Name of the University : Jadavpur University
Department : Material Engineering
Degree : M.Tech
Subject Name : Design And Selection Of Materials
Sem : II
Website : jaduniv.edu.in
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/dspace.jdvu.ac.in/5493-DESIGN%20AND%20SELECTION%20OF%20MATERIALS_Seme2_2006.pdf
Jadavpur Selection Of Materials Question Paper
M. Tech ( Mat. Engg ) Examination, 2006 :
( 2nd Semester )
Time : Three hours
Full Marks : 100
Related : Jadavpur University Physico Chemical Processing of Materials M.Tech Question Paper : www.pdfquestion.in/5491.html
Model Questions
Answer question no. 8 and five from the rest :
Assume any data if necessary for design :
1. a) State and explain principal properties to be. Considered for the selection of a matertial for a given compen. 10
b) What are basic requirement of machine parts ? 6
2. a) Derive the expression for tangential stress in a thin walled cylinder carrying a gas or fluid under a pressure. 10
b) A compressed air cylinder for a laboratory use carries approximately 7 MPa pressure at the time of delivery. The inside diameter of such a cylinder is 250 mm. If the steel has a yield point of 230 MPa and if a safely factor of 2.5 is adequate, Calculale the required wall thickness. 6
3. a) Define a flywheel. State the classes of machines requiring flywheels, Explain with at least two examples of machines for each class. 8
b) A gas engine develops 50 kW at 1500 rpm speed. The maximum variation of energy per revolution is 27% of mean energy. The co-efficient of fluctuation of speed may be taken as 0.2. Determine the necessary mass of the flywheel rim if the rim provides the 95% of the flywheel effect. The mean velocity of the flywheel rim is limited to 40 metre/ second. The density of cast iron may be taken as 7000 kg/ metre cube. 8
4. a) State.and explain determination of critical load for long column hinged at the ends. 10
b) An eccentric rod to drive the valve mechanism of a steam engine carries a maximum compressive load of 20 kW, the length of the rod being 1·2 metre. Assume the eccentric rod to be hinged at both ends. Determine the diameter of the rod in the middle. Assume modules of elasticity 0·21×106 MPa and factor of safely 30. 6
5. a) Derive the expression for spring deflection of a close coil helical spring elongated by an axial load ‘P’ and the spring composed of a wire or round rod of diameter ‘d’ wound into a helix of mean radius R. 8
b) A close coiled helical spring having mean dia of coil 30 mm is subjected to a maximum load of 180 N and the deflection at this load is to be 25 mm. The torsional shear strem must not exceed 300 MPa. Suggest the suitable diameter of the spring wire. 8
6. a) A steel shaft transmits l00 kW at 120 rpm. The maximum twisting moment during each revolution exceeds the mean by 30%. Suggest the suitable diameter for the solid shaft if the torsional shear stress is not to exceed 65 MPa. 8
6. b) It is desired to bend a strip 6 mm thick and 20 mm wide of Spring steel into a loop with ends overlapping and riveted. Find the minimum radius of the loop if the stresses due to bending are limited to 100 MPa. Also determine the bending moment required to bend the strip. Take E = 0·21 × 106 MPa. 8
7. a) State the law of gearing. 4
b) Discuss various materials and their limitations on the selection of Gear wheels. 4
c) In Belt drive what are the types of belts used ? 4
d) It is required to drive a shaft at 620 rpm by means of a belt from a parallel shaft, having a pulley A = 30 cm diameter on it and running at 240 rpm. What sized pulley is required on the shaft B ? 4
8. a) State common causes of failure of a structural component.
b) Write and explain application of various parameters to measure crack potency or crack extension force. 3
c) Determine the shape of the DCB (Double Cantilever Beam) specimen if G1 (Energy release rate in mde I) is to remain constant with the growth of the crack. The specimen is loaded in the constant load mode. Determine the depth ‘h’ of the specimen beyond the crack tip if thickness of specimen remains constant (B = 30 mm). The initial crack length is 50 mm, modules is 207 GPa. 12