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On site environmental modeling and monitoring: The Nordic scenario in HYDROSYS project

On site environmental modeling and monitoring: The Nordic sc...

5th Biennial Conference of the International Environmental modelling and Software Society: modelling for Environment's Sake, iEMSs 2010

作者： Ferencik, Ioan Niemi, Tero Jolma, Ari Lahti Center Departament of Civil and Environmental Engineering School of Science and Technology Finland

ISBN: (纸本)9788890357411

Environmental modeling represents a common method for improving the understanding of environmental phenomena and most of the times is carried out off site. The high computational requirements of environmental models coupled with large amounts of spatial data are the main causes for this situation. Conducting environmental simulations by means of environmental models on-site represents a challenge but with recent advances in Wireless Sensor Networks (WSN) and development of affordable smart hand-held devices new possibilities are opening. The work presented in this paper is related to the HYDROSYS project1 and is linked to the Nordic scenario located in south of Finland. The goal of the project is to provide end-users with advanced on-site and on-line spatial analysis tools for the purpose of environmental modeling. Thus, we have integrated a 1D hydraulic model with WSN and environmental modeling. This allows end users to carry out environmental simulation on-site almost in real time using smart clients improving their understanding in respect to environmental phenomena. The setup has a big potential for environmental management and decision support and could be highly exploited by environmental managers and specialists.

关键词： Wireless sensor networks

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modelling and simulation of advanced problems and smart systems in civil engineering

Modelling and simulation of advanced problems and smart syst...

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modelling and simulation of advanced problems and smart systems in civil engineering

作者： Maceri, Franco Casciati, Fabio Department of Civil Engineering University of Rome Tor Vergata 00133 Roma Via del Politecnico 1 Italy University of Pavia 27100 Pavia Via Ferrata 1 Italy

No abstract available

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modelling and simulation of advanced problems and smart systems in civil engineering

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simulation modelling PRACTICE AND THEORY 2003年第5-6期11卷 313-313页

作者： Maceri, F Casciati, F Univ Roma Tor Vergata Dept Civil Engn I-00133 Rome Italy Univ Pavia I-27100 Pavia Italy

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Numerical evaluation of shear strengthening performance of CFRP sheets/strips and sprayed epoxy coating repair systems

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COMPOSITES PART B-engineering 2008年第5期39卷 851-862页

作者： Lee, H. K. Kim, B. R. Ha, S. K. Korea Adv Inst Sci & Technol Dept Civil & Environm Engn Taejon 305701 South Korea

A numerical study is conducted to evaluate the shear strengthening performance of two repair systems: CFRP sheets/strips and a sprayed epoxy coating. Micromechanical constitutive models for the CFRP sheets/strips and sprayed FRP coating proposed by Liang et al. [Liang Z, Lee HK, Suaris W. Micromechanics-based constitutive modeling for unidirectional laminated composites. Int J Solids Struct 2006;43:5674-89] and Lee et al. [Lee HK, Avila G, Montanez C. Numerical study on retrofit and strengthening performance of sprayed fiber-reinforced polymer. Eng Struct 2005;27:1476-87] and Lee and Simunovic [Lee HK, Simunovic S. Modeling of progressive damage in aligned and randomly oriented discontinuous fiber polymer matrix composites. Composites: Part B 2000;31:77-86] in conjunction with damage models, are implemented into the finite element code ABAQUS to solve boundary value problems. Using the implemented computational model, numerical simulations of four-point bending tests on concrete beams repaired with the repair systems are conducted to quantify their strengthening abilities. The numerical tests yield load-deflection curves from which the shear strengthening performance of the repair systems is evaluated. Furthermore, the present prediction is compared with available experimental data to assess the accuracy of the proposed computational model. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： laminates discontinuous reinforcement micro-mechanics computational modelling

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An optimal approach to active vibration control of smart structures

An optimal approach to active vibration control of smart str...

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18th IASTED International Conference on modelling and simulation, MS 2007

作者： Mehrabian, Ali Reza Shahi, Hossein Yousefi-Koma, Aghil Advanced Dynamic and Control Systems Laboratory School of Mechanical Engineering University of Tehran P.O.Box: 14875-347 Tehran Iran

ISBN: (纸本)9780889866638

A solution to the problem of identification and control of smart structures is presented in this paper. smart structures with build-in sensors and actuators can actively and adaptively change their physical geometry and properties. As a particular example, a representative dynamic model of a typical fighter vertical tail, identified as the smart fin, is considered. Piezoelectric patches, which are mounted on the vertical tail, are employed as actuator. The Frequency Response Function (FRF) of the smart fin is obtained from experiment. The corresponding transfer function is then derived using system identification (ID) techniques, using MATLAB system identification toolbox, which is verified with the experimental data. The model obtained using system ID is then used to tune an optimal PID controller to reduce the vibration of the smart structure. Multiple objectives are considered for designing the active control system based on the frequency response of the open-loop and the closed-loop system. The multi-objective optimization problems are solved using Genetic Algorithms (GAs). The results are then studied and the best PID is chosen as the candidate for active vibration control for the smart fin. The reported results indicate that the designed optimal controller has better performance than an experimentally tuned PID controller.

关键词： Genetic algorithms

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Languages and metamodels for modelling frameworks

Languages and metamodels for modelling frameworks

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作者： Harvey, H. School of Civil Engineering and Geosciences University of Newcastle Upon Tyne United Kingdom

ISBN: (纸本)0975840002

The problem of decision making in environmental management is increasing steadily in complexity. A variety of pressure is leading to a requirement to consider the impacts of possible courses of action on a much wider basis than heretofore. modelling and simulation is becoming ever more fundamental to the decision making process. The models are becoming more complex, as is the context in which they are used. In flood defence asset management, for example, we see deterministic models of water flow being coupled with probabilistic models of flood defence reliability, and the result set within a calculation which derives distributed measures of economic risk, attributing that risk to particular parts of the flooding system. Even to provide the deterministic modelling element of next generation decision support systems a more modular approach to software construction is needed than that used to build the modelling systems of the past. This is recognised in the effort being invested in developing I will refer to here, somewhat indiscriminately, as "software frameworks". The design of a software framework consists in large part in the design of a language or of a set of languages. Languages in general are media for the expression of thought (and thus for communication) but, as George Boole observed, they are much more profoundly "instrument[s] of human reason": without them abstract thought is not possible. Formal languages enable a level of precision in thought and communication which cannot be achieved using informal languages. With well designed notation they also enable a level of concision which (Alfred North Whitehead), "By relieving the brain of all unnecessary work . . . sets it free to concentrate on more advanced problems". These benefits come at a cost, though, of effort in formalisation of concepts, and barriers to change once they are formalised. All languages which control the behaviour of our digital computers, which we may refer to as computer-based languag

关键词： Artificial intelligence

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simulation modelling Practice and Theory

Simulation Modelling Practice and Theory

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modelling and simulation of advanced problems and smart systems in civil engineering

The proceedings contains 10 papers from the conference on simulation modeling practice and theory. The topics discussed include: a numerical model for wind loads simulation on long-span bridges;simulating a conical tuned liquid damper;dynamic response and control of hysteretic structures;shape memory alloys and their application in structural oscillations attenuation;active vibration control of an elastic plate using multiple piezoelectric sensors and actuators and contact problems with friction: models and simulations.

关键词： Bridges

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Contact problems with friction: Models and simulations

Contact problems with friction: Models and simulations

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modelling and simulation of advanced problems and smart systems in civil engineering

作者： Lebon, F. Lab. Mécan. Mat. Structures Univ. Claude Bernard Lyon 1 82 Bd Niels Bohr 69622 Villeurbanne Cedex France

This article deals with the modeling and the numerical simulation of contact and friction problems. Some friction formulations are proposed and numerical methods of resolution by finite elements are presented. Two methods are more particularly developed. The first one is based on a formulation using displacements and the second one is based on a mixed formulation using displacements and contact forces. Then, some improvements of these two methods as well as a comparison of their respective performances are presented. © 2003 Elsevier B.V. All rights reserved.

关键词： Friction

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A numerical model for wind loads simulation on long-span bridges

A numerical model for wind loads simulation on long-span bri...

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modelling and simulation of advanced problems and smart systems in civil engineering

作者： Vairo, Giuseppe Department of Civil Engineering University of Rome 'Tor Vergata' Via del Politecnico 1 00133 Roma Italy

A numerical model of the air flow problem around the girder of a long-span bridge is presented. The model is based on a finite volume formulation and it is able to simulate steady and non-steady wind loading conditions on the structure under the simplifying assumption, which is plausible for bridges with long spans, of a two-dimensional-like approaching flow. For a given bridge deck cross-section the proposed model allows the numerical evaluation of the flutter derivatives, which is useful to characterize in an analytical way the stability conditions of the overall wind-induced bridge response. In order to obtain satisfactory accuracy and stability of the numerical solution, a two-equation k-Ε RNG turbulence model and special boundary conditions are employed. The accuracy and applicability of the model to wind engineering problems are successfully assessed by computing the aerodynamic behaviour of some simple cross-section shapes. Numerical results are also obtained for typical long-span bridge cross-sections and the comparison with the available wind tunnel measurements shows a good agreement. © 2003 Elsevier B.V. All rights reserved.

关键词： Bridges

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Simulating a conical tuned liquid damper

Simulating a conical tuned liquid damper

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modelling and simulation of advanced problems and smart systems in civil engineering

作者： Casciati, Fabio De Stefano, Alessandro Matta, Emiliano Department of Structural Mechanics University of Pavia Via Ferrata 1 27100 Pavia Italy Department of Structural Engineering Polytechnic of Turin Corso Duca degli Abruzzi 34 10100 Torino Italy

In recent years, tuned liquid dampers (TLD) have proved a successful control strategy for reducing structural vibrations. The present study focuses on the frustum-conical TLD as an alternative to the traditional cylindrical tank. If compared to the cylindrical reservoir, the cone-shaped TLD allows calibrating its natural frequency through varying liquid depth, which makes it suitable for a semi-active implementation, and attains the same level of performance with a fewer mass, at least for small fluid oscillations. A linear model is presented which can interpret TLD's behaviour for small excitations. For larger amplitudes, strong nonlinearities occur and the linear model is no longer predictive. Consequently, for a frustum-cone TLD subjected to harmonic excitations, a tuned mass damper (TMD) analogy is established where TMD parameters vary with the excitation amplitude. © 2003 Elsevier B.V. All rights reserved.

关键词： Damping

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