SPPU Mechanical Engineering (Semester 8)
Mechanical System Design
December 2016
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Solve any one question fromQ.1(a,b) and Q.2(a,b)
1(a) Write the procedure for kinemetic design of multispeed gear box for machine tools.
6 M
1(b) How the standard normal distribution curve differ than normal distribution curve.
4 M

2(a) A machine tool requires six speed gear box. Which having a 160 rpm minimum and 100 rpm maximum speed, when the motor shaft speed is 1440 rpm.
4 M
2(b) A particular type of rolling contact bearing has a normally distributed time to failure with a mean of 10,000 hours and a standard deviation of 750h. If there are 100 such bearings fitted at a time, how many may be expected to fail within the first 11000h?
Z 0 1 2 3 4 5
1.3 0.4032 0.4049 0.4066 0.4082 0.4099 0.4115
6 M

Solve any one question fromQ.3(a,b) and Q.4(a,b)
3(a) Give the advantages, disadvantages and applications of conveyors as material handling euipment.
4 M
3(b) A belt conveyor is to be designed to carry the bulk material at the rate of 350 ton/hour with the following detail's: weight density of material = 16700 N/m3, Angle of repose = 15°, belt speed = 120m/min, material factor for plies k1=2.0, Belt tension and arc of contact factor k2=70, No. of piles for the belt =4, C=0.075, S = 80mm, determine
i) width of belt ii) diameter and length of drive pulley.
6 M

4(a) Describe with neat sketch the procedure to calculate the power requirement for belt conveyors.
4 M
4(b) Folllowing data refers to a horiziontal belt conveyors used for transporting iron ore- capacity of conveyor = 300×103kg/hour, belt speed=180m/minute, density of coal (ρ)=7848N/m3, Number of piles for belt (Zp)=3, material factor for piles(k1=2, Belt tension and arc of contact factor for belt (k2)=60, Electric motor speed=1440 rpm, centre distance between snub pulleys, (d1=200m, centre distance between derive and tail pulley (d2)=240m. Pitch of carrying run idlers, (tc)=1m, Pitch or return run idlers(tr)=2.5m. Surchagre factor= 0.0725 determine:
i) Width of belt
ii) Reduction ratio of gear reducer
iii) The number of carrying and return run idlers.
6 M

Solve any one question fromQ.5(a,b) and Q.6(a,b)
5(a)(i) What are the types of end closure for cylindrical pressure vessel?
4 M
5(a)(ii) What are the methods of prestressing the cylinder?
4 M
5(b)(i) Derive the Lame's equation. Explain under what conditions it is used?
5 M
5(b)(ii) An air receiver consisting of a 500 mm diameter cylinder closed by hemi-spherical ends, is made of steel FeE 200 and the factor of safety is 2.5. The operating pressure is limited to 3MPa. Treating the reciver as a thin cylinder, calculate the thickness of the cylinder wall and the hemispherical ends. Neglect the effect of weldedjoints.
5 M

6(a) The hydraulic cylinder 400 mm bore operates at a maximum pressure of 5N/mm2. The piston rod is connected to the load and the cylinder to the frame through hinged joints. Design (1) cylinder (2) piston rod (3) hinge pin. The allowable tensile. Stress for cast steel cylinder and end cover is Mpa and for piston rod is 60MPa. Take τ=45N/mm2 for hinge pin draw the hydraulic cylinder with piston & piston rod.
8 M
6(a)(ii) Expalin with neat sketches the different tyes of formed heads used as end closures in cylindrical pressure vessels.
5 M
6(b)(i) A high pressure cylinder consists of a steel tube with inner and outer diameters of 20 mm and 40 mm resectively. It is jacketed by an outer steel tube having an outer diameter of 60 mm. The tubes are assembled by a shrinking process in such a way that maximum principal stress induced in any tube is limited to 100 N/mm2. Calculate the shrinkage pressure and original dimensions of the tube E = 207 kN/mm2.
5 M

Solve any one question fromQ.7(a,b) and Q.8(a,b)
7(a) Expalin the step by step procedure for designing of piston of IC engine.
6 M
7(b) Determine the dimension of the cross section of the connecting rod for a diesel engine with following data:
Cylinder bore = 100mm σc=275N/mm2 Maximum gas pressure = 4 MPa Length of connecting rod = 350mm Factor of safety = 5
10 M

8(a) Explain the step by step procedure for designing of crank pin of IC engine
6 M
8(b) Cylinder of four storke diesel engine has following specification:
Cylinder bore = 145mm Factor of safety =5 Cylinder material = FG200 Poisson's ratio=0.25 Maximum gas pressure =3.5MPa Re boaring allowance = 3mm Determine thickness of cylinder wall and calculate stresses in the cylinder wall.
10 M

Solve any one question fromQ.9(a,b) and Q.10(a,b)
9(a) Differentiate between adequate and optimum design. Also explain different types of equations that are used in 'Johnson's method of optimum design'.
6 M
9(b) A tensile bar of length 450mm is subjected to constant tensile force of 400N. If the factor safety is 1.5, design the bar diameter, using Johnson's method, with the objective of minimizing material weight using optimum material from the list given in Table 1.
Material Density(ρ)Kg/m2 Cost(c) Rs/Kg Syt N/mm2
Steel 7800 28 400
Aluminimum  Alloy 2800 132 150
Titanium Alloy 4500 2200 800
10 M

10(a) Write a short note on design for manufacturing and assembly.
6 M
10(b) In lightweight equipment, a shaft is required to transmit 45KW power at 480 RPM. Required stiffness of shaft is 90N-m/ Degree. Factor of safety based on Sys is 2. Using max shear stress theory of failure design the shaft with the objective of minimum weight by using optimum material from the list given in Table 1 above Assume G=70000N/mm2 for all materials.
10 M

More question papers from Mechanical System Design