A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation: implementation and comparison

Research output: Contribution to conferencePaper

Abstract

Ensuring sufficient safety against ratcheting is a fundamental requirement in pressure vessel design. However, determining the ratchet boundary using a full elastic plastic finite element analysis can be problematic and a number of direct methods have been proposed to overcome difficulties associated with ratchet boundary evaluation. This paper proposes a new lower bound ratchet analysis approach, similar to the previously proposed Hybrid method but based on fully implicit elastic-plastic solution strategies. The method utilizes superimposed elastic stresses and modified radial return integration to converge on the residual state throughout, resulting in one Finite Element model suitable for solving the cyclic stresses (Stage 1) and performing the augmented limit analysis to determine the ratchet boundary (Stage 2). The modified radial return methods for both stages of the analysis are presented, with the corresponding stress update algorithm and resulting consistent tangent moduli. Comparisons with other direct methods for selected benchmark problems are presented. It is shown that the proposed method evaluates a consistent lower bound estimate of the ratchet boundary, which has not previously been clearly demonstrated for other lower bound approaches. Limitations in the description of plastic strains and compatibility during the ratchet analysis are identified as being a cause for the differences between the proposed methods and current upper bound methods.
LanguageEnglish
PagesArticle PVP2012-78315
Number of pages27
Publication statusPublished - 15 Jul 2012
Event2012 ASME Pressure Vessel and Piping Conference - Toronto, Canada
Duration: 15 Jul 201220 Jul 2012

Conference

Conference2012 ASME Pressure Vessel and Piping Conference
CountryCanada
CityToronto
Period15/07/1220/07/12

Fingerprint

Ratchet
Evaluation
Plastics
Lower bound
Pressure vessels
Direct Method
Plastic deformation
Finite element method
Limit Analysis
Hybrid Method
Vessel
Tangent line
Finite Element Model
Compatibility
Strategy
Modulus
Safety
Update
Benchmark
Sufficient

Keywords

  • finite element analysis
  • ratchet boundary
  • lowr bound ratchet analysis
  • elastic plastic solution
  • upper bound

Cite this

Jappy, A., Mackenzie, D., & Chen, H. (2012). A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation: implementation and comparison. Article PVP2012-78315. Paper presented at 2012 ASME Pressure Vessel and Piping Conference, Toronto, Canada.
Jappy, Alan ; Mackenzie, Donald ; Chen, Haofeng. / A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation : implementation and comparison. Paper presented at 2012 ASME Pressure Vessel and Piping Conference, Toronto, Canada.27 p.
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Jappy, A, Mackenzie, D & Chen, H 2012, 'A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation: implementation and comparison' Paper presented at 2012 ASME Pressure Vessel and Piping Conference, Toronto, Canada, 15/07/12 - 20/07/12, pp. Article PVP2012-78315.

A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation : implementation and comparison. / Jappy, Alan; Mackenzie, Donald; Chen, Haofeng.

2012. Article PVP2012-78315 Paper presented at 2012 ASME Pressure Vessel and Piping Conference, Toronto, Canada.

Research output: Contribution to conferencePaper

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Jappy A, Mackenzie D, Chen H. A fully implicit multi-axial solution strategy for direct ratchet boundary evaluation: implementation and comparison. 2012. Paper presented at 2012 ASME Pressure Vessel and Piping Conference, Toronto, Canada.