For general information about how to apply loads and supports, see Apply Loads and Supports in the ANSYS Mechanical User's Guide

You can apply the following loads and supports in an explicit dynamics analysis:

Cylindrical coordinate systems are supported to define a single rotational displacement or velocity constraint on a rigid or flexible body. These coordinate systems are fixed, that is, they do not move with the body.

For Explicit Dynamics analyses, the y component (that is, Θ direction) of a velocity constraint defined with a cylindrical coordinate system has units of angular velocity.

For Explicit Dynamics analyses, the y component (that is, Θ direction) of a displacement constraint defined with a cylindrical coordinate system has units of rotation.

Step or time varying tabular loads can be applied in an explicit dynamics analysis. However, explicit dynamics does not support tabular data to specify the magnitude or components of Accelerations or Line Pressures.

For Explicit Dynamics analyses, functionally defined loads are supported for Pressure and Velocity but only when defined as varying in time. See

*Setting Up Boundary Conditions*.For Explicit Dynamics (LS-DYNA) analyses, functionally defined loads 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).

Detonation Points are only available for 3D Explicit Dynamics analyses, not for Explicit Dynamics (LS-DYNA Export) or 2D Explicit Dynamics analyses.

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 solve cannot be run in parallel if the model uses a boundary condition that contains an expression (for example, varying with time or spatial location).

The Remote Displacement boundary condition only works with the Explicit Dynamics system for 3D analyses, not the Explicit Dynamics (LS-DYNA Export) system or 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 object is scoped to a Remote Point that has its Behavior set to Rigid, the Remote Displacement Behavior will automatically be set to Rigid also.