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.
- University: Government College of Engineering and Technology, Jammu
- Subject: Machine Design
- Course: Machine Design
- Branch: Mechanical Engineering
- Year: 2018
- Paper: end-term
- Duration: 180 minutes
- Total marks: 75
Instructions
- Attempt any five questions selecting atleast two questions from each section.
- Each question carries equal marks.
Questions
Section - A
- Q1. A bolt is to a tensile load of $25\text{kN}$ and a shear load of $10\text{kN}$. Determine the diameter of the bolt according to (a) Maximum principal stress theory (b) maximum shear stress theory Assume factor of safety as $2.5$, yield point stress in simple tension = $300\text{N/mm}^2$.
- Q2. What are the factors to be considered for the selection of materials for the design of machine elements? Discuss.
- Q3. a. What are the advantages and disadvantages of welded joints over riveted joints? b. Design the longitudinal riveted joint for a boiler of diameter $2\text{m}$ taking the permissible pressure as $25\text{MPa}$. Assume the tensile, shear and compressive stresses for the material of shell and rivets as $90\text{MPa}$, $60\text{MPa}$ and $120\text{MPa}$ respectively.
- Q4. A square key is required for fixing a pulley on the shaft, which is $50\text{ mm}$ in diameter. The pulley transmits $10\text{kW}$ power at $200\text{ rpm}$ to the shaft. The key is made of steel $45\text{C8}$ ($\sigma_t=\sigma_c=380\text{N/mm}^2$) and the factor of safety is $3$. Determine the dimensions of the key. Assume $\sigma_s=0.577\sigma_t$.
Section - B
- Q5. A compressor running at $500\text{ rpm}$ is driven by a $15\text{kW}$ motor running at $1500\text{ rpm}$. The center distance is $0.375\text{ m}$. The motor pinion is to be of C-30 foged steel hardened and tampered, and the driven gear is to be of cast steel. Determine the module, the face width and the number of teeth on each gear. Design the drive completely.
- Q6. A cast iron fly wheel rotating at $600\text{ rpm}$ is brought to rest by a break in $2\text{ sec}$. The flywheel may be considered as a solid circular disc having a diameter of $400\text{ mm}$ and thickness $100\text{ mm}$. The density of cast iron is $7200\text{ kg/m}^3$. Determine: i. Energy absorbed by the brake. ii. Number of turns drum rotates before coming to rest. iii. The braking Torque.
- Q7. The piston rod of a hydraulic cylinder exerts an operating force of $10\text{KN}$. The friction due to piston packings and stuffing box is equivalent to $10\%$ of the operating force. The pressure in the cylinder is $10\text{MPa}$. The cylinder is made up of cast iron FG200, taking an F.O.S of $5$, determine the thickness of the cylinder?
- Q8. Design a cast iron piston for a single acting four stroke engine for the following data: Cylinder bore = $100\text{mm}$; Stroke = $125\text{mm}$; Maximum gas pressure = $5\text{ N/mm}^2$; Indicated mean effective pressure = $0.75\text{ N/mm}^2$; mechanical efficiency = $80\%$; Fuel consumption = $0.15\text{ kg}$ per brake power per hour; Higher calorific value of fuel = $42\times 10^3\text{ kJ/kg}$; speed = $2000\text{ rpm}$. Any other data required for the design may be assumed.
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- Machine Design 2018 question paper — end-term
- Machine Design 2018 question paper — end-term