85 research outputs found
Integrated design of Smart Structures
Much of structural control research and applications in civil engineering have been concerned with structures equipped with passive, hybrid, or active control devices in order to enhance structural performance under extraordinary loads. In most cases, the structure and the control system are individually designed and optimized. On the other hand, an exciting consequence of structural control research is that it also opens the door to new possibilities in structural forms and configurations, such as lighter buildings or bridges with longer spans without compromising on structural performance. Moreover, this can only be achieved through integrated design of structures with control elements as an integral part. This paper addresses the integrated design of structures with imbedded control systems and devices. Simultaneous optimization of such controlled structures is considered, showing that new structural forms and configurations can be achieved through integrated design. © 2008 Trans Tech Publications, Switzerlan
Optimal design of controlled structures
A formulation that finds the optimal design of a controlled structure is proposed. To achieve this goal, a composite objective composed of structural and control objectives is introduced to be optimized, and the effect of the control weighting is examined. A feedback control law is defined before the structural optimization and then the composite objective will only become a function of structural design variables. As a result, optimal structural design and control forces in steady state are obtained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46072/1/158_2005_Article_BF01279651.pd
Random non-autonomous second order linear differential equations: mean square analytic solutions and their statistical properties
[EN] In this paper we study random non-autonomous second order linear differential equations by taking advantage of the powerful theory of random difference equations. The coefficients are assumed to be stochastic processes, and the initial conditions are random variables both defined in a common underlying complete probability space. Under appropriate assumptions established on the data stochastic processes and on the random initial conditions, and using key results on difference equations, we prove the existence of an analytic stochastic process solution in the random mean square sense. Truncating the random series that defines the solution process, we are able to approximate the main statistical properties of the solution, such as the expectation and the variance. We also obtain error a priori bounds to construct reliable approximations of both statistical moments. We include a set of numerical examples to illustrate the main theoretical results established throughout the paper. We finish with an example where our findings are combined with Monte Carlo simulations to model uncertainty using real data.This work has been supported by the Spanish Ministerio de Economia y Competitividad grant MTM2017-89664-P. Marc Jornet acknowledges the doctorate scholarship granted by Programa de Ayudas de Investigacion y Desarrollo (PAID), Universitat Politecnica de Valencia.Calatayud-Gregori, J.; Cortés, J.; Jornet-Sanz, M.; Villafuerte, L. (2018). Random non-autonomous second order linear differential equations: mean square analytic solutions and their statistical properties. Advances in Difference Equations. (3):1-29. https://doi.org/10.1186/s13662-018-1848-8S1293Apostol, T.M.: Mathematical Analysis, 2nd edn. Pearson, New York (1976)Boyce, W.E.: Probabilistic Methods in Applied Mathematics I. Academic Press, New York (1968)Calbo, G., Cortés, J.C., Jódar, L.: Random Hermite differential equations: mean square power series solutions and statistical properties. Appl. Math. 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Narrow-Band Excitation of Hysteretic Systems
The stationary response of smooth and bilinear hysteretic systems to narrow-band random excitations is investigated by using the quasistatic method and digital simulation. It is shown that the response is qualitatively different in different ranges of values of the ratio of the excitation central frequency to the natural frequency of the system. In the resonant zone, the response is essentially non-Gaussian. For bilinear hysteretic systems with strong yielding, stochastic jumps may occur for a range of values of the ratio between nonresonant and resonant zones
Integrated Design of Smart Structures
Much of structural control research and applications in civil engineering have been concerned with structures equipped with passive, hybrid, or active control devices in order to enhance structural performance under extraordinary loads. In most cases, the structure and the control system are individually designed and optimized. On the other hand, an exciting consequence of structural control research is that it also opens the door to new possibilities in structural forms and configurations, such as lighter buildings or bridges with longer spans without compromising on structural performance. Moreover, this can only be achieved through integrated design of structures with control elements as an integral part. This paper addresses the integrated design of structures with imbedded control systems and devices. Simultaneous optimization of such controlled structures is considered, showing that new structural forms and configurations can be achieved through integrated desig
Integrated design of inelastic controlled structural systems
This paper addresses the integrated design of civil engineering inelastic structures with embedded control systems and devices. Simultaneous optimization of such controlled structures is considered, showing that new structural forms and configurations can be achieved through integrated design.
An optimization procedure for controlled structural systems is developed. The optimal design of (i) an SDOF steel portal frame and (ii) an 8-DOF shear-type structure is used as examples to illustrate the feasibility of the proposed approach, which reduces the structural weight of the buildings by incorporating active control elements while preserving the same performance objectives. The numerical results illustrated by these two examples show practical applicability, especially for the case of high-rise buildings
Pounding Reduction of Highway Bridges with Pounding Effect by Using Magnetorheological Dampers under Earthquake Excitations
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