Search results for "Structural engineering"
showing 10 items of 1998 documents
A methodology for assessing the impact of salinity gradient power generation in urban contexts
2018
Abstract The paper proposes a methodology to assess the potential impact of salinity gradient power technology in urban contexts. The idea to employ such energy source in urban contexts derives from the observation that, among the energy districts outputs, low-salinity treated wastewater can be used to produce electricity if a suitable source of high salinity feed (seawater of a salt-works) is also available. The methodology uses the HOMER software for assessing the district’s electric energy production, consumption and exchange with the main grid. Then, starting from the total gross surface and the number of inhabitants of the district, some possible realistic scenarios characterized by di…
Reverse electrodialysis with NH4HCO3-water systems for heat-to-power conversion
2017
Abstract A Reverse ElectroDialysis Heat Engine (REDHE) system operating with “thermolytic” ammonium hydrogen-carbonate (NH4HCO3) aqueous solutions as working fluids is studied. The engine is constituted by (i) a RED unit to produce electric power by mixing the solutions at different salinity and (ii) a thermally-driven regeneration unit including a stripping and an absorption column to restore the initial salinity gradient thus closing the cycle. In the present work only the RED unit and the stripping column are taken into account. In particular, a simplified integrated process model for the whole cycle was developed: it consists of (i) a lumped parameter model for the RED unit validated wi…
Sulla sincronizzazione delle misure wireless di scariche parziali con il segnale di tensione a 50 Hz
2017
L’articolo descrive i vari aspetti dei sistemi di misura wireless delle scariche parziali (PD). In particolare, sul problema della sincronizzazione dell’angolo di fase della tensione per il rilevamento e la classificazione delle PD.
On the history of torsional stress concentrations in shafts: From electrical analogies to numerical methods
2014
This article proposes a retrospective on experimental and numerical methods developed throughout the past century to solve the torsion problem in shafts, with particular emphasis on the determination of shear stress concentration factors in discontinuities of typical use in shaft design. This article, in particular, presents the theory and related solutions distinguishing between two classes of geometries: shafts with constant cross section and axisymmetric shafts with variable diameter. Emphasis is given to approaches based on physical analog methods and, in particular, those based on electrical analogies proposed since about 1925. Experimental methods based on structural physical models …
Shake-table testing of a stone masonry building aggregate: overview of blind prediction study
2023
Bulletin of earthquake engineering (2023). doi:10.1007/s10518-022-01582-x special issue: "Adjacent Interacting Masonry Structures"
Un nouvel algorithme pour une solution robuste des équations complètes de Saint-Venant
2003
A new procedure for the numerical solution of the fully dynamic shallow water equations is presented. The procedure is a fractional step methodology where the original system is split into two sequential ones. The first system differs from the original one because of the head gradient term, that is treated as constant and equal to the value computed at the end of the previous time step. The solution of this system, called kinematic, is computed in each element using a spatial zero order approximation for both the heads and the flow rates by means of integration of single ODEs. The second system is called diffusive, contains in the momentum equations only the complementary terms and can be e…
Experimental Studies Regarding the Mechanical Behaviour of Silicon-Coated and Uncoated P.A. 6.6 Fabrics
2014
These paper aims to present an experimental study for determining the mechanical properties of woven fabrics used for airbags manufacturing. In order to realise the study, there were chosen two types of fabric, one that is coated with silicon and one that is uncoated. The experimental tests that were carried out were uniaxial tension tests for samples extracted on the warp and on the weft direction, the Bias test, a test specific for shear loads and the dome test, a test specific for biaxial loads. For the uniaxial tension test the force-displacement curve was obtained and the maximum values of the loads and the displacement. For the last two tests (bias test and dome test) there have been …
Buckling of Elastic Beam Under Unilateral Constraint
1988
ABSTRACT A criterion is proposed to calculate the critical load of a continuous beam under unilateral constraint. The beam is assumed to be built in at the ends and to rest on equally spaced elastic supports, that have equal stiffness. The problem is solved by determining the length of the half-wave of the buckled shape, the number of supports involved, and their position with respect to the end of the half-wave. The analysis model thus defined is determined in relation to the geometry of the beam and to the ratio between the stiffness of the supports and the shearing stiffness of the generic span. It is shown that there exists a limiting value of this ratio, below which the critical load i…
Analysis of stamping performances of dual phase steels: A multi-objective approach to reduce springback and thinning failure
2009
The industrial interest on light weight components has contributed in the last years to a significant research effort on new materials able to guarantee high mechanical properties, good formability and reasonable costs together with reduced weights when compared to traditional mild steels. Among such materials advanced high strength steels (AHSS) such as transformations induced plasticity (TRIP) and dual phase (DP), and light weight alloys proved their usefulness in stamping of automotive components. As AHSS are concerned, one of the main drawbacks is related to springback occurrence. Many aspects have to be taken into account when springback reduction is investigated: material behavior iss…
Parameter tuning for nacelle-based passive structural control of a spar-type floating wind turbine
2013
This paper deals with the modeling and parameter tuning of a spar-type floating wind turbine with a tuned mass damper (TMD) installed in nacelle. Firstly, a mathematical model for the system surge-heave-pitch motion is established based on first principles. Secondly, different parameter tuning methods are adopted to find the optimal TMD parameters for load reduction. Thirdly, nonlinear wind turbine simulations with different designs are conducted under different wind and wave conditions. The results show that TMD with small spring and damping coefficients will help to produce much load reduction in above rated condition. However, it may deteriorate system performance when the turbine is wor…