A new test for sheet metal asperity flattening under varying subsurface strain conditions

Zwicker, Maximilian; Bay, Niels; Nielsen, Chris Valentin

doi:10.1016/j.triboint.2023.108249

Cited by 3 publications

(1 citation statement)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During forming, the undulations can act as stress risers, triggering an earlier localization of deformation in comparison to the same solid but with a smooth surface, hence limiting the capacity of the solid to stretch in the global sense (e.g., [ 1 ]). Furthermore, they can increase the friction between two solids [ 2 ] and contribute to, and accelerate, galling and die wear. During service, these surface undulations can impair the fatigue life, acting as nucleation sites for extrusions/intrusions, etc.…”

Section: Introductionmentioning

confidence: 99%

Deformation-Induced Surface Roughening of an Aluminum–Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

et al. 2023

View full text Add to dashboard Cite

The deformation-induced surface roughening of an Al-Mg alloy is analyzed using a combination of experiments and modeling. A mesoscale oligocrystal of AA5052-O, obtained by recrystallization annealing and subsequent thickness reduction by machining, that contains approx. 40 grains is subjected to uniaxial tension. The specimen contains one layer of grains through the thickness. A laser confocal microscope is used to measure the surface topography of the deformed specimen. A finite element model with realistic (non-columnar) shapes of the grains based on a pair of Electron Back-Scatter Diffraction (EBSD) scans of a given specimen is constructed using a custom-developed shape interpolation procedure. A Crystal Plasticity Finite Element (CPFE) framework is then applied to the voxel model of the tension test of the oligocrystal. The unknown material parameters are determined inversely using an efficient, custom-built optimizer. Predictions of the deformed shape of the specimen, surface topography, evolution of the average roughness with straining and texture evolution are compared to experiments. The model reproduces the averaged features of the problem, while missing some local details. As an additional verification of the CPFE model, the statistics of surface roughening are analyzed by simulating uniaxial tension of an AA5052-O polycrystal and comparing it to experiments. The averaged predictions are found to be in good agreement with the experimentally observed trends. Finally, using the same polycrystalline specimen, texture–morphology relations are discovered, using a symbolic Monte Carlo approach. Simple relations between the Schmid factor and roughness can be inferred purely from the experiments. Novelties of this work include: realistic 3D shapes of the grains; efficient and accurate identification of material parameters instead of manual tuning; a fully analytical Jacobian for the crystal plasticity model with quadratic convergence; novel texture–morphology relations for polycrystal.

show abstract

Section: Introductionmentioning

confidence: 99%

Deformation-Induced Surface Roughening of an Aluminum–Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

et al. 2023

View full text Add to dashboard Cite

show abstract

Flattening of Pyramidal Asperities Under Combined Normal Loading and In-Plane Biaxial Straining

Zwicker,

Arinbjarnar,

Knoll

et al. 2023

Lecture Notes in Mechanical Engineering

View full text Add to dashboard Cite

A discussion of model asperities as a method to study friction in metal forming

Zwicker

Bay²,

Nielsen³

2023

Discov Mechanical Engineering

View full text Add to dashboard Cite

The present work discusses the use of model asperities as a method for studying asperity flattening in metal forming. Asperity flattening and the resulting real contact area largely influence friction in metal forming. In order to gain a fundamental understanding of asperity flattening, a method of choice often is to use model asperities. Here, macroscopic model surfaces are emulating real surface topographies. The work presents the method in a historic context, explains the method, lists advantages and disadvantages, and discusses the method in terms of whether the insights gained on model asperities are of qualitative or quantitative nature. In conclusion, the method is a valid tool to fundamentally study asperity flattening. It is, however, not always possible to transfer obtained conclusions quantitatively from model surfaces to real surfaces.

show abstract

A new test for sheet metal asperity flattening under varying subsurface strain conditions

Cited by 3 publications

References 23 publications

Deformation-Induced Surface Roughening of an Aluminum–Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

Deformation-Induced Surface Roughening of an Aluminum–Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

Flattening of Pyramidal Asperities Under Combined Normal Loading and In-Plane Biaxial Straining

A discussion of model asperities as a method to study friction in metal forming

Contact Info

Product

Resources

About