Machine Design 2018 Question Paper — Government College of Engineerin…

The 2018 Machine Design previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.

Instructions

Q1. A helical spring is made from a wire of $6\text{ mm}$ diameter and has outside diameter of $75\text{ mm}$. If the permissible shear stress is $350\text{ MPa}$ and modulus of rigidity $84\text{ kN/mm}^2$, find the axial load which the spring can carry and the deflection per active turn. [20 marks]
Q2. (a) Explain with neat sketches the different types of compound wire ropes. (b) Describe the fiber ropes. What are its advantages? Draw a neat proportionate sketch of a sheave for fiber ropes. [20 marks]

Q3. A bronze spur pinion rotating at $600\text{ r.p.m.}$ drives a cast iron spur gear at a transmission ratio of $4:1$. The allowable static stresses for the bronze pinion and cast iron gear are $84\text{ MPa}$ and $105\text{ MPa}$ respectively. The pinion has $16$ standard $20^\circ$ full depth involute teeth of module $8\text{ mm}$. The face width of both the gears is $90\text{ mm}$. Find the power that can be transmitted from the standpoint of strength. [20 marks]
Q4. A pair of helical gears are to transmit $15\text{ kw}$. The teeth are $20^\circ$ stub in diametric plane and have a helix angle of $45^\circ$. The pinion runs at $10000\text{ r.p.m.}$ and has $80\text{ mm}$ pitch diameter. The gear has $320\text{ mm}$ pitch diameter. If the gears are made of cast steel having allowable static strength of $100\text{ MPa}$; determine a suitable module and face width from static strength considerations and check the gears for wear, give $\sigma_{es} = 618\text{ MPa}$. [20 marks]

Q5. A four stroke diesel has the following specifications. Brake power = $5\text{ kW}$; Speed = $1200\text{ r.p.m.}$; Indicated mean effective pressure = $0.35\text{ N/mm}^2$, Mechanical efficiency = $80\%$. Determine: (i) Bore and length of the cylinder (ii) Thickness of the cylinder head and (iii) size of studs for the cylinder head. [20 marks]
Q6. A vertical 4 stroke compression ignition engine has the following specification: Brake Power = $4.5\text{ kW}$ Speed $1200\text{ rev/min}$ $\text{I.m.e.p} = 0.35\text{ N/mm}^2$ $\eta_m = 80\% Determine the dimension of the cylinder. [20 marks]

Q7. (a) What is Lever? What is the principle on which it works? (b) What is the difference between simple and compound lever? [20 marks]