Computational Platforms
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| ABAQUS | DIANA | ENGSIM | FRANC | IDARC 2D | IDARC 3D | 3D BASIS | NSPECTRA |
ABAQUS is a suite of general-purpose, nonlinear finite element analysis (FEA) programs developed and supported by Hibbitt, Karlsson & Sorensen, Inc. ABAQUS is used throughout the world for stress, heat transfer, and other types of analysis in mechanical, structural, civil, biomedical, and related engineering applications.
Although ABAQUS is not developed solely for earthquake engineering applications, considerable capability is available for overall nonlinear dynamic analysis of structures and for detailed component-level analysis. ABAQUS is intended for the high-end user. A strong background in structural mechanics and finite element methods is generally required.
The following items are some of the more significant features of the code:
A wide range of element types, including continuum elements (1d, 2d, 3d), beams, membranes and shells
Element formulations suitable for large displacements, rotations and strains; Implemented within an updated Lagrangian framework
Material models for metals, sand, clay, concrete, jointed rock, plastics and rubber; In some cases these models are limited to mostly monotonic loading
User-defined subroutines permit inclusion of additional material models and element types
Automatic time incrementation within an implicit time integration algorithm (Hilber-Hughes) for nonlinear dynamic analysis
Sparse symmetric and unsymmetric solvers with capability for parallel processing; Lanczos eigensolver
Surface-to-surface contact with frictional sliding
Material removal and addition to model construction sequences
Simplified rebar placement facility
Fracture mechanics capability
Coupled formulations for quasistatic thermomechanics and for consolidation processes involving pore fluid flow
Extensive documentation, including a Theory Manual, User's Manual (3 vols.), Example Problems Manual (2 vols.) and Verification Manual
DIANA is a multi-purpose finite element package with special emphasis on advanced linear and nonlinear structural engineering and flow applications. Some of the key features include:
Full 2D and 3D modelling capabilities
Around 200 element types to meet your modelling requirements
Vast choice of concrete models
Advanced algorithms for discrete and smeared cracking, crushing, creep, shrinkage and bond slip
Unique feature for easy modelling of embedded reinforcement in concrete
Pre/Post-tensioning option
Influence lines, influence fields, tendon prestress optimization
Non-linear static, dynamic, thermal and flow stress analysis
Full 2D and 3D geotechnic capabilities for many soil models
Availability of interface elements to model soil-structure interaction
Simulation and analysis of construction sequence by unique 'phased analysis'
Special solution techniques for masonry structures
Extended flexibility through user-supplied subroutines
Availability on PC's and all popular UNIX platforms Interfaces to popular pre/postprocessors
World-wide technical support through extensive network of highly qualified agents/distributors and training programmes
CORNELL FRACTURE GROUP (AND
RELATED) SOFTWARE
The FRacture ANalysis Codes originally developed at Cornell University consist of a suite of finite element and boundary element analysis programs along with the appropriate modeling and meshing software for describing the real geometry and topology of an arbitrary cracked structure. This software is used throughout the world for fracture analysis in many engineering applications. The software is freely available and its use as a research and educational tool is highly encouraged. The software consists of the following individual titles:
FRANC2D is a finite element based simulator for curvilinear crack propagation in planar (plane stress, plane strain, and axisymmetric) structures
CASCA is a pre-processor for generating initial input files for FRANC2D.
FRANC2D/L is a modified version of FRANC2D with layer capabilities. This allows the user to model riveted and adhesively bonded structures, such as lap joints and bonded repairs. Elastic-plastic material behavior is also available.
FRANC3D is a software framework for simulating arbitrary non-planar 3D crack growth. It combines real geometry and topology with automated meshing, current fracture mechanics knowledge, and automate crack growth routines. Both 3D finite element (FE) and boundary element (BE) support are encapsulated within this framework; a number of external FE or BE programs are supported.
OSM is a solid modeling tool for building initial uncracked geometric models for FRANC3D.
BES is a 3D BE code that can be used with FRANC3D for doing a linear elastic stress analysis.
Developed at the State University of New York at Buffalo, IDARC was first introduced in 1987 for the purpose of analyzing earthquake damage in multistory, reinforced concrete buildings. Since then, numerous enhancements have been added, including the ability to analyze a wide variety of structures, structural materials, and, most recently, structural damping devices.
The computer program IDARC was conceived as a platform for nonlinear structural analysis in which various aspects of concrete behavior can be modeled, tested and improved upon. Program development and enhancements have been primarily to link experimental research and analytical developments.
The original release of the program consisted of three parts:
System identification: static analysis to determine component properties and the ultimate failure mode of the building.
Dynamic response analysis: step by step inelastic dynamic analysis.
Substructure analysis and damage analysis: analysis of selected substructures, and comprehensive damage evaluation.
For the new release of the program, Version 5.0, a number of enhancements were made to the previous releases:
New unified multilinear and smooth hysteresis models with degrading characteristics.
Concentrated plasticity model for beams and columns.
Analysis beyond first onset and failure
Computation of plastic rotations in beams and columns
Enhanced model adaptive pushover analysis
IDARC-BRIDGE is a computer program for nonlinear analysis of bridges that allows many aspects of bridge behavior to be explicitly modeled. Many of the primary developments and enhancements to this program have linked research with analytical developments.
Analysis Options:
Non-linear dynamic time-history analysis using uniform ground acceleration input.
Non-linear dynamic time-history analysis using ground displacement input. The displacement input may be different at each support to account for the spatial variability of seismic excitation.
Non-linear dynamic time-history analysis using specified forces as input.
Non-linear quasi-static analysis using incremental displacements as input.
Non-linear quasi-static analysis using incremental forces as input.
Eigenvalue analysis.
Monotonic pushover collapse-mode analysis with user-specified distribution of lateral forces. A prescribed displacement limit or base shear limit terminates the analysis.
Monotonic adaptive pushover analysis, in which the distribution of lateral forces acting on the structure is adjusted with regard of the instantaneous mode shapes. The stopping criteria are analogous to those of option 7.
Dynamic pushover analysis for a linearly increasing acceleration input. The analysis ends when a prescribed displacement limit is reached.
Element Types:
Three-dimensional beam-column element with linear elastic moment-rotation, shear and axial force-displacement relations at each end. This basic stick element of the matrix analysis theory is particularly useful for modeling deck and column segments in which the cracking moment capacity (of components made of reinforced concrete) or yielding moment capacity (of components of steel structures) is not likely to be exceeded during the analysis.
Three-dimensional beam-column element with: (i) nonlinear inelastic moment-curvature, (ii) linear elastic shear force-displacement, and (iii) linear elastic axial force-displacement laws. The element is an extension of the spread-plasticity model of IDARC family, and is typically used to model the hysteretic behavior of the bridge deck and columns.
Three-dimensional beam-column element with: (i) nonlinear inelastic moment-curvature, (ii) nonlinear inelastic shear force-displacement, and (iii) linear elastic axial force-displacement laws. Testing and calibration of the parameters controlling the hysteresis of this element is under way and although it is already implemented, directions for its use will appear in the next release.
Three-dimensional sliding isolator element with nonlinear inelastic force-displacement curves in each (global) horizontal direction. The effect of the variation of the vertical force on friction is considered explicitly in the model. The element is specifically developed to represent a class of bridge friction bearings.
Three-dimensional isolator element with (i) nonlinear inelastic force-displacement relations in each of the horizontal global directions, (ii) linear elastic bending moment-rotation, and (iii) axial force-displacement laws. The element can be used to model bridge elastomeric bearings.
Unidirectional bilinear element capable of modeling: (i) initial tension and compression gaps (F» 0, d ¹ 0), (ii) nonlinear inelastic axial force-displacement relation in tension, and (iii) nonlinear elastic axial force-displacement relation in compression. The element is developed to represent the interaction between adjacent deck element in a typical expansion joint characterized by minimal stiffness in the gap, possible yielding of the restrainers, and load transfer upon impact.
Three-dimensional spring element. Apart from the diagonal terms, the element includes the coupling terms between rotation and translation along the two horizontal axes, providing means for modeling flexible connections and soil-structure interaction.
Three-dimensional viscous damping element. The structure of the element is analogous to that of the three-dimensional spring element described above. The influence of sources of concentrated damping/energy dissipation is added directly to the global damping matrix.
Three-dimensional pile-group element with nonlinear inelastic moment-rotation, shear and axial force-displacement relations. The element has been developed to represent inelastic soil-structure-interaction effects. The theory and computer implementation of this model will be published in a separate MCEER report.
A computer program for the analysis of base isolated structures
Developed in the University at Buffalo, NSPECTRA is a computer program for obtaining the response spectra of nonlinear systems. Some of the key features include:
On execution, the program performs the analysis for obtaining the individual response spectra of a collection of ground motions and the statistics (mean and standard deviation) of these spectra.
Smooth hysteretic model with degradation
The time history response for a particular pendulum in the spectrum
Evolutionary Aseismic Design & Retrofit (EADR)
Over the past several years, MCEER has supported the development of an evolutionary optimization approach for the aseismic design and retrofit of passively damped structural systems. An initial beta version of the software is intended for use within the MCEER community of researchers and industry partners. This initial release of the code Evolutionary Aseismic Design and Retrofit (EADR_1.0) includes the capability to optimize the type, size and location of passive damping elements in a structure subjected to an uncertain seismic environment. Available damper types include metallic, viscous and viscoelastic devices. The seismic environment utilizes far-field and near-field synthetic ground motions based upon the Papageorgiou model for Eastern North America. The structural system idealization for EADR_1.0 is limited to lumped parameter models with the nonlinear transient dynamic analysis performed using an explicit state-space formulation. Options provide for the specification of the design space of possible structures, drift and acceleration limits, and cost/benefit functions.
Evolutionary Aseismic Decision Support (EADS)
While the evolutionary approach for aseismic design and retrofit is useful in distinguishing the various structural design alternatives, decisions regarding whether or not to retrofit an existing structure are seldom based strictly on engineering grounds. The sociotechnical nature of organizational decision-making must be considered. Beginning in Year 6, MCEER has supported the development of new evolutionary approaches for decision support associated with critical care organizations. The methodolgy represents an extension of the EADR framework to include an organizational model, a sociopolitical model, an enhanced damage model, and the definition of a decision space that incorporates retrofit options along with other organizational policies. A preliminary version of the corresponding software is now operational for model validation and hypothesis testing. An initial release of the code Evolutionary Aseismic Decision Support (EADS_1.0), within the MCEER research community, is targeted for the end of Year 8.
NYS-HIS: New Yorst State Hospital Information System.
Hospitals are one kind of the most important public facilities. They are expected to provide uninterrupted and efficient medical services during and after an earthquake or any natural hazard. Hospitals are also important part in public hazard emergency management. This database is set up to provide the necessary information of selected hospitals in New York State for the participating researchers to carry out their individual research tasks. We can regularly modify and update the database as more information becoming available. Because it is not easy to obtain a complete set of information to represent a typical hospital (especially difficult for all the non-structural components and medical equipment), we intend to provide databases for several different hospitals in this information system. We will label each hospital by roman numerals (e.g. Hospital I, Hospital II, etc.). In this way, we also protect the identities of those hospitals that cooperate with MCEER.
Please use the following information to Log on to the system, for further information please contact Dr. Mai Tong.
UserName: Guest Password: Guest
RDAT: Rehabilitation Decision Analysis Toolbox (RDAT).
A method is presented for calculating the seismic performance of
structural/nonstructural systems and developing rational strategies for increasing the seismic resilience of these systems. The seismic performance is measures by fragility surfaces, that is, the probability of system failure as a function of moment magnitude and site-to-source distance, consequences of system damage and failure, and system recovery time following seismic events. The input to the analysis consists of seismic hazard,
geo-technical and structural/nonstructural systems properties, performance criteria, rehabilitation strategies, and a reference time. Estimates of losses and recovery times, referred to as life cycle losses and recovery times, can be derived using fragility information, Financial models, and available resources. A structural/nonstructural system located in New York City is used to
demonstrate the methodology. Fragilities are obtained for nonstructural components and system for several limit states. Also, statistics are obtained for life time losses and recovery times corresponding to different rehabilitation alternatives.
GMS: Ground Motion Simulator (GMS).
A computer code along with a user interface is developed for the
seismic ground accelerations at a collection of sites in a specified region. The
code uses a stationary non-Gaussian model for the seismic ground accelerations.
The model is based on (i) the specific barrier model defining the spectral
densities of the ground motion at a site, (ii) a postulated coherence function
characterizing the phase differences between motions at different sites, and
(iii) non-Gaussian translation processes.
VIEWS: Visualizing the Impacts of Earthquakes using Remote Sensing Images
Through MCEER funding, considerable effort has been invested in developing automated building damage detection methods, together with techniques for visualizing damage. The Bam earthquake marks their first deployment as a post-earthquake reconnaissance tool, within the VIEWS
Running on a notebook for portability, VIEWS enables reconnaissance teams to compare satellite images acquired before and after an earthquake. The system directs responders to the hardest hit areas, using the damage assessment map. For more detailed damage information, collapsed buildings are easily identified on the high-resolution satellite coverage. This also serves as a base map and orientation device for teams deployed to unfamiliar cities. To help users gain and maintain their bearings, VIEWS tracks their current position using a real-time GPS feed. The system also provides easy recall for observations made in the field. As users enter comments such as building damage descriptions and the ID number of their photographs, all information is automatically linked to the current GPS location. Back in the office, VIEWS datasets are readily transferred to a GIS environment, for further analysis.
The VIEWS system was deployed by the EERI reconnaissance team. During the course of reconnaissance activities in Bam, the GPS functionality was used to track routes followed through the city. Figure 12 illustrates one of the routes taken towards the citadel. The position of digital photographs was also overlaid and their identification numbers and associated comments added as attributes. Following this initial trial, important lessons have been learned which will improve logistical and technical aspects of VIEWS deployment for future earthquakes.
VRS: Virtual Reconnaissance Survey
The use of
spatial information is a crucial element of emergency response efforts. However,
datasets are typically acquired through a range of media (CD, PDA, laptop, GPS)
and are therefore difficult to transmit, organize, project and analyze.
The objective of this research task is to develop an online GIS-type system, called the Virtual Reconnaissance Survey (VRS). It will allow responders to transmit and share remote sensing imagery and GIS databases online, and view them using a suite of custom visualization tools.
| ABAQUS | DIANA | ENGSIM | FRANC | IDARC 2D | IDARC 3D | 3D BASIS | NSPECTRA |
3D BASIS
