The present paper proposes a new technique for the definition of the shape design variables in 2D and 3D optimisation problems. It can be applied to the discrete model of the analysed structure or to the original geometry without any previous knowledge of the analytical expression of the CAD defining surfaces. The proposed technique allows the surface continuity to be preserved during the geometry modification process to be defined a priori. This capability allows for the definition of shape variables suitable for every kind of discipline involved in the optimisation process (structural analysis, fluid-dynamic analysis, crash analysis, aerodynamic analysis, etc.).
Abstract
The present paper proposes a new technique for the definition of the shape design variables in 2D and 3D optimisation problems. It can be applied to the discrete model of the analysed structure or to the original [...]
An adaptive strategy for nonlinear finite-element analysis, based on the combination of error estimation and h-remeshing, is presented. Its two main ingredients are a residual-type error estimator and an unstructured quadrilateral mesh generator. The error estimator is based on simple local computations over the elements and the so-called patches. In contrast to other residual estimators, no flux splitting is required. The adaptive strategy is illustrated by means of a complex nonlinear problem: the failure analysis of a single-edge notched beam. The quasi-brittle response of concrete is modelled by means of a nonlocal damage model.
Abstract
An adaptive strategy for nonlinear finite-element analysis, based on the combination of error estimation and h-remeshing, is presented. Its two main [...]
The development of urban mobility implies the construction of tunnels, often
interacting with valuable historical structures. It is thus necessary to develop rational and
reliable procedures to estimate the potential excavation-induced damage, dealing with complex
soil-structure interaction problems. Classical approaches are often characterised by relatively
simple schematisations for either one or both components of the problem, as, for example,
springs for the soil or equivalent plates for the structure. Such simplified assumptions prove to
be appropriate for simple soil-foundation cases, while show several limitations when tackling
more complex problems, as those involving the excavation in the vicinity or beneath historical
masonry structure. In such cases, the need for reliable prediction of the potential damage on
surface structures induced by construction activities justifies the adoption of advanced
numerical approaches. These need to be based on realistic constitutive assumptions for both
soils and masonry elements and require the definition of the three-dimensional geometry as
well as an accurate modelling schematisation of the excavation process. In this paper a 3D
Finite Element approach is proposed to model in detail the excavation of twin tunnels,
accounting for the strongly non-linear soil behaviour, interacting with monumental masonry
structures, carefully modelling their geometry and non-linear anisotropic mechanical
behaviour. The work focuses on a specific case-study related to the ongoing construction of the
line C of Rome underground.
Abstract
The development of urban mobility implies the construction of tunnels, often
interacting with valuable historical structures. It is thus necessary to develop rational and
reliable procedures to estimate the potential excavation-induced damage, dealing with [...]