Skip to main content

Blog posts

Dislocation Climb in Two-Dimensional Discrete Dislocation Dynamics

Submitted by Kamyar M Davoudi on

In this paper, dislocation climb is incorporated in a two-dimensional discrete dislocation dynamics model. Calculations are carried out for polycrystalline thin films, passivated on one or both surfaces. Climb allows dislocations to escape from dislocation pile-ups and reduces the strain-hardening rate, especially for fully passivated films. Within the framework of this model, climb modifies the dislocation structures that develop during plastic deformation and results in the formation of pile-ups on slip planes that do not contain any dislocation sources.

Vibration of wavy single-walled carbon nanotubes based on nonlocal Euler Bernoulli and Timoshenko models

Submitted by Payam Soltani on

Vibration of wavy single-walled carbon nanotubes based on nonlocal Euler Bernoulli and Timoshenko models

By: Payam SoltaniA KassaeiM M Taherian and A Farshidianfar

Fatigue of polymer-supported Ag thin films

Submitted by Gi-Dong Sim on

The fatigue behavior of Ag films on polyethyleneterephthalate substrates was studied using electrical resistance measurements.
Scanning electron microscopy images showed two types of failure: typical fatigue failure with extrusion–intrusion pairs, and ductile
failure with local necking. Once through-thickness cracks are formed in the metal layer, cracks propagate and the resistance increases abruptly for both failure modes. The effect of adhesion on fatigue life is discussed in terms of concurrent delamination, crack initiation and propagation.

Improving the stretchability of as-deposited Ag coatings on poly-ethylene-terephthalate substrates

Submitted by Gi-Dong Sim on

In this paper, we report that silver films evaporated on poly-ethylene-terephthalate (PET) substrates coated with an acrylic primer can be stretched beyond 70% without fracture. As-deposited films show a larger failure strain than annealed coatings. These observations are rationalized in light of a ductile fracture mechanism where debonding from the substrate coevolves with strain localization. The results of this study indicate that PET substrates coated with an acrylic primer layer may be suitable for stretchable electronics.

Proceedings

Submitted by shavijabranko on

Dear all,

 

Proceedings of the V International PhD workshop dealing with durability of concrete, which was held in Finland in February, have been published. The publication is available for free download at:  http://www.vtt.fi/inf/pdf/technology/2012/T65.pdf . Many interesting and innovative topic, dealing both with experimental and numerical research of concrete durability, are presented.

Journal Club Theme of December 2012: Metamaterials Inspired Concepts for Elastic Wave Energy Harvesting

Submitted by ruzzene on

Recent journal club posts have illustrated the interesting and unique dynamic properties of phononic crystals and acoustic metamaterials (see April and May journal club entries by M. Hussein and A. Spadoni respectively). The ability of this class of engineered materials and structures to guide and focus elastic and sound waves can be exploited in a number of new applications and exciting functionalities.