Simplified numerical approach for the thermo-mechanical analysis of steelmaking components under cyclic loading: an anode for electric arc furnace

Fatigue Fract Eng Mat Struct

Moro

et al. 2018

Self Cite

Strain‐life fatigue data on copper alloys, especially type CuAg, are seldom available in the literature. This work fills this gap by estimating the strain‐life curves of a CuAg alloy used for thermo‐mechanical applications, from isothermal low‐cycle fatigue tests at 3 temperatures (room temperature, 250°C, 300°C). Regression analysis is used to estimate the median fatigue curves at 50% survival probability. The comparison of median curves with the Universal Slopes Equation model, calibrated on monotonic tensile properties, shows a fairly good agreement. Design strain‐life curves with a lower failure probability and given confidence are estimated by several approximate statistical methods (“Equivalent Prediction Interval,” univariate tolerance interval, Owen's tolerance interval for regression). When higher survival probabilities are considered, the results show a marked decrease in the allowable design strain at a prescribed fatigue life. The suggested procedure thus improves the durability analysis of components loaded thermo‐mechanically.

Section: Design Strain-life Curves: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of a CuAg alloy for thermo‐mechanical applications. Part 2: Design strain‐life curves estimated via statistical analysis

Fatigue Fract Eng Mat Struct

Moro

et al. 2018

Self Cite

“…A noteworthy example-considered in this work-is the case of copper alloys used in components of steel making plants (e.g., mold for continuous steel casting, anode for electric arc furnace, etc.) [1,2]. The material model in FE model needs to be calibrated on experimental cyclic plasticity data, which for copper alloys are rarely available in the literature.…”

Section: Introductionmentioning

confidence: 99%

An Isotropic Model for Cyclic Plasticity Calibrated on the Whole Shape of Hardening/Softening Evolution Curve

Bona

2019

Metals

This work presents a new isotropic model to describe the cyclic hardening/softening plasticity behavior of metals. The model requires three parameters to be evaluated experimentally. The physical behavior of each parameter is explained by sensitivity analysis. Compared to the Voce model, the proposed isotropic model has one more parameter, which may provide a better fit to the experimental data. For the new model, the incremental plasticity equation is also derived; this allows the model to be implemented in finite element codes, and in combination with kinematic models (Armstrong and Frederick, Chaboche), if the material cyclic hardening/softening evolution needs to be described numerically. As an example, the proposed model is applied to the case of a cyclically loaded copper alloy. An error analysis confirms a significant improvement with respect to the usual Voce formulation. Finally, a numerical algorithm is developed to implement the proposed isotropic model, currently not available in finite element codes, and to make a comparison with other cyclic plasticity models in the case of uniaxial stress and strain-controlled loading.

“…models, while cyclic hardening/softening behaviour can be captured with a nonlinear isotropic model (Voce) . Most theories are now implemented in commercial finite element software and used routinely …”

Section: Introductionmentioning

confidence: 99%

“…Although this work focuses on the material characterization of a copper alloy for a mould, the proposed procedure can be also extended to other applications and materials: for example, a similar copper alloy is adopted in the water‐cooled part of anodes for electric arc furnaces, where the scrap steel is melted . Cyclic hardening material models are also of interest for the simulation of cyclic thermal shocks in steel parts and can be used, for instance, to develop numerical analyses for life prediction in tool steel .…”

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of a CuAg alloy for thermo‐mechanical applications. Part 1: Identifying parameters of non‐linear plasticity models

Fatigue Fract Eng Mat Struct

Moro

et al. 2018

Self Cite

Despite the wide use of copper alloys in thermo‐mechanical applications, there is little data on their cyclic plasticity behaviour, particularly for CuAg alloys. This prevents the behaviour of the materials from being correctly described in numerical simulations for design purposes. In this work CuAg0.1 alloy used for thermo‐mechanical applications was tested by strain‐controlled cyclic loading at 3 different temperatures (room temperature, 250°C, 300°C). In each test, stress‐strain cycles were recorded until the alloy had completely stabilised. These cycles were then used to identify material parameters of non‐linear kinematic and isotropic models. The focus was on plasticity models (Armstrong‐Frederick, Chaboche, Voce) that are usually implemented in commercial finite element codes. Simulated cyclic responses with the identified material models were compared with experiments and showed a good agreement. The identified material parameters for the CuAg alloy under investigation can be used directly in finite element models for cyclic plasticity simulations, thus enabling a durability analysis of components under thermo‐mechanical loads to be performed, particularly in the field of steel‐making plants.