No description available.

Syftet med uppsatsen ”Medmänsklighet och Gudomligt Beskydd – en receptionsestetisk studie av Maria (Återkomsten) och Skyddsmantelmadonnan” är att ur ett receptionsestetiskt perspektiv närma sig skulpturerna Maria (Återkomsten) av Anders Widoff och Skyddsmantelmadonnan av Lena Lervik. Skulpturerna finns i och i anslutning till Uppsala respektive Lunds domkyrka. Genom receptionsestetikens metod där man tittar på ett konstverks interna faktorer som rör verkets inre organisation samt externa faktorer såsom platsen där konstverken är placerade, andra konstverk som relaterar till verket, en myt eller berättelse som är viktig för förståelsen av konstverken etcetera, rör sig uppsatsen fram mot en diskussion kring vem som är verkens implicite betraktare, dvs. ideala betraktare. Uppsatsen ämnar även diskutera hur jungfru Maria gestaltas i de berörda skulpturerna: vilken bild konstverken ger av Maria. Metoden för att diskutera vem som är verkens implicite betraktare och hur betraktaren aktiverar konstverken i relation till platserna är besök på de platser där konstverken finns för att i denna miljö möta verken och läsning av relevant litteratur. Slutsatsen är att skulpturerna är medvetet placerade i anslutning till kyrkorum och att platserna utgör en viktig dialog med konstverken. Skulpturerna ger väldigt olika bilder av jungfru Maria: Maria (Återkomsten) gestaltar Marias mänskliga sida och Skyddsmantelmadonnan är mer av en gudinnegestalt, en Moder Jord och urmoder som beskyddar mänskligheten. Verkens implicite betraktare är någon som vistas på platsen och möter verken med en öppenhet; verken har båda en öppenhet i framförallt ansiktsuttryck som öppnar för olika tolkningar. Den implicite betraktaren – i meningen den ideala betraktaren – är en människa med en öppenhet för en andlig dimension men är inte nödvändigtvis troende. Betraktaren behöver inte ha kunskap om vem jungfru Maria är, verkens tillkomsthistoria, verk som kan tänkas relatera till skulpturerna etcetera men det kan fördjupa upplevelsen. / The purpose of the essay "Humanity and Heavenly Protection – a Study of Mary (The Return) and the Protective Cloak Madonna Based on the Theory and Method of Reception Aesthetics" is to approach the sculptures Mary (The Return) by the artist Anders Widoff, and The Protective Cloak Madonna by the artist Lena Lervik. The sculptures are placed inside Uppsala Cathedral and outside Lund Cathedral respectively, and the study is based on the theory and method of reception aesthetics, where one looks at an artwork's internal factors that relate to the work's internal organization, as well as external factors, such as the situation of the work, relating works, or myths or stories that are important to understanding the work. Through this theory, a discussion about the implicit (ideal) beholder of the works takes place. Furthermore, the essay aspires to discuss the representation of Virgin Mary in the sculptures: what images of her the artworks present. The discussion of the implicit beholder, as well as the question of how locations affect the viewer’s activation of the works, was based on visits to the sites, as well as the study of literature on the artworks and the theory used.  The conclusion is that the sculptures are intentionally placed in the vicinity of cathedrals, and that the sites constitute an important dialogue with the artworks. The sculptures present very different images of the Virgin Mary: Mary (The Return) embodies Mary's human side, while the Protective Cloak Madonna is more of a Goddess figure, a Mother Earth and ancestor who protects humanity. The implicit beholder of the works is someone who visits the sites and encounters the works with an open mind; the sculptures have openness to them, especially in the facial expressions that invite different interpretations. The implicit (ideal) beholder is a person with an open mind to a spiritual dimension, but is not necessarily a Christian. The viewer does not need to know who Virgin Mary is, nor the history of the artworks or relating works, even though such knowledge might deepen the experience.

The first part of this Thesis deals with the analysis of piecewise-smooth mechanical systems and the definition of special stability criteria in presence of non-conservative follower forces. To illustrate the peculiar stability properties of this kind of dynamical system, a reference 2 d.o.f. structure has been considered, composed of a rigid bar, with one and constrained to slide, without friction, along a curved profile, whereas the other and is subject to a follower force. In particular, the curved constraint is assumed to be composed of two circular profiles, with different and opposite curvatures, defining two separated subsystems. Due to this jump in the curvature, located at the junction point between the curved profiles, the entire mechanical structure can be modelled by discontinuous equations of motion, the differential equations valid in each subsystem can be combined, leading to the definition of a piecewise-smooth dynamical system. When a follower force acts on the structure, an unexpected and counterintuitive behaviour may occur: although the two subsystems are stable when analysed separately, the composed structure is unstable and exhibits flutter-like exponentially-growing oscillations. This special form of instability, previously known only from a mathematical point of view, has been analysed in depth from an engineering perspective, thus finding a mechanical interpretation based on the concept of non-conservative follower load. Moreover, the goal of this work is also the definition of some stability criteria that may help the design of these mechanical piecewise-smooth systems, since classical theorems cannot be used for the investigation of equilibrium configurations located at the discontinuity. In the literature, this unusual behaviour has been explained, from a mathematical perspective, through the existence of a discontinuous invariant cone in the phase space. For this reason, starting from the mechanical system described above, the existence of invariant cones in 2 d.o.f. mechanical systems is investigated through Poincaré maps. A complete theoretical analysis on piecewise-smooth dynamical systems is presented and special mathematical properties have been discovered, valid for generic 2~d.o.f. piecewise-smooth mechanical systems, which are useful for the characterisation of the stability of the equilibrium configurations. Numerical tools are implemented for the analysis of a 2~d.o.f. piecewise-smooth mechanical system, valid for piecewise-linear cases and extendible to the nonlinear ones. A numerical code has been developed, with the aim of predicting the stability of a piecewise-linear dynamical system a priori, varying the mechanical parameters. Moreover, “design maps” are produced for a given subset of the parameters space, so that a system with a desired stable or unstable behaviour can easily be designed. The aforementioned results can find applications in soft actuation or energy harvesting. In particular, in systems devoted to exploiting the flutter-like instability, the range of design parameters can be extended by using piecewise-smooth instead of smooth structures, since unstable flutter-like behaviour is possible also when each subsystem is actually stable. The second part of this Thesis deals with the numerical analysis of an elastic cloak for transient flexural waves in Kirchhoff-Love plates and the design of special metamaterials for this goal. In the literature, relevant applications of transformation elastodynamics have revealed that flexural waves in thin elastic plates can be diverted and channelled, with the aim of shielding a given region of the ambient space. However, the theoretical transformations which define the elastic properties of this “invisibility cloak” lead to the presence of a strong compressive prestress, which may be unfeasible for real applications. Moreover, this theoretical cloak must present, at the same time, high bending stiffness and a null twisting rigidity. In this Thesis, an orthotropic meta-structural plate is proposed as an approximated elastic cloak and the presence of the prestress has been neglected in order to be closer to a realistic design. With the aim of estimating the performance of this approximated cloak, a Finite Element code is implemented, based on a sub-parametric technique. The tool allows the investigation of the sensitivity of specific stiffness parameters that may be difficult to match in a real cloak design. Moreover, the Finite Element code is extended to investigate a meta-plate interacting with a Winkler foundation, to analyse how the substrate modulus transforms in the cloak region. This second topic of the Thesis may find applications in the realization of approximated invisibility cloaks, which can be employed to reduce the destructive effects of earthquakes on civil structures or to shield mechanical components from unwanted vibrations.