Machine Design interview questions

1. A.conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts
2. B.initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life
3. C.ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress
4. D.bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication

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1. A.Lewis equation
2. B.Factor of safety
3. C.Sommerfeld number
4. D.Preloaded bolted joint

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1. A.Factor of safety — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
2. B.Factor of safety — bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication
3. C.Factor of safety — ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress
4. D.Factor of safety — friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis

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1. A.gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
2. B.correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
3. C.stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress

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1. A.Petroff's equation
2. B.Sommerfeld number
3. C.Endurance limit
4. D.Soderberg line

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1. A.Endurance limit — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
2. B.Endurance limit — friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
3. C.Endurance limit — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
4. D.Endurance limit — stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa

Answer + AI explanation with Pro

1. A.friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
2. B.conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts
3. C.stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield

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1. A.Petroff's equation
2. B.Soderberg line
3. C.Endurance limit
4. D.Sommerfeld number

Answer + AI explanation with Pro

1. A.Soderberg line — Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield
2. B.Soderberg line — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
3. C.Soderberg line — conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts
4. D.Soderberg line — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index

Answer + AI explanation with Pro

1. A.bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication
2. B.conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts
3. C.Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield
4. D.ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress

Answer + AI explanation with Pro

1. A.Maximum principal stress theory
2. B.Preloaded bolted joint
3. C.Sommerfeld number
4. D.Lewis equation

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1. A.Maximum principal stress theory — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
2. B.Maximum principal stress theory — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
3. C.Maximum principal stress theory — stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.Maximum principal stress theory — Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield

Answer + AI explanation with Pro

1. A.gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
2. B.correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
3. C.friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
4. D.initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life

Answer + AI explanation with Pro

1. A.Sommerfeld number
2. B.Wahl factor
3. C.Endurance limit
4. D.Soderberg line

Answer + AI explanation with Pro

1. A.Wahl factor — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
2. B.Wahl factor — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
3. C.Wahl factor — friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
4. D.Wahl factor — bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication

Answer + AI explanation with Pro

1. A.stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
2. B.gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
3. C.friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
4. D.bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication

Answer + AI explanation with Pro

1. A.Preloaded bolted joint
2. B.Lewis equation
3. C.Soderberg line
4. D.Maximum principal stress theory

Answer + AI explanation with Pro

1. A.Lewis equation — bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication
2. B.Lewis equation — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
3. C.Lewis equation — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
4. D.Lewis equation — initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life

Answer + AI explanation with Pro

1. A.Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield
2. B.initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life
3. C.friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
4. D.conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts

Answer + AI explanation with Pro

1. A.Preloaded bolted joint
2. B.Petroff's equation
3. C.Endurance limit
4. D.Sommerfeld number

Answer + AI explanation with Pro

1. A.Preloaded bolted joint — initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life
2. B.Preloaded bolted joint — Rankine's criterion suited to brittle materials such as cast iron, where failure is by fracture rather than yield
3. C.Preloaded bolted joint — stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.Preloaded bolted joint — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index

Answer + AI explanation with Pro

1. A.initial tightening keeps mated parts clamped so external load is shared between bolt and members in proportion to stiffness, improving bolt fatigue life
2. B.ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress
3. C.stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication

Answer + AI explanation with Pro

1. A.Sommerfeld number
2. B.Maximum principal stress theory
3. C.Endurance limit
4. D.Lewis equation

Answer + AI explanation with Pro

1. A.Sommerfeld number — friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
2. B.Sommerfeld number — bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication
3. C.Sommerfeld number — stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
4. D.Sommerfeld number — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index

Answer + AI explanation with Pro

1. A.stress amplitude below which steel survives an unlimited number of fully reversed cycles, roughly half the tensile strength up to 1400 MPa
2. B.bearing characteristic (r/c)²·μN/p that governs hydrodynamic film thickness and friction and marks the change from boundary lubrication
3. C.friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis
4. D.ratio of failure stress (yield for ductile, ultimate for brittle materials) to the allowable working stress

Answer + AI explanation with Pro

1. A.Petroff's equation
2. B.Maximum principal stress theory
3. C.Wahl factor
4. D.Factor of safety

Answer + AI explanation with Pro

1. A.Petroff's equation — conservative fatigue design line joining the endurance limit to yield strength on the mean-stress axis, preferred for ductile parts
2. B.Petroff's equation — gear tooth bending strength modelled as a cantilever beam, Wt = σ·b·m·Y with the form factor Y rising with tooth count
3. C.Petroff's equation — correction applied to helical spring shear stress for wire curvature and direct shear, larger for a lower spring index
4. D.Petroff's equation — friction coefficient 2π²(μN/p)(r/c) for a lightly loaded concentric journal bearing, the starting point of bearing friction analysis

Answer + AI explanation with Pro