Strategies for coupled analysis of thermal strain history during continuous solidification processes

Boehmer, J.R.; Funk, G.; Jordan, Mabel; Fett, F.N.

doi:10.1016/s0965-9978(98)00033-7

Cited by 18 publications

(22 citation statements)

References 5 publications

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“…This hypothesis is similar to that adopted by Weiner and Boley in their semianalytical study. Two-dimensional approaches based on a plane strain hypothesis perpendicular to the casting direction have been used in the literature for thermal stress evaluation of continuous casting simulations [4,[10][11][12][13]. Nevertheless, these slice models are questionable to reproduce accurately the 3D mechanical state at some critical zones, like the mould exit in slab continuous casting, where stress state is clearly fully 3D.…”

Section: Introductionmentioning

confidence: 99%

Thermal stress evaluation in the steel continuous casting process

Risso

Huespe

Cardona

2005

Numerical Meth Engineering

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Section: Introductionmentioning

confidence: 99%

Thermal stress evaluation in the steel continuous casting process

Risso

Huespe

Cardona

2005

Numerical Meth Engineering

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“…The rate representation of total strain in this elastic-viscoplastic model is given bẏ =˙ el +˙ ie +˙ th (13) where˙ el ,˙ ie ,˙ th are the elastic, inelastic (plastic + creep), and thermal strain rate tensors, respectively. Stress rate˙ depends on elastic strain rate and in this case of linear isotropic material and negligible large rotations it is given by (14)…”

Section: Mechanical Governing Equationsmentioning

confidence: 99%

“…Later, separate creep laws were added [9,10]. With the rapid advance of computer hardware, more computationally challenging elastic-viscoplastic models have been used [2,3,6,[11][12][13][14][15][16][17][18] which treat the phenomena of creep and plasticity together since only the combined effect is measurable. Most models use a Lagrangian approach with a fixed mesh due to its easy implementation, although an alternative Eularian-Langrangian approach has also been used [6,14].…”

Section: Introductionmentioning

confidence: 99%

Efficient thermo-mechanical model for solidification processes

Korić

Thomas

2006

Int. J. Numer. Meth. Engng

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SUMMARYA new, computationally efficient algorithm has been implemented to solve for thermal stresses, strains, and displacements in realistic solidification processes which involve highly nonlinear constitutive relations. A general form of the transient heat equation including latent-heat from phase transformations such as solidification and other temperature-dependent properties is solved numerically for the temperature field history. The resulting thermal stresses are solved by integrating the highly nonlinear thermo-elastic-viscoplastic constitutive equations using a two-level method. First, an estimate of the stress and inelastic strain is obtained at each local integration point by implicit integration followed by a bounded Newton-Raphson (NR) iteration of the constitutive law. Then, the global finite element equations describing the boundary value problem are solved using full NR iteration. The procedure has been implemented into the commercial package Abaqus (Abaqus Standard Users Manuals, v6.4, Abaqus Inc., 2004) using a user-defined subroutine (UMAT) to integrate the constitutive equations at the local level. Two special treatments for treating the liquid/mushy zone with a fixed grid approach are presented and compared. ISS, vol. 76, 1993) specialized in thermo-mechanical modelling of continuous casting. Both finite element codes are then applied to simulate temperature and stress development of a slice through the solidifying steel shell in a continuous casting mold under realistic operating conditions including a stress state of generalized plane strain and with actual temperaturedependent properties. Other local integration methods as well as the explicit initial strain method used in CON2D for solving this problem are also briefly reviewed and compared.

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“…which Grill et al, 2) Kristiansson, 3) Thomas et al, 4) Boehmer et al 5) It consists in conveying throughout the machine a transverse section of the product: either a plane section or a volumic domain having a small thickness in the casting direction. Regarding heat transfer, top and bottom surfaces are adiabatic, the heat being extracted through the lateral boundary.…”

Section: Resolution Strategies For Cc: Literature Review and Present mentioning

confidence: 99%

A Two-dimensional Finite Element Thermomechanical Approach to a Global Stress-Strain Analysis of Steel Continuous Casting

Bellet

Heinrich

2004

ISIJ International

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This paper addresses the two-dimensional finite element simulation of steel continuous casting using a global non steady-state approach. The method aims at the calculation of the thermomechanical state (temperature, deformation, stresses) of steel all along the continuous casting machine. Both plane deformation and axisymmetric versions have been developed. The first one addresses the simulation of continuous casting of slabs, taking into account the possible curvature of the machine, whereas the second one applies to cylindrical billets. The implementation of the method is validated by comparison with results from the literature. It is applied to the study of a slab continuous caster for which successive depressive and compressive stress states are revealed in the secondary cooling region.KEY WORDS: continuous casting; finite elements; thermomechanics; stress-strain calculation.which Grill et al., 2) Kristiansson, 3) Thomas et al.,4) Boehmer et al.5) It consists in conveying throughout the machine a transverse section of the product: either a plane section or a volumic domain having a small thickness in the casting direction. Regarding heat transfer, top and bottom surfaces are adiabatic, the heat being extracted through the lateral boundary. As thermal gradients are very low along the casting direction in steel CC, this method yields good thermal results. However, it has major drawbacks regarding the mechanical analysis. Generally, a plane strain deformation state is assumed in the slice. Some authors, like Pascon 6) have extended this concept by assuming a state of generalized plane strain in order to cope with the bending and unbending. In spite of this, the slice approach does not take into account any shear effect and then cannot be representative of complex deformation states such as those associated with bulging. Global Steady-state MethodAn alternative consists of a Eulerian steady-state formulation, which operates on a quasi static computational domain covering the whole machine. This requires the integration of highly non linear constitutive equations (elasticviscoplasticity) along streamlines, which needs specific advection methods, such as those proposed by Huespe et al. 7)In addition, such a problem is a free surface problem, since the location of the mesh boundary is unknown, because of bulging. Therefore specific algorithms must be used in order to move boundary nodes so that the velocity field be tangent to the surface. This has been done by Dalin and Chenot 8) but only on short isolated sections of the secondary cooling. In order to overcome this difficulty, Fachinotti and Huespe have proposed to keep the mesh identical in the analysis and to deduce the bulging a posteriori, 7,9) which makes yet the steady-state formulation not fully consistent. In the authors' opinion, it would be extremely challenging to develop a fully consistent free surface steady-state model, especially because of the contact conditions to be satisfied with a great number of rolls (typically more than 100). The converge...

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Strategies for coupled analysis of thermal strain history during continuous solidification processes

Cited by 18 publications

References 5 publications

Thermal stress evaluation in the steel continuous casting process

Thermal stress evaluation in the steel continuous casting process

Efficient thermo-mechanical model for solidification processes

A Two-dimensional Finite Element Thermomechanical Approach to a Global Stress-Strain Analysis of Steel Continuous Casting

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