Project Area M: Mechanisms, Modeling and Simulation

The major objective of the research work in the SFB/TRR 136 is to investigate the relationship between material stress and modification to establish process signature components (PSCs). With the help of the latter, a paradigm shift in manufacturing technology is to be initiated: For a desired material modification, for example a change in hardness, the PSCs allow the determination of the material stress to be achieved within the processes in question.

It is obvious that, in addition to work on experimental characterization (see project area C), techniques for a better understanding of the mechanisms occurring in the material and multi-scale modeling and simulation techniques must be used to establish the PSCs. This is where project area M comes in. The aim is not only to develop new models, but also to merge them with existing submodels from the other project areas at the most generally valid level possible. The models are formulated on the basis of mechanical, thermal, chemical and electrical quantities. Thus, project area M contributes significantly to the establishment of suitable PSCs.


SP M01 – Energy based process analysis for characteristic process signatures

The central task of M01 is to formulate approaches for Process Signatures that link material modifications and internal loads for different manufacturing processes. The sub-project works with numerical methods to determine load characteristics and modifications that are difficult to access experimentally. Currently, the already developed Process Signature components for ferritic-pearlitic input conditions for single loads with one impact are being further developed so that they also take into account modifications for different input conditions with multiple loads and multiple impacts.

The current results in SP M01 are summarized here on one page.

PIs: Prof. Dr.-Ing. habil. Prof. h.c. Dr. h.c. Dr. h.c. Bernhard Karpuschewski, Dr.-Ing. Thomas Lübben, Dr.-Ing. Jens Sölter


SP M03 – Thermo-mechanically coupled process modeling including microstructural material modifications

For the development of process signatures it is crucial to consider the influence of the material microstructure on manufacturing induced material modifications. To model this influence, a two-scale continuum model has been developed during the first funding period for macroscopic material behavior depending on the evolution of the material microstructure in polycrystalline metallic materials.  This two-scale model combines micromechanical phase field modeling of microstructure evolution and unit cell (volume) averaging to model the corresponding macroscopic material behavior. Assuming a periodic microstructure, this model has been numerically implemented using fast Fourier transform methods and employed at the Gauss point-level as the material model in a finite element implementation of the macroscopic model. Current research is concerned, among other things, with (i) extending the two-scale model to additional processes such as recrystallization and (ii) improving its computational efficiency using model order reduction techniques. With the help of these further developments, it is planned in the third funding period to conduct two-scale simulations of selected processes and process chains from SFB Project Area F. 

The current results in SP M03 are summarized here on one page.

PIs: Prof. Dr.-Ing. habil. Stefanie Reese, Prof. Dr. rer. nat. habil. Bob Svendsen


SP M04 – Modeling of transport mechanisms for erosion processes

It is the project’s objective to determine spatial and temporal interactions of the flushing process with the energy input and the energy dissipation in the workpiece surface layer such that a flushing process model can be formulated for electrical discharge machining. The unsteady spatial conservation equations are solved by a Lattice-Boltzmann method (LBM) for flushing processes defined by differing geometry and flow parameters. The analyses enable the consideration of interactions between workpiece and surrounding medium in the formulation of process signatures.

The current results in SP M04 are summarized here on one page.

PIs: Prof. Dr.-Ing. Wolfgang Schröder, Dr.-Ing. Matthias Meinke


SP M05 – Numerically efficient multi scale material models for processes under thermal and chemical impact

Subproject M05 deals with the modeling of material behavior during thermal and thermo-chemical processes. The aim is to develop a methodology that enables the influence of the mechanisms occurring at the microstructural level to be mapped onto the polycrystalline level.
In addition to the variational modeling of thermally induced phase transformations, M05 is dedicated to the development of a methodology for mapping electro-chemical machining (ECM). For this purpose, the damage methodology already established in mechanics was further developed to the extent that the mechanism of anodic dissolution can now also be mapped.
Both methods developed make use of an effective formulation of the material behavior, hence allowing the scale transition from the microstructural to the polycrystalline level and thus efficient computation times. By describing material modification in this way, M05 makes an important contribution to the formulation of process signatures for processes with thermal, chemical and thermo-chemical main impact.

The current results in SP M05 are summarized here on one page.

Pl: Prof. Dr.-Ing. habil. Stefanie Reese


SP M06 – Mechanism Analysis of Machining-Induced Chemical Material Modifications and their Effect on the Component Functionality

Subproject M06 focusses on the comprehensive mechanistic analysis of chemical loads on the basis of electrochemical and microstructural characterization methods. On the one hand, the aim is to identify reaction mechanisms in processes with a chemical impact. On the other hand, the experimental quantification of chemical stresses and rim zone modifications is planned. The quantification of the rim zone modifications is carried out comparatively to the material input state via AC/DC methods, residual stresses, roughness and edge zone chemistry; the chemical load is determined via mass spectrometry using the process electrolyte. In addition, preliminary testing is carried out with regard to the influence of modified rim zone properties on oxidation mechanisms in oxygen-containing atmospheres with respect to component functionality.

The current results in SP M06 are summarized here on one page.

PI: Prof. Dr.-Ing. habil. Daniela Zander