Search results for "Structural Engineering"
showing 10 items of 1998 documents
Using Hydrus 2-D Simulation model to evaluate wetted soil volume in subsurface drip irrigation systems.
2007
Drip irrigation is considered one of the most efficient irrigation systems. Alternatively to the traditional drip irrigation systems, laterals can be installed below the soil surface. Realizing the subsurface drip irrigation (SDI), which recently has been increasing in use as a consequence of advances in plastics technology, making SDI equipment more affordable and long lasting. Due to its potential high efficiency SDI may produce benefits, especially in places where water is a limited source. As the use of SDI is relatively new, a better understanding of the infiltration process around a buried point source can contribute to increased water use efficiency and consequently the success of dr…
Evaluation of innovative thermal insulation systems for a sustainable envelope
2017
La memoria presenta i risultati ottenuti su sistemi di isolamento termico per l’involucro edilizio. Si presentano i risultati ottenuti tramite simulazioni informatiche che hanno consentito di verificare e ottimizzare la trasmissione del calore attraverso un sistema sottovuoto in vetro per le facciate trasparenti. Inoltre la possibilità offerta dal riciclo del materiale di scarto della potatura dell’Opunthia Ficus Indica (fichi d’india) che,opportunamente trattato ha permesso di ottenere un materiale isolante (Brevetto n. 1402131), in forma di pannello o in grani sfusi, (valori di coibenza termica 0.0710.057 W/mK). The paper presents the results of the research on thermal insulation systems…
Iterative closure method for non-linear systems driven by polynomials of Gaussian filtered processes
2008
This paper concerns the statistical characterization of the non-Gaussian response of non-linear systems excited by polynomial forms of filtered Gaussian processes. The non-Gaussianity requires the computation of moments of any order. The problem is solved profiting from both the stochastic equivalent linearization (EL), and the moment equation approach of Ito's stochastic differential calculus through a procedure divided into two parts. The first step requires the linearization of the system, while retaining the non-linear excitation; the response statistical moments are calculated exactly, and constitute a first estimate of the moments of the actual non-linear system. In the second step, t…
On relation between J-integral and heat energy dissipation at the crack tip in stainless steel specimens
2019
In this paper, an experimental procedure to evaluate the elastic-plastic J-integral at the tip of a fatigue crack is presented. According to this new approach, the elastic component of the J-integral is derived from Thermoelastic Stress Analysis, while the plastic component of the J-integral is derived from the heat energy loss. An analytical link is proposed to apply this new experimental technique. Therefore, the elastic-plastic J-integral range was evaluated starting from infrared temperature maps measured in situ during crack propagation tests of AISI 304L stainless steel specimens. It was found that the range of the infrared thermography-based J-integral correlated well the crack growt…
Fatigue Design of Cruciform Joints including V-notch Effect at the Weld Toe
2014
Abstract The present paper proposes a new and more accurate fatigue life prediction model for fillet welded joints in steel subjected to constant amplitude loading. With the traditional fracture mechanics approach, the greatest difficulty when computing the fatigue life of a welded detail is to determine the initial crack size a0. The classical way to determine the stress intensity factor K (SIF) is by using the following formula Where σ is the applied stress, a is the crack size and g(a/T) the geometrical correction factor which has been determined by Gurney function or similar solutions. This approach is not accurate for short crack because of the singular V-notch behaviour close to the c…
Bio materials with reclaimed asphalt: from lab mixes properties to non-damaged full scale monitoring and mechanical simulation
2019
Three innovative environmentally friendly pavement materials, designed with 50% of Reclaimed Asphalt and three different biomaterials (2 bio-additivated bitumens and 1 bio-binder), were produced in an industrial plant. These mixes were tested in lab and also at full scale using an Accelerated Pavement Test facility. The asphalt mix viscoelastic properties were measured in lab and their intrinsic viscoelastic response were simulated. These rheological models are used to simulate the pavement mechanical response using both elastic and viscoelastic multilayer codes. Hence, full scale measurement performed during the full scale test at an early stage (without damages) can be compared with these…
Scour on Alluvial Bed Downstream of Grade-Control Structures
2004
This paper describes an approach for predicting local scour downstream of grade control structures. The developed analysis applies the incomplete self-similarity (ISS) theory for deducing some physically based dimensionless groups controlling the geometrical pattern of the scour profile. The scour measurements available in the literature in conjunction with numerous unpublished data allow a multiregressive calibration of the ISS relationships. The experimental sample includes different bed grain-size distributions and scales of the erosive phenomenon. The results prove that the ratio between the upstream water head and the weir height is able to explain the measurements of scour depth carri…
Interaction of a liquid gallium jet with the tokamak ISTTOK edge plasma
2008
Abstract The interaction of a liquid gallium jet with plasma has been investigated in the tokamak ISTTOK. This paper presents a description of the conceived experimental setup, a detailed characterization of the produced jets and the first experimental results related to the gallium–plasma interaction. A stable jet has been obtained, which was not noticeably affected by magnetic field transients. ISTTOK has been successfully operated with the gallium jet without degradation of the discharge or a significant plasma contamination by liquid metal. This observation is supported by spectroscopic measurements showing that gallium radiation is limited to the region around the jet. Furthermore, the…
Spectrometric analysis of inner divertor materials of JET carbon and ITER-like walls
2019
Abstract One of main reasons of the Joint European torus (JET) transformation from the carbon (JET-C) to ITER-like (JET-ILW) wall was high tritium retention of carbon. In order to compare the tritium retention, samples of analogous positions of the plasma-facing side of vertical tiles No. 3 of two campaigns: JET-C (2008–2009) and JET-ILW (2011–2012) were cut out. Temperature-programmed tritium desorption spectrometry in He + 0.1% H2 gas flow showed that JET-C sample without a tungsten coating had by a factor of >20 higher surface concentration of tritium than JET-ILW tungsten-coated sample: 4.9 × 1013 and 1.7–2.2 × 1012 T atoms/cm2 respectively. Installation of metallic plasma facing wall i…
Response spectrum analysis of frame structures: reliability-based comparison between complete quadratic combination and damping-adjusted combination
2019
In the framework of seismic design of structures, response spectrum analysis (RSA) is the most commonly used approach in practice. The most popular combination rule is the complete quadratic combination (CQC) which is also prescribed by the most of seismic design codes and is based on the assumptions that the seismic acceleration is a white noise process and the peak factor ratios associated to the total and modal responses are unitary. Recently, the damping adjusted combination (DAC) rule has been developed for base-isolated structures to overcome the aforementioned simplified assumptions. Although it has been proved that the simplifications about peak factors lead to noticeable errors in …