• Acceleration

• Standard Earth Gravity

• Pressure

• Hydrostatic Pressure

• Force

• Nodal Force

• Line Pressure

• Joint Load

• Fixed Support

• Displacement

• Nodal Displacement

• Detonation Point

• Velocity

• Impedance Boundary

• Simply Supported

• Fixed Rotation

• Remote Displacement

• Remote Force

• Limit Boundary

• SPH Activation and Deactivation

Notes

• Cylindrical coordinate systems allow the definition of a single rotational displacement or velocity constraint on a rigid or flexible body. These coordinate systems are fixed and so do not move with the body.

  • For Explicit Dynamics analyses, the Y component (that is, Θ direction) of a velocity constraint defined by a cylindrical coordinate system has units relating to angular velocity.

  • For Explicit Dynamics analyses, the Y component (that is, Θ direction) of a displacement constraint defined by a cylindrical coordinate system has units relating to rotation.

• Stepped or time varying tabular loads can be applied in an Explicit Dynamics analysis. However, Explicit Dynamics does not support using tabular data to specify the magnitude or components of Accelerations or Line Pressures.

• Displacement and rotation boundary conditions must be ramped, meaning that they cannot have non-zero values at the first cycle.

• For Explicit Dynamics analyses, loads defined by functions are supported for Pressure, Velocity, and Remote Force boundary conditions, but only when defined as varying in time. Spatially varying function definitions are not supported in Explicit Dynamics. See Boundary Conditions.

• For LS-DYNA, loads defined by functions are not supported.

• Loads must be applied in a single step.

• Loads and supports are not valid when applied to bodies having a Reference Frame of Eulerian (Virtual).

• The results DET_INIT_TIME and ALPHA are not available for LS-DYNA.

• For Explicit Dynamics analyses, if multiple constraints (for example, displacements) are applied to a node then they must use the same coordinate system. This restriction is especially applicable at nodes on a shared topology such as an edge, where two adjacent faces, each with different constraints, may come together. These constraints must use the same coordinate system in their specification.

• In the LS-DYNA solver, a Velocity or Displacement boundary condition (implemented with the *BOUNDARY_PRESCRIBED_MOTION keyword) will override a Fixed Support or a Simple Support or a Fixed Rotation boundary condition (implemented with the *BOUNDARY_SPC keyword). Hence if a body has a Velocity constraint and a Fixed Support applied to it, the whole body will move in the direction of the applied velocity.

• The default unconstrained body is valid. It is not a requirement to constrain any DOF of a body In Explicit Dynamics systems.

• An Explicit Dynamics solve can be performed if the model contains at least one Initial Condition (Translational or Rotational velocity) or a non-zero constraint (displacement or velocity) or a valid load.

• An Explicit Dynamics analysis which contains Pressure, Velocity, Displacement, Force, or Remote Displacement boundary conditions defined with a function cannot be run in parallel.

• The Remote Force boundary condition is not supported in LS-DYNA.

• The Remote Displacement and Remote Force boundary conditions are not supported in 2D Explicit Dynamics analyses.

• A Remote Displacement boundary condition must have the Behavior field set to Rigid for an Explicit Dynamics analysis. An error will be reported if it is set to Deformable. If the Remote Displacement or Remote Force object is scoped to a Remote Point that has its Behavior set to Rigid, the Remote Displacement or Remote Force Behavior will automatically be set to Rigid also.

• For bodies with reference frame of Particle, the only supported boundary conditions are Acceleration, Standard Earth Gravity, Displacement, Velocity, and Limit Boundary. These boundary conditions cannot be scoped to faces, edges, or vertices of the body as these scoping entities may not be coincident with any particle mesh entity. Contrary to other body types, Displacement, Velocity and Limit Boundaries may be scoped to collections of mesh nodes or Named Selections scoped to collections of mesh nodes. Limit Boundary is not available for LS-DYNA.