Loads

Load entities have an associated load configuration. A load configuration determines how to draw, store, and work with the load. The follwoing load configurations are supported:

Solver Card Support for Loads

General boundary conditions should not be collected into specific load collectors. Organizing loads and constraints into a specific load collector may result in an error termination.

The following is a list of OptiStruct cards, which are represented as various types of loads.

Supported Card	Solver Description	Supported Load Types	Notes
ASET	Defines the boundary degrees of freedom of a superelement assembly for matrix reduction.	Constraints
ASET1	Defines the boundary degrees of freedom of a superelement assembly for matrix reduction.	Constraints
DAREA	Defines scale (area) factors for dynamic loads.	Constraints
DELAY	Defines the time delay term tau in the equations of the dynamic loading function.	Constraints
DEFORM	Defines enforced axial deformation for one-dimensional elements for use in statics problems.	Flux
DPHASE	Defines the phase lead term lower theta in the equation of the dynamic loading function.	Constraints
FORCE	Defines a static force at a grid point by specifying a vector.	Force
FORCE1	Static Force, Alternate Form 1	Force
MBFRC	Defines a constant force at a grid point by specifying a vector.	Force
MBFRCC	Defines a curve force at a grid point by specifying a vector.	Force
MBMNT	Defines a constant moment at a grid point by specifying a vector.	Moment
MBMNTC	Defines a curve moment at a grid point by specifying a vector.	Moment
MOMENT	Defines a static moment at a grid point by specifying a vector.	Moment
MOMENT1	Static Moment, Alternate Form 1	Moment
MOTNG	Defines a constant grid point motion.	Constraint
MOTNGC	Defines a grid point motion vs. time by specifying a curve.	Constraint
PLOAD	Defines a static pressure load on a triangular or quadrilateral element.	Pressure
PLOAD1	Defines concentrated, uniformly distributed, or linearly distributed applied loads to the CBAR or CBEAM elements at user-chosen points along the axis.	Pressure
PLOAD2	Defines a uniform static pressure load applied to two-dimensional elements. Only QUAD4 or TRIA3 elements may have a pressure load applied to them via this entry.	Pressure
PLOAD4	Defines a load on a face of a HEXA, PENTA, TETRA, PYRA, TRIA3, or QUAD4 element.	Pressure
QBDY1	Defines a uniform heat flux for CHBDYE elements.	Flux
QVOL	Rate of volumetric heat addition for a conduction element.	Flux
SPC	Defines sets of single-point constraints and enforced displacements.	Constraint
SPCD	Defines an enforced displacement value for static analysis, which is requested as a LOAD.	Constraint
SUPORT	Defines determinate reaction degrees of freedom in a free body.	Constraint
SUPORT1	Defines determinate reaction degrees of freedom in a free body. The SUPORT1 bulk data entry must be requested in the I/O Options or Subcase Information sections by the SUPORT1 data selection command.	Constraint
TEMP	Defines temperature at grid points for determination of Thermal Loading and Stress recovery.	Temperature
TIC(D) or (V)	Defines values for the initial conditions of variables used in structural transient analysis. Both displacement and velocity values may be specified at independent degrees-of-freedom.	Constraint
USET	Set of Degrees of Freedom for Residual Vector Calculation.	Constraint
USET1	Alternate Form of USET1	Constraint

Each load or constraint must belong to a load collector. Loads or constraints in history data (under *STEP) should be organized into load collectors with HISTORY card image. These load collectors need to be added to a load step from the Load Steps panel. Loads or constraints in model data, however, should be organized into load collectors with the INITIAL_CONDITION card image. These load collectors do not need to be added to a load step. All loads and boundary conditions are recommended to be defined from the Step Manager in the Abaqus user profile.

Note:

The Import tab - Options section provides the user to select to Expand Loads on Sets. Selecting this option means that all loads and boundary conditions on sets are expanded to individual nodes and elements.

Supported Card	Solver Description	Supported Load Types	Supported Parameters
*BOUNDARY (electric potential, dof 9)	Specifies flux boundary conditions for piezoelectric analysis.	Flux	FIXED USER LOADCASE AMPLITUDE REGION TYPE = {LAGRANGIAN, SLIDING, EULERIAN} OP
*BOUNDARY (structural)	Creates structural boundary conditions.	Constraint	TYPE = {DISPLACEMENT, VELOCITY, ACCELERATION} FIXED USER LOADCASE AMPLITUDE REGION TYPE = {LAGRANGIAN,SLIDING, EULERIAN} OP
*BOUNDARY (temperature, dof 11)	Specifies temperature boundary conditions.	Temperatures	FIXED USER LOADCASE AMPLITUDE REGION TYPE = {LAGRANGIAN,SLIDING, EULERIAN} OP
*CECHARGE	Specifies concentrated electric charges for piezoelectric analysis.	Flux	OP
*CECURRENT	Specifies concentrated current in electric conduction.	Flux	OP
*CFLUX	Specify concentrated fluxes in heat transfer or mass diffusion analyses.	Flux	OP
*CLOAD	Creates concentrated forces.	Force	AMPLITUDE LOADCASE CYCLIC MODE FOLLOWER REGION TYPE = {LAGRANGIAN, SLIDING, EULERIAN} OP
*CLOAD	Creates concentrated moments.	Moment	AMPLITUDE LOADCASE CYCLIC MODE FOLLOWER REGION TYPE = {LAGRANGIAN, SLIDING, EULERIAN} OP
*COUPLING	Define a surface-based coupling constraint	Constraint	CONSTRAINT NAME REF NODE SURFACE INFLUENCE RADIUS ORIENTATION
*DECHARGE	Distributes electric charges for piezoelectric analysis.	Pressure	OP
*DFLUX	Specify distributed fluxes in heat transfer or mass diffusion analyses.	Pressure	OP
*DISTRIBUTING	Define a distributing coupling constraint	Constraint	WEIGHTING METHOD = {UNIFORM, LINEAR, QUADRATIC, CUBIC}
*DISTRIBUTING COUPLING	Specify nodes and weighting for distributing coupling elements	See Elements.	MASS
*DLOAD	Specifies distributed loads	Pressure	AMPLITUDE LOADCASE CYCLIC MODE REGION TYPE = {LAGRANGIAN, SLIDING, EULERIAN} OP
*FILM	Define film coefficients and associated sink temperatures.	Pressure	AMPLITUDE FILM AMPLITUDE REGION TYPE = {LAGRANGIAN/SLIDING, EULERIAN} OP
*KINEMATIC	Define a kinematic coupling constraint	Multi-point Constraints
*KINEMATIC COUPLING	Constrain all or specific degrees of freedom of a set of nodes to the rigid body motion of a reference node	Multi-point Constraints See Elements.	ORIENTATION
*MPC	Define multi-point constraints	Multi-point Constraints See Elements.	BEAM LINK PIN TIE
*RADIATE	Specify radiation conditions in heat transfer analyses	Pressure	AMPLITUDE OP REGION TYPE (explicit)
*TEMPERATURE	Specifies predefined temperature field.	Temperature	AMPLITUDE BSTEP BINC ESTEP EINC INPUT FILE MIDSIDE OP

Supported Card	Solver Description	Supported Load Types	Notes
BF	Defines a nodal body force load.	Flux	FLUE and HGEN labels are
BF_FLUE		Flux	Supported under the Flux panel.
BF_HGEN		Flux	Supported under the Flux panel.
BF_TEMP		Temperatures	(Structural temperatures) label is supported under the Temperatures panel.
BFE_FLUE	Defines an element body force load	Flux
BFE_HGEN		Flux
BFE_TEMP		Flux
ConvBulkTe		Pressure
ConvFilmCo		Pressure
D_CONSTRNT	Defines DOF constraints at nodes.	Constraint
D_TEMP		Temperature
D_VOLT		Constraint
F_FLOW	Specifies force loads at nodes.	Flux
F_HEAT		Flux
FLOTRAN	Specifies "FLOTRAN data settings" as the subsequent status topic.	Pressure	FLOTRAN surface load label “FSI [fluid-structure interaction flag]” is available under pressure load. You must use DOF1 to add value for this label.
FORCE	Selects the element nodal force type for output.	Force
FORCE2		Moment
HFLUX		Pressure
IC_CONSTRN	Specifies initial conditions at nodes.	Constraint
IC_TEMP		Temperature
IC_VOLT		Constraint
PRESSURE		Pressure
SFE	Defines elemental surface load	Pressure, Convection, Heatflux	Structural, thermal and Fluid labels are covered
SFE	Surface load	Structural, thermal, and fluid	Structural label: PRES Thermal label: CONV, HLFUX Fluid label: FSI

Several load types cause three cards to be output for x, y, and z components. During input, these are grouped into one load. Loads cannot be applied to sets, components, or boxes. Load curves are input and output. Use the Card Editor to select load curves.

Unless mentioned in the Notes column, load cards cannot be edited.

Supported Card	Solver Description	Supported Load Types	Notes
*BOUNDARY_ PRESCRIBED_MOTION_ NODE	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	Constraints Type 2; Card 26, VAD = 2 DEATH, BIRTH	DOF 4, -4, 8, -8, 9, -9, 10, -10, 11, -11 are not supported
*BOUNDARY_ PRESCRIBED_MOTION_ NODE	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	Velocity Type 1; Card 26; VAD = 0	DOF 4, -4, 8, -8, 9, -9, 10, -10, 11, -11 are not supported
*BOUNDARY_ PRESCRIBED_MOTION_ NODE	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	Acceleration Type 1 Card 26 VAD = 1	DOF 4, -4, 8, -8, 9, -9, 10, -10, 11, -11 are not supported
*BOUNDARY_ PRESCRIBED_MOTION_ NODE_(ID)		Velocity
*BOUNDARY_ PRESCRIBED_MOTION_ NODE_(ID)		Constraints Type 2; Card 26, VAD = 2 dynaName, DEATH, BIRTH
*BOUNDARY_ PRESCRIBED_MOTION_ RIGID	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	PID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH	RIGID_LOCAL and _SET options are supported.
*BOUNDARY_ PRESCRIBED_MOTION_ RIGID_ID	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	Dyna_Name PID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH
*BOUNDARY_ PRESCRIBED_MOTION_ RIGID_LOCAL		PID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH Title
*BOUNDARY_ PRESCRIBED_MOTION_ RIGID_LOCAL_ID		Dyna_Name PID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH
*BOUNDARY_ PRESCRIBED_MOTION_ SET	Define an imposed nodal motion (velocity, acceleration, or displacement) on a node or a set of nodes.	NSID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH TITLE
*BOUNDARY_ PRESCRIBED_MOTION_ SET_ID		Dyna_Name NSID, DOF, VAD, LCID, SF, VID, DEATH, BIRTH
*BOUNDARY_SPC_NODE	Define nodal single point constraint	Constraints Type 1; Card 13 SPC CID
*BOUNDARY_SPC_NODE_ (ID)		Constraints dynaName, CID
*BOUNDARY_ TEMPERATURE_NODE	Define temperature boundary conditions for a thermal or coupled thermal/structural analysis.	Temperature LCID, LOC
*CONSTRAINED_GLOBAL	Define a global boundary constraint plane.	Constraints
*INITIAL_TEMPERATURE_ NODE	Define initial nodal point temperatures using nodal set IDs or node number.s	Temperatures LOC
*INITIAL_VELOCITY	Define initial nodal point translational velocities using nodal set IDs.	Type 2 Card 30 INITV = 3	For structured output, global velocity is set to 0.0. For structured input, non-zero values for INITV = 1 or INITV = 5 create velocities. INITV values of 2, 4, 6, and 7 are ignored.
*INITIAL_VELOCITY_NODE	Define initial nodal point velocities for a node.	Rotation
*LOAD_BEAM_ELEMENT	Defines load on beam elements	Pressure
*LOAD_MASK	Apply a distributed pressure load over a three-dimensional shell part	n/a
*LOAD_NODE_POINT	Apply a concentrated nodal force to a node or a set of nodes.	Force Type 1; Card 23; Point Loads FollowerForce	LS-DYNA Load Configs 1, 2, 3 and 4 A load curve can be selected for these loads.
*LOAD_NODE_POINT	Apply a concentrated nodal force to a node or a set of nodes.	Moment Type 1 Card 23 Point Loads	LS-DYNA Load Configs 5, 6 7 and 8.
*LOAD_SEGMENT	Apply the distributed pressure load over one triangular or quadrilateral segment defined by four, six or eight nodes.	Pressure LCID, AT
*LOAD_SEGMENT_ID	Apply the distributed pressure load over one triangular or quadrilateral segment defined by four, six or eight nodes.	Pressure LCID, AT
*LOAD_SHELL_ELEMENT	Apply the distributed pressure load over one shell element or shell element set.	Pressure AT, LCIDoption
*LOAD_SHELL_ELEMENT_ ID	Apply the distributed pressure load over one shell element or shell element set.	Pressure LCID, AT
*LOAD_SHELL_ PRESSURE	Apply the distributed pressure load over one shell element or shell element set.	Pressure Type 2 Card 24 Pressure BC
*LOAD_THERMAL_ CONSTANT_NODE	Define nodal sets giving the temperature that remains constant for the duration of the calculation.	Temperature n/a
*LOAD_THERMAL_ VARIABLE_NODE	Define nodal temperature that is variable during the calculation.	Temperature TS, LCID

Supported Card	Solver Description	Supported Load Types	Notes
ASET	Defines degrees-of-freedom in the analysis set (a-set)	Constraints
ASET1	Defines degrees-of-freedom in the analysis set (a-set)	Constraints
BNDFIX1	Defines analysis set (a-set) degrees-of-freedom to be fixed (b-set) during generalized dynamic reduction or component mode synthesis calculations.	Constraints
BOLTFOR		Flux
BSET1	Defines analysis set (a-set) degrees-of-freedom to be fixed (b-set) during generalized dynamic reduction or component mode synthesis calculations.	Constraints
CSET1	Defines analysis set (a-set) degrees-of-freedom to be free (c-set) during generalized dynamic reduction or component modes calculations.	Constraints
DAREA	Defines scale (area) factors for static and dynamic loads. In dynamic analysis, DAREA is used in conjunction with RLOADi and TLOADi entries.	Constraints
DEFORM	Defines enforced axial deformation for one-dimensional elements for use in statics problems.	Flux
FORCE	Requests the form and type of element force output or particle velocity output in coupled fluid-structural analysis.	Force
MOMENT	Defines a static concentrated moment at a grid point by specifying a scale factor and a vector that determines the direction.	Moment
OMIT1	Defines degrees-of-freedom to be excluded (o-set) from the analysis set (a-set).	Constraints
PLOAD	Defines a uniform static pressure load on a triangular or quadrilateral surface comprised of surface elements and/or the faces of solid elements.	Pressure
PLOAD1	Defines concentrated, uniformly distributed, or linearly distributed applied loads to the CBAR or CBEAM elements at user-chosen points along the axis.	Pressure
PLOAD2	Defines a uniform static pressure load applied to CQUAD4, CSHEAR, or CTRIA3 two-dimensional elements.	Pressure	The THRU field is supported for feinput only. On export, additional pressure cards for the range specified are written.
PLOAD4	Defines a pressure load on a face of a CHEXA, CPENTA, CTETRA, CTRIA3, CTRIA6, CTRIAR, CQUAD4, CQUAD8, or CQUADR element.	Pressure	The THRU field is supported for feinput only. On export, additional pressure cards for the range specified are written. Unequal nodal pressures are now supported. The average pressure value is used as the magnitude of the pressure for visualization only. The individual field values, P1-P4, can be viewed or edited using the card editor. Updating the magnitude of pressure from the Pressures panel will have no effect on PLOAD4 cards defined using unequal nodal pressures.
QBDY1	Defines a uniform heat flux into CHBDYj elements.	Flux
QSET1	Defines generalized degrees-of-freedom (q-set) to be used for generalized dynamic reduction or component mode synthesis.	Constraints
QVOL	Volume Heat Addition - Defines a rate of volumetric heat addition in a conduction element.	Flux
SPC	Defines a set of single-point constraints and enforced motion (enforced displacements in static analysis and enforced displacements, velocities or acceleration in dynamic analysis).	Constraints	Constraints on nodes are supported through SPC cards. PS field in GRID card is not supported. Upon import, any PS entry on the GRID card will be converted into an SPC card.
SPC1	Defines a set of single-point constraints.	Constraints	Supported for feinput only. On export, equivalent SPC cards are written. Alternate format with THRU in the fifth field is supported.
SPCD	Defines an enforced displacement value for static analysis and an enforced motion value (displacement, velocity or acceleration) in dynamic analysis.	Constraints
SUPORT	Defines determinate reaction degrees-of-freedom in a free body.	Constraints
SUPORT1	Defines determinate reaction degrees-of-freedom (r-set) in a free body-analysis. SUPORT1 must be requested by the SUPORT1 Case Control command.	Constraints
TIC(D)	Transient Initial Condition - Defines values for the initial conditions of variables used in structural transient analysis.	Constraints
TIC(V)	Transient Initial Condition - Defines values for the initial conditions of variables used in structural transient analysis.	Constraints
TEMP	Defines temperature at grid points for determination of thermal loading, temperature-dependent material properties, or stress recovery.	Temperatures
TEMPBC	Defines the temperature boundary conditions for heat transfer analysis.	Temperatures
USET	Defines a degree-of-freedom set.	Constraints
USET1	Defines a degrees-of-freedom set.	Constraints

Note:

Other loads such as SPCADD, MPCADD, FREQ, FREQ1, EIGR, EIGRL, EIGC, EIGP, EIGB, GRAV, and RFORCE are supported as load collectors.

PAM-CRASH 2G

Supported Card	Solver Description	Supported Load Types	Notes
ACC3D /	Imposed accelerations	Acceleration	Acceleration type can be specified in the Acceleration panel.
BOUNC /	Define boundary condition	Constraints
CONLO /	Concentrated nodal load	Force(1)
DIS3D /	Imposed displacement	Constraints
DIS3DM /	Imposed minimum displacement	Constraints
DIS3DX /	Imposed maximum displacement	Constraints
INVEL /	Define initial velocity	Velocity
PREFA /	Pressure on shells	Pressure(1)
RAC3D /	Imposed rotational acceleration	Acceleration	Acceleration type can be specified in the Acceleration panel.
RAN3D /	Imposed angular rotations	Constraints
RDA3D /	Radial 3D boundary conditions	Acceleration	Acceleration type can be specified in the Acceleration panel.
RDD3D /		Constraints
RDV3D /	Radial 3D boundary conditions	Velocity
RVE3D /	Imposed rotational velocities	Velocity
RWALL /	Rigid wall definition
SECFO_PLANE /
VEL3D /	Imposed velocities	Velocity

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See Also: