Product: ABAQUS/Explicit
User subroutine VDLOAD:
can be used to define the variation of the distributed load magnitude as a function of position, time, velocity, etc. for a group of points, each of which appears in an element-based or surface-based nonuniform load definition;
will be called for load integration points associated with each nonuniform load definition;
does not make available the current value of the nonuniform distributed loads for file output purposes; and
recognizes an amplitude reference (“Amplitude curves,” Section 27.1.2 of the ABAQUS Analysis User's Manual) if it appears with the associated nonuniform load definition.
subroutine vdload (
C Read only (unmodifiable)variables -
nblock, ndim, stepTime, totalTime,
amplitude, curCoords, velocity, dirCos, jltyp, sname,
C Write only (modifiable) variable -
value )
C
include 'vaba_param.inc'
C
dimension curCoords(nblock,ndim), velocity(nblock,ndim),
1 dirCos(nblock,ndim,ndim), value(nblock)
character*80 sname
C
do 100 km = 1, nblock
user coding to define value
100 continue
return
endnblock
Number of points to be processed in this call to VDLOAD.
ndim
Number of coordinate directions: 2 for two-dimensional models, 3 for three-dimensional models. The model will be considered three-dimensional if any three-dimensional elements are defined (including SPRINGA elements).
stepTime
Value of time since the step began.
totalTime
Value of total time. The time at the beginning of the step is given by totalTime – stepTime.
amplitude
Current value of the amplitude referenced for this load (set to unity if no amplitude is referenced). You must multiply the load by the current amplitude value within the user subroutine if the amplitude is required.
curCoords (nblock, ndim)
Current coordinates of each point for which the load is to be calculated.
velocity (nblock, ndim)
Current velocity of each point for which the load is to be calculated.
dirCos (nblock, ndim, ndim)
Current orientation of the face, edge, or beam for pressure type loads (not applicable for body force type loads). The second dimension indicates the vector, and the third dimension indicates the components of that vector. For faces (pressures on three-dimensional continuum, shell, and membrane elements), the first and second vectors are the local directions in the plane of the surface and the third vector is the normal to the face, as defined in “Conventions,” Section 1.2.2 of the ABAQUS Analysis User's Manual. For edges (pressures on two-dimensional continuum elements and two-dimensional beams), the first vector is the normal to the edge, the second vector is the tangent to the edge, and, if ndim=3, the third vector will be a unit normal in the out-of-plane direction. For three-dimensional beam elements, the first and second vectors are the local beam axes (
, 
) and the third vector is the tangent vector (
), as defined in “Beam element cross-section orientation,” Section 23.3.4 of the ABAQUS Analysis User's Manual.
jltyp
Key that identifies the distributed load type. The load type may be a body force, a surface-based load, or an element-based surface load. For element-based surface loads, this variable identifies the element face for which this call to VDLOAD is being made. See Part VI, “Elements,” of the ABAQUS Analysis User's Manual for element load type identification. This information is useful when several different nonuniform distributed loads are being imposed on an element at the same time. The key is as follows:
sname
Surface name for a surface-based load definition (JLTYP=0). For a body force or an element-based load the surface name is passed in as a blank.