GFOSUB

Use

User-defined force using forces and torques computed in a GFOSUB:

<Force_Vector_TwoBody
     id                   = "30701"
     type                 = " ForceAndTorque"
     i_marker_id          = "30701010"
     body1_id             = "30301"
     j_floating_marker_id = "30701012"
     body2_id             = "30101"
     ref_marker_id        = "30301010"
     ref_body_id          = "30101"
     usrsub_param_string  = "USER(1,30700800,30700700,30301011)"
     usrsub_dll_name      = "NULL">
</Force_Vector_TwoBody>

Format

Fortran Calling Syntax

SUBROUTINE GFOSUB (ID, TIME, PAR, NPAR, DFLAG, IFLAG, RESULTS)

C/C++ Calling Syntax

void STDCALL GFOSUB (int *id, double *time, double *par, int *npar, int *dflag, int *iflag, double *result)

Python Calling Syntax

def GFOSUB(id,  time, par, npar, dflag, iflag):
    return result

MATLAB Calling Syntax

function results = GFOSUB(id, time, par, npar, dflag, iflag)

Attributes

ID: [integer]; The general force element identifier.
TIME: [double precision]; The current simulation time.
PAR: [double precision]; An array that contains the constant arguments from the list provided in the user defined statement.
NPAR: [integer]; The number of entries in the PAR array.
DFLAG: [logical]; The differencing flag.
IFLAG: [logical]; The initialization flag.

Output

RESULT: [double precision]; The vector output value of dimension 6 that contains the computed forces/torques (three translational and three rotational components).

Example

Here, GFOSUB is used to compute the six components of GFORCE with three translational (Force) and three rotational (Torque) components, below.

The following mathematical equation is used for GFOSUB computation:

f = -k*x - c*xdot