This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on “Eccentrically Loaded Riveted Joints”.
Answer the following questions in context to figure 1.
1. A bracket is attached to a vertical wall by means of four rivets. Find the rivet which is under maximum stress.
a) 1 and 4
b) 2 and 3
c) 3 and 1
d) 4 and 2
Explanation: Primary Shear act vertically upward on all the rivets. Secondary shear is proportional to the distance from CG. Hence rivets 1 and 4 are under maximum stress.
2. Calculate the primary shear stress on each rivet if P=30kN and diameter of rivets is 15mm.
a) None of the listed
b) 21.2 N/mm²
d) 169.6 N/mm²
Explanation: τ₁=P/4A or 7500/A.
3. If secondary shear stress acting on any bolts is given by Cxr₁ where r₁ is the distance of bolt from CG, then find the value of C. Bolts are equidistant with spacing of 100mm. Force P=30kN.
4. Calculate the effective force in vector form to which rivet 2 is subjected. Bolts are separated by 100mm and force P=30kN.
d) None of the listed
Explanation: Primary force=7500j, Sec Force=Cx50(-i) where C=72.
5. Calculate the effective force in vector form to which rivet 4 is subjected. Bolts are separated by 100mm and force P=30kN.
b) None of the listed
Explanation: Primary force=7500j, Sec Force=Cx100 i where C=72.
6. Calculate the diameter of the rivets if permissible shear stress is 60N/mm². Bolts are separated by 100mm and force P=30kN.
Explanation: Magnitude of force acting on Bolt 4 or Bolt 1=√7500²+7200² or 10396.6=πd²τ/4.
7. Are the bolts 2 and 3 under same force?
c) Depends on nature of force whether it is of shear or bending in nature
d) Can’t be determined
Explanation: Primary shear force is same but secondary shear forces direction are different in the two bolts.
8. Are the bolts 2 and 3 subjected to same magnitude of force?
Explanation: Although the vectors are different for the forces on two bolts but their magnitudes are same.
9. Can we use the rivets of diameter 18mm in the following case if P=30kN and bolts are separated by 100mm each. Maximum permissible shear stress is 60N/mm².
c) In some cases
d) Cannot be determined
Explanation: The minimum diameter required for the rivets is obtained 15mm. Any rivet greater than this diameter is safe to use.
Sanfoundry Global Education & Learning Series – Machine Design.
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