Vibrations interview questions

1. A.the square root of the ratio of stiffness to mass, being the frequency at which the undamped system oscillates freely
2. B.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
3. C.a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions
4. D.the slow periodic rise and fall in amplitude produced when two harmonic motions of slightly different frequencies are superposed

Answer + AI explanation with Pro

1. A.Damping ratio
2. B.Equivalent stiffness of springs in series
3. C.Natural frequency of a single-degree-of-freedom system
4. D.Vibration isolation criterion

Answer + AI explanation with Pro

1. A.Natural frequency of a single-degree-of-freedom system — an energy estimate of the fundamental frequency obtained by equating maximum kinetic and maximum potential energy for an assumed mode shape, which always overestimates it
2. B.Natural frequency of a single-degree-of-freedom system — the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
3. C.Natural frequency of a single-degree-of-freedom system — the square root of the ratio of stiffness to mass, being the frequency at which the undamped system oscillates freely
4. D.Natural frequency of a single-degree-of-freedom system — the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance

Answer + AI explanation with Pro

1. A.the ratio of the actual damping coefficient to the critical damping coefficient, which classifies the response as under-, critically or over-damped
2. B.isolation is achieved only when the ratio of forcing to natural frequency exceeds the square root of two, below which a mount amplifies rather than isolates
3. C.the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance
4. D.a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions

Answer + AI explanation with Pro

1. A.Vibration isolation criterion
2. B.Damping ratio
3. C.Transmissibility
4. D.Logarithmic decrement

Answer + AI explanation with Pro

1. A.Damping ratio — the ratio of the actual damping coefficient to the critical damping coefficient, which classifies the response as under-, critically or over-damped
2. B.Damping ratio — a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions
3. C.Damping ratio — isolation is achieved only when the ratio of forcing to natural frequency exceeds the square root of two, below which a mount amplifies rather than isolates
4. D.Damping ratio — the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one

Answer + AI explanation with Pro

1. A.the reciprocal of the sum of the reciprocals of the individual stiffnesses, so a series combination is always softer than its softest spring
2. B.the slow periodic rise and fall in amplitude produced when two harmonic motions of slightly different frequencies are superposed
3. C.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
4. D.the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally

Answer + AI explanation with Pro

1. A.Damping ratio
2. B.Vibration isolation criterion
3. C.Critical damping
4. D.Transmissibility

Answer + AI explanation with Pro

1. A.Critical damping — the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
2. B.Critical damping — the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator
3. C.Critical damping — an approximate estimate of the fundamental frequency of a shaft carrying several loads, combining the reciprocals of the squares of the individual frequencies
4. D.Critical damping — the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one

Answer + AI explanation with Pro

1. A.the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance
2. B.an approximate estimate of the fundamental frequency of a shaft carrying several loads, combining the reciprocals of the squares of the individual frequencies
3. C.the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
4. D.the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally

Answer + AI explanation with Pro

1. A.Equivalent stiffness of springs in series
2. B.Resonance
3. C.Magnification factor
4. D.Transmissibility

Answer + AI explanation with Pro

1. A.Resonance — the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
2. B.Resonance — an energy estimate of the fundamental frequency obtained by equating maximum kinetic and maximum potential energy for an assumed mode shape, which always overestimates it
3. C.Resonance — the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
4. D.Resonance — the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance

Answer + AI explanation with Pro

1. A.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
2. B.the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
3. C.the ratio of the actual damping coefficient to the critical damping coefficient, which classifies the response as under-, critically or over-damped
4. D.the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally

Answer + AI explanation with Pro

1. A.Magnification factor
2. B.Equivalent stiffness of springs in series
3. C.Logarithmic decrement
4. D.Dunkerley's method

Answer + AI explanation with Pro

1. A.Logarithmic decrement — the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally
2. B.Logarithmic decrement — a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions
3. C.Logarithmic decrement — the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
4. D.Logarithmic decrement — the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator

Answer + AI explanation with Pro

1. A.the square root of the ratio of stiffness to mass, being the frequency at which the undamped system oscillates freely
2. B.the slow periodic rise and fall in amplitude produced when two harmonic motions of slightly different frequencies are superposed
3. C.the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance
4. D.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one

Answer + AI explanation with Pro

1. A.Magnification factor
2. B.Resonance
3. C.Equivalent stiffness of springs in series
4. D.Logarithmic decrement

Answer + AI explanation with Pro

1. A.Magnification factor — the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
2. B.Magnification factor — the ratio of the steady-state forced amplitude to the static deflection the same force would produce, peaking near resonance
3. C.Magnification factor — the slow periodic rise and fall in amplitude produced when two harmonic motions of slightly different frequencies are superposed
4. D.Magnification factor — a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions

Answer + AI explanation with Pro

1. A.the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator
2. B.the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally
3. C.the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
4. D.an energy estimate of the fundamental frequency obtained by equating maximum kinetic and maximum potential energy for an assumed mode shape, which always overestimates it

Answer + AI explanation with Pro

1. A.Damping ratio
2. B.Natural frequency of a single-degree-of-freedom system
3. C.Vibration isolation criterion
4. D.Transmissibility

Answer + AI explanation with Pro

1. A.Transmissibility — isolation is achieved only when the ratio of forcing to natural frequency exceeds the square root of two, below which a mount amplifies rather than isolates
2. B.Transmissibility — the slow periodic rise and fall in amplitude produced when two harmonic motions of slightly different frequencies are superposed
3. C.Transmissibility — the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping
4. D.Transmissibility — the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator

Answer + AI explanation with Pro

1. A.isolation is achieved only when the ratio of forcing to natural frequency exceeds the square root of two, below which a mount amplifies rather than isolates
2. B.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
3. C.the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally
4. D.the reciprocal of the sum of the reciprocals of the individual stiffnesses, so a series combination is always softer than its softest spring

Answer + AI explanation with Pro

1. A.Resonance
2. B.Vibration isolation criterion
3. C.Node of a torsional vibration
4. D.Rayleigh's method

Answer + AI explanation with Pro

1. A.Vibration isolation criterion — the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
2. B.Vibration isolation criterion — the reciprocal of the sum of the reciprocals of the individual stiffnesses, so a series combination is always softer than its softest spring
3. C.Vibration isolation criterion — the natural logarithm of the ratio of two successive amplitudes of a freely decaying oscillation, from which the damping ratio can be extracted experimentally
4. D.Vibration isolation criterion — isolation is achieved only when the ratio of forcing to natural frequency exceeds the square root of two, below which a mount amplifies rather than isolates

Answer + AI explanation with Pro

1. A.the smallest amount of damping for which the disturbed system returns to equilibrium without oscillating, corresponding to a damping ratio of exactly one
2. B.an approximate estimate of the fundamental frequency of a shaft carrying several loads, combining the reciprocals of the squares of the individual frequencies
3. C.the reciprocal of the sum of the reciprocals of the individual stiffnesses, so a series combination is always softer than its softest spring
4. D.the condition in which the forcing frequency equals the system's natural frequency, so amplitude grows and is limited only by damping

Answer + AI explanation with Pro

1. A.Dunkerley's method
2. B.Beat phenomenon
3. C.Rayleigh's method
4. D.Equivalent stiffness of springs in series

Answer + AI explanation with Pro

1. A.Equivalent stiffness of springs in series — the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator
2. B.Equivalent stiffness of springs in series — the square root of the ratio of stiffness to mass, being the frequency at which the undamped system oscillates freely
3. C.Equivalent stiffness of springs in series — an approximate estimate of the fundamental frequency of a shaft carrying several loads, combining the reciprocals of the squares of the individual frequencies
4. D.Equivalent stiffness of springs in series — the reciprocal of the sum of the reciprocals of the individual stiffnesses, so a series combination is always softer than its softest spring

Answer + AI explanation with Pro

1. A.an approximate estimate of the fundamental frequency of a shaft carrying several loads, combining the reciprocals of the squares of the individual frequencies
2. B.a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions
3. C.an energy estimate of the fundamental frequency obtained by equating maximum kinetic and maximum potential energy for an assumed mode shape, which always overestimates it
4. D.the square root of the ratio of stiffness to mass, being the frequency at which the undamped system oscillates freely

Answer + AI explanation with Pro

1. A.Damping ratio
2. B.Resonance
3. C.Dunkerley's method
4. D.Node of a torsional vibration

Answer + AI explanation with Pro

1. A.Node of a torsional vibration — the ratio of the actual damping coefficient to the critical damping coefficient, which classifies the response as under-, critically or over-damped
2. B.Node of a torsional vibration — the ratio of the force or motion transmitted through a mount to that applied at its base, the figure of merit for an isolator
3. C.Node of a torsional vibration — a cross-section of a shaft that remains stationary while the portions on either side twist in opposite directions
4. D.Node of a torsional vibration — an energy estimate of the fundamental frequency obtained by equating maximum kinetic and maximum potential energy for an assumed mode shape, which always overestimates it

Answer + AI explanation with Pro