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Polymer constitutive modelling: Formulation and computational aspects

Submitted by Mirkhalaf on
  • This work formulates an elasto-viscoplastic model at finite strains.
  • A particularly efficient numerical integration algorithm is presented.
  • A closed-form analytical expression is derived for the consistent tangent operator.
  • The non-linear behaviour of polymers is captured in the numerical examples.
  • Quadratic rate of convergence is successfully achieved.

doi:10.1016/j.compstruc.2016.01.002

 

Funded PhD studentship: Modelling of Fibroblast Mechanobiology

Submitted by paulwatton on

Supervisor: PN Watton, Department of Computer Science, University of Sheffield.

Co-supervisors: Prof Ray Ogden, School of Mathematics and Statistics & Dr Huabing Yin, Bioengineering, University of Glasgow

We are seeking applications from motivated mathematics, science or engineering graduates with strong mathematical/computational modelling skills interested in studying for a Ph.D. in an exciting interdisciplinary environment.

Harnessing atomistic simulations to predict the rate at which dislocations overcome obstacles

Submitted by sepehr.saroukhani on

Predicting the rate at which dislocations overcome obstacles is key to understanding the microscopic features that govern the plastic flow of modern alloys. In this spirit, the current manuscript examines the rate at which an edge dislocation overcomes an obstacle in aluminum. Predictions were made using different popular variants of Harmonic Transition State Theory (HTST) and compared to those of direct Molecular Dynamics (MD) simulations. The HTST predictions were found to be grossly inaccurate due to the large entropy barrier associated with the dislocation–obstacle interaction.

Continuous and discrete microstructured materials with null Poisson's ratio

Submitted by Giorgio Carta on

In this paper we propose diff erent classes of isotropic microstructured media with tunable Poisson's ratio. The elastic periodic systems are continuous porous media and two- and three-dimensional lattices. The microstructural parameters can be tuned in order to have an eff ective Poisson's ratio equal to zero. The connection between microstructural parameters and eff ective properties is shown in detail both analytically and numerically.

 

Continuous system with null Poisson's ratio:

Design of a porous material with isotropic negative Poisson's ratio

Submitted by Giorgio Carta on

This paper proposes the design of a two-dimensional porous solid with omnidirectional negative Poisson's ratio. The hexagonal periodic distribution of the pores makes the e ffective behavior isotropic. Both experimental tests and numerical simulations have been performed to determine the e ffective properties of the porous solid. A parametric study on the e ffect of the geometrical microstructural parameters is also presented. This auxetic structure is easy to fabricate and can be very useful in several engineering applications.