1,721,124 research outputs found
An analytical model to predict the ripp-off failure load of R/C beams externally strengthened with FRP
No full textIn the present paper, the authors consider the crack pattern developed by 4 FRP strengthened R/C beams brought to failure for flexure under uniform load conditions. All of the observed failure modes are due to concrete cover rip-off; the plate strain distribution and beam deflection for increasing load values are fully documented. Based on the available experimental results, a comparative study of different models for crack spacing evaluation is presented, accounting the influence of the FRP strengthening for flexure on crack development and stabilization. The proposed models are mechanically sound and derived by previous formulations developed for conventional R/C beams. Among the considered models, the authors select a simple and efficient expression suitable to be proposed as a design tool.
Finally, thanks to the selected crack spacing model, the authors work out a simple model that can predict the rip-off failure load of R/C beams externally strengthened with FRP with an acceptable accuracy. The model is calibrated making use of the 4 available experimental beams and is validated accounting for 23 experimental beams derived from the literature. All of the considered experimental beams present concrete cover rip-off failure mode, despite the very different geometrical and mechanical characteristics
Disabilità e amicizia. Rappresentazioni grafiche del rapporto amicale con un compagno disabile.
No full textObiettivo: attraverso lo strumento del disegno, cogliere eventuali differenze nelle rappresentazioni grafiche che giovani adulti danno di una ipotetica loro relazione con un coetaneo gay.
Risultati: la parola ricorrente è sta diversità; non si è mai riscontrato un cenno alla coppia ed all'amore. Nel disegno, le figure omosessuali appaiono con maggiori cancellature, indice di ansia e disagio
Il nuovo concorso a cattedra. Psicologia e scienze dell'educazione nella scuola secondaria.
No full text
I fondamenti epistemologici delle scienze dell'educazione
No full textIl contributo muove da una riflessione sui fondamenti epistemologici delle scienze dell'educazione
Il nuovo Concorso a Cattedra – Psicologia e Scienze dell’Educazione - Manuale Teorico (Nuova edizione)
No full text
Hygro-thermal bending behavior of porous FG nano-beams via local/nonlocal strain and stress gradient theories of elasticity
Full text linkThis work studies the bending response of porous functionally graded Bernoulli-Euler nano-beams under hygro-thermo-mechanical loadings. The governing equations of the elastostatic problems associated with both local/nonlocal stress- and strain-driven gradient models of elasticity were derived by using the virtual work principle. A Wolfram language code in Mathematica was then written to carry out a numerical investigation for different boundary conditions including cantilever and simply-simply conditions. The effects of the different parameters, such as porosity volume fraction, gradient index, nonlocal parameter, gradient length parameter and mixture parameter are presented. It is shown how the proposed approach is able to capture the structural behavior of porous functionally graded Bernoulli–Euler nano-beams under a hygro-thermal environment
A critical review of numerical methods for the simulation of pultruded fiber-reinforced structural elements
No full textPultruded Fiber-Reinforced Polymers (FRP) are innovative structural elements that are experiencing a steady increase in use for different structural applications. Due to their appealing properties that set them apart from traditional construction materials, such as magnetic transparency and excellent strength-to-weight ratio, numerous experimental and numerical studies have been performed in the last decades to assess their performance as structural components. The description of the micro- and macro-scale mechanical features of FRP elements requires multiple levels of information to be accurately characterized to predict their strength, and as a result, researchers have developed computational models with varying levels of complexity to parametrize their response and investigate design parameters through numerical simulations. This paper presents a critical review of the current state-of-the-art in numerical modeling of structural fiber-reinforced polymeric elements for the prediction of their mechanical behavior under serviceability and failure limit state conditions, with particular attention devoted to pultruded Glass Fiber Reinforced Polymers (GFRP), and their use as load-bearing structural elements. The most commonly adopted numerical methods for the solution of this set of problems range from classical Finite Element Method (FEM) approaches to eXtended Finite Element Method (XFEM), Virtual Crack Closure Technique (VCCT), Cohesive Zone Modeling (CZM), Multiscale Reduced Order Modeling (ROM), as well as Random Lattice Modeling (RLM) techniques recently developed by the co-authors. Each one of these methods has its own distinctive features and brings specific challenges and capabilities that will be presented and discussed in detail in the manuscript. This paper, therefore, aims at illustrating the reliability of existing numerical models for the simulation of FRP structural elements and draw conclusions and recommendations for future research, discussing 160 references from the available literature
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