Presentation on theme: "PEER Seismic Simulation: Advances with OpenSees Gregory L. Fenves University of California, Berkeley PEER Annual Meeting January 18, 2002."— Presentation transcript:
PEER Seismic Simulation: Advances with OpenSees Gregory L. Fenves University of California, Berkeley PEER Annual Meeting January 18, 2002
Simulation in PBEE Performance 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: –Assessment –Design using parameterized models –Reliability-based design Improved software needed for PBEE methodologies. OpenSees is PEERs software framework for seismic simulation to support these applications.
Status of OpenSees All information available on website at opensees.berkeley.edu –Documentation –Source code browser –Downloads (source code, Win32 exe) Version 1.2 is the current release Development versions ahead of release, but most developments available in CVS (source code versioning system) for checkout.
OpenSees in 2001 Nonlinear 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.
Open-Source Community Simulation Framework Conceptual Approach for Simulation Information Technology Software framework, Databases, Visualization, Internet/grid computation Computation Algorithms, Solvers, Parallel/distributed computing Models Material, component, system models Simulation models, Performance models, Limit state models
Summary of Models Elements –Beam-column elements for 2D and 3D based on force formulation –Zero-length elements –Plate elements (new) –2D and 3D continuum elements (including mixed formulation for incompressibility) Materials –Library of 1D uniaxial models Fairly general hysteretic models New p-y models –Constitutive models (e.g. J2 plasticity, soil models)
Element Basic System GeometricTran Linear LinearPD Corotational (Filippou) Beam-Column Geometry
Section e, s Material No assumptions are made on section or material behavior; each level in the hierarchy can be defined independently of other levels Beam-Column Models Basic System DisplacementForce
Aggregation of Section Model yield ultimate residual M residual ultimate cracking V 0,1 ForceDeformation SectionAggregator UniaxialMaterial Decorator PatternOptions for coupling: New ForceDeformation Class Inter-object communication
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
Computational Procedures Nonlinear solution algorithms: –Newton-Raphson –BFGS and Broydens –Other quasi-newton methods (e.g. using Krylov subspace updates) –Line search options –Converge options and remediation Load stepping procedures: –Variety of nonlinear static, arc-length, displacement control… –Dynamic including Newmark, HHT Equation solvers –Several equation solvers available depending on problem topology and computer hardware.