Name of the College : DMI College OF Engineering
Department : Mechanical Engineering
Subject Name : Design Of Machine Elements
Degree : B.E
Website : dmice.ac.in
Document Type : Question Bank
Design Of Machine Elements : https://www.pdfquestion.in/uploads/dmice.ac.in/1503-ME2303.docx
DMI Design Of Machine Elements Question Paper
UNIT-I
(STEADY STRESSES AND VARIABLE STRESSES IN MACHINE MEMBERS)
PART – A :
** Define ‘ Design’ and explain the design process
** What is ‘innovative design”?
** Explain a method of reducing cost of the final product from the design perspective.
Related : DMI College OF Engineering ME2027 Process Planning & Cost Estimation B.E Question Bank : www.pdfquestion.in/1520.html
** What is ‘optimization’? What are the methods for optimization?
** Define factor of safety. What factor dictate the selection of factor of safety?
** Differentiate between hardness and toughness of materials.
** Explain ‘ creep’, resilience’.
** List the various types of loads and explain.
** Distinguish between different types of variable stresses.
** Explain endurance limit. What factors influence endurance strength?
** Explain the effect of product reliability on endurance strength.
** State the significance of S-N curve.
** Define stress intensity factor.
** Explain Goodman and Seidenberg diagrams
** Differentiate between the use of Goodman diagram and Seidenberg diagram for designing.
** Comment on the statement “ In curved beams maximum stress always occurs at the inner fibre “.
** What is stress concentration? What are the methods to determine it? What are the methods to reduce it?
** Explain how the maximum shear stress theory is used for biaxial and trysail stress cases.
** Define fatigue stress concentration factor.
** Define Notch sensitivity factor.
UNIT – II
(DESIGN OF SHAFTS, KEYS AND COUPLINGS)
PART – A :
1. What is shaft?
2. What are the types of shafts?
3. List all the shaft materials.
4. What is simple torsion?
5. What is simple bending moment?
6. Write down the formula for finding equivalent twisting moment.
7. What are types of rigidity?
8. What are different measures followed to control the lateral deflection?
9. What are the different ways to limit the maximum permissible transverse deflection?
10. Define the term critical speed.
11. Write down the dunkerley’s equation for the critical speed of the shaft.
12. What is key?
13. What are types of keys?
14. How are sunk keys designed?
15. What is the main use of woodruff keys?
16. How is a couplings specified?
17. What are the purposes in machinery for which couplings are used?
18. Name any two of the rigid and flexible couplings?
19.What is material used for flange or flange couplings?
20.What is the advantage of Gear coupling?
PART – B :
** A line shaft rotating at 200rpm is to transmit 20KW power. the allowable shear stress for the shaft material is 42N/mm2.If the shaft carries a central load of 900N and is simply supported between bearing 3meters apart determine the diameter of the shaft. The maximum tensile or compressive stress is not to exceed 56N/mm2.
** An electric generator rotates at 200rpm and receives 300KW from the driving engine. The armature of the generator is 60cm long and located between bearing 120cm center to center.Owing to the combined weight of armature and magnetic pull, the shaft is subjected to 9000kg acting at right angles to the shaft. The ultimate stress for the shaft is 4480kg/cm2 and shear stress is 3920kg/cm2.Find the diameter of the shaft for a factor of safety of 6.
** A mild steel shaft transmit 23KW to 200rpm.It carries a central load of 900N and is simply supported between the bearing 2.5meters apart. Determine the size of the shaft, if the allowable shear stress is 42MPa and the maximum tensile or compressive stress is not exceed 56MPA.What size of the shaft will be required, if it is subjected to gradually applied load?
** A shaft to transmit 50KW at 1200rpm.It is also subjected to a bending moment of 275Nm.Allowable shear stress is 60N/mm2.The shaft is not to twist more than 2° in a length of 2m.G=80X103N/mm2.Design a shaft.