What is the primary purpose of the factor of safety in machine design?
A Minimize cost
B Prevent failure
C Improve efficiency
D Reduce weight
The factor of safety is used to ensure that a component or structure is strong enough to withstand unexpected stresses. By providing a safety margin, the factor of safety prevents failure under normal and extreme conditions.
Which stress is primarily responsible for material failure in bending?
A Tensile stress
B Torsional stress
C Shear stress
D Compressive stress
In bending, the material experiences both compressive and tensile stresses. Tensile stress, occurring on the outermost surface of the bending material, is most responsible for causing failure, especially when the stress exceeds the material’s tensile strength.
Which material is commonly used in bearings due to its low friction?
A Brass
B Steel
C Bronze
D Copper
Bronze is often used in bearings because it has low friction, which reduces wear and tear in moving parts. Its resistance to corrosion and good bearing properties make it ideal for this purpose.
What is the role of a clutch in mechanical power transmission?
A To store energy
B To control speed
C To reduce friction
D To transfer power
A clutch is used to connect and disconnect two rotating shafts, allowing power transmission when engaged. It is commonly used in vehicles to control the flow of power from the engine to the transmission.
What type of failure occurs when a material experiences repeated loading?
A Yielding failure
B Fatigue failure
C Torsional failure
D Shear failure
Fatigue failure occurs when a material is subjected to cyclic or repeated loads. Even if these loads are below the material’s yield strength, they cause microscopic cracks that eventually lead to failure after numerous cycles of loading and unloading.
Which component is essential for reducing vibrations in mechanical systems?
A Damper
B Bearing
C Gear
D Shaft
Dampers are used in mechanical systems to absorb and dissipate vibrational energy. By converting vibration into heat energy, they reduce unwanted oscillations, helping to maintain the stability and smooth operation of machines.
What does the term ‘fatigue limit’ refer to in materials?
A Maximum stress before fracture
B Maximum stress before permanent deformation
C Stress level below which failure does not occur
D Stress at fracture point
The fatigue limit refers to the maximum stress level a material can endure indefinitely without failing under repeated loading. If the stress is below this limit, the material will not experience fatigue failure regardless of the number of cycles.
What is the most common type of weld used in machine design?
A Groove weld
B Fillet weld
C Spot weld
D Butt weld
Fillet welds are the most common type of weld used in machine design. They are used to join two surfaces at a right angle, making them ideal for connecting structural components in a wide variety of applications.
Which material is commonly chosen for high-strength shafts?
A Cast iron
B Copper
C Aluminum
D Steel
Steel is the material of choice for high-strength shafts due to its excellent tensile strength, durability, and ability to withstand shear and torsional forces. It is commonly used in machinery and automotive applications.
What does CAD software allow engineers to do in machine design?
A Manufacture parts
B Perform simulations
C Test materials
D Reduce cost
CAD (Computer-Aided Design) software allows engineers to create detailed digital models of machine components. It enables simulations of mechanical behaviors like stress, thermal effects, and motion, ensuring that designs are efficient and feasible before production.
What is the function of a bearing in machine design?
A To support rotating parts
B To store energy
C To increase friction
D To transfer energy
Bearings are used to reduce friction and support rotating parts. They allow for smooth motion of components like shafts, ensuring that the rotating parts experience less wear and tear, thus increasing their lifespan and efficiency.
Which of the following is essential in ensuring a machine’s components can handle high-speed rotation?
A Material hardness
B Gear ratio
C Thermal expansion
D Bearing design
Bearings are crucial in ensuring that rotating components can handle high speeds without causing excessive wear or failure. Proper bearing design ensures smooth rotation and reduces friction, which is vital for high-speed machinery.
What is the purpose of using a gear in machine design?
A To prevent corrosion
B To reduce weight
C To transfer motion
D To store energy
Gears are used to transfer motion between shafts in mechanical systems. They can change the direction of motion, adjust rotational speed, and alter torque, making them vital for machinery that requires precise control of movement.
Which of the following is a primary consideration in material selection for machine components?
A Cost-effectiveness
B Mechanical properties
C Aesthetic value
D Color
The mechanical properties of a material, such as strength, hardness, and ductility, are the primary considerations when selecting materials for machine components. These properties ensure the component can withstand the operating conditions without failure.
What is meant by the term “structural design” in machine design?
A Developing lubrication systems
B Creating detailed CAD models
C Ensuring the stability of components
D Designing electrical systems
Structural design in machine design focuses on ensuring that components can withstand forces without failing. It involves calculating stresses, selecting materials, and designing components to ensure stability and durability under operational loads.