1,721,170 research outputs found
Un approccio perturbativo misto per valutare l'ordine di meccanismi infinitesimi in strutture reticolari spaziali
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A mixed solution strategy for the nonlinear analysis of brick masonry walls
No full textThe paper presents a discrete mechanical model for masonry walls based on a Lagrangean description where each brick is described as a rigid body and each mortar joint as an interface element. Constitutive assumptions, characterized by elasticity, damage and friction, are associated to the joints only. A numerical solution strategy, based on a mixed path-following approach in terms of stresses, strains, displacements, damage and load parameters, is proposed for avoiding convergence problems related to the joint softening behaviour. Some numerical results are also presented showing the robustness and effectiveness of this proposal
Growth and Remodeling of Intracranial Saccular Aneurysms
No full textWe present a mechanical model--a growing spherical shell--suitable for predicting the evolution of a Saccular Cerebral Artery Aneurysms (SCAA). It relies basically on the Kroner-Lee decomposition, used to describe the interplay between the current and the relaxed configuration of body elements.
Rupture or stabilization of a SCAA are the end effect of a number of biological mechanisms, still
poorly understood.
We propose a model based on three competing remodeling mechanisms-- one passive and two active.
Despite drastic simplifying assumptions, preliminary numerical experiments attest to the potential of our model to account for nontrivial evolutions ensuing from accidental perturbations of a homeostatic state
Living shell-like structures
No full textA decade ago, the so-called Kr\"{o}ner-Lee decomposition---primarily introduced to discern between elastic and (visco-)plastic strains---was given a broader scope and a deeper interpretation than the original ones, as describing the interplay between the actual and the relaxed configuration of each body element. The main intended application was to growth mechanics of soft living tissues. In 2002, a novel (tensorial) balance law governing the time evolution of the relaxed configuration was devised, and endowed with a proper constitutive theory, thus establishing the foundations of a dynamical theory of material remodelling. Material remodelling does not describe explicitly the chemistry or whatever else is acting behind the changes in material structure. However, it does account explicitly for the power expended by the biochemical control system, which is of the essence for modelling the mechanics of living tissue. Material remodelling discriminates active from passive remodelling, while treating both on the same footing. Thus it provides mechanistic models of living materials without conceiving of them as inert materials engineered with magic constitutive recipes. The present study develops a toy model of saccular aneurysms, focussing on the two-way coupling between growth and stress
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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