Specifies loads for an explicit dynamics analysis.
Label identifying the load option to be performed.
Define a load (default). If
Delete specified load. If
List specified load. If
Valid load labels for loads applied to nodes:
FX, FY, FZ
MX, MY, MZ
UX, UY, UZ
ROTX, ROTY, ROTZ
VX, VY, VZ
OMGX, OMGY, OMGZ
AX, AY, AZ
Accelerations (on nodes).
ACLX, ACLY, ACLZ
Valid load labels for loads applied to elements:
Pressure (applied to an element).
Valid load labels for loads applied to rigid bodies:
RBFX, RBFY, RBFZ
Forces on rigid bodies.
RBMX, RBMY, RBMZ
Moments on rigid bodies.
RBUX, RBUY, RBUZ
Displacements on rigid bodies.
RBRX, RBRY, RBRZ
Rotations on rigid bodies.
RBVX, RBVY, RBVZ
Velocities on rigid bodies.
RBOX, RBOY, RBOZ
Angular velocities on rigid bodies.
Lab = PRESS,
Load key (face number) associated with a surface pressure load. Load keys
(1,2,3, etc.) are listed under "Surface Loads" in the input data tables for
each element type in the Element Reference.
For most other values of
a coordinate system identification number, CID from the EDLCS command.
The CID will represent either a local coordinate system (used for loads labels
FX, MX, etc.) or a direction vector (used for prescribed motion labels UX,
ROTX, VX, AX, etc.). See the Notes section for more information on how the
CID is used. If the load is in the global coordinate system, set
to zero, or leave it blank. Some load types do not support the CID key; see Table 122: Birth Time, Death Time, and CID Support in the Notes section for more information.
Lab = PRESS,
to 1 when
KEY is blank or when
zero. For all other values of
Name of existing component [CM] or PART
number [EDPART] to which this load is to be applied. For
all load labels except the pressure load (
PRESS) and the rigid body loads (
Lab = RB
xx), the component must consist of nodes. For pressure
loads, the component must consist of elements. For rigid body loads, a part
number must be input instead of a component name. The part number must correspond
to a set of elements that has been identified as a rigid body [EDMP,RIGID,
Name of user-defined array parameter that contains the time values of the load.
Name of user-defined array parameter that contains the "data"
values of the load corresponding to the time values in
Note: If the length of
different, the shortest length will be used.
Phase of the analysis in which the load curve is to be used.
Curve is used in transient analysis only (default).
Curve is used in stress initialization or dynamic relaxation only.
Curve is used in both stress initialization (or dynamic relaxation) and transient analysis.
Data curve ID number representing the load curve to be applied.
The load curve must have been previously defined using the EDCURVE command.
LCID is specified,
be left blank (in the GUI, select “None” for
Load curve scale factor applied to the specified load curve.
The scale value is applied to the data in
to the ordinate data in the load curve specified by
Birth time, or time when imposed motion is activated. The default is 0.0. Some load types do not support birth and death time; see Table 122: Birth Time, Death Time, and CID Support in the Notes section for more information.
Death time, or time when imposed motion is removed. The default is 1 x 1038. Some load types do not support birth and death time; see Table 122: Birth Time, Death Time, and CID Support in the Notes section for more information.
If a component name is input (
the specified component definition is changed before the SOLVE command,
the last definition will be used.
You can specify the load data by inputting
ID number of a previously defined load curve) or by inputting the two array
contain time and load values, respectively). The input for
be a single column array parameter, or a specific column from a multi-column
array parameter. A starting array element number can be specified for
if none is specified, array element 1 is used by default.
Note: You cannot update a previously defined load by changing the array
parameters that were input as
The load definition is written to the database at the time EDLOAD is
issued. Therefore, subsequent changes to the array parameters that were used
as input on EDLOAD will not affect the load curve definition.
If you need to change the load definition, you must delete the load (EDLOAD,DELE)
and define it again.
EDLOAD automatically assigns a load number to each defined load. Use EDLOAD,LIST to obtain a list of loads and their corresponding load numbers. You can plot a load curve by inputting the load number on the EDPL command. The load numbers may change when loads are deleted (EDLOAD,DELE). Therefore, you should obtain a current list of load numbers (EDLOAD,LIST) before plotting a load curve.
For prescribed motion, we recommend that you specify velocity time histories instead of displacement time histories. Also, you should not specify nonzero initial displacements. A piecewise linear displacement time history may lead to discontinuous velocities and infinite accelerations.
By default, the load will be applied in the global Cartesian direction.
You can define the load in a different direction by inputting a CID (coordinate
system ID) value in the
KEY field. The CID must
be previously defined using the EDLCS command. For load
Lab = FX, FY, FZ, MX, MY, MZ, RBFX, RBFY,
RBFZ, RBMX, RBMY, RBMZ), the load will be applied in the direction of the
local coordinate system defined by EDLCS. For prescribed
motion degrees of freedom labels (Lab = UX, UY, UZ, ROTX, ROTY, ROTZ, VX,
VY, VZ, AX, AY, AZ, RBUX, RBUY, RBUZ, RBRX, RBRY, RBRZ, RBVX, RBVY, RBVZ,
RBOX, RBOY, RBOZ), the motion will act in the direction of a vector defined
by two points input on the EDLCS command. The origin and
terminus ends of the vector are defined by the
respectively, of EDLCS.
Lab = OMGX, OMGY, and OMGZ, you may need
to specify the origin location of the acceleration coordinate system [CGLOC].
When applying a temperature load (
Lab = TEMP),
you may also need to define a reference temperature via the TREF command.
The thermal loading is defined as the difference between the applied temperature
and the reference temperature. Note that EDLOAD,LIST will
list only the temperature values specified on EDLOAD, not
the temperature difference.
When applying loads to axisymmetric PLANE162 elements, the load may be interpreted differently depending on whether you use the area weighted or volume weighted option (KEYOPT(2)). See the PLANE162 element description in the Element Reference for details.
PHASE = 0 when you are using the LS-DYNA
solver to conduct a transient explicit analysis only or when you are conducting
a sequential implicit/explicit analysis, in which the ANSYS (implicit) resulting
displacements (stored in the `drelax' file from the REXPORT command)
are used to preload the explicit model [EDDRELAX,ANSYS]
PHASE = 1 or 2 when you need to use LS-DYNA
to preload the model (as opposed to ANSYS) before running the transient portion
of the analysis.
PHASE = 1 applies the load initially
and then immediately removes the load. As a result, the load is removed, and
the structure vibrates freely.
PHASE = 2 applies
the load and then continues to apply the load over the course of the transient
analysis, so that the transient analysis includes the effect of the initial
loading and continues to account for the initial loading.
Birth and Death times, as well as the CID key are supported only for the EDLOAD labels specified with a Yes in the following table.
Table 122: Birth Time, Death Time, and CID Support
|EDLOAD Label||Birth Time||Death Time|
|FX, FY, FZ||No||No||Yes|
|MX, MY, MZ||No||No||Yes|
|UX, UY, UZ||Yes||Yes||Yes|
|ROTX, ROTY, ROTZ||Yes||Yes||Yes|
|VX, VY, VZ||Yes||Yes||Yes|
|OMGX, OMGY, OMGZ||No||No||No|
|AX, AY, AZ||Yes||Yes||Yes|
|ACLX, ACLY, ACLZ||No||No||No|
|RBFX, RBFY, RBFZ||No||No||Yes|
|RBMX, RBMY, RBMZ||No||No||Yes|
|RBUX, RBUY, RBUZ||Yes||Yes||Yes|
|RBRX, RBRY, RBRZ||Yes||Yes||Yes|
|RBVX, RBVY, RBVZ||Yes||Yes||Yes|
|RBOX, RBOY, RBOZ||Yes||Yes||Yes|
This command is also valid in PREP7.
Distributed ANSYS Restriction This command is not supported in Distributed ANSYS.