Structural Dynamics Quiz 1

Mass = 10 kg, K = 10 N/m, C = 10 Ns/m, The system is

• Overdamped

• Underdamped

• Critically damped

• Viscous damped

Damping ratio is 0.5%, Logarithmic decrement is ______

• .03

• .5

• 36.2

• 2.5

Natural undamped frequency is 20 rad/s, Damping ratio is 50%, Damped frequency is ______

• 20 rad/s

• 10 rad/s

• 5 rad/s

• 17.3 rad/s

Harmonic force exerted by the system is 40 sin 15t, Stiffness = 900 N/m, Assume 5% critical damping, Resonant amplitude of steady state vibration is ___

• 0.444 m

• 0.222 m

• 0.11 m

• 10 m

Duhamel integral is used to calculate response due to _______

• Wind load

• Snow load

• Blast load

• Earthquake load

The two modes are orthogonal when

• Φ₁^T mΦ₂ = 0 Φ₁^T kΦ₂ = 0

• Φ₁^T mΦ₂ = 1 Φ₁^T kΦ₂ = 1

• Φ₁^T mΦ₂ = 0 Φ₁^T kΦ₂ = 1

• Φ₁^T mΦ₂ = 1 Φ₁^T kΦ₂ = 1

7. Consider the following assumptions made in idealization of shear building

i. No joint rotations in the structure.

ii. Loads acts horizontally so that slabs move parallel to each other.

iii. Deformation of structures is affected by the axial force in the column.

iv. Horizontal members are infinitely rigid

• 1,2 and 3 are correct

• 1,2 and 4 are correct

• 1,3 and 4 are correct

• 1,2,3,4 are correct

________ is the graphical representation of the relative amplitudes of the two coordinates and their phase angle relationship.

• Stiffness

• Mode shape

• Node

• Flexibility

For which case there is an oscillatory motion

• Overdamped system

• Underdamped system

• Critically damped system

• undulated damped system

Response due to dynamic load is

• Displacement

• Velocity

• Acceleration

• Displacement, Velocity, Acceleration