Creo Simulate > Creating Analyses > Vibration Analysis > Dynamic Random Analysis > Translations at Three Points
Translations at Three Points
For a dynamic time, frequency, or random analysis, to specify the motion of the base in terms of translations at three point supports you need to constrain your model in a specific way. In the referenced modal analysis you must define point constraints for 3 non-collinear points in your model.
The point constraints must satisfy the criteria illustrated in the following example:
Consider three points as shown in the figure. The first point, must have all translational degrees of freedom (DOFs) fixed, the second point must be constrained along 2 axes and the third point must be constrained along only one axis. With these three point constraints only the rigid body motion of the model is constrained.
The constraint set for the three point constraints must be in terms of the WCS or a common Cartesian UCS.
The first point must have all translational DOFs fixed. In the example Point 1 must have translations constrained along the X-, Y- and Z- directions.
The line joining Point 1 to Point 2 must be parallel to one of the axes of the coordinate system. Point 2 must be free along this axis. It should be constrained along the other two axes. In the example the line joining Point 1 and Point 2 is parallel to Y-axis. Point 2 should have translations in the X- and Z- directions constrained.
Point 3 must be in the plane through line joining Point1 and Point2 and parallel to one of the coordinate planes. Point 3 must be constrained in the direction normal to the plane defined by the three points. In the example the three points define the X-Y plane. Point 3 must have translation in the Z- direction constrained.
Return to Base Excitation for a Dynamic Time Analysis.or Base Excitation for a Dynamic Frequency Analyses or Base Excitation for a Dynamic Random Analysis