Search results for "Transports"
showing 10 items of 485 documents
Onset of Convection in an Inclined Anisotropic Porous Layer with Internal Heat Generation
2019
The onset of convection in an inclined porous layer which is heated internally by a uniform distribution of heat sources is considered. We investigate the combined effects of inclination, anisotropy and internal heat generation on the linear instability of the basic parallel flow. When the Rayleigh number is sufficiently large, instability occurs and a convective motion is set up. It turns out that the preferred motion at convection onset depends quite strongly on the anisotropy ratio, &xi
Integration of finite displacement interface element in reference and current configurations
2017
In the present paper the non-linear behaviour of a solid body with embedded cohesive interfaces is examined in a finite displacements context. The principal target is the formulation of a two dimensional interface finite element which is referred to a local reference frame, defined by normal and tangential unit vectors to the interface middle surface. All the geometric operators, such as the interface elongation and the reference frame, are computed as function of the actual nodal displacements. The constitutive cohesive law is defined in terms of Helmholtz free energy for unit undeformed interface surface and, in order to obtain the same nodal force vector and stiffness matrix by the two i…
Effectiveness of BFRP confinement on the compressive behaviour of clay brick masonry cylinders
2020
Abstract This paper presents the results of an experimental and analytical study on the compressive behaviour of small clay brick masonry cylinders reinforced with a basalt fibre reinforced polymer (BFRP) composite. Fourteen cylinders, manufactured using two assembling schemes and confined using either one or two layers of BFRP grids, were tested under monotonic compression loading. Traditional strain measuring systems were integrated with digital image correlation (DIC) technique. The BFRP confined masonry cylinders showed a ductile behaviour characterised by a softening branch of the stress–strain curve. The experimental strains, strength, and full stress–strain curves were modelled using…
Koplietošanas transporta optimizācijas lēmumu vizualizēšana
2022
Bakalaura darbā “Koplietošanas transporta optimizācijas lēmumu vizualizēšana” tiek aplūkotas problēmas, ar ko saskaras koplietošanas transporta uzņēmumi, aplūkoti un analizēti pieejamie dati, par kuriem ir iespējama to vizualizācija lietotājam saprotamā un analīzei ērtā veidā. Tāpat tiek aplūkoti un izanalizēti jau pieejamie vizualizācijas risinājumi, kas saskaras ar līdzīgu problēmu risināšanu – pārvietošanās datu attēlošanu kartē. Balstoties uz analīzē iegūtajiem datiem, kur tika vērtētas risinājumu īpašības, tiek izveidots prototips, kas tiek izmantots koplietošanas transporta optimizācijas vizualizēšanā.
Influence of design mistakes and material degradation on the collapse of a long-span RC roof in South Italy
2020
Abstract In 2004, during ordinary maintenance work, consisting in the waterproofing of a building located in the South of Italy, the long-span (14.50 m) in situ cast reinforced concrete (RC) roof partially collapsed. The building, constructed in 1950, was in service as a cinema up to 1967 and utilized as a school up to 1985. Finally, it was a hotel up to 2000. In 2004, when the building was not in service and underwent maintenance work, it partially collapsed under the dead load. After the collapse, which involved a large portion of the roof, several beams and two columns, the Court nominated a first Official Technical Consultant in order to investigate on the causes of failure and related …
A hierarchy of simplified constitutive models within isotropic strain gradient elasticity
2017
Abstract Simplified isotropic models of strain gradient elasticity are presented, based on the mutual relationship between the inherent (dual) gradient directions (i.e. the gradient direction of any strain gradient source and the lever arm direction of the promoted double stress). A class of gradient-symmetric materials featured by gradient directions obeying a reciprocity relation and by 4 independent h.o. (higher order) coefficients is envisioned, along with the sub-classes of hemi-collinear materials (3 h.o. coefficients, gradient directions in part coincident), collinear materials (2 h.o. coefficients, equal gradient directions) and micro-affine materials (1 h.o. coefficient, behavioral…
Speckle Interferometry Analysis of Full-bending Behavior of GFRP Pultruded Material
2016
Abstract The use of Glass Fiber Reinforced Polymer materials (GFRP) has increased in the last years even among civil structural engineering due to their high specific strength, lightweight and excellent corrosion resistance. With application of the pultrusion method, the manufacture of large-scale profiles with various cross-section forms became potentially possible with relatively low costs. Usually two different technological approaches are available to realize the element: in the first one a mat-roving-mat sequence is adopted, in the second one only roving is present. Continuous filament mat (CFM, fibers distributed randomly in all directions) is often used to build up laminate thickness…
Targeted steel frames by means of innovative moment resisting connections
2021
Abstract The present paper proposes the use of stepped cross section devices on steel frames aiming at reproducing a pre-established target push-over curve. To this aim a Limited Resistance Plastic Device (LRPD) to be inserted along selected structural members is proposed. The following two main specific features for LRPD are required: any elastic flexural stiffness variation of the original selected member must be avoided; an ultimate plastic bending moment value equal to an assigned percentage of the original limit resistance value must be ensured. Steel frames equipped with LRPD are modeled by means of an extension of a recently proposed Fibre Smart Displacement Based (FSDB) beam element…
Stochastic response determination of structural systems modeled via dependent coordinates: a frequency domain treatment based on generalized modal an…
2019
Generalized independent coordinates are typically utilized within an analytical dynamics framework to model the motion of structural and mechanical engineering systems. Nevertheless, for complex systems, such as multi-body structures, an explicit formulation of the equations of motion by utilizing generalized, independent, coordinates can be a daunting task. In this regard, employing a set of redundant coordinates can facilitate the formulation of the governing dynamics equations. In this setting, however, standard response analysis techniques cannot be applied in a straightforward manner. For instance, defining and determining a transfer function within a frequency domain response analysis…
Fractional Derivatives in Interval Analysis
2017
In this paper, interval fractional derivatives are presented. We consider uncertainty in both the order and the argument of the fractional operator. The approach proposed takes advantage of the property of Fourier and Laplace transforms with respect to the translation operator, in order to first define integral transform of interval functions. Subsequently, the main interval fractional integrals and derivatives, such as the Riemann–Liouville, Caputo, and Riesz, are defined based on their properties with respect to integral transforms. Moreover, uncertain-but-bounded linear fractional dynamical systems, relevant in modeling fractional viscoelasticity, excited by zero-mean stationary Gaussian…