Decorative photo-montage
Photo-montage of shape memory alloy tests

The Mechanics and the Physics of high rate deformation and fracture is the central theme of the Dynamic Fracture Laboratory. The Dynamic Fracture Laboratory was started within the Materials Mechanics Center in 1994 by D. Rittel, to address specific issues in dynamic fracture mechanics and stress wave physics. Since then, the Dynamic Fracture Laboratory has been actively developing new tools and techniques to address these issues, while expanding its activity to other related domains.

The activity of our group is largely experimental, with a strong numerical modeling component. We develop ad-hoc experimental specimens and methods to investigate high rate fracture mechanics, like the Compact Compression Specimen and the One-Point Impact Technique.

Thermomechanical couplings in solids is also a central theme of our activity, such as the determination of the Taylor-Quinney factor in various metals and polymers, as well as thermomechanical coupling effects in dynamic fracture, using non-contact infrared thermometry.

Structural reliability is also investigated in the context of scaling issues for large, close-range explosions, or structural health monitoring using electrical impedance tomography, or end-effects monitoring using evanescent waves for instance.

The ballistic behavior of lightweight materials (amorphous glassy polymers) is another subject of interest. The constitutive behavior of materials at high strain-rates is a central theme in our group. We use our Shear Compression Specimen (SCS) to investigate dynamic shear localization, model the phenomenon and understand its physical roots.

More recently, we started investigating the dynamic mechanical response of soft matter (gels) to gain a deeper insight into modeling of human organs and tissues subjected to traumatic impacts.

Another recent field of interest addresses the mechanical reliability of dental implants, including failure analysis and prevention based on the development of new fatigue testing protocols in simulated intraoral media.

For all our activities, a strong emphasis is put on the physics of failure, including the identification of failure micro-mechanisms using both scanning and transmission electron microscopy.

Numerical modeling is routinely used to “fine tune” or develop new experiments, as well as part of hybrid experimental-numerical approaches. Our models are developed within the group by the same people who carry out the experiments, so that our modeling activity is driven by our physical observations.

D. Rittel’s philosophy in a nutshell:
If it is measurable, no need for guesswork