Janardan Rai Nagar Rajasthan Vidyapeeth 2007 Diploma Automobile Engineering MACHINE DESIGN - Question Paper

DTA4 / DTM4 - MACHINE DESIGN

Time : 3 hrs Maximum marks : 75

 

Instruction:

1. Question paper is divided into Group A, Group B and Group C

2. Each Group is 25 Marks

3. Figure to the right in bracket indicates marks.

4. Good Handwriting is expected

5. Assume suitable data if necessary.

 

Group A (25 Marks)

 

Answer any three questions (Question 1 is compulsory)

 

Q.1. What are the basic requirements for designing any machine element? (05)

Q.2. Design for diameter of the shaft considering the strength of a shaft? (10)

Q.3. Write the design procedure of sleeve or muff coupling with a neat diagram? (10)

Q.4. Explain different forms of V-threads with neat diagram and write the advantage

of V-threads (10)

Q.5. Explain the design procedure for helical compression spring? (10)

 

 

Group B (25 Marks)

 

Answer any three questions (Questions 6 is compulsory)

Q.6. A flange coupling is used to transmit 3.75 nw at 150 r.p.n. The allowable shear stress in and bolts is 50n/mn². Determine the shaft diameter. (05)

Q.7. Two plates of 10 mm thickness are to be joined by a single V-butt weld. The permissible stress in fusion is 70 N/M². Determine the length of weld (10)

(i) For static loading

(ii) For dynamic loading with stress concentration factor 1.5 Take load of 35KN

Q.8. The lead screw of lathe has square threads of 24 mm outside diameter and 5mm pitch in order to drive the tool carriage the screw exerts an axial pressure of 2.5 KN. Find the efficiency of screw and power required to drive the screw. If it rotates at 30 rpm neglect bearing friction Assume coefficient of friction of screw threads as 0.12 (10)

Q.9. Power is transmitted by a single plate clutch from the engine shaft to transmission shaft. The maximum thrust provided by 8 springs is 2400 N. Determine the wire dia, coil dia and number of effective turns using following data (10)

δ= 25 mm, C=8, fs=400 N/MM², G=84 X 103 N/mm²

Q.10. What is locking of Screw? What are the conditions of self locking? (10)

 

Group C (25 Marks)

 

All Questions are Compulsory.

 

Q.11 (A) Fill in the blanks ( each question carry 2 marks)

(i) Factor of safety = _______.

(ii) _______ joint is used in the air brake of locomotives.

(iii) From normal stress theory equivalent bending moment MC = _______.

(iv) _______ are the machine elements having property of storing energy while deforming under external load.

(v) The engineering which combines the knowledge of anatomy physiology, anthropometry and psychology is _______.

 

 

(B) Multiple choice Question (Each question carries 2 marks)

i)                    Stress concentration factor for reinforced butt weld is

a) 1 b) 2

c) 2.2 d) 1.2

ii)                  The angel of the thread for British Association thread is

a) 55⁰ b) 47.5⁰

c) 60⁰ d) 75⁰

iii)                Screw is said to be self locking if

a) > α b) = α

c) < α d) none

iv)                Ratio of mean coil diameter to the wire diameter is called

a) spring rate b) spring index

c) none

v)                  The slow and progressive deformation of a material with time under a constant stress is called

a) Fatigne b) Endurance

c) Creep d) none

 

 

(C) True or false (each question carry 1 marks).

i)                    Rolling is the process to form long members of uniform section

ii)                  The value of kt for gradually applied lad is one

iii)                Equivalent twisting moment for shafts is

iv)                The innermost portion thread is called crest

v)                  Springs are used to connect two rotating members like flexible couplings.

 

 

 

 

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