Fertig Research Group

Stress Level Biases Types of Dislocation Interactions in Thin Films

Recently we discovered (Fertig and Baker (2012) Mat. Sci. Eng. A 551:67-72) that the likelihood of a threading dislocation interacting with another threading dislocation is strongly dependent on film stress. Our modeling efforts showed that films near their critical stress had the highest likelihood of interaction, as measured by a capture cross-section the thread. This is highly significant because it opens up the possiblity of tailoring dislocation structures (interaction types) using very specific stresses during film deposition--potentially controlling the number of threads remaining in the film.

Improving Composite Failure Prediction: Augmenting Volume Average Stresses with Energy

Composite failure prediction is often considered by non-specialists to be a solved problem. But among composites researchers, the challenges of predicting composite failure under arbitrary load states for arbitrary laminate configurations are well known. One approach to this difficult problem has been to use hierarchical theories to extract volume average constituent stresses, and apply failure criteria to the constituents directly. This approach is particularly appealing for integrating realistic physics into composites. However, it is well-known that the strain energy computed from volume average quantities does not account for all of the strain energy in a composite. We are developing an approach to augment the volume average constituent stresses with the "missing" energy for improved predictions of matrix-dominated composite failure.

Fertig Research Group

Physics-Based Multiscale Modeling of Material Failure

Stress Level Biases Types of Dislocation Interactions in Thin Films

Improving Composite Failure Prediction: Augmenting Volume Average Stresses with Energy