Large time increment approach for fatigue damage computations

Alameddin, Shadi; Bhattacharyya, Mainak; Fau, Amélie; Nackenhorst, Udo; Néron, David

doi:10.1002/pamm.201710085

Cited by 3 publications

(2 citation statements)

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“…Enhancements to the LATIN method was proposed to be used in conjunction with proper generalized decomposition (PGD) (Alameddin et al, 2018;Bhattacharyya et al, 2018aBhattacharyya et al, , 2018b model reduction technique, called LATIN-PGD, showing further improvements in computational efficiency. Non-proportional fatigue analysis (Bhattacharyya et al, 2018a) and damage computations (Alameddin et al, 2018 andBhattacharyya et al, 2018b) in 2D structures have been carried out using the mentioned method. Based on the concavity of the hysteresis loop automatic adjustments to chosen time increments have been proposed (Szmytka et al, 2015) which reduces the increment when a strong non-linearity is faced, otherwise a free evolution is allowed.…”

Section: Introductionmentioning

confidence: 99%

“…An iterative Large Time Increment Method (LATIN) (Ladev eze, 1984(Ladev eze, , 1985 considers the whole loading process in a single time increment (unlike the conventional step-by-step methods) showed significant improvement in computational performance (Boisse et al, 1990) with the ability to solve complex loading histories (Cognard and Ladev eze, 1993) and cyclic viscoplasticity (Cognard and Ladev eze, 1993;Stehly and Remond, 2002). Enhancements to the LATIN method was proposed to be used in conjunction with proper generalized decomposition (PGD) (Alameddin et al, 2018;Bhattacharyya et al, 2018aBhattacharyya et al, , 2018b model reduction technique, called LATIN-PGD, showing further improvements in computational efficiency. Non-proportional fatigue analysis (Bhattacharyya et al, 2018a) and damage computations (Alameddin et al, 2018 andBhattacharyya et al, 2018b) in 2D structures have been carried out using the mentioned method.…”

Section: Introductionmentioning

confidence: 99%

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Continuum damage mechanics of cyclic viscoplasticity using asymptotic numerical method

Sen,

Patel

2023

International Journal of Damage Mechanics

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Conscious efforts on reduction of greenhouse gas emissions have led to an energy transition to renewable energy, however uncertainties of renewable energy production have resulted in higher thermal cycling demands from conventional power plants. Thermal load cycling at high temperature regions of steam turbine components leads to enhanced creep-fatigue damage accumulation. It is well established that such damage mechanism is numerically best predicted by unified constitutive modeling including damage as a variable as per the formalism of continuum damage mechanics at an expense of considerable computational efforts using finite element analysis. In this paper, the non-iterative Asymptotic Numerical Method (ANM), currently limited to partial cycle analysis with linear hardening plasticity model, is proposed for the first time to address cyclic viscoplasticity problems including damage capable of handling multiple cycles and most generalized loading conditions. Regularization techniques additionally necessary to implement loading-unloading-reloading criteria and advanced constitutive models etc. are presented. The constitutive model chosen for the formulation includes the non-linear multiple back stress variable modified Chaboche model to include damage combined with modified Chaboche-Rousselier isotropic hardening model to include damage, power law for viscoplasticity, Lemaitre’s damage potential and Kachanov-Rabotnov’s creep damage law. The method is verified with defined error measures and then applied to two high pressure steam turbine rotors, one with and another without thermal stress relief groove (TSRG) at the inlet under service type loading conditions to study the beneficial effect of the TSRG on creep-fatigue damage evolution. The accumulated errors of the proposed ANM and computational time are compared to a conventional Newton-Raphson solution.

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