# The Boundary Conditions You Must Know in ANSYS Workbench

In ANSYS Workbench, supports are like invisible forces that interact with the model. They help in obtaining numerically accurate results without including parts of the geometry that aren’t important. Choosing the right support type is crucial because it ensures that the simulation model will represent the boundary condition properly.

Different Support Types in Ansys Workbench Mechanical :

1. Fixed support
2. Displacement support
3. Frictionless support
4. Cylindrical support
5. Compression only support
6. Elastic support
7. Remote Displacement support

### Fixed Support

In this support condition, the surface/edge/point is completely restricted from displacement and rotation. Beams fixed to walls are one example of this type of support.

However, it’s important to make sure the model isn’t over-constrained, which can cause local peak stress areas.

### Displacement Support

This type of support specifies a zero or non-zero displacement to any of three orthogonal directions. In other words, you can restrict or give movement to your selected surface/edge/point in any direction (x,y,z). For example, in a tensile test, the test specimen is pulled in a uniaxial direction, which can be represented with displacement support.

### Frictionless Support

This type of support restricts translational movement in the direction normal to the surface but allows in-plane motion. For instance, imagine a cube subjected to pressure in the vertical direction. The cube’s bottom face is subjected to frictionless support, which restricts the bottom from moving in the vertical direction but allows it to enlarge in-plane direction.

### Cylindrical Support

Cylindrical support defines a radial and axial clearance between two parts, which can be used to model a ring on or in a shaft. The constraint can be rigid or stiffness can be defined. You can also apply cylindrical support to holes, but please note that it’s often only valid for small deflections.

### Compression Only Support

Compression only support allows the surface to move tangentially and lift off in negative normal direction but cannot move in the positive normal direction.

### Elastic Support

An Elastic Support defines an elastic foundation between the selected faces of a part or assembly and the ground. It’s based on a Foundation Stiffness, which is defined as the pressure required to produce a unit normal deflection of the foundation. Elastic support applies flexible frictionless support to a face. It’s commonly used to model piles or base frames/skids mounted on foundations.

### Remote Displacement Support

Remote displacement is a practical support type that allows you to control both rotations and displacement in the selected axis. In this boundary condition, there are 6 numbers of degrees of freedom, rotations, and displacements in x,y, and z. It’s useful for showing simply supported beams with boundary conditions that allow one end to pivot and the other to rotate and move laterally.

Good Luck!