Search results for "Structural Engineering"
showing 10 items of 1998 documents
Effect of uncertain damping coefficient on the response of a SDOF system
2022
In this paper, a full probabilistic description of the response of a randomized SDOF system in both the time and the frequency domain is done. Considering that the damping of the structure does not simply relate to any single physical phenomenon, the sensitivity of the response to the randomness of the damping parameter is investigated. The stochastic analysis is conducted via the Probability Transformation Method therefore the first probability density function of the response is evaluated. The effect of the uncertain damping coefficient on the response of the SDOF system has been investigated through several numerical examples. From the response probability density function as well as fro…
Probabilistic solution of a homogeneous linear second-order differential equation with randomized complex coefficients
2022
In this paper, an exact expression for the first probability density function of the solution stochastic process to a randomized homogeneous linear second-order complex differential equation is determined. To complete the probabilistic analysis, the first probability density functions of the real and complex contributions of the solution stochastic process are also calculated. To compute the densities, the random variable transformation method is applied under general hypothesis, all coefficients and initial conditions are absolutely continuous complex random variables. The capability of the theoretical results established is demonstrated by several numerical examples. Finally, we show the …
Estimation of Daily Solar Radiation from Measured Air Temperature Extremes in the Mid-Mediterranean Area
2012
AbstractDaily solar radiation Rs at ground level is a necessary input variable required for the evaluation of evapotranspiration and crop growth, development, and yield-simulation models. Nevertheless, it is measured in few weather stations and at many locations it is not observed; also, available Rs temporal series are generally no longer than a few years. A valid surrogate of Rs measurement is the diurnal air-temperature range (ΔT); indeed, ΔT is inversely proportional to cloudiness and therefore could be a good indicator of atmospheric transmittance. As opposed to Rs, daily maximum and minimum air temperatures are measured at many locations and their observations in developed countries b…
Critical Fracture Plane Under Multiaxial Random Loading by Means of Euler Angles Averaging
1999
ABSTRACT Several authors have experimentally observed that the position of the fatigue fracture plane strongly depends on the directions of the principal stresses or strains. The expected principal stress directions under multiaxial random loading are obtained herein by averaging the instantaneous values of the three Euler angles through some suitable weight functions, in order to take into account the main factors influencing the fatigue fracture behaviour. Then the correlation between such theoretical principal directions and the experimental fracture plane is examined for some biaxial random fatigue tests.
Stochastic response determination of nonlinear oscillators with fractional derivatives elements via the Wiener path integral
2014
A novel approximate analytical technique for determining the non-stationary response probability density function (PDF) of randomly excited linear and nonlinear oscillators endowed with fractional derivatives elements is developed. Specifically, the concept of the Wiener path integral in conjunction with a variational formulation is utilized to derive an approximate closed form solution for the system response non-stationary PDF. Notably, the determination of the non-stationary response PDF is accomplished without the need to advance the solution in short time steps as it is required by the existing alternative numerical path integral solution schemes which rely on a discrete version of the…
A new approach to exergoeconomic analysis and design of variable demand energy systems
2006
Exergoeconomics is an attractive research field regarding the optimisation of design and operability where complex energy systems are concerned. The different approaches to thermoeconomics can easily achieve optimal or near-optimal solutions for the design of energy systems in industrial applications, characterised by regular energy demand profiles; for applications in buildings, however, the great number of components operating at unsteady conditions due to the demand variability make these methodologies hard to use. Furthermore, in project phases of complex plants such as Combined Heat and Power (CHP) or Combined Heat Cooling and Power (CHCP), energy demand can be satisfied with different…
Exergetic and exergoeconomic analysis of a renewable polygeneration system and viability study for small isolated communities
2015
Abstract A great interest has recently arisen for the sustainable supply of energy and fresh water, due to the growing demand from developing countries. Facing this demand by traditional technologies implies evident risks related with the high cost of fossil fuels and their environmental impact. Then, alternative solutions based on the use of renewable sources and innovative technologies must be considered. In this paper a renewable polygeneration system is examined, which includes a solar field based on parabolic trough photovoltaic/thermal collectors, a biomass heater, an absorption chiller and a Multiple Effect Distillation desalination unit. Plant operation under dynamic conditions has …
A methodology for selecting a sustainable development strategy for connecting low heat density consumers to a district heating system by cascading of…
2021
Abstract The paper presents a methodology for supporting the decision making on how to sustainably develop an existing district heating system when consumers located in a remote, low-heat consumption density area are connected to the system. Several scenarios are proposed where a multi-generative system is assessed by implementation of industrial heat pumps (HP), solar photovoltaic (PV) system, and low-temperature regime into an existing district heating system in various combinations. The methodology is based on multi-criteria analysis allowing for energy, economic, exergy, and environmental (4E) assessment. The research is based on a case study of an autonomous district heating system in …
User acceptance of automated public transport
2020
Abstract Autonomous driving is receiving increasing attention in the automotive industry as well as in public transport. However, it is still unclear whether users are willing to use automated public transportation at all. In order to answer this and other questions, the transport company of the city of Mainz, Germany, tested the autonomous minibus EMMA (Elektro-Mobilitat Mainz Autonom) on a 600-meter-long test track in public space. The study presented here was conducted with the aim of exploring crucial determinants for the use of an autonomous minibus. On the basis of established acceptance models, a questionnaire was developed, which was completed in a field survey by a total of 942 par…
On the Stiffness and the Reinforcement Effect of Electrical Resistance Strain Gauges
2006
The reinforcement effect of a strain gauge installed on low modulus materials can be significant. The increasing use of low modulus materials requires therefore the evaluation of such effect. This paper concerns the relationship between the local reinforcement effect and the strain gauge stiffness. The conclusion is that the gauge stiffness alone does not allow the user a thorough evaluation of the reinforcement effect.