GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER-V (NEW) EXAMINATION - WINTER 2020
--- Content provided by FirstRanker.com ---
Subject Code:2151907Subject Name:Design of Machine Elements
Time:10:30 AM TO 12:30 PM Date:20/01/2021 Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.
--- Content provided by FirstRanker.com ---
2. Make suitable assumptions wherever necessary.3. Figures to the right indicate full marks.
Q1 (a) Distinguish between open and cross belt drive. MARKS 03
(b) Solve the numbers of RS basic series from 1 to 10. 04
(c) Decide appropriate manufacturing consideration in design. 07
--- Content provided by FirstRanker.com ---
Q2 (a) Explain stress concentration. 03
(b) Explain factors affecting endurance limit. 04
(c) A machine component is subjected to fluctuating stress that varies from 40 to 100 N/mm². The corrected endurance limit stress for the machine components is 270 N/mm². The ultimate tensile strength and yield strength of the material are 600 and 450 N/mm² respectively. Solve the factor of safety using (1) Gerber theory (2) Soderberg line (3) Goodman line. 07
Q3 (a) Design of thin cylinder. 03
(b) Classify types of springs. 04
--- Content provided by FirstRanker.com ---
(c) A semi elliptic multi leaf spring is used for the suspension of the rear axle of a truck. It consists of two extra full length and ten graduated length leaves including the master leaf. The center to centre distance between the spring is 1200 mm and width of leaves is 60 mm. The leaves are made of steel 55Si2Mo90 and Sy=1500 N/mm² and E=207 GPa and factor of safety is 2.5. The spring is to be designed for a maximum force of 30 kN. The leaves are pre stressed so as to equalize stress in all leaves. Solve (1) thickness of the leaves (2) deflection at the end of the spring. 07Q4 (a) Design of thin spherical vessels. 03
(b) Analyze of stresses in helical spring. 04
(c) It is required to design a helical compression spring subjected to a maximum force of 1.25 KN. The deflection of the spring corresponding to the maximum force should be approximately 30 mm. the spring index can be taken as 6. The spring is made of patented and cold drawn steel wire. The ultimate tensile strength and modulus of rigidity of spring material are 1090 and 81370 N/mm² respectively. The permissible shear stress for the spring wire should be taken as 50 % of the wire diameter (2) total number of coils. 07
Q.5 (a) Describe creep in belt. 03
--- Content provided by FirstRanker.com ---
(b) List advantages and disadvantage of chain drive. 04(c) Design an equation for ratio of tensions on tight side to slack side of flat belt drive. 07
Q.6 (a) List application of V belt drive. 03
(b) List advantages and disadvantage of belt dive. 04
(c) Design of pully for flat belt drive. 07
--- Content provided by FirstRanker.com ---
Q.7 (a) Define: (1) Pressure vessel (2) thick cylinder (3) thin cylinder 03
(b) The inner diameter of a cylindrical tank for liquefied gas is 250 mm. the gas pressure is limited to 15 MPa. The tank is made of plain carbon steel 10C4 (Sut=340 N/mm² and p=0.27 ) and the factor of safety is 5. Calculate the cylinder wall thickness. 04
(c) Explain principle stresses in thick cylinder. 07
Q.8 (a) Describe briefly Autofrettage. 03
(b) A seamless steel pipe of 100 mm internal diameter is subjected to internal pressure of 12 MPa. It is made of steel (Syt=230 N/mm² and p=0.27) and the factor of safety is 2.5. Calculate the thickness of the pipe. 04
--- Content provided by FirstRanker.com ---
(c) Explain end closures with neat sketch. 07--- Content provided by FirstRanker.com ---
This download link is referred from the post: GTU B.Tech 2020 Winter Question Papers || Gujarat Technological University