Manipal University 2008 B.E Mechanical Engineering V SEM%28MECHANICAL ENGG.%29 END SEMESTER S SUBJECT %3A MECHANICAL DESIGN - II %28MEE-303%29 %28MAKE UP%29 REVISED CREDIT SYSTEM - Question Paper

V SEM. B.E. (MECHANICAL ENGG.) DEGREE END SEMESTER exams AUGUST 2008
SUBJECT : MECHANICAL DESIGN - II (MEE-303)(MAKE UP)
REVISED CREDIT SYSTEM

Reg.No.

MANIPAL INSTITUTE OF TECHNOLOGY

(A constituent college of Manipal University, Manipal)

V SEM. B.E. (MECHANICAL ENGG.) DEGREE END SEMESTER EXAMINATIONS AUGUST 2008

SUBJECT : MECHANICAL DESIGN - II (MEE-303)

REVISED CREDIT SYSTEM 01/08/08

Time: 3 Hours.    MAX.MARKS: 50

Instructions to Candidates:

Answer ANY FIVE FULL questions.

   Use of design data handbook is permitted.

   Writing appropriate units at the end of each answer is mandatory.

IA)    Define i) Spring stiffness ii) Spring ratio iii) Prestressing of plate 4 springs.

IB)    A helical cylindrical compression spring has 2mm diameter wire of high 6 carbon steel. The yield strength of this metal in shear is 760 Mpa . The spring has 6 active coils. End coils are square and ground. If the spring

has outside diameter of 12.7mm, what should be the free length of the spring, so that when it is compressed to solid length, the stress does not exceed 90% of the yield strength ? Modulus of rigidity is 78.95 X10³ . Mpa .

2A) Under what circumstances helical gears are prefered?. What is normal 2 module?

2B) For an industrial application, a pair of spur gears is to be designed with 8 equal strength . Speed reduction required is 5:1. Pinion transmits 30kw of power at 1600rpm. 20⁰ stub involute teeth cutter is to be used for cutting gear teeth. Gears would be operating 8 hrs per day against steady loads. Design and specify the gears completely. To what hardness numbers, the gears are to be heat treated?.

3A) Define the term "formative number of teeth as applicable to a bevel 2 gear.

3B) A hardened steel worm rotating at 1250 rpm has to transmit power to 8 a phosphor bronze gear, in a belt conveyer system, with a transmission ratio of 15 :1 . The center distance is to be restricted to 240 mm. Design the drive the completely with standard size worm with 14.5⁰ full depth tooth profile. Estimate power ratings from strength, endurance and heat dissipation aspects .

4A) What is "bearing modulus "of sliding contact bearings?.    2

4B) A soft steel machine shaft has its journal portion 80 mm nominal diameter. It has a speed of 1500rpm .The bearing sleeves are of rigid bronze . Shaft is subjected to rection of 14 KN at each bearing. SAE 40 lubricating oil is to be used. Atmospheric temperature is 25⁰ Celsius. i) Suggest bearing dimensions.

ii Estimate the operating temperature, to maintain thermal equilibrium. iii) Does the bearing operate satisfactorily? Justify your answer.

5A) What are "basic load capacity and "Equivalent dynamic load "of rolling contact bearings?.

5B) Design a "V belt drive for connecting 2.5 kw ,1200rpm motor to a 300rpm blower , which is part of an air conditioning unit. The center distance may be approximately 1.5 times the diameter of larger pulley. Belt speed should not be more than 80%of the maxim recommended value. Specify the type &size of belts, number of belts, sheave sizes and exact center distance to be provided .

6A) What is "chordal action in chain -on-sprocket drives?. What is a "hunting link?.

6B) For lifting 10KN of load from a depth of 50 meters, wire rope is to be suggested, for a factor of safety not less than 6. The bucket weighs 6KN .Lifting is at a speed of 150 meters /minute and it is to be achieved in 2 seconds. Suggest a std size wire and the sheave to be used.

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(MEE-303)

Attachment: manipal-university-2008-b-e-mechanical-engineering-3411-1.pdf

Earning:   Approval pending.