Avoiding trial and error loops in the development stage

Material modeling and simulation

Materials models and simulation tools are necessary in order to eliminate trial-and-error loops during the development of materials, components and manufacturing processes, to illustrate complex load scenarios and to make reliable predictions of the behavior of existing materials and components as well as for those in the process of development.

For the most part the Fraunhofer IWM obtains the relevant material properties experimentally, determines the associated model parameters and develops methods and algorithms. Material properties are predicted in virtual test laboratories, alongside the safety and service life of components. Process simulation is used to match manufacturing parameters and tools to assure optimum component properties. The Fraunhofer IWM describes corresponding deformation, damage, fracture and function behavior for materials and models mechanisms on the macro, micro, meso and nano scales under load for components or material systems such as solid bodies, fluids, powders and composites.

The competence spectrum of scientists at the Fraunhofer IWM ranges from quantum mechanics and molecular dynamics to computational physics and from homogenization methods to continuum models. In the areas of continuum mechanics, material theory, fracture mechanics and thermodynamics we describe the behavior of materials on the macroscopic scale all the way through to manufacturing processes and component properties. This includes problems of a multi-field nature: examples might include materials under thermo-mechanically or thermo-electrically coupled load conditions.

What is decisive for significant improvements and innovations in the areas of functionality, reliability, life or economic viability is the integral approach or, where applicable, the coupling together of information from different scales and the following of changes in material properties over multiple process steps. Integrated computational materials engineering (ICME) is the tool for quantitively describing the relationships between process steps, material microstructure, material properties and component behavior. ICME can be used to track the changes in material properties throughout the entire manufacturing process of the component and then during operation, and to describe those changes in numerical terms. On this basis, experts at the Fraunhofer IWM can detect weaknesses in the process chain and during the component lifetime and can remedy these.

Examples of the types of problems that can be solved with ICME include:

The design of materials

The calculation of the microstructure development

Virtual determination of materials data and development of suitable material models

Virtual prediction and real-life pre-adjustment of component features such as freedom from cracks, contour accuracy, service life and crash resistance

Optimization of tools and process steps to improve manufacturing yield 

 

How to work with the Fraunhofer IWM

Methods
 

For our simulations we use both commercial and in house-developed software. We use the following techniques in our simulation approach:

Finite element, finite difference and finite volume methods

Mesh-free methods such as the discrete element method

Parameter identification

Machine learning

Thermokinetic simulations

High throughput screening

Materials models are available for metals, ceramics, glass, composite materials, semiconductors and biological materials. These include micromechanical models for predicting ductile damage in metals, models to depict the behavior of metals and plastics both at high deformation speeds and under creep stress, and brittle fracture models for high-strength steels, cast materials, ceramics, glass, silicon and composite semiconductors. We describe the following mechanisms at the atomic, microstructural or macroscopic scale: deformation, wear, hardening, fatigue, crash, creepage, aging, damage, failure, piezo effects, diffusion, migration, phase formation and microstructure development. We use high-throughput methods to efficiently find new materials.

For the simulation calculations we use a high-performance computing cluster.

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Simulation of material properties and material development

Quantum mechanical calculations and atomism

Microstructure property relationships

Probabilistic material simulation

Material behavior under high-temperature conditions

Friction and wear processes

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Simulation of component behavior

Probabilistic component simulation

Fracture mechanics simulation of components subject to cracking

Component behavior under high-temperature conditions

Behavior of welds

Behavior of joints

Crash simulations of metallic and composite materials and adhesives

Prediction of safety and service life

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Manufacturing and process simulation
 

Microstructure development

Structural composition

Heat treatment

Material degradation

Forming and forming process chains

Welding and joining processes

Layer growth

Particles and flow

Granulate-based manufacturing steps (granulate pouring, die pressing, sintering, tape casting)

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