The Experts below are selected from a list of 1829517 Experts worldwide ranked by ideXlab platform
Shujun Su - One of the best experts on this subject based on the ideXlab platform.
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general atomic and molecular electronic Structure System
Journal of Computational Chemistry, 1993Co-Authors: Michael W Schmidt, Kim K Baldridge, Jerry A Boatz, Steven T Elbert, Jan H Jensen, Shiro Koseki, Nikita Matsunaga, Kiet A Nguyen, Shujun SuAbstract:A description of the ab initio quantum chemistry package GAMESS is presented. Chemical Systems containing atoms through radon can be treated with wave functions ranging from the simplest closed-shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication. Emphasis is given to novel features of the program. The parallelization strategy used in the RHF, ROHF, UHF, and GVB sections of the program is described, and detailed speecup results are given. Parallel calculations can be run on ordinary workstations as well as dedicated parallel machines. © John Wiley & Sons, Inc.
Sekhar Chandra Dutta - One of the best experts on this subject based on the ideXlab platform.
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a critical review on idealization and modeling for interaction among soil foundation Structure System
Computers & Structures, 2002Co-Authors: Sekhar Chandra DuttaAbstract:Abstract The interaction among Structures, their foundations and the soil medium below the foundations alter the actual behaviour of the Structure considerably than what is obtained from the consideration of the Structure alone. Thus, a reasonably accurate model for the soil–foundation–Structure interaction System with computational validity, efficiency and accuracy is needed in improved design of important Structures. The present study makes an attempt to gather the possible alternative models available in the literature for this purpose. Emphasis has been given on the physical modeling of the soil media, since it appears that the modeling of the Structure is rather straightforward. The strengths and limitations of the models described in a single paper may be of help to the civil engineers to choose a suitable one for their study and design.
Peizi Wei - One of the best experts on this subject based on the ideXlab platform.
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Theoretical Derivation and Parameters Analysis of a Human-Structure Interaction System with the Bipedal Walking Model
Journal of Mathematics, 2021Co-Authors: Huiqi Liang, Zhiqiang Zhang, Peizi WeiAbstract:The excessive vertical vibration of Structures induced by walking pedestrians has attracted considerable attention in the past decades. The bipedal walking models proposed previously, however, merely focus on the effects generated by legs and ignore the effects of the dynamics of body parts on pedestrian-Structure interactions. The contribution of this paper is proposing a novel pedestrian-Structure interaction System by introducing the concept of the continuum and a different variable stiffness strategy. The dynamic model of pedestrian-Structure coupling System is established using the Lagrange method. The classical mode superposition method is utilized to calculate the response of the Structure. The state-space method is employed to determine natural frequencies and damping ratio of the coupled System. Based on the proposed model, numerical simulations and parametric analysis are conducted. Numerical simulations have shown that the continuum enables the pedestrian-Structure System to achieve the stable state more efficiently than the classic model does, which idealizes the body as a concentrated or lumped mass. The parametric study reveals that the presence of pedestrians is proved to significantly decrease the frequency of human-Structure interaction System and improve its damping ratio. Moreover, the parameters of the bipedal model have a noticeable influence on the dynamic properties and response of the pedestrian-Structure System. The bipedal walking model proposed in this paper depicts a pattern of pedestrian-Structure interactions with different parameter settings and has a great potential for a wide range of practical applications.
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Identification of Dynamic Parameters of Pedestrian Walking Model Based on a Coupled Pedestrian–Structure System
'MDPI AG', 2021Co-Authors: Huiqi Liang, Peizi Wei, Wenbo Xie, Zhiqiang ZhangAbstract:As human occupancy has an enormous effect on the dynamics of light, flexible, large-span, low-damping Structures, which are sensitive to human-induced vibrations, it is essential to investigate the effects of pedestrian–Structure interaction. The single-degree-of-freedom (SDOF) mass–spring–damping (MSD) model, the simplest dynamical model that considers how pedestrian mass, stiffness and damping impact the dynamic properties of Structures, is widely used in civil engineering. With field testing methods and the SDOF MSD model, this study obtained pedestrian dynamics parameters from measured data of the properties of both empty Structures and Structures with pedestrian occupancy. The parameters identification procedure involved individuals at four walking frequencies. Body frequency is positively correlated to the walking frequency, while a negative correlation is observed between the body damping ratio and the walking frequency. The test results further show a negative correlation between the pedestrian’s frequency and his/her weight, but no significant correlation exists between one’s damping ratio and weight. The findings provide a reference for structural vibration serviceability assessments that would consider pedestrian–Structure interaction effects
Ehsan Ahmadi - One of the best experts on this subject based on the ideXlab platform.
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effects of pulse period of near field ground motions on the seismic demands of soil mdof Structure Systems using mathematical pulse models
Earthquake Engineering & Structural Dynamics, 2013Co-Authors: Faramarz Khoshnoudian, Ehsan AhmadiAbstract:SUMMARY In this paper, the effects of pulse period associated with near-field ground motions on the seismic demands of soil–MDOF Structure Systems are investigated by using mathematical pulse models. Three non-dimensional parameters are employed as the crucial parameters, which govern the responses of soil–Structure Systems: (1) non-dimensional frequency as the Structure-to-soil stiffness ratio; (2) aspect ratio of the superStructure; and (3) structural target ductility ratio. The soil beneath the superStructure is simulated on the basis of the Cone model concept. The superStructure is modeled as a nonlinear shear building. Interstory drift ratio is selected as the main engineering demand parameter for soil–Structure Systems. It is demonstrated that the contribution of higher modes to the response of soil–Structure System depends on the pulse-to-interacting System period ratio instead of pulse-to-fixed-base Structure period ratio. Furthermore, results of the MDOF superStructures demonstrate that increasing structural target ductility ratio results in the first-mode domination for both fixed-base Structure and soil–Structure System. Additionally, increasing non-dimensional frequency and aspect ratio of the superStructure respectively decrease and increase the structural responses. Moreover, comparison of the equivalent soil–SDOF Structure System and the soil–MDOF Structure System elucidates that higher-mode effects are more significant, when soil–Structure interaction is taken into account. In general, the effects of fling step and forward directivity pulses on activating higher modes of the superStructure are more sever in soil–Structure Systems, and in addition, the influences of forward directivity pulses are more considerable than fling step ones. Copyright © 2013 John Wiley & Sons, Ltd.
Michael W Schmidt - One of the best experts on this subject based on the ideXlab platform.
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general atomic and molecular electronic Structure System
Journal of Computational Chemistry, 1993Co-Authors: Michael W Schmidt, Kim K Baldridge, Jerry A Boatz, Steven T Elbert, Jan H Jensen, Shiro Koseki, Nikita Matsunaga, Kiet A Nguyen, Shujun SuAbstract:A description of the ab initio quantum chemistry package GAMESS is presented. Chemical Systems containing atoms through radon can be treated with wave functions ranging from the simplest closed-shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication. Emphasis is given to novel features of the program. The parallelization strategy used in the RHF, ROHF, UHF, and GVB sections of the program is described, and detailed speecup results are given. Parallel calculations can be run on ordinary workstations as well as dedicated parallel machines. © John Wiley & Sons, Inc.
