An engineer insists that a component is fully constrained wi

An engineer insists that a component is fully constrained with 0 DOF because 2 plates are bolted together with 4 screws (assuming one of the 2 plates is considered \"grounded\"). Is he/she correct? Explain why or why not using concepts discussed in this text.

Solution

Any 3 dimensional object will have 6 degrees of freedom. Translational and Rotational across X,Y and Z.

In the Question the engineer insists 2 plates to have 0 DOF as they are bolted together with 4 screws. With one of them grounded.

The grounded plate has 0 DOF, that is no movement whatsoever. The other plate however can have two scenarios.

1) Plate 2 (non-Grounded) is screwed directly onto the Plate 1 (Grounded) with 4 screws. In this case the DOF is zero. A minimum of two screws are sufficient to lock the plate in place.

2) If Plate 2 is screwed onto the Plate 1 as a hinge. (as in a Door Hinge). We will have another DOF, a rotational DOF across the particular axis.