Rigid body constraint

Rigid body node sets are defined to contain all nodes along the edges of a rectangular plate modeled with shell elements. The rigid body reference node is constrained against all rotations and $u_x$- and $u_y$-displacements. A saw-tooth velocity pattern acting in the z-direction is applied at the reference node of the rigid body. Starting at 0 m/s, the velocity is ramped down to −10 m/s at time 2.0 × 10⁻³ s and is ramped back to 0 m/s at time 6.0 × 10⁻³ s. Thereafter, the analysis is continued up to time 48.0 × 10⁻³ s. The following three cases are considered:

1. A rigid body TIE NSET is defined to contain all the edge nodes. The results are compared to the solution of the same problem with the rigid body TIE NSET replaced with equivalent boundary conditions applied at the edge nodes.

2. A rigid body PIN NSET is defined to contain all the edge nodes. The results are compared to the solution of the same problem with the rigid body PIN NSET replaced with equivalent boundary conditions applied at the edge nodes.

3. A rigid body TIE NSET is defined to contain all the nodes along two opposite edges of the plate. The remaining edge nodes are included in a PIN NSET. The results are compared to the solution of the same problem with the rigid body TIE and PIN node sets replaced with equivalent boundary conditions applied at the edge nodes.