Presentation on theme: "Seismic Simulation: Advances with OpenSees"— Presentation transcript:
1 Seismic Simulation: Advances with OpenSees Gregory L. Fenves University of California, BerkeleyPEER Annual Meeting January 18, 2002
2 Simulation in PBEEPerformance Based Engineering depends on evaluation seismic demands (EDP) and damage (DM).Rational, validated models of behavior of structural and geotechnical materials, components and systems are needed for simulating performance.Simulation applications:AssessmentDesign using parameterized modelsReliability-based designImproved software needed for PBEE methodologies.OpenSees is PEER’s software framework for seismic simulation to support these applications.
3 Status of OpenSeesAll information available on website at opensees.berkeley.eduDocumentationSource code browserDownloads (source code, Win32 exe)Version 1.2 is the current releaseDevelopment versions ahead of release, but most developments available in CVS (source code versioning system) for checkout.
4 OpenSees in 2001Nonlinear static and dynamic analysis of 3D structural and soil-foundation systems.Increase robustness and performance.Begin to support simulation needs for testbeds.Continue as research platform for modeling of non-ductile components, particularly degrading shear behavior.Work on documentation and user/developer workshops.
5 Conceptual Approach for Simulation Open-Source CommunitySimulation FrameworkComputationAlgorithms,Solvers,Parallel/distributedcomputingInformation TechnologySoftware framework,Databases, Visualization,Internet/grid computationModelsMaterial, component, system modelsSimulation models,Performance models,Limit state models
6 Summary of Models Elements Beam-column elements for 2D and 3D based on force formulationZero-length elementsPlate elements (new)2D and 3D continuum elements (including mixed formulation for incompressibility)MaterialsLibrary of 1D uniaxial modelsFairly general hysteretic modelsNew p-y modelsConstitutive models (e.g. J2 plasticity, soil models)
7 Beam-Column Geometry Element GeometricTran Basic System Linear LinearPDCorotational (Filippou)
8 Beam-Column Models Basic System Section Material Displacement Force e, sseMaterialNo assumptions are made on section or material behavior; each level in the hierarchy can be defined independently of other levels
10 Aggregation of Section Model yieldultimateresidualfMresidualultimatecrackingVg0,1ForceDeformationSectionAggregatorUniaxialMaterialDecorator PatternOptions for coupling:New ForceDeformation ClassInter-object communication
11 Models under Development Generalized hinge models for beam-columns (Deierlein)Beam-column joint models (Lowes)Coupled shear-axial-flexure models (Filippou)Continuing work on soil models
12 Computational Procedures Nonlinear solution algorithms:Newton-RaphsonBFGS and Broyden’sOther quasi-newton methods (e.g. using Krylov subspace updates)Line search optionsConverge options and “remediation”Load stepping procedures:Variety of nonlinear static, arc-length, displacement control…Dynamic including Newmark, HHTEquation solversSeveral equation solvers available depending on problem topology and computer hardware.
18 Issues for 2002 PEER Testbeds Models Degradation, shear-flexure, bond slip, jointsSoil-pore fluid modelsPile-foundation modelsValidation protocolsInput motions and coupled simulationsPBEE Design and SimulationParameterization of models, sensitivityReliabilityComputing and Information TechnologyParallel and distributed computingVisualizationInternet and “Grid Aware” applications (NEES)PEER Testbeds