BME Machine Design 3

Question 1

In journal bearing design, the Sommerfeld number represents:

Accepted Answer

A dimensionless parameter relating speed, viscosity, load, and geometry

Answer

The Sommerfeld number is a dimensionless bearing parameter combining viscosity, speed, load, and bearing geometry used to predict performance.

Question 2

Which type of welded joint is most efficient under tensile loading?

Accepted Answer

Butt joint

Answer

A butt joint aligns members end-to-end and, when fully penetrated, provides nearly the same strength as the base metal under tensile loads.

Question 3

What does 'L10 life' represent for a rolling element bearing?

Accepted Answer

Life at which 90% of bearings will survive

Answer

L10 life is the number of revolutions (or hours) at which 90% of a group of identical bearings will still be operating without fatigue failure.

Question 4

A power screw is primarily designed to:

Accepted Answer

Convert rotary motion to linear motion and transmit power

Answer

A power screw converts rotational input torque into translational output force, used in jacks, presses, and lead screws.

Question 5

The interference fit between a shaft and a hub is designed to transmit load by:

Accepted Answer

Friction from radial pressure

Answer

An interference fit creates a radial compressive pressure at the interface, generating sufficient friction to transmit torque and axial loads.

BME - Bachelor of Mechanical Engineering Practice Test