1,537 research outputs found
Computational multiscale modelling of FSI in arterial vessels: tissue mechanics and WSS analysis
No full textScenario of the organic food market in Europe
No full textScenario analysis is a qualitative tool for strategic policy analysis that enables researchers and policymakers
to support decision making, and a systemic analysis of the main determinants of a business or sector.
In this study, a scenario analysis is developed regarding the future development of the market of organic
food products in Europe. The scenario follows a participatory approach, exploiting potential interactions
among the relevant driving forces, as selected by experts. Network analysis is used to identify the roles of
driving forces in the different scenarios, and the results are discussed in comparison with the main findings
from existing scenarios on the future development of the organic sector
Design and characterization of a magnetorheological elastomer linear actuator for low-frequency applications
No full textThis work presents the design and characterization of an innovative linear actuator for low-frequency applications based on a magnetorheological elastomer (MRE) disc coupled to an electromagnet. MREs are a class of smart materials in which micrometre-sized magnetic particles are suspended in an elastomeric matrix. Most research works study their applicability as semi-active systems, but less effort is devoted to their applicability in actuators, but their applicability in the field is possible and could lead to potential advantages in terms of integration of the system especially for microactuation. The proposed MRE device relies on a commercial electromagnet which provides linear motion of the MRE element. The stiffness of the elastomeric matrix is exploited to bring the system back to its initial position, so that the system is monostable. The magneto-mechanical behaviour is modelled both analytically and by means of finite element magneto-mechanical simulations, and the models are compared with the experimental tests. Two membrane thicknesses and two different gaps between the membrane and the electromagnetic actuator were manufactured and characterized. The results show the effect of the design variable on the actuator behaviour and confirm that the analytical model provided can predict the actuator's behaviour with a good approximation in all the configuration analysed. The dynamic range of the proposed system, regardless of the configuration selected, demonstrates that the magnetic contribution is always able to increase the actuator force by 50% and that the provided model can easily be used as a reliable design tool for this kind of smart system
Un approccio variazionale alla modellazione della trave a parete sottile in elasticità anisotropa (in Italian) - A variational approach for modelling thin-walled beam in anisotropic elasticity
No full textIn questo lavoro si deduce in modo razionale una teoria del tipo Vlasov/Eulero-Bernoulli in elasticità lineare anisotropa per la trave a sezione sottile attraverso un approccio variazionale basato sul metodo dei vincoli interni duali. Partendo dal problema dell’equilibrio elastico tridimensionale, formulato mediante il funzionale di Hu Washizu, si impongono vincoli coerenti e duali sia sul campo di deformazione che su quello di tensione costitutiva, attraverso un’applicazione non standard della teoria dei moltiplicatori di Lagrange. Il metodo consente di introdurre in modo coerente il legame elastico ridotto e di portare in conto effetti non convenzionali dipendenti dallo spessore della trave e dalla curvatura della linea media della sua sezione retta
The Dalkon Shield Claimants Trust: Paradigm Lost (Or Found)?
No full textIn this Essay, Dean Vairo discusses the policies and procedures governing the Dalkon Shield Claimants Trust After raising questions about the Trust\u27s experience in a theoretical and jurisprudential context Dean Vairo describes the historical development of the Trust and provides a preliminary aosesment of the Trust\u27s performance. Dean Vairo addresses various criticisms of the Trust and calls for a reasoned analysis of the Trust\u27s policies in light of the theoretical questions raised in this Essay to determine whether the Trust should be considered as a model for resolving other mass tort cases
A closed-form refined model of the cables' nonlinear response in cable-stayed structures
No full textIn this paper a refined second-order model for the analysis of the elastic response of cables in cable-stayed structures is proposed. Starting from the exact catenary theory, the Dischinger-Ernst formulation is rationally deduced and, performing a second order approximation both with respect to the stress variation and the apparent chord-strain one, a refined explicit equivalent constitutive relationship for elastic stays is obtained. Moreover, the geometrical non-linearities induced on the cable by the deformation of the stay-supported structure are taken into account through a second order displacement approach. Accordingly, a closed-form formulation describing nonlinear cable-structure interaction effects is obtained which, unlike the classical secant model, does not need iterative procedures, opening the possibility to develop refined analytical solutions for cable structures. Several numerical examples and benchmarks on different stay configurations are presented, showing the effectiveness and the accuracy of the proposed model
A numerical model for wind loads simulation on long-span bridges
No full textA numerical model of the air flow problem around the girder of a long-span bridge is presented. The model is based on a finite
volume formulation and it is able to simulate steady and non-steady wind loading conditions on the structure under the
simplifying assumption, which is plausible for bridges with long spans, of a two-dimensional-like approaching flow. For a given bridge deck cross-section the proposed model allows the numerical evaluation of the flutter derivatives, which is useful to
characterize in an analytical way the stability conditions of the overall wind-induced bridge response. In order to obtain
satisfactory accuracy and stability of the numerical solution, a two-equation k-epsilon RNG turbulence model and special boundary conditions are employed. The accuracy and applicability of the model to wind engineering problems are successfully
assessed by computing the aerodynamic behaviour of some simple cross-section shapes. Numerical results are also obtained for typical long-span bridge cross-sections and the comparison with the available wind tunnel measurements shows a good agreement
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