Skip to main content

2015 | OriginalPaper | Buchkapitel

Improved Integration of High-Cycle Accumulated Strain Using Hierarchical and EAS Finite Elements

verfasst von : A. Niemunis, I. Melikayeva

Erschienen in: Holistic Simulation of Geotechnical Installation Processes

Verlag: Springer International Publishing

Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.

search-config
loading …

Abstract

The spatial variability of high-cycle accumulated strain is larger than the variability obtained from monotonic loading. Gradients of strain cause that the fit of a given strain field \(\epsilon _{ij}^{\text {acc}}\) is difficult for the conventional elements (if no refinement is used). Usage of identical mesh for monotonic and cumulative deformations leads to numerical self-stresses in elements. More flexible elements are therefore examined. They can reduce the self-stresses considerably.

Sie haben noch keine Lizenz? Dann Informieren Sie sich jetzt über unsere Produkte:

Springer Professional "Wirtschaft+Technik"

Online-Abonnement

Mit Springer Professional "Wirtschaft+Technik" erhalten Sie Zugriff auf:

  • über 102.000 Bücher
  • über 537 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Maschinenbau + Werkstoffe
  • Versicherung + Risiko

Jetzt Wissensvorsprung sichern!

Springer Professional "Technik"

Online-Abonnement

Mit Springer Professional "Technik" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 390 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Maschinenbau + Werkstoffe




 

Jetzt Wissensvorsprung sichern!

Springer Professional "Wirtschaft"

Online-Abonnement

Mit Springer Professional "Wirtschaft" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 340 Zeitschriften

aus folgenden Fachgebieten:

  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Versicherung + Risiko




Jetzt Wissensvorsprung sichern!

Fußnoten
1
Obtained from \( u^{\text {acc}}_{1,122} + u^{\text {acc}}_{2,211} - (u^{\text {acc}}_{1,212} + u^{\text {acc}}_{2,212} ) = 0\).
 
2
The brackets in the index part denote symmetrization \( u_{(i,j)} = \frac{1}{2} \left( u_{ i,j } + u_{ j,i } \right) \).
 
3
Similarly one could also weaken the constitutive relationship and instead of the usual strong connection \(\sigma _{ij} = E_{ijkl} (u_{k,l} {- \epsilon ^\text {acc}_{kl} }) \) we could introduce an independent unknown field of stress \(\sigma _{ij}\) which should be compatible with the constitutive stress \(\sigma _{ij}^\epsilon = E_{ijkl} (\epsilon _{kl} - \epsilon _{kl}^\text {acc})\). This \(\sigma _{ij}^\epsilon \) would be treated as a slave of the master field \(\epsilon _{kl}\). The weak for of the connection \(\sigma _{ij} - \sigma _{ij}^\epsilon \) is \( \lambda _{ij}^{\sigma } (\sigma _{ij} - \sigma _{ij}^\epsilon ) \) with the Lagrangian multipliers \(\lambda _{ij}^{\sigma }\).
Similarly, we may also proceed with the essential BCs in the form \(u_i - \breve{u_i} = 0\) defined on \(S_u\). They will be added to the functional with the help of Lagrange multipliers \(\lambda ^u_{i}\) in the form \( - \int _{S_u} \lambda ^u_{i} (u_i - \breve{u_i}) \mathrm{d}S \)
This term should be added to the extended potential. The result is called the Hu-Washizu functional.
 
4
Note that \(\lambda ^{\epsilon }_{ij} = \sigma _{ij}\) must be symmetric and hence \(\lambda ^\epsilon _{ij} \delta u_{(i,j)} = \lambda ^\epsilon _{ij} \delta u_{ i,j }\) i.e. symmetrization may be omitted in (11), (12).
 
5
The enforcement of full orthogonality of \( \tilde{\epsilon }_{ij} \) with \(\sigma _{ij} = E_{ijkl} \epsilon ^{el}_{kl}\) would imply \( \tilde{\epsilon }_{ij} = 0\).
 
6
\(\int _\square \ldots \mathrm{d}\varvec{\xi }\) represents \(\mathop {\int }\limits _{-1}^1 \int \limits _{-1}^1 \ldots \mathrm{d}\xi \mathrm{d}\eta \).
 
7
hence we may omit symmetrization brackets in \(u_{(i,j)}\).
 
Literatur
1.
Zurück zum Zitat Babuska, I., Griebel, M., Pitkaranta, J.: The problem of selecting the shape functions for a p-type finite element. Technical report final report, Institute for Physical Science and Technology, University of Maryland (1988) Babuska, I., Griebel, M., Pitkaranta, J.: The problem of selecting the shape functions for a p-type finite element. Technical report final report, Institute for Physical Science and Technology, University of Maryland (1988)
2.
Zurück zum Zitat Flaherty, J.E., Eaton, A.: Finite element analysis. Lecture notes. Technical report, CSCI, Math 6860, Rensselaer Polytechnic Institute (2000) Flaherty, J.E., Eaton, A.: Finite element analysis. Lecture notes. Technical report, CSCI, Math 6860, Rensselaer Polytechnic Institute (2000)
3.
Zurück zum Zitat Hu, H.C.: On some variational principles in the theory of elasticity and plasticity. Sci. Sin 4, 33–54 (1955)MATH Hu, H.C.: On some variational principles in the theory of elasticity and plasticity. Sci. Sin 4, 33–54 (1955)MATH
4.
Zurück zum Zitat Niemunis, A., Wichtmann, T., Triantafyllidis, T.: A high-cycle accumulation model for sand. Comput. Geotech. 32(4), 245–263 (2005)CrossRef Niemunis, A., Wichtmann, T., Triantafyllidis, T.: A high-cycle accumulation model for sand. Comput. Geotech. 32(4), 245–263 (2005)CrossRef
5.
Zurück zum Zitat Simo, J.C., Rifai, M.S.: A class of mixed assumed strain methods and the method of incompatible modes. Int. J. Numer. Meth. Eng. 29, 1595–1638 (1990)MATHMathSciNetCrossRef Simo, J.C., Rifai, M.S.: A class of mixed assumed strain methods and the method of incompatible modes. Int. J. Numer. Meth. Eng. 29, 1595–1638 (1990)MATHMathSciNetCrossRef
6.
Zurück zum Zitat Washizu, K.: On the variational principles of elasticity and plasticity. Technical report, 25–18, Aeroelastic and Structures Research Laboratory, Massachusetts Institute of Technology, Cambridge (1955) Washizu, K.: On the variational principles of elasticity and plasticity. Technical report, 25–18, Aeroelastic and Structures Research Laboratory, Massachusetts Institute of Technology, Cambridge (1955)
7.
Zurück zum Zitat Wichtmann, T., Niemunis, A., Triantafyllidis, Th.: Towards the FE prediction of permanent deformations of offshore wind power plant foundations using a high-cycle accumulation model. In: International Symposium: Frontiers in Offshore Geotechnics, pp. 635–640, Perth, Australia (2010) Wichtmann, T., Niemunis, A., Triantafyllidis, Th.: Towards the FE prediction of permanent deformations of offshore wind power plant foundations using a high-cycle accumulation model. In: International Symposium: Frontiers in Offshore Geotechnics, pp. 635–640, Perth, Australia (2010)
8.
Zurück zum Zitat Zhou, X.X., Chow, Y.K., Leung, C.F.: Application of enhanced assumed strain finite element method to predict collapse loads of undrained geotechnical problems. Int. J. Numer. Anal. Meth. Geomech. 31, 1033–1043 (2007)MATHCrossRef Zhou, X.X., Chow, Y.K., Leung, C.F.: Application of enhanced assumed strain finite element method to predict collapse loads of undrained geotechnical problems. Int. J. Numer. Anal. Meth. Geomech. 31, 1033–1043 (2007)MATHCrossRef
9.
Zurück zum Zitat Zienkiewicz, O.C., Taylor, R.L., Zhu, J.Z.: The Finite Element Method, 6th edn. Elsevier, Oxford (2005) Zienkiewicz, O.C., Taylor, R.L., Zhu, J.Z.: The Finite Element Method, 6th edn. Elsevier, Oxford (2005)
Metadaten
Titel
Improved Integration of High-Cycle Accumulated Strain Using Hierarchical and EAS Finite Elements
verfasst von
A. Niemunis
I. Melikayeva
Copyright-Jahr
2015
DOI
https://doi.org/10.1007/978-3-319-18170-7_10