| Computational mechanics, finite elements and fracture
Giulio
Ventura's research is focused on computational mechanics, particularly
on finite elements and their application to nonlinear constitutive models,
discontinuities and fracture.
Topics of interest include modelling of reinforced concrete members by fracture mechanics, stone and masonry structures, development of new computational models and algorithms.
Since
2000 he has been working with Prof. Ted Belytschko (Northwestern University,
Evanston, IL, USA). This research activity started on Meshfree methods
and then continued on the development of several aspects of the eXtended
Finite Element Method (XFEM), such as Level Set representation of fractures
and discontinuities. More recently the research activity has been focused
on dislocations, with the aim of reducing the high computational cost
required by classical literature approaches.
Moreover,
he works with Prof. Alberto Carpinteri on the development of the Bridged
Crack Model for the analysis of concrete beams under bending and shear.
The goal of the research project is to develop a unified model for the
three main reinforced concrete beams collapse modes: steel yielding,
shear and concrete crushing, able of predicting failure mode transitions
as the scale, reinforcement, slenderness and material properties are
varied. The collapse load and mode are determined through a few nondimensional
parameters. The research framework is placed in the extension of the
Bridged Crack Model (originally proposed by Carpinteri) to shear and
concrete crushing as well as to the study of the relevant failure mode
transitions.
More
recently, this semianalytical model is being paired with a new numerical
approach based on the extended finite element method (XFEM) and including
a more evolute criterion for the crushing failure named by Carpinteri
Overlapping Crack Model, based on a fictitious cohesive crack in compression.
This project is currently under development.
The
theoretical and numerical research on reinforced concrete beams has
been supported by experimental tests, including steel fiber reinforced
concrete. A second experimental program is being started to investigate
the failure mode transitions with varying scale, reinforcement and slenderness.
The
experimental tests have been carried out with the support of Buzzi-Unicem.
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