- Mapdl.sload(secid='', plnlab='', kinit='', kfd='', fdvalue='', lsload='', lslock='', **kwargs)¶
Load a pretension section.
APDL Command: SLOAD
secid – Unique section number. The number must already be assigned to a pretension section.
plnlab – Label representing the pretension load sequence number in the format “PLnn” where nn is an integer from 1 through 99 (for example, PL01 through PL99).
Initial action key for pretension load PL01. (This field is omitted for PL02 and up.) Three scenarios are possible:
- LOCK - Constrains (connects) the cutting plane on the pretension section. This value
is the default.
SLID - Unconstrains (disconnects) the cutting plane on the pretension section.
- TINY - Applies a very small pretension load (0.1% of FDVALUE) before the desired load
is established. The small load prevents convergence problems which can occur when the desired load is not established in the first load step. This value is valid only if KFD = FORC.
Force/Displacement key. Specifies whether FDVALUE is a force or a displacement:
FORC - Apply a force on the specified pretension section. This value is the default.
DISP - Apply a displacement (adjustment) on the specified pretension section.
fdvalue – Pretension load value. If KFD = FORC, this value is a pretension force. If KFD = DISP, this value is a pretension displacement (adjustment).
lsload – Load step in which to apply the FDVALUE.
lslock – The load step in which the displacement value resulting from the pretension force is locked. This value is valid only if KFD = FORC.
The SLOAD command applies pretension loads to specified pretension sections (created via the PSMESH command). A pretension load is ramp- applied (KBC = 0) if it is a force (KFD = FORC), and step-applied (KBC = 1) if it is a displacement (KFD = DISP).
You can “lock” the load value at a specified load step. When locked, the load changes from a force to a displacement, and ANSYS applies the load as a constant displacement in all future load steps. Locking is useful when applying additional loadings. The additional loadings alter the effect of the initial load value, but because locking transforms the load into a displacement, it preserves the initial load’s effect.
In modal and harmonic analyses, any pretension load (force, displacement, or locked) is ignored and no load is produced.
The following command shows how to establish loads on a pretension section:
In this example, the load is applied to pretension section 1, and the sequence begins with the initial action key, KINIT, set to TINY. A small stabilization load (5 = 0.10% of 5000) is applied in the first load step, as the actual pretension force is not applied until the second load step. The next four fields set the actual load: the KFD value FORC specifies the type of load, FDVALUE defines the pretension load value (5000), LSLOAD specifies the load step in which the force is applied (2), and the LSLOCK field specifies the load step in which the force is locked (3). Additional sets of four fields can be used to define additional loads.
You can use the SLOAD command to edit (overwrite) existing loads on a pretension section. This example changes the load on pretension section 1 (set above) to 6000:
Unspecified values (blank fields), as shown in this example, remain unchanged from prior settings. If no prior specifications exist, then default values (KINIT = LOCK and KFD = FORC) apply.
The command can also delete all loads on a specified pretension section, as shown here:
For a prestressed modal analysis, this command locks the pretension element: