3.5.12. CREATE-CONSTRAINT function

optional

This function is used to create a constraint case on your model. Currently it allows single point constraint (SPC) definition, and thus it enables the definition of prescribed displacements at the nodes degrees of freedom.

By default, SesamX will understand the degrees of freedom provided in the global basis. However, you can also inform SesamX to use a previously defined basis to prescribe the degrees of freedom values (as showcased in the examples).

optional

This branch is used to create a single point constrain (SPC) on the displacements at the nodes (translation and rotation degrees of freedom).

In the following example, a single point constraint is created in the global basis.

CREATE-CONSTRAINT  
  MODEL: MY_MODEL
  NAME: CONST_CASE
  DISPLACEMENT-SPC
    TX: 0.  
    RZ: 0.
    ON-NODES-FROM: HOLE_1

For each node of the HOLE_1 selection, this constraint object enforces $T_X = 0$ and $R_Z = 0$, where $T_X$ and $R_Z$ are the degrees of freedom at the nodes in the global basis.

In the following example, a single point constraint is created relative to a previously defined user basis (BASIS_A).

CREATE-CONSTRAINT  
  MODEL: MY_MODEL
  NAME: CONST_CASE
  DISPLACEMENT-SPC
    BASIS: BASIS_A
    TX: 3.  
    RY: 5. 
    ON-NODES-FROM: HOLE_1

For each node of the HOLE_1 selection, this constraint object enforces $T_X = 0$ and $R_Y = 0$, where $T_X$ and $R_Y$ are the degrees of freedom at the nodes in the user basis.

If $(\underline{u_1}, \underline{u_2}, \underline{u_3})$ are the vectors of BASIS_A, these 2 constraints translate to:

• $u_1^1T_X + u_1^2T_Y + u_1^3T_Z = 3.$
• $u_2^1R_X + u_2^2R_Y + u_2^3R_Z = 5.$

Where $u_1^i$ and $u_2^i$ are the components of the user basis vectors $\underline{u_1}$ and $\underline{u_2}$ in the global basis. And $T_X, T_Y, T_Z, R_X, R_Y, R_Z$ are the degrees of freedom at the node in the global basis.

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