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Keyword type: step

For surface loading the faces of the elements are numbered as follows (for the node numbering of the elements see Section 3.1):

for hexahedral elements:

• face 1: 1-2-3-4
• face 2: 5-8-7-6
• face 3: 1-5-6-2
• face 4: 2-6-7-3
• face 5: 3-7-8-4
• face 6: 4-8-5-1

for tetrahedral elements:

• Face 1: 1-2-3
• Face 2: 1-4-2
• Face 3: 2-4-3
• Face 4: 3-4-1

for wedge elements:

• Face 1: 1-2-3
• Face 2: 4-5-6
• Face 3: 1-2-5-4
• Face 4: 2-3-6-5
• Face 5: 3-1-4-6
for quadrilateral plane stress, plane strain and axisymmetric elements:
• Face 1: 1-2
• Face 2: 2-3
• Face 3: 3-4
• Face 4: 4-1

for triangular plane stress, plane strain and axisymmetric elements:

• Face 1: 1-2
• Face 2: 2-3
• Face 3: 3-1

for beam elements:

• Face 1: pressure in 1-direction
• Face 2: pressure in 2-direction

For shell elements no face number is needed since there is only one kind of loading: pressure in the direction of the normal on the shell.

Edge loading is only provided for shell elements. Its units are force per unit length. The label is EDNORx where x can take a value between one and three for triangular shells and between one and four for quadrilateral shells. This type of loading is locally orthogonal to the edge. Internally, it is replaced by a pressure load, since shell elements in CalculiX are expanded into volumetric elements. The numbering is as follows:

for triangular shell elements:

• Edge 1: 1-2
• Edge 2: 2-3
• Edge 3: 3-1

• Edge 1: 1-2
• Edge 2: 2-3
• Edge 3: 3-4
• Edge 4: 4-1

For centrifugal loading (label CENTRIF) the rotational speed square () and two points on the rotation axis are required, for gravity loading with known gravity vector (label GRAV) the size and direction of the gravity vector are to be given. Whereas more than one centrifugal load for one and the same set is not allowed, several gravity loads can be defined, provided the direction of the load varies. If the gravity vector is not known it can be calculated based on the momentaneous mass distribution of the system (label NEWTON). This requires the value of the Newton gravity constant by means of a *PHYSICAL CONSTANTS card.

The limit of one centrifugal load per set does not apply to linear dynamic (*MODAL DYNAMIC) and steady state (*STEADY STATE DYNAMICS) calculations. Here, the limit is two. In this way a rotating eccentricity can be modeled. Prerequisite for the centrifugal loads to be interpreted as distinct is the choice of distinct rotation axes.

The AMPLITUDE parameter allows for the specification of an amplitude by which the force values are scaled (mainly used for dynamic calculations). Thus, in that case the values entered on the *DLOAD card are interpreted as reference values to be multiplied with the (time dependent) amplitude value to obtain the actual value. At the end of the step the reference value is replaced by the actual value at that time. In subsequent steps this value is kept constant unless it is explicitly redefined or the amplitude is defined using TIME=TOTAL TIME in which case the amplitude keeps its validity. For nonuniform loading the AMPLITUDE parameter has no effect.

The TIME DELAY parameter modifies the AMPLITUDE parameter. As such, TIME DELAY must be preceded by an AMPLITUDE name. TIME DELAY is a time shift by which the AMPLITUDE definition it refers to is moved in positive time direction. For instance, a TIME DELAY of 10 means that for time t the amplitude is taken which applies to time t-10. The TIME DELAY parameter must only appear once on one and the same keyword card.

The SECTOR parameter can only be used in *MODAL DYNAMIC and *STEADY STATE DYNAMICS calculations with cyclic symmetry. The datum sector (the sector which is modeled) is sector 1. The other sectors are numbered in increasing order in the rotational direction going from the slave surface to the master surface as specified by the *TIE card. Consequently, the SECTOR parameters allows to apply a distributed load to any element face in any sector.

Notice that in case an element set is used on any line following *DLOAD this set should not contain elements from more than one of the following groups: {plane stress, plane strain, axisymmetric elements}, {beams, trusses}, {shells, membranes}, {volumetric elements}.

If more than one *DLOAD card occurs within the input deck, or a *DLOAD and at least one *DSLOAD card, the following rules apply:

If a *DLOAD or *DSLOAD with label P1 up to P6 or EDNOR1 up to EDNOR4 or BF is applied to an element for which a *DLOAD or *DSLOAD with the SAME label was already applied before, then

• if the previous application was in the same step the load value is added, else it is replaced
• the new amplitude (including none) overwrites the previous amplitude

If a *DLOAD with label CENTRIF is applied to the same set AND with the same rotation axis as in a previous application, then

• If the prevous application was in the same step, the CENTRIF value is added, else it is replaced
• the new amplitude (including none) overwrites the previous amplitude

If a *DLOAD with label GRAV is applied to the same set AND with the same gravity direction vector as in a previous application, then

• If the prevous application was in the same step, the GRAV value is added, else it is replaced
• the new amplitude (including none) overwrites the previous amplitude

First line:

• Enter any needed parameters and their value

• Element number or element set label.
• Actual magnitude of the load (for Px type labels) or fluid node number (for PxNU type labels)
Repeat this line if needed.

Example:

Se1,P3,10.


assigns a pressure loading with magnitude 10. times the amplitude curve of amplitude A1 to face number three of all elements belonging to set Se1.

Example files: beamd.

• Element number or element set label.
• CENTRIF
• rotational speed square ()
• Coordinate 1 of a point on the rotation axis
• Coordinate 2 of a point on the rotation axis
• Coordinate 3 of a point on the rotation axis
• Component 1 of the normalized direction of the rotation axis
• Component 2 of the normalized direction of the rotation axis
• Component 3 of the normalized direction of the rotation axis
Repeat this line if needed.

Example:

Eall,CENTRIF,100000.,0.,0.,0.,1.,0.,0.


Example files: achtelc, disk2.

assigns centrifugal loading with about an axis through the point (0.,0.,0.) and with direction (1.,0.,0.) to all elements.

• Element number or element set label.
• GRAV
• Actual magnitude of the gravity vector.
• Coordinate 1 of the normalized gravity vector
• Coordinate 2 of the normalized gravity vector
• Coordinate 3 of the normalized gravity vector
Repeat this line if needed. Here "gravity" really stands for any acceleration vector.

Example:

Eall,GRAV,9810.,0.,0.,-1.


assigns gravity loading in the negative z-direction with magnitude 9810. to all elements.

Example files: achtelg, cube2.

• Element number or element set label.
• NEWTON
Repeat this line if needed. Only elements loaded by a NEWTON type loading are taken into account for the gravity calculation.

Example: