Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=DENT-Prüfkörper}} {{PSM_Infobox}} DENT-specimen FORCETOC ==General information== The Anglo-Saxon abbreviation DENT stands for ‘Double-edged Notched Tension’ and the DENT-specimen is referred to in German as a double-sided notched tensile test specimen (or a tensile test specimen notched on both sides). ==Test specimen shape== 180px {| |- valign="top" |w..."

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Created page with "{{Language_sel|LANG=ger|ARTIKEL=DENT-Prüfkörper}} {{PSM_Infobox}} DENT-specimen __FORCETOC__ ==General information== The Anglo-Saxon abbreviation DENT stands for ‘Double-edged Notched Tension’ and the DENT-specimen is referred to in German as a double-sided notched tensile test specimen (or a tensile test specimen notched on both sides). ==Test specimen shape== 180px {| |- valign="top" |w..."

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{{Language_sel|LANG=ger|ARTIKEL=DENT-Prüfkörper}}
{{PSM_Infobox}}
DENT-specimen
__FORCETOC__

==General information==

The Anglo-Saxon abbreviation DENT stands for ‘Double-edged Notched Tension’ and the DENT-specimen is referred to in German as a double-sided notched tensile test specimen (or a tensile test specimen notched on both sides).

==Test specimen shape==

[[File:dent.jpg|180px]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px" |Schematic representation of the DENT-specimen (B = thickness, W = width, a = initial crack length and H = length)
|}

'''Dimensions (according to [1]):'''
 
<math>\frac{H}{W} \geq 3</math>
 
'''Typical dimensions for plastics [2]:'''
 
H = 75 <math>\pm</math> 1 mm
 
W = 10 <math>\pm</math> 0.5 mm
 
B = 3 bzw. 4 mm
 
a = 1 <math>\pm</math> 0.2 mm

'''Equation for determining the stress intensity factor [3]'''

{|
|-
|width="20px"|
|width="500px" | <math>K_I = \frac{F_{max}}{B \cdot W} \cdot f_1(a/W)</math>
|}

{|
|-
|width="20px"|
|width="500px" | <math>K_I = \frac{F_{max}}{B \cdot W} \cdot f_2(a/W)</math>
|}

{|
|-
|width="20px"|
|width="500px" | <math>f_1(a/W) = \sqrt{\pi a} \cdot \frac{1}{1-\frac{2a}{W}} \cdot \sqrt{\frac{1.26+2.18\frac{a}{W\left(\frac12-a\right)}}{1+3.63\frac{a}{W\left(\frac12-a\right)}+5.31\left [\frac{a}{W\left (\frac12 -a\right )}\right]^2}} \!\ </math>
|}

{|
|-
|width="20px"|
|width="500px" | <math>f_2(a/W) = \sqrt{\pi a} \cdot \sqrt{\frac{W}{\pi a}\left (tan\frac{\pi a}{W}+0.1 sin\frac{\pi a}{W \cdot \frac12} \right )}</math>
|}

==Application==

The DENT-specimen is used in quasi-static [[Tensile Test|tensile tests]], primarily for [[Plastics|plastics]] with high matrix [[Toughness|toughness]], but in recent years also in [[Elastomers|elastomer]] and [[Film Testing|film testing]] [2, 4]. Due to problems with clamping, an additional hole is drilled in the DENT-specimens to improve the holder.

[[File:dent-folie.jpg|180px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px" |Schematic representation of a DENT-specimen for [[Fracture Mechanical Testing|fracture mechanics experiments]] on [[Elastomers|elastomeric]] [[Material & Werkstoff|materials]] using the [[Instrumented Tensile Impact Test (ITIT)|instrumented tensile impact test]]
|}

==Evaluation==

The following Eqs. (1) and (2) are used to evaluate [[Instrumented Tensile Impact Test (ITIT), Examples|instrumented tensile impact tests]] on [[Elastomers|elastomer materials]], i.e. to calculate [[J-Integral Evaluation Methods (Overview)|Jd-values]] as resistance to unstable crack initiation and [[Crack Propagation|propagation]].

{|
|-
|width="20px"|
|width="500px" | <math>J_d = \frac{\eta \cdot A_{max}}{B \cdot \left (W-a\right )}</math>
|}

mit
{|
|-
|''A''max
|width="15px" |
|deformation energy and
|-
|<math>\eta</math>
|
|according [5] in the form
|}
{|
|-
|width="20px"|
|width="500px" | <math>\eta = -0.06+5.99(a/W)-7.42(a/W)^2+3.29(a/W)^3 \!\ </math>
|}

An extensive overview of suitable test specimens for [[Fracture Mechanical Testing|fracture mechanics investigations]] on [[Plastics|plastics]] and [[Composite Materials Testing|composite materials]] can be found in [[Specimen for Fracture Mechanics Tests|fracture mechanics test specimens]].

==See also==

* [[Essential Work of Fracture (EWF)-Concept|Essential Work of Fracture (EWF)-concept]]
* [[Instrumented Tensile Impact Test (ITIT)|Instrumented tensile impact test (ITIT)]]
* [[Film Testing|Film testing]]
* [[Fracture Mechanical Testing|Fracture mechanical testing]]
* [[Specimen for Fracture Mechanics Tests|Specimen for fracture mechanics tests]]

==References==

{|
|-valign="top"
|[1]
|Sähn, S., Göldner, H.: Bruch- und Beurteilungskriterien in der Festigkeitslehre. Fachbuchverlag, Leipzig Köln (1993) p. 36, (ISBN 3-343-00854-0; see [[AMK-Library]] under E 26)
|-valign="top"
|[2]
|[[Reincke, Katrin|Reincke, K.]], [[Grellmann, Wolfgang|Grellmann, W.]]: Instrumentierte Schlagzugprüfung von Elastomeren. In: Frenz, H. und Wehrstedt, A. (Eds.): Kennwertermittlung für die Praxis – Proceedings Werkstoffprüfung 2002. Wiley-VCH, Weinheim (2003) pp. 340–344, (ISBN 3-527-30674-9; see [[AMK-Library]] under M 10)
|-valign="top"
|[3]
|Richard, H.-A.: Interpolationsformel für Spannungsintensitätsfaktoren VDI-Zeitschrift 121 (1979) 22 - Nov. II 1138–1143
|-valign="top"
|[4]
|Reincke, K.: Bruchmechanische Bewertung von ungefüllten und gefüllten Elastomerwerkstoffen. Mensch und Buch (2005), (ISBN 978-3-86664-021-4; see [[AMK-Library]] under B 1-13)
|-valign="top"
|[5]
|Anderson, T. L.: Fracture Mechanics. Fundamentals and Applications, 3rd Ed., CRC Press Boca Raton (2005), (ISBN 978-08493-4260-8; see [[AMK-Library]] under E 8), DOI: https://doi.org/10.11201/9781420058215
|}

[[Category:Fracture Mechanics]]
[[Category:Specimen]]
[[Category:Film Testing]]

DENT-Specimen - Revision history