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Dr. Giulio Alfano, Cohesive-zone models for the numerical simulation of crack growth on interfaces accounting for friction and rate-dependence

Date: Tue 29 Oct 2013, 14:30 - 15:30

Location: Nanoforce Seminar Room

Dr. Giulio Alfano, Senior Lecturer in Computational Mechanics, Brunel University

SEMS Simulation & Modelling Seminar
Cohesive-zone models for the numerical simulation of crack growth on interfaces accounting for friction and rate-dependence

In many engineering applications structural failure involves initiation and propagation of cracks along interfaces. Examples include cracks in dams, mortar-joint failure in brick masonry, delamination or fibre-matrix debonding in composites, debonding of adhesive joints, frictional slipping of steel bars in concrete, among many others. Despite the different materials and scales involved, these problems share common features and, therefore, they can be treated with similar approaches. In particular, for many of them the failure process involves a region which is thin enough to be effectively lumped on a zero-thickness interface surface for modelling purposes. Furthermore a finite process zone can be identified around the propagating crack, where cohesive stresses on the interface gradually decrease from a peak value to zero. In the early sixties these observations led to the development of cohesive-zone models (CZMs), which introduce nonlinear relations between stresses and displacement discontinuities on interfaces. The link between this approach and fracture mechanics lies in the energy dissipated per unit of surface, which for CZMs is typically made equal to the fracture energy.
In this talk, after a brief review of the topic the attention will be focused on a number of CZMs recently developed by the speaker and some of his co-workers. Two of these models simulate the interaction between interface damage and friction and applications will be presented on the simulation of fibre-matrix debonding in composites and bond-slip of bars in reinforced concrete. Other models simulate the possible interaction between damage and rate-dependent dissipative mechanisms on the interface and applications will be presented for the crack growth along rubber interfaces and for problems where the challenge is to numerically simulate stick-skip crack propagation.

http://www.brunel.ac.uk/sed/mecheng/people/drgiulioalfan…

WHO COULD BE INTERESTED: Anyone interested in modelling or experiments on fracture of composites and delamination problems, and want to know more about rate-dependent cohesive zone models and interface characterization. Students (including undergraduate) are welcome to attend

Updated by: Jonathon Hills