Numerical Evaluation of Surface Roughness Influences on Cold Formability of Dual‐Phase Steel

Wechsuwanmanee, Peerapon; Lian, Junhe; Liu, W.; Münstermann, Sebastian

doi:10.1002/srin.202000141

Cited by 4 publications

(4 citation statements)

References 17 publications

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“…It starts to play a role upon the time instant that the equivalent plastic strain

{\bar{ε}}^{p}

reaches the stress‐state dependent ductile damage initiation locus (DIL)

{\bar{ε}}^{i}

, which reads

{\bar{ε}}^{i} (η, \bar{θ}) = c_{normals} [(c_{1}^{i} \cdot exp (- c_{2}^{i} \cdot η) - c_{3}^{i} \cdot exp (- c_{4}^{i} \cdot η)) {\overset{θ}{true}}^{2} + c_{3}^{i} \cdot exp (- c_{4}^{i} \cdot η)]

c_{normals} = \frac{{\bar{ε}}_{meso}^{i}}{{\bar{ε}}_{micro}^{i}}

where

c_{1}^{i}

c_{2}^{i}

c_{3}^{i}

, and

c_{4}^{i}

are DIL parameters to be calibrated from mechanical experiments. The surface factor

c_{normals}

was introduced in Wechsuwanmanee et al [ 15 ] to incorporate the fact that surface imperfection plays a role in local material softening during deformation. This factor is ranged between

0 \leq c_{normals} \leq 1

for the material point on the surface and

c_{normals} = 1

on the bulk material.…”

Section: Mbw Materials Model With Surface Roughness Correctionmentioning

confidence: 99%

“…where c i 1 , c i 2 , c i 3 , and c i 4 are DIL parameters to be calibrated from mechanical experiments. The surface factor c s was introduced in Wechsuwanmanee et al [15] to incorporate the fact that surface imperfection plays a role in local material softening during deformation. This factor is ranged between 0 ≤ c s ≤ 1 for the material point on the surface and c s ¼ 1 on the bulk material.…”

Section: Mbw Materials Model With Surface Roughness Correctionmentioning

confidence: 99%

“…[ 14 ] Some evidence indicates that different roughness levels on samples, in particular, ground samples and polished samples, result in different response on cyclic loading [ 13 ] as well as in‐plane strain loading. [ 15 ] Finite element (FE) model with roughness consideration in cyclic loading can be found in Ås et al [ 12 ] In addition, McMillan et al [ 16 ] propose a technique to model roughness geometry based on Minkowski curve [ 17 ] in axisymmetric loading. A multiscale strategy has been introduced at first in cold forming application in plane strain loading case.…”

Section: Introductionmentioning

confidence: 99%

“…Later, an extension to the MBW model regarding surface condition has been introduced. [ 15 ] It adds an additional surface factor as a multiplier to lower the damage initiation criteria as well as fracture criteria of the elements at the surface to reflect the vulnerability of the surface comparing to the bulk material. Still, a limitation for this approach is the representative surface generation in 2D.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

3D Multilevel Modeling of Surface Roughness Influences on Hole Expansion Ratios

Wechsuwanmanee

Lian

Münstermann

2021

steel research int.

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The steel grade DP1000 is widely used in various industrial application fields. Its mechanical properties satisfy basic requirements in terms of strength and global formability due to the tailored microstructure composed of ductile ferrite and hard martensite. Nevertheless, the edge crack sensitivity of dual‐phase steels is still of interest. For its evaluation, hole expansion tests have become a standard experimental approach. Finite element simulation is a tool that further supports the assessment of edge crack resistance by providing insights into local stress and strain fields at the formed edges during hole expansion tests. However, there are still discrepancies between the experiments and simulations in terms of force–displacement curves and hole expansion ratios due to several factors including the hole edge surface condition. To overcome these discrepancies, this work proposes a 3D multiscale simulation strategy to quantify this factor under a complex loading case and to include it into the simulation approaches. The workflow is sufficiently general to handle arbitrary load cases. Compared with state‐of‐the‐art ductile damage mechanics simulations, the accuracy of the simulations is significantly improved.

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“…It starts to play a role upon the time instant that the equivalent plastic strain

{\bar{ε}}^{p}

reaches the stress‐state dependent ductile damage initiation locus (DIL)

{\bar{ε}}^{i}

, which reads

{\bar{ε}}^{i} (η, \bar{θ}) = c_{normals} [(c_{1}^{i} \cdot exp (- c_{2}^{i} \cdot η) - c_{3}^{i} \cdot exp (- c_{4}^{i} \cdot η)) {\overset{θ}{true}}^{2} + c_{3}^{i} \cdot exp (- c_{4}^{i} \cdot η)]

c_{normals} = \frac{{\bar{ε}}_{meso}^{i}}{{\bar{ε}}_{micro}^{i}}

where

c_{1}^{i}

c_{2}^{i}

c_{3}^{i}

, and

c_{4}^{i}

are DIL parameters to be calibrated from mechanical experiments. The surface factor

c_{normals}

was introduced in Wechsuwanmanee et al [ 15 ] to incorporate the fact that surface imperfection plays a role in local material softening during deformation. This factor is ranged between