This study examines the performance of integration methods for hybrid simulation of large and complex structural systems in the context of structural collapse due to seismic excitations. The target application is not ...This study examines the performance of integration methods for hybrid simulation of large and complex structural systems in the context of structural collapse due to seismic excitations. The target application is not necessarily for real-time testing, but rather for models that involve large-scale physical sub-structures and highly nonlinear numerical models. Four case studies are presented and discussed. In the first case study, the accuracy of integration schemes including two widely used methods, namely, modified version of the implicit Newmark with fixed-number of iteration （iterative） and the operator-splitting （non-iterative） is examined through pure numerical simulations. The second case study presents the results of 10 hybrid simulations repeated with the two aforementioned integration methods considering various time steps and fixed-number of iterations for the iterative integration method. The physical sub-structure in these tests consists of a single-degree-of-freedom （SDOF） cantilever column with replaceable steel coupons that provides repeatable highly- nonlinear behavior including fracture-type strength and stiffness degradations. In case study three, the implicit Newmark with fixed-number of iterations is applied for hybrid simulations of a 1：2 scale steel moment frame that includes a relatively complex nonlinear numerical substructure. Lastly, a more complex numerical substructure is considered by constructing a nonlinear computational model of a moment frame coupled to a hybrid model ofa 1：2 scale steel gravity frame. The last two case studies are conducted on the same porotype structure and the selection of time steps and fixed number of iterations are closely examined in pre-test simulations. The generated unbalance forces is used as an index to track the equilibrium error and predict the accuracy and stability of the simulations.展开更多
Hybrid simulation can be a cost effective approach for dynamic testing of structural components at full scale while capturing the system level response through interactions with a numerical model.The dynamic response ...Hybrid simulation can be a cost effective approach for dynamic testing of structural components at full scale while capturing the system level response through interactions with a numerical model.The dynamic response of a seismically isolated structure depends on the combined characteristics of the ground motion,bearings,and superstructure.Therefore,dynamic full-scale system level tests of isolated structures under realistic dynamic loading conditions are desirable towards a holistic validation of this earthquake protection strategy.Moreover,bearing properties and their ultimate behavior have been shown to be highly dependent on rate-of-loading and scale size effects,especially under extreme loading conditions.Few laboratory facilities can test full-scale seismic isolation bearings under prescribed displacement and/or loading protocols.The adaptation of a full-scale bearing test machine for the implementation of real-time hybrid simulation is presented here with a focus on the challenges encountered in attaining reliable simulation results for large scale dynamic tests.These advanced real-time hybrid simulations of large and complex hybrid models with several thousands of degrees of freedom are some of the first to use high performance parallel computing to rapidly execute the numerical analyses.Challenges in the experimental setup included measured forces contaminated by delay and other systematic control errors in applying desired displacements.Friction and inertial forces generated by the large-scale loading apparatus can affect the accuracy of measured force feedbacks.Reliable results from real-time hybrid simulation requires implementation of compensation algorithms and correction of these various sources of errors.Overall,this research program confirms that real-time hybrid simulation is a viable testing method to experimentally assess the behavior of full-scale isolators while capturing interactions with the numerical models of the superstructure to evaluate system level and in-structure response.展开更多
Design Safe addresses the challenges of supporting integrative data-driven research in natural hazards engineering.It is an end-to-end data management,communications,and analysis platform where users collect,generate,...Design Safe addresses the challenges of supporting integrative data-driven research in natural hazards engineering.It is an end-to-end data management,communications,and analysis platform where users collect,generate,analyze,curate,and publish large data sets from a variety of sources,including experiments,simulations,field research,and post-disaster reconnaissance.DesignSafe achieves key objectives through:(1)integration with high performance and cloud-computing resources to support the computational needs of the regional risk assessment community;(2)the possibility to curate and publish diverse data structures emphasizing relationships and understandability;and(3)facilitation of real time communications during natural hazards events and disasters for data and information sharing.The resultant services and tools shorten data cycles for resiliency evaluation,risk modeling validation,and forensic studies.This article illustrates salient features of the cyberinfrastructure.It summarizes its design principles,architecture,and functionalities.The focus is on case studies to show the impact of Design Safe on the disaster risk community.The Next Generation Liquefaction project collects and standardizes case histories of earthquake-induced soil liquefaction into a relational database—Design Safe—to permit users to interact with the data.Researchers can correlate in Design Safe building dynamic characteristics based on data from building sensors,with observed damage based on ground motion measurements.Reconnaissance groups upload,curate,and publish wind,seismic,and coastal damage data they gather during field reconnaissance missions,so these datasets are available shortly after a disaster.As a part of the education and community outreach efforts of Design Safe,training materials and collaboration space are also offered to the disaster risk management community.展开更多
基金National Science Foundation(NSF)under grant No.CMMI-0748111
文摘This study examines the performance of integration methods for hybrid simulation of large and complex structural systems in the context of structural collapse due to seismic excitations. The target application is not necessarily for real-time testing, but rather for models that involve large-scale physical sub-structures and highly nonlinear numerical models. Four case studies are presented and discussed. In the first case study, the accuracy of integration schemes including two widely used methods, namely, modified version of the implicit Newmark with fixed-number of iteration （iterative） and the operator-splitting （non-iterative） is examined through pure numerical simulations. The second case study presents the results of 10 hybrid simulations repeated with the two aforementioned integration methods considering various time steps and fixed-number of iterations for the iterative integration method. The physical sub-structure in these tests consists of a single-degree-of-freedom （SDOF） cantilever column with replaceable steel coupons that provides repeatable highly- nonlinear behavior including fracture-type strength and stiffness degradations. In case study three, the implicit Newmark with fixed-number of iterations is applied for hybrid simulations of a 1：2 scale steel moment frame that includes a relatively complex nonlinear numerical substructure. Lastly, a more complex numerical substructure is considered by constructing a nonlinear computational model of a moment frame coupled to a hybrid model ofa 1：2 scale steel gravity frame. The last two case studies are conducted on the same porotype structure and the selection of time steps and fixed number of iterations are closely examined in pre-test simulations. The generated unbalance forces is used as an index to track the equilibrium error and predict the accuracy and stability of the simulations.
文摘Hybrid simulation can be a cost effective approach for dynamic testing of structural components at full scale while capturing the system level response through interactions with a numerical model.The dynamic response of a seismically isolated structure depends on the combined characteristics of the ground motion,bearings,and superstructure.Therefore,dynamic full-scale system level tests of isolated structures under realistic dynamic loading conditions are desirable towards a holistic validation of this earthquake protection strategy.Moreover,bearing properties and their ultimate behavior have been shown to be highly dependent on rate-of-loading and scale size effects,especially under extreme loading conditions.Few laboratory facilities can test full-scale seismic isolation bearings under prescribed displacement and/or loading protocols.The adaptation of a full-scale bearing test machine for the implementation of real-time hybrid simulation is presented here with a focus on the challenges encountered in attaining reliable simulation results for large scale dynamic tests.These advanced real-time hybrid simulations of large and complex hybrid models with several thousands of degrees of freedom are some of the first to use high performance parallel computing to rapidly execute the numerical analyses.Challenges in the experimental setup included measured forces contaminated by delay and other systematic control errors in applying desired displacements.Friction and inertial forces generated by the large-scale loading apparatus can affect the accuracy of measured force feedbacks.Reliable results from real-time hybrid simulation requires implementation of compensation algorithms and correction of these various sources of errors.Overall,this research program confirms that real-time hybrid simulation is a viable testing method to experimentally assess the behavior of full-scale isolators while capturing interactions with the numerical models of the superstructure to evaluate system level and in-structure response.
基金The National Science Foundation(NSF)financially supports the Design Safe project under grant CMMI-1520817NSF grant ACI1134872 for high performance computing,and grants ACI-1127210 and ACI-1450459 for the development of the Agave API
文摘Design Safe addresses the challenges of supporting integrative data-driven research in natural hazards engineering.It is an end-to-end data management,communications,and analysis platform where users collect,generate,analyze,curate,and publish large data sets from a variety of sources,including experiments,simulations,field research,and post-disaster reconnaissance.DesignSafe achieves key objectives through:(1)integration with high performance and cloud-computing resources to support the computational needs of the regional risk assessment community;(2)the possibility to curate and publish diverse data structures emphasizing relationships and understandability;and(3)facilitation of real time communications during natural hazards events and disasters for data and information sharing.The resultant services and tools shorten data cycles for resiliency evaluation,risk modeling validation,and forensic studies.This article illustrates salient features of the cyberinfrastructure.It summarizes its design principles,architecture,and functionalities.The focus is on case studies to show the impact of Design Safe on the disaster risk community.The Next Generation Liquefaction project collects and standardizes case histories of earthquake-induced soil liquefaction into a relational database—Design Safe—to permit users to interact with the data.Researchers can correlate in Design Safe building dynamic characteristics based on data from building sensors,with observed damage based on ground motion measurements.Reconnaissance groups upload,curate,and publish wind,seismic,and coastal damage data they gather during field reconnaissance missions,so these datasets are available shortly after a disaster.As a part of the education and community outreach efforts of Design Safe,training materials and collaboration space are also offered to the disaster risk management community.
