The Solid Mechanics, Explicit Dynamics (solid) interface (), found under the Structural Mechanics branch () when adding a physics interface, is intended for general time explicit analysis of 3D, 2D plane strain, or 2D axisymmetric bodies. The Solid Mechanics, Explicit Dynamics interface is based on solving the equations of motion together with a constitutive model for a solid material. Results such as displacements, stresses, and strains are computed.

This interface is similar to the The Solid Mechanics Interface, upon which it is based. There are a number of specializations for explicit dynamics, but the interface can also be used with most other study types. The most important use case for that is to provide initial conditions for a time-explicit analysis.

The default material is a Linear Elastic Material. With either the Nonlinear Structural Materials Module or the Geomechanics Module, the physics interface is extended with more materials, for example, material models for plasticity, creep, and concrete.

When this physics interface is added, the following default nodes are also added to the Model Builder: Linear Elastic Material, Free (a boundary condition where boundaries are free, with no loads or constraints), and Initial Values. For axisymmetric models, an Axial Symmetry node is also added.

Then, from the Physics toolbar, you can add other nodes that implement, for example, solid mechanics material models, boundary conditions, and loads. You can also right-click Solid Mechanics, Explicit Dynamics to select physics features from the context menu.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is solid.

From the Structural transient behavior list, select Include inertial terms (the default) or Quasistatic. Use Quasistatic to treat the dynamic behavior as quasistatic (with no mass effects; that is, no second-order time derivatives). Selecting this option gives a more efficient solution for problems where the variation in time is slow when compared to the natural frequencies of the system.

From the Store dissipation list, select Individual contributions, Total, or Off.

Select Individual contributions to treat each dissipative process independently. Selecting this option gives a more flexible implementation for problems where dissipation occurs at different time scales, and you want to distinguish each phenomenon separately.

Select Total to accumulate all the dissipative processes into one variable.

To display other settings for this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog.

The physics interface uses the global spatial components of the Displacement field u as dependent variables. The default names for the components are (u, v, w) in 3D. In 2D the component names are (u, v), and in 2D axisymmetry they are (u, w). You can however not use the ‘missing’ component names in 2D as a parameter or variable name, since they are used internally.