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Dynamics (advanced) - surfaces (esas.24)

esas.24

As an extension to the calculation of the natural modes (esas.22), the advanced dynamics module (esas.24) includes harmonic and seismic analysis as well as direct time integration method for structures containing surface elements (plates and shells).

- Harmonic load calculation can be required to check vibrations due to machinery, to verify structural integrity of a floor loaded by an aerobics class… Calculation is performed according to harmonic load frequency and damping of the structure input by user.
- The calculation under seismic load is used for simulating earthquakes. The behaviour of the structure under a dynamic load of the spectral type (i.e. a load of which the spectral density is known) is calculated. This calculation method is typically used to check structures against earthquakes.
- Direct time integration can be used e.g. for simulation of explosion, running load .

Highlights |
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Reaction of the structure due to a harmonic, a seismic load and direct time integration can be calculated. |

For the harmonic load, the frequency and the damping will be defined. The calculation under seismic load is used, amongst others, for simulating earthquakes; the spectra of the EC 8, NPR 9998, DIN 4149 (German standard), SIA 261 (Swiss standard) and the Turkish standard are available by default and can be extended by the user. |

The modal participation factors are indicated. |

For mentioned analyses, the results can be combined with the results from a static calculation. |

## Harmonic calculation

- User input of load frequency and overall damping (logarithmic decrement) for each load case
- More than one harmonic load case can be input, each with a different value of frequency
- Results from modal analysis are available: eigen frequencies, mass participation factors and eigenmode shapes
- The same menus as for static load cases are available to view numerical or graphical results: displacements, internal forces and reactions

## Seismic calculation

- Spectrum of the EC 8 and national codes: India, Czech Republic, Slovakia, Austria, France, Germany,Italy, Switzerland, Romania and U.S. are available by default.
- Additional spectrum can defined by the user using table input (copy/paste from Excel is also possible).
- Type of modal superposition: SRSS or CQC method can be selected by user.
- Accidental eccentricity or torsion can be taken into account for buildings.
- Automatic generation of Newmark seismic combinations.
- Results from modal analysis are available: eigen frequencies, mass participation factors and eigenmode shapes.
- The same menus as for static load cases are available to view numerical or graphical results: displacements, accelerations, internal forces and reactions.

## Direct Time Integration

- Can be used for different purposes, for example: harmonic loads, explosions, …
- The user has to input a dynamic function which presents the frequency in function of the time.

02/09/2014