Constraints for shells can be either applied to points or lines. In this example, the constraints are applied to 3 lines of the boundary of the shell, and two points A and D.
The contour lines AB, BC and CD have symmetry constraints. The points A and D have isostatic constraints. Their prescriptions are:
- Displacements prescribed in Y axis and rotations in thetaX axis and theta Z axis for AB, BC and CD.
- Line AD is free.
- Displacements prescribed in X axis and Z axis for point A
- Displacements prescribed in Z axis for D
In this condition, the local axes have no relationship with the shell local axes defined in the properties section. The GLOBAL option means to prescribe related to the global axes of the problem. This is used in this case. Local axes are used to prescribe the displacement or rotation in a direction not coincident with any of the global axes. The values part of the condition is used to prescribe a fixed amount of displacement or rotation. Default units are meters for the X, Y and Z displacements and radians for the prescribed rotations. In this case, the prescribed displacements and rotations are all zero.
X Constraint, Y Constraint and Z Constraint mean the displacements along the axes. Theta X Constraint, theta Y constraints and theta Z constraints mean the rotations around the axes