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*WINCH, file=$path\filename.dat

Data format:

One line with 1 values

NSPR

Status :

Optional

Purpose :

To define winch pay-out rates that can vary with time.

Restrictions :

A spring element must have been created.

Details :

Parameter	Description
NSPR	either a spring element number or a group number. If is s spring element, the reference length of the element is increased/decreased with time. If it a group number, the total length of the entire group is adjusted keeping the same original length ratio between elements. Also applies if the winch is defined with constant velocity (not file).
Filename.dat	Must be an ASCII file with two columns like shown below : Time_1 speed_1 Time_2 speed_2 Time_n speed_n

Note

The velocity is interpolated between two timestep of the file. Note that if no data is given at=0, velocity is assumed to be 0. If final time step in datafile is smaller then computational time, the velocity is considered constant equal to the last velocity value in the file from the last time step of the file.

A winch can be considered as a kinematic relationship between a reference point (master) and a second point (slave) requiring that, at time t, the slave is located at distance R(t) of the master point in the three dimensional space. As the force applied by a spring element is K (xl-x0), we obviously have xl->x0 as K->∞. Therefore, K can be considered as a penalization factor in order to obtain our kinematic condition.