Contrib:KeesWouters/spring

Spring construction

The spring construction consists of two rectangular plates with four spring leaves between them. The springs are symmetrical with respect to forces in x, y and z directions.

*

The outer rectangular plate together with the spring leaves consists of the same face. The inner rectangulare plate is a different face and has set different wall thickness in the C-A command file. In the picture at the right hand side the transition between the two part is clearly visible with the straight mesh line.

In the python script the geometry and the mesh are defined: Media:kw_spring3.zip

In this file you can see how the geometry is defined by:

• points to define the inner and outer rectangles and the spring positions
• lines between these points to define inner and outer rectangle and springs
• lines and wire to define the dividing between springs and inner rectangle (partitioning)
• partitioning of the outer rectangle and springs and inner rectangle
• grouping of the various elements:
  
• >> faces: outer rectangle and springs shout, inner rectangle shin
• >> lines for boundary conditions and forces: inedge, outedge
• >> nodes: node1 (N1), node13 (N1 and N3) and node4 (N1, N2, N3 and N4)

Results

Four vertical forces applied
Applying four vertical forces at the corner nodes (Fz = -0.25 N per node, 1 N total force), the vertical displacements at the four corner nodes are:

• dz at nodes N25 and N28 -0.1855 and
• dz at nodes N26 and N27 -0.1856 (opposite nodes have the same values).

Displacements - two forces at inside corners
Applying four vertical forces at the opposite corner nodes (Fz = -0.50 N per node, 1 N total force), the vertical displacements at the four corner nodes are:

• dz at nodes N26 and N27: -1.840 mm and
• dz at nodes N25 and N28: -1.870 mm (opposite nodes have the same values).
  

Roughly the same values as previously, and some additional bending of the inner plate.

One force at inside corner applied
Applying one vertical force at a corner node (Fz = -1.00 N per node, 1 N total force), the vertical displacements at the four corner nodes are:

• dz at node N25: -0.423 mm
• dz at node N26: -0.191 mm
• dz at node N27: -0.177 mm and
• dz at node N28: +0.049 mm, i.e. average displacement in z direction is -0.21 mm.

Displacements - two forces at inside corners

The results are written to a file with the following C-A commands:

# ================================
# define values for printing displacements at four inside corner nodes
meshmod=DEFI_GROUP(reuse =meshmod,
              MAILLAGE=meshmod,
              #CREA_GROUP_MA=_F(NOM='test',GROUP_MA=('outedge',),),
              CREA_GROUP_NO=_F(NOM='nforce',GROUP_NO='nodes4',),
              INFO=2,);

#================================================                   
TB_nodf=POST_RELEVE_T(ACTION=(_F(OPERATION='EXTRACTION',
                             INTITULE='Displacements',
                             RESULTAT=result,
                             NOM_CHAM='DEPL',
                             TOUT_ORDRE='OUI',
                             GROUP_NO='nforce',
                             NOM_CMP=('DZ',),),),
                             #TOUT_CMP='OUI',
                             #RESULTANTE=('DZ',),),),
                     TITRE='DX-DY-DZ-DRX-DRY',);

# print displacements to file                       
IMPR_TABLE(TABLE=TB_nodf,
         FORMAT='TABLEAU',
         UNITE=26,
         SEPARATEUR=' * ',
         TITRE='displacements at nodes',);

And the result file, defined in ASTK by mast-type, name ./nd3.txt and unit (LU) 26, is as follows:

2. --------------------------------------------------------------------------------
4. displacements at nodes
5. DX-DY-DZ-DRX-DRY

* INTITULE         * NOEUD    * RESU     * NOM_CHAM         * NUME_ORDRE   * INST         * ABSC_CURV    * COOR_X       * COOR_Y       * COOR_Z       * DZ          
* Displacements    * N25      * result   * DEPL             *            1 *  0.00000E+00 *  0.00000E+00 *  2.30000E+00 *  2.30000E+00 *  0.00000E+00 * -1.85489E-01
* Displacements    * N28      * result   * DEPL             *            1 *  0.00000E+00 *  6.38122E+00 *  7.70000E+00 *  5.70000E+00 *  0.00000E+00 * -1.85486E-01
* Displacements    * N26      * result   * DEPL             *            1 *  0.00000E+00 *  9.78122E+00 *  7.70000E+00 *  2.30000E+00 *  0.00000E+00 * -1.85623E-01
* Displacements    * N27      * result   * DEPL             *            1 *  0.00000E+00 *  1.61624E+01 *  2.30000E+00 *  5.70000E+00 *  0.00000E+00 * -1.85611E-01