This set of Machine Design test focuses on “Eccentric Loaded Perpendicular to axis of Bolt”.
1. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. Find the direct shear stress in bolts if diameter=18mm.
a) 16.9N/mm²
b) 19.6 N/mm²
c) 78.6 N/mm²
d) 76.8 N/mm²
View Answer
Explanation: Direct shear stress=one fourth of P/A.
2. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. If distance between the bolts from the axis of tilting is 125mm and 25mm, then find the effective tensile force acting on the bolts lying at 125mm from tilting axis.
a) 6765.2N
b) 8798.2N
c) 7692.3N
d) 7962.11N
View Answer
Explanation: Tensile force=Pe x 125/2(125²+25²).
3. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. If distance between the bolts from the axis of tilting is 125mm and 25mm, then find the effective tensile force acting on the bolts lying at 25mm from tilting axis.
a) None of the listed
b) 7692.3N
c) 2345.2N
d) 1538.46N
View Answer
Explanation: Tensile force=Pe x 25/2(125²+25²).
4. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. Which bolt can be used as criteria for designing?
a) Left top bolt
b) Both top bolts
c) Left bottom bolt
d) Both bottom bolt
View Answer
Explanation: The bolts farthest from the tilting axis are under the maximum tensile force.
5. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. Find the principal shear stress in the top bolts in terms of area A?
a) None of the listed
b) 5309.2/A
c) 6308.2/A
d) 6980.4/A
View Answer
Explanation: Shear Stress in one bolt=5000/A and tensile stress in upper bolt=7692.3/A. τ(max)=√[(σ/2)²+ τ²].
6. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. Find the size of the bolt using maximum shear stress theory.
a) 11mm
b) 12mm
c) 13mm
d) 14mm
View Answer
Explanation: 400 x 0.5/3 =6308.2 x 4 /πd².
7. Given data for bracket is P=20kN, e=100mm, S(yt)=400N/mm², FS=3. Find the size of the bolt using maximum principal stress theory.
a) None of the listed
b) 19.2mm
c) 15.3mm
d) 21.2mm
View Answer
Explanation: σ(max)=σ/2 + √[(σ/2)²+ τ²]=10154.35/A = 35N/mm².
8. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Which bolt is used a criterion for designing?
a) A
b) B
c) A or B
d) None of the listed
View Answer
Explanation: The bolt lying farthest from the axis of tilt experience the maximum stress.
9. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Find the effective tensile force acting in the two bolts.
a) Bolt B=792.07N & Bolt A=792.07N
b) Bolt B=792.07N & Bolt A=7920.8N
c) Bolt B=7920.8N & Bolt A= 792.07N
d) Bolt B=7920.8N & Bolt A=7920.8N
View Answer
Explanation: F₁=Pel₁/2(l₁² + l₂²) and F₂= Pel₂/2(l₁² + l₂²).
10. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Find the radius of Mohr circle which can be made from the shear stress and tensile stress acting on bolts.(Consider bolt under max stress and area of bolt is A)
a) 10000/A N/mm²
b) 6378.5/A N/mm²
c) 10755.7/A N/mm²
d) None of the listed
View Answer
Explanation: r=√(σ/2)²+ τ² where σ=7920.8/A and τ=20000/4A.
11. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Find the ratio of the effective tensile load to which the two bolts are subjected.
a) 1
b) 10
c) 12
d) 8
View Answer
Explanation: F₁=Pel₁/2(l₁² + l₂²) and F₂= Pel₂/2(l₁² + l₂²) or F₁/F₂ =l₁/ l₂.
12. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Determine the size of bolts using maximum shear stress theory.
a) 12mm
b) 9mm
c) 16mm
d) 18mm
View Answer
Explanation: Considerig bolt B as a criterion, τ(max)= √(σ/2)²+ τ² where σ=7920.8/A and τ=20000/4A or 4 x 6378.5/πd²=100.
13. A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Determine the size of bolts using maximum principal stress theory.
a) 16.1mm
b) 22.2mm
c) 20.2mm
d) 18.1mm
View Answer
Explanation: σ(max)=σ/2 + √[(σ/2)²+ τ²] = 7920.8/2A + 6378.5/A =40.
Sanfoundry Global Education & Learning Series – Machine Design.
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