16. Introduction to MDOF Systems

Try these first

1. 1.

   What does MDOF stand for?

   Hint

   Think about how many degrees of freedom are involved.

2. 2.

   How many DOFs does a three-floor building have in a lumped mass model?

   Hint

   Each floor accounts for one degree of freedom.

3. 3.

   What does MDOF stand for?

   • Single-Degree-of-Freedom
   • Multi-Degree-of-Freedom
   • Double-Degree-of-Freedom

   Hint

   Think about how many degrees of freedom structures typically have.

4. 4.

   True or False: Torsional effects are often negligible in symmetrical buildings.

   • True
   • False

   Hint

   Consider what symmetry means in structural terms.

5. 5.

   Consider a 4-story building modeled as an MDOF system. If the first mode shape is {1, -0.5, 0.3, 0.2}, what does this imply about the relative motion of the floors during the first mode?

   Hint

   Consider the ratios of movement indicated in the mode shape.

6. 6.

   A given MDOF system experiences a torsion when eccentric loading is applied. If the center of mass shifts to the right, how would you model this interaction?

   Hint

   Think about how the loading impacts the movement of mass and stiffness in the model.