MISS, a Powerful tool in Earthquake Engineering

BEM, Substructuring, 3D-2.5D,Quality, Performance, Pre-post processing, modules, gallery

Structural Dynamics and Geophysics.

In the field of Earthquake Engineering MISS provides the engineer with a unified approach to account for phenomena such as : 
  • site effects
  • amplifications due to soil heterogeneities
  • out of phase displacements on foundations
  • soil-fluid-structure interactions
  • structure and equipment vibrations.
    • This software is also useful in related fields such as structural dynamics, geophysics and acoustics. 
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    Boundary Element Method

    MISS includes a Boundary Element Module (BEM) dealing with homogeneous or stratified visco-elastic or acoustic domains that can be either bounded or unbounded. Small surface meshes are required while radiation conditions are accounted for automatically. Several integration and regularisation techniques are provided to ensure accuracy. Coupled with the substructuring approach this module can deal with a broad range of wave propagation problems.
     

    Substructuring

    MISS is based on a dynamic substructuring method. Elastic solids, fluids, rigid bodies and structures can be mixed. Classical substructuring techniques are available and a general interface with finite element software is implemented. MISS also handles FEM-BEM coupling and is modular and evolutive. Results can be reused and modifications to a design require little additional computations. 

    2D-3D-2.5D-Periodic

    MISS is a family of modules including a 2D, 3D and 2.5D version. The latter handles 2D geometries with 3D loadings and is particularly useful to model dynamic moving sources. 3D models made of 1D and 2D periodic networks are also available.
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    MISS has been designed to fit engineers' needs and to facilitate their job

    Quality insurance

    Ask for Pro_MISS, the qualified version for the nuclear industry (In collaboration with EDF/DR)


    User friendliness

    Users working with MISS can easily define their data using a set of commands and menus including several options. Commands can be gathered into several easy to read input files including user comments. Template input files can be defined and can be reused for similar studies. A data coherency check is performed by the software. MISS also provides the user with several tools to analyse and modify his data.

    Matlab-SDT pre and post-processing and coupling with general FEM softwares.

    Project management

    MISS' modular architecture allows project management in an industrial context. Users' models can be modified during the analysis process taking advantage of previous results. Designs can evolve smoothly from preliminary to detailed stages and can include parametric studies. Several types of loadings can be computed simultaneously without any additional CPU cost.

    MISS is an open sofware. It can communicate with other sofwares and can be easily integrated in an existing UNIX environment.

    Specific tools

    MISS includes libraries of seismic incident fields and seismic signals. Normalisation, filtering and deconvolution tools can be applied to the input and output signals. Three output formats are available : time history, Fourier spectrum or spectral ratio for displacements, velocities, accelerations, pressures, tractions, impedances, seismic forces and participation factors.

    Performance

    MISS can match with the best of your computational facilities.

    The data file manager reduces both storage space and access time. Runtimes can be tuned depending on available computer resources. Execution can be restarted after system crash.

    The time consuming parts of the software have been vectorized and parallelised. Its efficiency has been demonstrated on workstations (SGI, HP, IBM,SUN) and super-computers (CRAY, DEC, SGI).

    MISS MODULES

     
     
     

    Pre-processing (DATA 2D-3D-2.5D)

    • Mesh reading, verification and correction.
    • Boundary conditions : displacements, tractions.
    • Domains' definition.
    • Materials' definition ; fluid, solid and structure.
    • Frequency range.
    • Matlab/SDT interface.
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    Incident fields (INCI)

    • Elastic and acoustic plane waves (2D-3D),
    • full space and halfspace.
    • Elastic plane waves in a layered halfspace,
    • DOSWV module ( 3D).
    • Sources points in an elastic or fluid space (2D-3D).
    • Sources points in a layered half-space,

    Boundary Element Method (2D-3D-2.5D)

    • Regularized in homogeneous visco-elastic domains.
    • Regularized in stratified visco-elastic domains.
    • Compressible and uncompressible fluids.
    • Interior field points.
    • Impedances and equivalent forces.
    • 1D and 2D periodic network.
     

    Layered domains

    • Green's functions (DOS2M 2D-3D).
    • Plane waves (DOSWV 3D).

    Multi-domains (GLOBAL 2D-3D-2.5D)

    • Assembling of Impedances and forces..
    • Synthesis of fields in the different domains.
    • Impedances of composite domains

    Outer domains (EXTE)

    • Assembling of impedance and equivalent forces.
    • Eigenmodes and static modes input.
    • Eigenmodes and interface modes input.
    • FEM mass and stiffness matrices input

    Moving sources (2.5D)

    Signal processing (SIGNAL 2D-3D-2.5D)

    • User defined signals.
    • Ricker, Heaviside, Dirac, half-sine, random
    • Processing : normalisation, filtering, deconvolution,
    • shift, integration, derivation.

    Post-processing (POST 2D-3D-2.5D)

    • Time history, fourier spectum, spectral ratio.
    • Fourier transform.
    • Fields on nodes or elements,
    • displacement, velocity, acceleration,
    • stress, traction, pressure.
    • Impedances, resultant forces.
    • Modal participation factors.
    • Animation,
    • Matlab/SDT interface.

    Gallery


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