currently used specifically for PE pipes to be loaded with internal pressure, the FNCT was selected early for standardization within the ISO framework (see also: [[Accreditation and Certification|accreditation and certification]]). This was done against the backdrop that this test is relatively simple and sufficiently sensitive to structural variables (see: [[Microscopic Structure|microscopic structure]]) in PE materials [2, 3]. However, it should always be noted that the validity of data obtained from the FNCT must be critically evaluated due to the large standard deviation of the [[Measured Value|measured values]]. Since the introduction of ISO 16770, several [[Round Robin Test|round robin tests]] have therefore been carried out with the aim of reducing the standard deviation of the measured values. Compared to the fracture mechanics-based [[Pennsylvania Edge Notch Tensile (PENT) Test|Pennsylvania Edge Notch Tensile (PENT) test]], the low depth of information provided by the FNCT has a negative impact too.

[[File:FNCT-1.jpg|550px]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px" |Schematic representation of the Full Notch Creep Test (FNCT)
|}

==See also==

* [[Slow Crack Growth|Slow crack growth]]
* [[Pennsylvania Edge Notch Tensile (PENT) Test|Pennsylvania edge notch tensile (PENT) test]]
* [[Strain Hardening Test (SHT)|Strain hardening test (SHT)]]

'''References'''

{|
|-valign="top"
|[1]
|ISO 16770 (2019-09): Plastics – Determination of Environmental Stress Cracking (ESC) of Polyethylene – Full-Notch Creep Test (FNCT)
|-valign="top"
|[2]
|Nezbedova, E., Hodan, J., Kotek, J., Krulis, Z., Hutar, P., [https://researchgate.net/profile/Ralf-Lach Lach, R.]: Lifetime of Polyethylene (PE) Pipe Materials – Prediction using Strain Hardening Test. In: [[Grellmann, Wolfgang|Grellmann, W.]], Langer, B. (Eds.): Deformation and Fracture Behaviour of Polymer Materials. Springer, Berlin (2017) 203–210 (ISBN 978-3-319-41877-3; see [[AMK-Büchersammlung|AMK-Library]] under A 19)
|-valign="top"
|[3]
|Lach, R., Nezbedova, E., Langer, B., [https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.]: Schnelle Abschätzung des mechanischen Langzeitverhaltens moderner Werkstoffe für Kunststoffrohre mittels des einachsigen Zugversuchs. In: Frenz, H., Langer, J. B. (Eds.): Fortschritte in der Werkstoffprüfung für Forschung und Praxis. Prüftechnik – Kennwertermittlung – Schadensvermeidung, „Werkstoffprüfung 2017“, 30.11./01.12.2017, Berlin, Proceedings pp. 259–264 (ISBN 978-3-9814516-7-2; see [[AMK-Büchersammlung|AMK-Library]] under A 20)
|}

[[Category:Fracture Mechanics]]

Full Notch Creep Test (FNCT) - Revision history