A numerical procedure for the shakedown analysis of structures under cyclic thermomechanical loading

Under cyclic thermomechanical loading conditions, various effects such as strain accumulation, creep damage, ageing, fatigue etc. may occur in the material of a gas turbine blade. Depending on the loading conditions, all these effects contribute to reduce the lifetime of the component. Subject of the present work is the development of a lifetime model able to discriminate between the different damage mechanisms, as well as the development of a material model to describe the mentioned effects and thus providing the input data for lifetime prediction.

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Failure of thermal barrier coating systems under cyclic thermomechanical loading

Acta Materialia ◽

10.1016/s1359-6454(00)00260-3 ◽

2000 ◽

Vol 48 (18-19) ◽

pp. 4699-4707 ◽

Cited By ~ 110

Author(s):

E Tzimas ◽

H Müllejans ◽

S.D Peteves ◽

J Bressers ◽

W Stamm

Keyword(s):

Thermal Barrier Coating ◽

Thermal Barrier ◽

Thermomechanical Loading ◽

Barrier Coating ◽

Cyclic Thermomechanical Loading

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Material Modelling and Lifetime Prediction of Ni-Base Gas Turbine Blades under TMF Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.1277 ◽

2014 ◽

Vol 891-892 ◽

pp. 1277-1282 ◽

Cited By ~ 2

Author(s):

Stefan Gruetzner ◽

Bernard Fedelich ◽

Birgit Rehmer ◽

Bjoern Buchholz

Keyword(s):

Gas Turbine ◽

Turbine Blades ◽

Material Model ◽

Loading Conditions ◽

Thermomechanical Loading ◽

Damage Mechanisms ◽

Surface Cracking ◽

Gas Turbine Blades ◽

Creep Cavitation ◽

Cyclic Thermomechanical Loading

Under cyclic thermomechanical loading conditions, various damage mechanisms such as strain accumulation, creep cavitation, ageing, fatigue surface cracking etc. may take place in the material of a gas turbine blade. Depending on the loading conditions, all these effects can contribute to reduce the lifetime of the component. Subject of the present work is the development of a material model to describe the mechanical effects mentioned above, as well as the development of a lifetime model able to discriminate the different damage mechanisms.

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Stress Compensation Method for Structural Shakedown Analysis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.794.169 ◽

2019 ◽

Vol 794 ◽

pp. 169-181

Author(s):

Heng Peng ◽

Ying Hua Liu

Keyword(s):

Large Scale ◽

Direct Method ◽

Numerical Procedure ◽

Compensation Method ◽

Control Technique ◽

Collapse Mechanism ◽

Residual Stress Field ◽

Engineering Structures ◽

Shakedown Analysis ◽

Stress Compensation

This paper presents a novel direct method called the stress compensation method (SCM) for structural shakedown analysis. Being different from the popular direct method of mathematical programming, the SCM just carries out some iterative calculations. Making full use of static shakedown theorem, the residual stress field is constructed via solving the modified global equilibrium equations. An effective and robust iteration control technique is adopted to generate a sequence of decreasing load multipliers. The numerical procedure is incorporated into the ABAQUS platform via some user subroutines. The shakedown problems for a cantilever beam, a symmetric continuous beam and a practical shell with nozzles are effectively solved and analyzed. These results are compared to the analytical solutions and those found in literatures. Both the incremental collapse mechanism and the alternating plasticity mechanism are revealed to determine the shakedown boundaries. Numerical examples show that the SCM is of numerical stability, good accuracy, high computational efficiency, and can effectively perform shakedown analysis of large-scale practical engineering structures.

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