Reference problem
=====================

The POST_COMBINAISON command calculates linear combinations of various calculation results associated with user-defined coefficients.

:math:`{C}_{i}\text{}\text{}\text{}=\text{}\text{}\text{}({\mathrm{\alpha }}_{i\mathrm{,1}}\times {Q}_{1})\text{}\text{}\text{}+\text{}\text{}\text{}({\mathrm{\alpha }}_{i\mathrm{,2}}\times {Q}_{2})`

Where:

- is the combination number

- Q1 is the result/table from a first finite element calculation

- Q2 is the result/table from a first finite element calculation

- αi,1 is the coefficient associated with Q1

- αi,2is the coefficient associated with Q2

- This is the result from the combination made.


Geometry
---------

The structure is a straight parallelepiped with a rectangular base. The dimensions of the block are: :math:`L=\mathrm{12,0}m`, :math:`H=\mathrm{3,0}m`, and :math:`B=\mathrm{0,3}m` [:ref:`Figure 1.1-1 <Ref116447775>`].


.. image:: images/10000201000003F600000156B0F8367D5EB03EB8.png
    :width: 6.1028in
    :height: 2.0575in


.. _RefImage_10000201000003F600000156B0F8367D5EB03EB8.png:


.. _Ref116447775:

**Figure** 1.1-1 **: Geometry** **of the structure**


Material properties
----------------------

Young's module: :math:`E=30000\mathit{MPa}`.

Poisson's ratio: :math:`\nu =\mathrm{0,3}`.

Density: :math:`\rho =2500\mathit{kg}/m\mathrm{³}`


Boundary conditions and loads
-------------------------------------

The left side is embedded.

*Loading 1:*

The right face is subject to three load cases:


* Force distributed along axis :math:`x`: FX = 100 kN


* Force distributed along axis :math:`y`: FY = 6000 kN


* Force distributed along axis :math:`z`: FZ = 600 kN

*Loading 2:*

The structure is subject to its own weight.

*Loading* 3 *:*

The structure is subject to seismic stresses.

The combination CQC (Full Quadratic Combination) via COMB_SISM_MODAL is calculated for the spectra described below.

The spec5 spectrum has a damping of 0.05.

The spec10 spectrum has a damping of 0.1.

The spec15 spectrum has a damping of 0.15.


.. image:: images/100002010000025D000001545CE39C3EACC4640D.png
    :width: 3.7882in
    :height: 2.4898in


.. _RefImage_100002010000025D000001545CE39C3EACC4640D.png:

Figure 1.3-1: Spec5 spectrum


.. image:: images/100002010000025D00000154DA974FA32F2B7326.png
    :width: 4.1862in
    :height: 2.822in


.. _RefImage_100002010000025D00000154DA974FA32F2B7326.png:

Figure 1.3-2: Spec10 spectrum


.. image:: images/100002010000025D000001549DDDB7BC84C31779.png
    :width: 3.7693in
    :height: 2.5425in


.. _RefImage_100002010000025D000001549DDDB7BC84C31779.png:

Figure 1.3-3: Spec15 spectrum


Bibliography
-------------