A direct method for the evaluation of lower and upper bound ratchet limits

James Michael Ure, Haofeng Chen, Weihang Chen, Tianbai Li, James Tipping, Donald Mackenzie

Research output: Contribution to conferencePaper

8 Citations (Scopus)
488 Downloads (Pure)

Abstract

The calculation of the ratchet limit is often vital for the assessment of the design and integrity of components which are subject to cyclic loading. This work describes the addition of a lower bound calculation to the existing Linear
Matching Method upper bound ratchet analysis method. This lower bound calculation is based on Melan's theorem, and makes use of the residual and elastic stress fields calculated by the upper bound technique to calculate the lower bound ratchet limit multiplier. By doing this, the method combines the stable convergence of the upper bound method but retains the conservatism offered by the lower bound. These advantages are complemented by the ability of the Linear Matching Method to consider real 3D geometries subject to complex load histories including the effect of temperature dependent yield stress.
The convergence properties of this lower bound ratchet limit are investigated through a benchmark problem of a plate with a central hole subject to cyclic thermal and mechanical loads. To demonstrate the effectiveness of the method,
the ratchet limit of a thick walled pipe intersection, also subject to cyclic thermal and mechanical loads, is considered. Validation of these results is provided by full elastic-plastic FEA in Abaqus.
Original languageEnglish
Number of pages6
Publication statusPublished - 5 Jun 2011
Event11th International Conference on Mechanical Behaviour of Materials - Lake Como, Italy
Duration: 5 Jun 20119 Jun 2011

Conference

Conference11th International Conference on Mechanical Behaviour of Materials
CountryItaly
CityLake Como,
Period5/06/119/06/11

Keywords

  • ratchet limit
  • shakedown limit
  • lower and upper bound
  • cyclic loading

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  • Projects

  • Activities

    • 1 Participation in conference

    11th International Conference on the Mechanical Behavior of Materials

    Haofeng Chen (Participant)

    6 Jun 2011

    Activity: Participating in or organising an event typesParticipation in conference

    Cite this

    Ure, J. M., Chen, H., Chen, W., Li, T., Tipping, J., & Mackenzie, D. (2011). A direct method for the evaluation of lower and upper bound ratchet limits. Paper presented at 11th International Conference on Mechanical Behaviour of Materials, Lake Como, Italy.