20. Keyword MASS_REP

20.1. Syntax

MASS_REP = _F (

# Surface or line used to distribute mass

♦ GROUP_MA = gr_ma, [group_ma]

# POI1 meshes corresponding to the masses

♦ GROUP_MA_POI1 = gr_poi1, [group_ma]

# Mass to be distributed over the stitches of GROUP_MA

♦ VALE = mass, [real]

♦ TYPE = [“SURFACIQUE”, “LINEIQUE”, “TOTALE”], [txt]

# Mass distribution function

◊ FONC_MULT = mult_function, [function]

),

20.2. Affordable characteristics

The objective of this keyword is to simply take into account a mass and to distribute it over a surface. Option MASS_REP allows to distribute to the nodes discretes of characteristic “M_T_D_N” of the mass values obtained in proportion to the area of the surface cells or the length of the line cells.

The assignment (modeling “DIS_T” to be declared in AFFE_MODELE) is done at point meshes POI1données to GROUP_MA_POI1. A distinction must be made between point cells and area cells to be declared behind the keyword GROUP_MA.

The overload rule applies [U1.03.00]. If a POI1est mesh is present in several occurrences of MASS_REPc “is the last assignment that is taken into account.

In case of overload, information is written to the “message” file, indicating the number of overloads performed.

20.3. Description of operands

♦ GROUP_MA

Surface mesh groups.

♦ GROUP_MA_POI1

Group of point cells, of type “DIS_T” to be declared in AFFE_MODELE.

♦ VALE = mass

Value of the mass to be distributed for the area concerned by GROUP_MA. Its unit is homogeneous to \({\mathit{surface}}^{-1}\), \({\mathit{longueur}}^{-1}\) depending on the value of TYPE.

♦ TYPE = [“SURFACIQUE”, “LINEIQUE”, “TOTALE”]

Allows you to define the mass to be assigned to discretes of type “M_T_D_N”. This mass is a function of the area of the meshes that are connected to the discrete node. We can either give:

• a MASSE of TYPE = “SURFACIQUE”: this mass is distributed in proportion to the area of the surface cells connected to the discrete node. POI1 meshes are affected by mass:

\({\mathit{Masse}}_{\mathit{POI1}}={\mathit{Masse}}_{\mathit{Surfacique}}\ast {\mathit{Surface}}_{\mathit{Noeud}}\)

• a MASSE of TYPE = “LINEIQUE”: this mass is distributed in proportion to the length of the line cells connected to the discrete node. POI1 meshes are affected by mass:

\({\mathit{Masse}}_{\mathit{POI1}}={\mathit{Masse}}_{\mathit{Linéique}}\ast {\mathit{Longueur}}_{\mathit{Noeud}}\)

• a MASSE with TYPE = “TOTALE”: this is the total mass to be distributed either in proportion to the area of the surface cells or in proportion to the length of the line cells, connected to the node of the discretes. POI1 meshes are affected by mass:

\({\mathit{Masse}}_{\mathit{POI1}}=\frac{{\mathit{Masse}}_{\mathit{Totale}}\ast {\mathit{Surface}}_{\mathit{Noeud}}}{{\mathit{Surface}}_{\mathit{Totale}}}\) or \({\mathit{Masse}}_{\mathit{POI1}}=\frac{{\mathit{Masse}}_{\mathit{Totale}}\ast {\mathit{Longueur}}_{\mathit{Noeud}}}{{\mathit{Longueur}}_{\mathit{Totale}}}\)

◊ FONC_MULT = mult_function

We can give a function (X, Y, Z) that multiplies the mass to be distributed by the cell. This function is evaluated at the center of gravity of the mesh.