Mechanical properties of materials in the meso- and microregime

Meso- and Micromechanics

Applying self-developed test set-ups and experimental mechanics, we are capable of determining the material properties of samples with at least one dimension in the microscale. The testing of micro-parts is a routine, everyday occurrence for us, and we also carefully prepare small samples from larger components in order to determine the local material characteristics of critical parts. Our aim is to contribute to current material models, the design of metamaterials, the optimization of local materials properties and the understanding of size effects, which frequently appear in micro-regime samples. 

Services

Methods in experimental mechanics from the micro- to milliscale

Conception and implementation of micromechanical tests (including sample preparation)

Lifetime models with size effect considerations

Development of mechanical metamaterials

Sensor technology: novel load cells, optical strain measurements

Process optimization through statistical experiment planning and neural networks

Metrology / Software development

Topics

 

Mechanical testing of micro-samples


Special test set-ups are used in order to determine the properties of very small material samples. For example, the fatigue characteristics of 200 µm cantilevers were tested, the samples coming from electrical steel sheets that typically find application in the automotive sector. From mechanical construction, to the control and DAQ systems, the test set-ups are constantly being further developed. The set-ups are used in order to determine ...

 

 

Detection of fatigue damage before crack initiation


With a micro resonance fatigue set-up, we are capable of detecting early-stage fatigue damage in samples with thicknesses of approximately 200 µm. This is accomplished by tracking changes in the sample’s eigenfrequency. Through SEM analysis of fatigued nickel samples, it was possible to correlate measured eigenfrequency changes with the following fatigue stages: extrusion development, crack initiation in single grains, and micro-crack growth. The ...

 

Development of nanostructures for the creation of mechanical metamaterials 


In order to design the mechanical properties of metamaterials, we employ three-dimensional nanolithography. In our application, framework structures with a minimal thickness of 100 nm are polymerized out of a photoresist by a femtosecond laser. The unit cells of these structures are constructed so that they show a desired mechanical property when coupled in a large matrix. The structure shown...

 

 

 

Process optimization 


The interdisciplinary field of process optimization deals primarily with multi-dimensional optimization tasks from materials science and other relevant engineering sciences. These tasks are solved by applying methods from computer science and mathematics. For example, the optical strain measurement parameters in a scanning electron microscope can be optimally set with only a few tests. Furthermore, complex production processes can be described through approximation...

 

 

 

Publications regarding Meso- and Micromechanics


Contributions to newspapers, books and conferences as well as dissertations and project reports...