A harmonic one-dimensional element for non-linear thermo-mechanical analysis of axisymmetric structures under asymmetric loads: The case of hot strip rolling

et al. 2018

MATEC Web Conf.

Self Cite

Abstract. Numerical simulations of components subjected to cyclic thermo-mechanical loads require an accurate modelling of their cyclic plasticity behaviour. Combined models permit to capture monotonic hardening as well as cyclic hardening/softening phenomena, that occur in reality. In principle the durability assessment of a component under thermal loads can be performed only if the cyclic behaviour is simulated until complete material stabilization. As materials stabilize approximately at half the number of cycles to failure, it follows that in case of small plastic strains a huge number of cycles must be considered and an unfeasible simulation time would be required. Accelerated models have thus been proposed in literature. The aim of this work is that of comparing the different acceleration techniques in the case a round mould for continuous casting loaded thermo-mechanically. It can be observed that the usual approach of using the stabilized stress-strain curve already from the first cycle could lead to relevant errors. An alternative method is that of increasing the value of the parameter that controls the speed of stabilization in the combined model. This approach permits the number of cycles to reach stabilization to be drastically reduced, without affecting the overall mechanical behaviour. Based on this approach, a simple design rule, that can be adopted, particularly when relatively small plastic strains occur, is finally proposed.

Section: Numerical Simulation Of Mechanical Components Under Thermal mentioning

confidence: 99%

Acceleration techniques for the numerical simulation of the cyclic plasticity behaviour of mechanical components under thermal loads

Novak¹,

Bona

et al. 2018

MATEC Web Conf.

Self Cite

“…On the contrary, a kinematic hardening model captures Bauschinger's effect and, in the considered uniaxial case, it stabilises into an elastic-plastic hysteresis loop after the first cycle. In [24] and [25], the thermo-mechanical behaviour of hot rolling mills is analysed by using a kinematic model. In [26], a combined model is used to evaluate permanent deformation during the roll levelling of thin strip steel.…”

Section: Materials Properties and Modelsmentioning

confidence: 99%

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

Moro

Ironmaking & Steelmaking

Bona

2017

The need of a strong improvement of productivity and reliability led the adoption of advanced modeling techniques in the design of steelmaking plants components. In this work a procedure based on a finite element simulation is proposed in order to perform a durability analysis of an anode for electric arc furnace. This component undergoes cyclic thermal loads, which also produce a partial melting of one part, meanwhile the other is maintained at almost constant temperature by a cooling system. A simplified, but effective, procedure is developed to take into account steel melting during the heating phase. Considering the cyclic loading conditions, several material cyclic plasticity models, and their effect on the thermal fatigue behavior, are also systematically investigated. The proposed approach permits the component fatigue life to be assessed by a simple and fast uncoupled thermo-mechanical simulation in steady-state conditions. © 2017 Institute of Materials, Minerals and Minin

“…The mold is made of a copper alloy, whose characteristics are available in [6]. An uncoupled transient thermomechanical finite element analysis was performed [7]. Only 1/8 of the component can be considered due to symmetries.…”

Section: Numerical Model and Thermal Analysismentioning

confidence: 99%

Copper Mold for Continuous Casting of Steel: Modelling Strategies to Assess Thermal Distortion and Durability

Moro

Novak

et al. 2017

KEM

In this work the durability assessment and the permanent deformation of a copper mold for continuous casting of steel have been investigated using mathematical models based on the Finite Element method. The cyclic plasticity behavior of the material is represented by a combined kinematic-isotropic model experimentally validated. Results from thermo-mechanical analysis are in good agreement with measurements. In particular, creep effects included into the model permit the evolution of bulging near the meniscus area to be correctly predicted. A life estimation is performed considering strain-life and stress-rupture time curves according to a cumulative damage law.