181 research outputs found
Interactive reflexive musical systems for music education
No full textIl Symposio è stato organizzato all'interno della 9th International Conference on Music Perception and Cognition che ha avuto luogo a Bologna, Università di Bologna, dal 22 al 26 agosto 2006.Il Symposium era dedicato agli aspetti pedagogici dei sistemi musicali interattivi "riflessivi". Vi hanno preso parte: F.Pachet (SONY, Computer Science Laboratory, Paris) S. Young (Exeter University), D. Hargreaves (Roehampton University), G. Folkestad (Malmo Academy of Music), A. Camurri (Università di Genova), A. Addessi (università di Bologna)
Shell-3D multiscale modeling of masonry vaults based on the TFA procedure
No full textThis paper investigates the response of masonry-curved structural elements with periodic texture by adopting the modeling strategy recently developed by the authors (Addessi et al., 2021). Relying on a multiscale approach, the Mindlin−Reissner shell formulation is assumed at the macroscale and the classical 3D Cauchy continuum is adopted at the microscopic level to model the representative masonry unit cell (UC). The procedure for linking the two scales involves a transformation field analysis (TFA) homogenization technique based on piece-wise uniform distributions of the damaging and frictional mechanisms over the mortar joints. Advantages and limitations of this assumption are explored considering a masonry vault with stack bond texture, that is, assuming a UC made of one linear elastic brick surrounded by one head and one bed joint modeled as nonlinear interfaces. The more appropriate interface discretizations required by the TFA model are identified in relation to the activated deformation modes and the resulting computational effort is evaluated. Hence, an enriched TFA procedure is proposed to limit the computational cost and the time of analysis associated with the denser joint partitions, while still preserving the model accuracy. Finally, the efficiency of the model is investigated at the structural level by analyzing the response of the vault to differential settlements. The comparison between results obtained with the proposed multiscale formulation and those recovered by detailed micromechanical analysis confirms that the TFA approach is a very reliable and effective method for resorting to a fast reduced-order model also for curved geometries
A 2D finite element based on an enriched kinematics for nonlinear analysis of masonry walls
No full textThis paper presents a kinematic enriched finite element model for nonlinear analysis of brick masonry walls loaded in their plane. The finite element accounts for the transverse deformation of the wall and permits to reproduce mortar-brick interaction in wall thickness direction. Non-local constitutive relationships are considered both for mortar and bricks, adopting a damage-friction law for the mortar and an isotropic damage model for the bricks, both accounting for tensile failure mechanisms. A numerical procedure is developed for evaluation of damage and friction in mortar and brick materials. Numerical applications are presented, comparing results obtained by the proposed finite element with experimental outcomes
Ensinando a improvisar com o MIROR-Impro
No full textEste capítulo irá descrever algumas atividades didáticas que podem ser realizadas com MIROR-Impro (Pachet et al., 2011), um dos três softwares implementados durante o Projeto MIROR: jogos musicais, explorações sonoras e performances improvisadas
Nonlinear analysis of masonry panels using a kinematic enriched plane state formulation
No full textThis paper deals with the nonlinear analysis of masonry walls loaded in their plane. The masonry is regarded as a composite material made of bricks joined by mortar. To correctly reproduce the mortar-brick interaction in the direction of the thickness of the wall, an enriched kinematic model is proposed, so that the model is able, in a feasible form, to account for the out-of-plane strains due to the in-plane loading acting on the wall. Nonlocal nonlinear constitutive laws are considered both for the mortar and the bricks. In particular, a damage-friction law is considered for the mortar, while a damage model with two alternative yield functions is proposed for the bricks, both based on a tensile failure mechanism. A 2D finite element (FE) accounting for the three-dimensional kinematic effect is developed. This is implemented in a numerical procedure based on the backward Euler step-by-step time integration of the constitutive evolution laws and on the predictor-corrector algorithm for the solution of the nonlinear problem. Five applications are presented to highlight the effectiveness of the proposed nonlinear model and the implemented FE procedure. The first aims to show the model's ability to reproduce the failure of the masonry for transversal damage; the others deal with comparisons with classical small scale and structural scale experimental tests
A multi-scale enriched model for the analysis of masonry panels
No full textA multi-scale model for the structural analysis of the in-plane response of masonry panels, characterized by periodic arrangement of bricks and mortar, is presented. The model is based on the use of two scales: at the macroscopic level the Cosserat micropolar continuum is adopted, while at the microscopic scale the classical Cauchy medium is employed. A nonlinear constitutive law is introduced at the microscopic level, which includes damage, friction, crushing and unilateral contact effects for the mortar joints. The nonlinear homogenization is performed employing the Transformation Field Analysis (TFA) technique, properly extended to the macroscopic Cosserat continuum. A numerical procedure is developed and implemented in a Finite Element (FE) code in order to analyze some interesting structural problems. In particular, four numerical applications are presented: the first one analyzes the response of the masonry Representative Volume Element (RVE) subjected to a cyclic loading history; in the other three applications, a comparison between the numerically evaluated response and the micromechanical or experimental one is performed for some masonry panels. (c) 2012 Elsevier Ltd. All rights reserved
A kinematic enriched plane state formulation for the analysis of masonry panels
No full textA kinematic enriched formulation for the analysis of the in-plane behavior of regular masonry walls is proposed in order to overcome the limits of the typical plane stress and plane strain assumptions. The boundary value problem for the masonry RVE subjected to periodic boundary conditions is formulated for the enriched plane state. In particular, the displacement field is represented assuming that the components can be written using the separation of variables; in fact, they are obtained as product of in-plane and transversal functions. The in-plane displacement components are expressed as the superposition of a known field, depending on the macroscopic deformations applied to the RVE, and a periodic perturbation described as an even function of the transversal coordinate. The bending effects is avoided representing the out-of-plane displacement field in terms of odd functions of the transversal coordinate. A 2D finite element is formulated and used for performing micro-mechanical and homogenization analyses. Numerical results are compared with analytical ones in order to assess the accuracy of the numerical procedure. Results obtained by employing the proposed model are compared with the ones evaluated on the basis of the classical plane stress, plane strain, generalized plane strain assumptions and with the three-dimensional solution. Finally, the proposed kinematically enriched model is used to derive the elastic domain of the masonry material. (C) 2013 Elsevier Masson SAS. All rights reserved
Enriched plane state formulation for nonlinear homogenization of in-plane masonry wall
No full textThe present study deals with the determination of the nonlinear response of the masonry regarded as a regular, i.e. periodic, composite material made of bricks and mortar. A homogenization procedure is applied deriving the masonry overall mechanical response on the basis of the study of a single unit cell. An enriched plane state kinematic model including the effect of the transversal strains of the masonry is presented. This is a simplified form of the full three-dimensional approach. Different cohesive constitutive models are introduced for the brick and mortar; in particular, the frictional effect, playing an important role in the masonry response, is accounted for in the mortar joints. Two main issues are addressed: (a) different structural models are considered at macro- and micro-scale: the macro-model is formulated in the two-dimensional plane state context, while the enriched plane state kinematic approach is adopted at the microlevel; (b) a nonlocal integral strain technique, able to overcome the classical localization drawbacks due to the softening response of the masonry constituents, is developed for the case of periodic media. Numerical applications are presented to assess the effectiveness of the proposed modeling approach
A study about children's musical improvisation in an interactive reflexive musical context
No full textAbstract: This paper introduces the study of the process of musical improvisation of two children in interactive/reflexive musical context. The data were collected in Italy within the EC-ICT MIROR Project (Music Interaction Relaying On Reflexion /Commission ́s Seventh Framework Programme - European Community) polo at the University of Bologna. Several improvisational sessions were carried out in a primary school, with two 8 years old children who played together a keyboard augmented with an interactive reflexive musical system, based on the Continuator system (Pachet 2003, Addessi and Pachet 2005) and improved in the MIROR Platform. In this study, children played several games with and without the system that organized responses to the various children musical interventions (melodic, harmonic, rhythmic) by imitating the children's musical style. The case study was based on Csikszentmihalyi's Flow theory (Csikszentmihalyi 2003, 1999, 1996, 1992, 1990). According to this author, the "flow state" is generated from affective components of motivation that drive the execution of an activity, favoring the persistence of the person in their activity through components such as emotion, goals and cognitive operations (concentration). The analysis was based on the observation of video recordings collected during the sessions (in 2011). In the micro-analysis we considered the elements of the flow experience and the musical elements of the children experience, based on some aspects such as: the exploration ways of playing, exploration of the keyboard; music improvisation (repetition, variation, musical ideas, elaboration, musical form, texture, musical gesture); listening conducts; and elements of social interaction between children. The results analysed so far indicate that the children engaging in interactive/reflective environments, and in the context of collective practice in pairs), can generate a flow state, promoting intrinsic motivation and creative musical practice. This results therefore, have revealed many implications to the studies about motivation and music education with a interactive reflexive musical system
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