Search results for "Structural engineering"
showing 10 items of 1998 documents
Stochastic response of linear and non-linear systems to α-stable Lévy white noises
2005
Abstract The stochastic response of linear and non-linear systems to external α -stable Levy white noises is investigated. In the literature, a differential equation in the characteristic function (CF) of the response has been recently derived for scalar systems only, within the theory of the so-called fractional Einstein–Smoluchowsky equations (FESEs). Herein, it is shown that the same equation may be built by rules of stochastic differential calculus, previously applied by one of the authors to systems driven by arbitrary delta-correlated processes. In this context, a straightforward formulation for multi-degree-of-freedom (MDOF) systems is also developed. Approximate CF solutions to the …
Mathematical Modeling and Optimization of a Vehicle Crash Test based on a Single-Mass
2014
In this paper mathematical modelling of a vehicle crash test based on a single mass is studied. The models under consideration consist of a single mass, a spring and/or a damper. They are constructed according to the measured vehicle speed before the collision and measured vehicle accelerations in three directions at the centre of gravity. A new model of nonlinear spring-mass-damper is also proposed to describe the crash. Simulation results are provided to show the effectiveness and applicability of the proposed methods.
Studies on predictive virtual models based on finite element analysis of the behaviour of geomembranes
2017
The study shown in this paper presents the behaviour of geomembranes used at the ecological landfills. For this goal was used a method designed to elaborate the virtual models of 3D geomembrane with one ply or 2 plies disposed at 30°, 45° and 90° and based on this model there were developed a number of 20 particular cases. For each situation it was realized the nonlinear analyses for all the developed cases with different vertical pressures representing different loads for the waste layer (1m, 2m, 10m, 15m, 20m). The main results are obtained in graphical form and represent the Maximum tensions Von Mises and total displacements of the geomembrane.
Indentation of rigidly supported sandwich beams with foam cores exhibiting non-linear compressive behaviour.
2011
A generalized analytical approach to investigate the indentation of sandwich beams under concentrated loads is presented, based on the Winkler foundation theory. A segment-wise model is implemented to the case of fully backed sandwich beams with polymeric foam cores exhibiting generic non-linear compressive behaviours. Closed-form analytical solutions of the indentation curve are obtained for simplified foam compression behaviours: elastic-perfectly-plastic, bilinear and bilinear-perfectly-plastic. Analytical predictions are compared with experimental data from sandwiches employing foam cores with peculiar non-linear behaviours. The proposed models are found to give a better match of the e…
Nontraditional configuration of tuned liquid column damper inerter for base-isolated structures
2023
In this paper, the concept of a novel passive control device, namely the Nontraditional Tuned Liquid Column Damper Inerter (NT-TLCDI), is investigated in combination with seismic base isolation (BI), to control lateral displacement demands in base-isolated structures during seismic events. The considered NT-TLCDI is a revision of the ordinary configuration of the recently proposed Tuned Liquid Column Damper Inerter (TLCDI). Unlike the traditional TLCDI layout, which involves a secondary liquid mass in a U-shaped tank coupled with a grounded inerter and connected to the isolation system by a spring-dashpot system, in the NT-TLCDI configuration, the damper is in parallel with the inerter rath…
Sustainable Development of Energy, Water and Environment Systems
2014
The Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) in 2015 returned to its hometown, Dubrovnik, and once again served as a significant venue for scientists and specialists in different areas of sustainable development from all over the world to initiate, discuss, share, and disseminate new ideas.At the 10th SDEWES Conference, about 500 participants from 64 countries delivered total 541 contributions - 5 invited lectures, 3 panels, 49 regular sessions, 17 special sessions and 5 poster sessions, aimed at deepening the knowledge body and scientific understanding, improvement of long-term scientific assessments, strengthening of scientific capacities aro…
Compatibility, effectiveness and susceptibility to degradation of alkoxysilane-based consolidation treatments on a carbonate stone
2021
Abstract Alkoxysilane-based consolidation treatment are commonly employed in restoration and conservation works of Cultural Heritage buildings. However, their poor affinity to carbonate stones is well-known. In this paper, we evaluate three consolidant treatments (two of them modified to incorporate hydrophobic or photocatalytic properties), formulated to circumvent this drawback and their cracking during drying, through a surfactant-assisted synthesis. The consolidants were applied on Noto stone, a biocalcarenite (~95% CaCO3 ) employed in numerous Cultural Heritage buildings of Southern Italy. A comprehensive validation of the three consolidants, compared to a commercial TEOS based consoli…
Self-similarity and response of fractional differential equations under white noise input
2022
Self-similarity, fractal behaviour and long-range dependence are observed in various branches of physical, biological, geological, socioeconomics and mechanical systems. Self-similarity, also termed self-affinity, is a concept that links the properties of a phenomenon at a certain scale with the same properties at different time scales as it happens in fractal geometry. The fractional Brownian motion (fBm), i.e. the Riemann-Liouville fractional integral of the Gaussian white noise, is self-similar; in fact by changing the temporal scale t -> at (a > 0), the statistics in the new time axis (at) remain proportional to those calculated in the previous axis (t). The proportionality coeffi…
Spatial Reconstruction Algorithm of DT Layer in Cryogenic Targets Using Optical Techniques
2007
The measurements of the solid DT layer, in terms of thickness and roughness, in the LMJ geometry (i.e. in a hohlraum) are not trivial. The DT layer measurements will be done using a Matsukov-Cassegrain telescope placed 39 cm away from the target. This telescope will be used to acquire shadowgraphy images on equators, and interferometric measurements on pole areas using optical coherence tomography (OCT). Optical coherence tomography allows determining the DT layer thickness on a few points, in the polar regions of the target. By scanning around the poles, several points can be acquired in order to calculate the roughness and the local shape of the DT layer at the pole. Both techniques were …
Advancements in the Helium-Cooled Pebble Bed Breeding Blanket for the EU DEMO: Holistic Design Approach and Lessons Learned
2019
The helium-cooled pebble bed (HCPB) blanket is one of the two concepts proposed as a driver blanket for the European Union Demonstration Fusion Power Reactor (EU DEMO). In contrast to past conceptual design studies, in the frame of the current Power Plant Physics and Technology of the EUROfusion Consortium, the ongoing EU DEMO preconceptual design activities have adopted a holistic and integrated (i.e., systems engineering) design approach. As a consequence of this new approach, many interfaces and requirements have been identified, some of them driving the design of the blankets. This paper shows the advancements in the HCPB breeding blanket and describes the lessons learned after implemen…