Concepts for Integrating Plastic Anisotropy into Metal Forming Simulations

Raabe, Dierk; Klose, Peter; Engl, Bernhard; Imlau, Klaus-Peter; Friedel, F.; Roters, Franz

doi:10.1002/1527-2648(200204)4:4<169::aid-adem169>3.0.co;2-g

Cited by 77 publications

(52 citation statements)

References 17 publications

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“…The evolution of the dislocations is mapped separately for each slip system according to the dyadic formulation of the crystal plasticity kinematics. [14] The Orowan equation serves as the kinetic equation of state and the evolution laws for the immobile SSDs are formulated as rate equations based on distinct dislocation processes such as lock formation or annihilation. Constitutive parameters for the copper single crystal were taken from Zaafarani et al [15] , Appendix A.…”

Section: Simulation Methodsmentioning

confidence: 99%

Texture Evolution During Bending of a Single Crystal Copper Nanowire Studied by EBSD and Crystal Plasticity Finite Element Simulations

et al. 2008

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Section: Simulation Methodsmentioning

confidence: 99%

Texture Evolution During Bending of a Single Crystal Copper Nanowire Studied by EBSD and Crystal Plasticity Finite Element Simulations

et al. 2008

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“…It will be shown that such an approach allows to reduce the number of crystal orientations significantly. In contrast to other texture component models [28,22], the present approach takes into account the half-width of the texture components during the computation of the stresses.…”

Section: Introductionmentioning

confidence: 99%

A texture component model for anisotropic polycrystal plasticity

Böhlke

Risy

Bertram

2005

Computational Materials Science

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There are many crystallographic textures which can be approximated by a small number of texture components [see, e.g., Int. J. Mech. Sci. 31(7) (1989) 549]. In some cases, such texture components can be described by central distributions. Central distributions are characterized by a mean orientation and a half width. The classical Taylor model for viscoplastic polycrystals assumes that a discrete set of single crystals deforms homogeneously. If the viscoplastic version of the Taylor model is numerically implemented then the crystallite orientation distribution function (codf) is usually discretized by a set of Dirac distributions, where each of the Dirac distributions represents a single crystal. Due to the specific discretization of the codf this approach requires usually a large number of discrete crystal orientations even if the texture can be described by a small number of texture components. In the present work, we consider face-centered cubic (fcc) polycrystals and compare the classical upper bound model with an approach based on texture components. The texture components are modeled by Mises-Fischer distributions, which are central distributions. The stress of the polycrystal is obtained by a numerical integration of the single crystal stress state over the orientation space.

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“…Thermo-mechanically processed metallic materials commonly display mechanical anisotropy [7]- [10]. This has been examined extensively, by analysing the effects of microstructural parameters and texture.…”

Section: Influence Of Plate Rolling On Mechanical Anisotropy Of the Coilmentioning

confidence: 99%

The influence of material anisotropy and spiral welding on tensile strain capacity of spiral welded pipes

Backer

Minnebruggen

Waele

2015

SCAD

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Abstract:The longitudinal strain capacity of spiral welded pipelines displays to some extents unexplained behaviour. Therefore, they are not (yet) used extensively in offshore applications and harsh conditions, demanding a strain based design. An important factor that influences the tensile strain capacity is the quantity of anisotropy in terms of strength and toughness. Starting from an anisotropic hot rolled highstrength steel skelp, the process of helical forming and post-treating of the pipe adds heterogeneity and changes the level of anisotropy of the product. A parameter that should be examined with respect to anisotropy is the crack driving force, a measure for the toughness of the pipeline steel. Additional to the mode I loading (opening of the crack), the mode III component drives the in-plane shear motion of a crack in the spiral weld when the pipe is subjected to longitudinal deformation. This action, not present in longitudinal welded pipes, shows a decreasing contribution with increasing plasticity. FE simulations have demonstrated a rise of crack driving force in anisotropic cases with respect to an isotropic reference. However, exact data and variation of various parameters, along with experimental testing need to be conducted. The outcome analysis of such simulations and tests can validate existing models, or help create a better understanding of anisotropic and heterogenic influences on the tensile strain capacity of spiral welded pipes.Keywords: Spiral welded pipeline; tensile strain capacity; strain based design; anisotropy; heterogeneity INTRODUCTIONThe oil & gas industry is reluctant to use spiral welded pipelines in harsh conditions. For the last decade, usage has increased in onshore areas, and only slightly in offshore applications. Examples are the start of the greatest gas pipeline in Chinese history, the 4000 km long production, use and inspection [3]. This report indicates which characteristics of spiral welded pipes need to be examined in detail. The spiral weld and the material anisotropy, two effects highlighted and questioned in the report, are the principal subjects of this paper. Production of spiral welded pipes consists of more than just helical forming of plates. The starting material, hot rolled TMCP plates, have anisotropic microstructures and mechanical properties. Helical forming angles determine the diameter of the pipe and its overall performance capacity. The spiral welding accompanied with this process locally introduces an extra level of heterogenity to the spiral welded pipeline. A post-heattreatment changes the mechanical properties to a more preferred level, like higher yield strength, and less distinct anisotropy or heterogeneity into the product. The effects of mechanical deformation and thermal treatments during subsequent helical pipe making processes that influence anisotropy and heterogenity, and thus the straining capacity, need to be studied in detail [4]. This paper takes a look at the influencing factors of (mainly) anisotropy and heterogeneity in spira...

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Concepts for Integrating Plastic Anisotropy into Metal Forming Simulations

Cited by 77 publications

References 17 publications

Texture Evolution During Bending of a Single Crystal Copper Nanowire Studied by EBSD and Crystal Plasticity Finite Element Simulations

Texture Evolution During Bending of a Single Crystal Copper Nanowire Studied by EBSD and Crystal Plasticity Finite Element Simulations

A texture component model for anisotropic polycrystal plasticity

The influence of material anisotropy and spiral welding on tensile strain capacity of spiral welded pipes

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