<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In the process of materials fracture, a very important parameter to study is the cracking rate growth da/dN. This paper proposes an analysis of the cracking rate, in a comparative way, by using four mathematical models:1 - polynomial method, by using successive iterations according to the ASTM E647 standard; 2 - model that uses the Paris formula; 3 - Walker formula method; 4 - NASGRO model or Forman - Newman - Konig equation, abbreviated as FNK model. This model is used in the NASA programs studies. For the tests, CT type specimens were made from stainless steel, V2A class, 10TiNiCr175 mark, and loaded to a variable tensile test axial - eccentrically, with the asymmetry coefficients: R= 0.1, 0.3 and 0.5; at the 213K (-60°C) temperature. There are analyzed the cracking rates variations according to the above models, especially through FNK method, highlighting the asymmetry factor variation.</p></abstract>

In the process of materials fracture, a very important parameter to study is the cracking rate growth da/dN. This paper proposes an analysis of the cracking rate, in a comparative way, by using four mathematical models:1 - polynomial method, by using successive iterations according to the ASTM E647 standard; 2 - model that uses the Paris formula; 3 - Walker formula method; 4 - NASGRO model or Forman - Newman - Konig equation, abbreviated as FNK model. This model is used in the NASA programs studies. For the tests, CT type specimens were made from stainless steel, V2A class, 10TiNiCr175 mark, and loaded to a variable tensile test axial - eccentrically, with the asymmetry coefficients: R= 0.1, 0.3 and 0.5; at the 213K (-60°C) temperature. There are analyzed the cracking rates variations according to the above models, especially through FNK method, highlighting the asymmetry factor variation.

Fnk Model of Cracking Rate Calculus for a Variable Asymmetry Coefficient

Acta Universitatis Cibiniensis. Technical Series

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

{"article-title":"Fnk Model of Cracking Rate Calculus for a Variable Asymmetry Coefficient"}

In the process of materials fracture, a very important parameter to study is the cracking rate growth da/dN. This paper proposes an analysis of the cracking...

Fnk Model of Cracking Rate Calculus for a Variable Asymmetry Coefficient

Published Online: Jan 11, 2018

Page range: 72 - 81

DOI: https://doi.org/10.1515/aucts-2017-0010

Keywords
fracture mechanics, crack, asymmetry factor, stress intensity factor

© 2018

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Fnk Model of Cracking Rate Calculus for a Variable Asymmetry Coefficient

Published Online: Jan 11, 2018

Page range: 72 - 81

DOI: https://doi.org/10.1515/aucts-2017-0010

Keywordsfracture mechanics, crack, asymmetry factor, stress intensity factor

© 2018

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
fracture mechanics, crack, asymmetry factor, stress intensity factor