Mach Dyn Exam 3

Vibration

Any motion that exactly repeats itself as a periodic motion after a certain interval of time

Free vibration

The periodic motion continues after the cause of the original disturbance is removed

Forced vibration

A motion persists because of the continuing existence of a disturbing force

Damping factor

Accounts for energy losses in a vibrating system

Period

Time for a single cycle

Frequency

The number of periods occurring in unit time

Natural frequency

Frequency of a free vibration

Resonance

Occurs when forcing frequency equals natural frequency

Steady state vibration

Motion that repeats itself exactly in each cycle

Transient vibration

Vibration that changes in character

Torsional vibration

Alternating twisting and untwisting of a rotating shaft

2 different ways to say vibration analysis

Elastic body analysis and deformable body analysis

Elasticity

Ability of a material to deform and return to its original shape

Stiffness

k, force required to deflect a spring a certain distance

Degree of freedom

Number of coordinates needed to describe the position of a system

Amplitude

Max displacement of the mass

Phase angle

Angular lag of the motion with respect to the cosine function

Constraint forces

The action and reaction forces between any two of the connected bodies in a system

Couple

Two equal, opposite, parallel, but non collinear forces acting on a body

Moment

A force that causes an object to rotate around an axis

Equilibrium

All forces exerted on a system are in balance

Member

A rigid body subjected to only forces, no applied torque

Concurrent