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Halûk Sucuoğlu - One of the best experts on this subject based on the ideXlab platform.

  • Generalized Force vectors for multi-mode pushover analysis of bridges
    Bulletin of Earthquake Engineering, 2017
    Co-Authors: Camilo Perdomo, Ricardo Monteiro, Halûk Sucuoğlu
    Abstract:

    Nonlinear static procedures (NSPs) are gaining wider use in performance based earthquake engineering practice due to their simplicity compared to rigorous nonlinear time history analysis (NTHA), and being implemented in the new generation of seismic design codes. In this study, a recently proposed Nonlinear Static Procedure (NSP) for the seismic performance assessment of building structures using the concept of Generalized Force vectors (GFV), is further validated through application to reinForced concrete bridges. This method, named Generalized pushover analysis (GPA), maximizes the response of a chosen parameter during the seismic response, through the use of the GFV, which are a combination of modal Forces representing the instantaneous Force acting on the system when such parameter reaches its maximum. In this study, the original GPA implemented in buildings is adapted to bridge structures and four versions of the algorithm are tested. Two straight bridges, featuring different levels of vertical irregularity, are used as case study to validate the procedure, and the accuracy of the GPA algorithm is assessed by comparing the nonlinear static results with the “exact” prediction from NTHA. Several levels of seismic hazard, represented in the expected return period of the target spectra, are considered to test the accuracy of the method for low and high seismic demand. Furthermore, the GPA results are also compared with a commonly employed NSP, the capacity spectrum method. The results obtained for the case study suggest that GPA algorithm for bridges is suitable as a NSP approach for the seismic assessment of bridge structures, demonstrating a good fit with NTHA results and superiority with respect to the predictions of the selected traditional NSP.

  • Practical Implementation of Generalized Force Vectors for the Multimodal Pushover Analysis of Building Structures
    Earthquake Spectra, 2015
    Co-Authors: F. Soner Alıcı, Halûk Sucuoğlu
    Abstract:

    A practical implementation of Generalized multimodal pushover analysis is presented in this study, where the number of pushovers is reduced significantly in view of the number of modes contributing to seismic response. It has been demonstrated in two case studies that the reduced procedure for Generalized push-over analysis is equally successful in estimating the maximum member deformations and Forces under a ground excitation with reference to nonlinear response history analysis. It is further shown that the results obtained by using the mean spectrum of a set of ground motions are almost identical to the mean of the results obtained from separate Generalized pushover analyses. These results are also very close to the mean results of the nonlinear response history analyses, hence motivating the implementation of Generalized pushover analysis with design spectrum.

  • Generalized Force vectors for multi mode pushover analysis of torsionally coupled systems
    Earthquake Engineering & Structural Dynamics, 2014
    Co-Authors: Kaan Kaatsz, Halûk Sucuoğlu
    Abstract:

    SUMMARY A Generalized multi-mode pushover analysis procedure was developed for estimating the maximum inelastic seismic response of symmetrical plan structures under earthquake ground excitations. Pushover analyses are conducted with story-specific Generalized Force vectors in this procedure, with contributions from all effective modes. Generalized pushover analysis procedure is extended to three-dimensional torsionally coupled systems in the presented study. Generalized Force distributions are expressed as the combination of modal Forces to simulate the instantaneous Force distribution acting on the system when the interstory drift at a story reaches its maximum value during seismic response. Modal contributions to the Generalized Force vectors are calculated by a modal scaling rule, which is based on the complete quadratic combination. Generalized Forces are applied to the mass centers of each story incrementally for producing nonlinear static response. Maximum response quantities are obtained when the individual frames attain their own target interstory drift values in each story. The developed procedure is tested on an eight-story frame under 15 ground motions, and assessed by comparing the results obtained from nonlinear time history analysis. The method is successful in predicting the torsionally coupled inelastic response of frames responding to large interstory drift demands. Copyright © 2014 John Wiley & Sons, Ltd.

  • Generalized Force vectors for multi‐mode pushover analysis of torsionally coupled systems
    Earthquake Engineering & Structural Dynamics, 2014
    Co-Authors: Kaan Kaatsz, Halûk Sucuoğlu
    Abstract:

    SUMMARY A Generalized multi-mode pushover analysis procedure was developed for estimating the maximum inelastic seismic response of symmetrical plan structures under earthquake ground excitations. Pushover analyses are conducted with story-specific Generalized Force vectors in this procedure, with contributions from all effective modes. Generalized pushover analysis procedure is extended to three-dimensional torsionally coupled systems in the presented study. Generalized Force distributions are expressed as the combination of modal Forces to simulate the instantaneous Force distribution acting on the system when the interstory drift at a story reaches its maximum value during seismic response. Modal contributions to the Generalized Force vectors are calculated by a modal scaling rule, which is based on the complete quadratic combination. Generalized Forces are applied to the mass centers of each story incrementally for producing nonlinear static response. Maximum response quantities are obtained when the individual frames attain their own target interstory drift values in each story. The developed procedure is tested on an eight-story frame under 15 ground motions, and assessed by comparing the results obtained from nonlinear time history analysis. The method is successful in predicting the torsionally coupled inelastic response of frames responding to large interstory drift demands. Copyright © 2014 John Wiley & Sons, Ltd.

  • Generalized Force vectors for multi mode pushover analysis
    Earthquake Engineering & Structural Dynamics, 2011
    Co-Authors: Halûk Sucuoğlu, Selim M Gunay
    Abstract:

    A Generalized pushover analysis (GPA) procedure is developed for estimating the inelastic seismic response of structures under earthquake ground excitations. The procedure comprises applying different Generalized Force vectors separately to the structure in an incremental form with increasing amplitude until a prescribed seismic demand is attained for each Generalized Force vector. A Generalized Force vector is expressed as a combination of modal Forces, and simulates the instantaneous Force distribution acting on the system when a given response parameter reaches its maximum value during dynamic response to a seismic excitation. While any response parameter can be selected arbitrarily, Generalized Force vectors in the presented study are derived for maximum interstory drift parameters. The maximum value of any other response parameter is then obtained from the envelope of GPAs results. Each nonlinear static analysis under a Generalized Force vector activates the entire multi-degree of freedom effects simultaneously. Accordingly, inelastic actions develop in members with the contribution of all 'instantaneous modes' in the nonlinear response range. Target seismic demands for interstory drifts at the selected stories are calculated from the associated drift expressions. The implementation of the proposed GPA is simpler compared with nonlinear response history analysis, whereas it is less demanding in computational effort when compared with several multi-mode adaptive nonlinear static procedures. Moreover, it does not suffer from the statistical combination of inelastic modal responses obtained separately. The results obtained from building frames have demonstrated that GPA is successful in estimating maximum member deformations and member Forces with reference to the response history analysis. When the response is linear elastic, GPA and response spectrum analysis produce identical results.

Farhad Aghili - One of the best experts on this subject based on the ideXlab platform.

  • inverse and direct dynamics of constrained multibody systems based on orthogonal decomposition of Generalized Force
    International Conference on Robotics and Automation, 2003
    Co-Authors: Farhad Aghili
    Abstract:

    This paper presents a unified approach for inverse and direct dynamics of constrained multibody systems that can be served as a basis for analysis, simulation, and control. The compactness of the dynamics formulation can result in computational efficiency. Furthermore, the acceleration is explicitly related to the Generalized Force by an introduced "constraint inertia matrix" which is proved to be always invertible. Thus a simulation may proceed even with the presence of redundant constraints or singular configurations. The Generalized Forces are decomposed onto two orthogonal subspaces which are considered as control inputs for controlling position and constraint Force. The motion controller scheme, remarkably, requires no Force feedback, proves to be stable, and minimizes actuation Force. Finally, numerical and experimental results obtained from dynamic simulation and control of constrained mechanical systems, based on the proposed inverse and direct dynamics formulations, are documented.

  • ICRA - Inverse and direct dynamics of constrained multibody systems based on orthogonal decomposition of Generalized Force
    2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422), 1
    Co-Authors: Farhad Aghili
    Abstract:

    This paper presents a unified approach for inverse and direct dynamics of constrained multibody systems that can be served as a basis for analysis, simulation, and control. The compactness of the dynamics formulation can result in computational efficiency. Furthermore, the acceleration is explicitly related to the Generalized Force by an introduced "constraint inertia matrix" which is proved to be always invertible. Thus a simulation may proceed even with the presence of redundant constraints or singular configurations. The Generalized Forces are decomposed onto two orthogonal subspaces which are considered as control inputs for controlling position and constraint Force. The motion controller scheme, remarkably, requires no Force feedback, proves to be stable, and minimizes actuation Force. Finally, numerical and experimental results obtained from dynamic simulation and control of constrained mechanical systems, based on the proposed inverse and direct dynamics formulations, are documented.

Kaan Kaatsz - One of the best experts on this subject based on the ideXlab platform.

  • Generalized Force vectors for multi mode pushover analysis of torsionally coupled systems
    Earthquake Engineering & Structural Dynamics, 2014
    Co-Authors: Kaan Kaatsz, Halûk Sucuoğlu
    Abstract:

    SUMMARY A Generalized multi-mode pushover analysis procedure was developed for estimating the maximum inelastic seismic response of symmetrical plan structures under earthquake ground excitations. Pushover analyses are conducted with story-specific Generalized Force vectors in this procedure, with contributions from all effective modes. Generalized pushover analysis procedure is extended to three-dimensional torsionally coupled systems in the presented study. Generalized Force distributions are expressed as the combination of modal Forces to simulate the instantaneous Force distribution acting on the system when the interstory drift at a story reaches its maximum value during seismic response. Modal contributions to the Generalized Force vectors are calculated by a modal scaling rule, which is based on the complete quadratic combination. Generalized Forces are applied to the mass centers of each story incrementally for producing nonlinear static response. Maximum response quantities are obtained when the individual frames attain their own target interstory drift values in each story. The developed procedure is tested on an eight-story frame under 15 ground motions, and assessed by comparing the results obtained from nonlinear time history analysis. The method is successful in predicting the torsionally coupled inelastic response of frames responding to large interstory drift demands. Copyright © 2014 John Wiley & Sons, Ltd.

  • Generalized Force vectors for multi‐mode pushover analysis of torsionally coupled systems
    Earthquake Engineering & Structural Dynamics, 2014
    Co-Authors: Kaan Kaatsz, Halûk Sucuoğlu
    Abstract:

    SUMMARY A Generalized multi-mode pushover analysis procedure was developed for estimating the maximum inelastic seismic response of symmetrical plan structures under earthquake ground excitations. Pushover analyses are conducted with story-specific Generalized Force vectors in this procedure, with contributions from all effective modes. Generalized pushover analysis procedure is extended to three-dimensional torsionally coupled systems in the presented study. Generalized Force distributions are expressed as the combination of modal Forces to simulate the instantaneous Force distribution acting on the system when the interstory drift at a story reaches its maximum value during seismic response. Modal contributions to the Generalized Force vectors are calculated by a modal scaling rule, which is based on the complete quadratic combination. Generalized Forces are applied to the mass centers of each story incrementally for producing nonlinear static response. Maximum response quantities are obtained when the individual frames attain their own target interstory drift values in each story. The developed procedure is tested on an eight-story frame under 15 ground motions, and assessed by comparing the results obtained from nonlinear time history analysis. The method is successful in predicting the torsionally coupled inelastic response of frames responding to large interstory drift demands. Copyright © 2014 John Wiley & Sons, Ltd.

Petr Plecháč - One of the best experts on this subject based on the ideXlab platform.

  • The geometry of Generalized Force matching and related information metrics in coarse-graining of molecular systems
    The Journal of chemical physics, 2015
    Co-Authors: Evangelia Kalligiannaki, Vagelis Harmandaris, Markos A. Katsoulakis, Petr Plecháč
    Abstract:

    Using the probabilistic language of conditional expectations, we reformulate the Force matching method for coarse-graining of molecular systems as a projection onto spaces of coarse observables. A practical outcome of this probabilistic description is the link of the Force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean Force and to optimally approximate the potential of mean Force through Force matching. We introduce a Generalized Force matching condition for the local mean Force in the sense that allows the approximation of the potential of mean Force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of Force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the Generalized Force matching condition through applications to specific examples in molecular systems.

  • The geometry of Generalized Force matching in coarse-graining and related information metrics
    arXiv: Numerical Analysis, 2015
    Co-Authors: Evangelia Kalligiannaki, Vagelis Harmandaris, Markos A. Katsoulakis, Petr Plecháč
    Abstract:

    Using the probabilistic language of conditional expectations we reformulate the Force matching method for coarse-graining of molecular systems as a projection on spaces of coarse observables. A practical outcome of this probabilistic description is the link of the Force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean Force in order to optimally approximate the potential of mean Force through Force matching. We introduce a Generalized Force matching condition for the local mean Force in the sense that allows the approximation of the potential of mean Force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of Force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the Generalized Force matching condition through applications to specific examples in molecular systems.

Evangelia Kalligiannaki - One of the best experts on this subject based on the ideXlab platform.

  • The geometry of Generalized Force matching and related information metrics in coarse-graining of molecular systems
    The Journal of chemical physics, 2015
    Co-Authors: Evangelia Kalligiannaki, Vagelis Harmandaris, Markos A. Katsoulakis, Petr Plecháč
    Abstract:

    Using the probabilistic language of conditional expectations, we reformulate the Force matching method for coarse-graining of molecular systems as a projection onto spaces of coarse observables. A practical outcome of this probabilistic description is the link of the Force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean Force and to optimally approximate the potential of mean Force through Force matching. We introduce a Generalized Force matching condition for the local mean Force in the sense that allows the approximation of the potential of mean Force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of Force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the Generalized Force matching condition through applications to specific examples in molecular systems.

  • The geometry of Generalized Force matching in coarse-graining and related information metrics
    arXiv: Numerical Analysis, 2015
    Co-Authors: Evangelia Kalligiannaki, Vagelis Harmandaris, Markos A. Katsoulakis, Petr Plecháč
    Abstract:

    Using the probabilistic language of conditional expectations we reformulate the Force matching method for coarse-graining of molecular systems as a projection on spaces of coarse observables. A practical outcome of this probabilistic description is the link of the Force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean Force in order to optimally approximate the potential of mean Force through Force matching. We introduce a Generalized Force matching condition for the local mean Force in the sense that allows the approximation of the potential of mean Force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of Force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the Generalized Force matching condition through applications to specific examples in molecular systems.