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# ME6503 - DESIGN OF MACHINE ELEMENTS UNIT - IV NOTES

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ME6503 - DESIGN OF MACHINE ELEMENTS UNIT - IV NOTES
THE QUESTION NUMBER WILL MATCH TO THE QUESTION BANK ATTACHED AT THE END

ME6503 - DESIGN OF MACHINE ELEMENTS UNIT - IV NOTES
THE QUESTION NUMBER WILL MATCH TO THE QUESTION BANK ATTACHED AT THE END

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### ME6503 - DESIGN OF MACHINE ELEMENTS UNIT - IV NOTES

1. 1. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 64 UNIT – IV – ENERGY STORING ELEMENTS AND ENGINE COMPONENTS PART – A 4.1) What is a spring? 4.2) What is the use of springs? [AU, Nov / Dec - 2008] 4.3) Give some of materials used for spring [AU, Nov / Dec - 2008] 4.4) Give a list of the different types of springs 4.5) Mention any four types of springs. [AU, May / Jun - 2012] 4.6) Distinguish between close coiled and open coiled springs. [AU, Nov / Dec –2014] 4.7) Explain the following terms of the spring. (a) Free length (b) Spring index [AU, April / May – 2011] 4.8) Define (a) Spring Index (b) Spring rate. [AU, Nov / Dec –2011] 4.9) Define spring rate. [AU, May / Jun – 2016] 4.10) Define spring index and spring constant. [AU, Nov / Dec –2012] 4.11) What are the functions of springs? In which type of spring is the behavior non - linear? 4.12) Write the formula for natural frequency of spring. [AU, Nov / Dec –2012] 4.13) What are the different materials used for manufacturing springs? 4.14) What is the difference between open coiled and close coiled springs? 4.15) Explain helical spring. What are its types? 4.16) What is stiffness of spring? [AU, Nov / Dec – 2015, May / Jun – 2016] 4.17) Obtain the expression for stiffness of helical spring. [AU, May / Jun - 2012] 4.18) Two springs of stiffness K1 and K2 are connected in series. What is the stiffness of the connection [AU, April / May – 2010] 4.19) For a springs in series, the spring rate ( stiffness) add reciprocally prove [AU, April / May – 2010] 4.20) How will you find whether the given helical spring is a compression or tension spring? 4.21) What is Whal’s factor? Why it is used? [AU, April / May – 2011] 4.22) Why is Wahl’s factor to be considered in the design of helical compression springs? [AU, April / May – 2010]
2. 2. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 65 4.23) What is the effect of change in spring index on Whal’s factor and on the stress induced in a helical compression spring? [AU, Apr / May – 2015] 4.24) What are the different styles of end for helical compression spring? [AU, Nov / Dec - 2009] 4.25) What type of spring is used to maintain an effective contact between a cam and a reciprocating roller or flat faced follower? [AU, Nov / Dec – 2015] 4.26) What are conical springs? 4.27) Explain torsion spring. 4.28) On what basis are the materials for helical springs selected? Give some of the materials used for spring. 4.29) What is the effect of increase in wire diameter on the allowable stress value? [AU, Nov / Dec - 2010] 4.30) Define solid length and free length of the helical spring. 4.31) Define the terms stiffness and spring index. 4.32) What is pitch? 4.33) On what concepts are helical springs designed? 4.34) What are the different types of stresses induced in coil springs? 4.35) Why is Wahl's factor to be considered in the design of helical compression springs? 4.36) A helical spring of rate 10 N/mm is mounted on top of another spring of rate 8 N/mm. Find the force required to give a total deflection of 45 mm. 4.37) A helical spring of rate 12 N/mm is mounted on the top of another spring of rate 8 N/mm. Find the force required to give a deflection of 50mm. [AU, Nov / Dec –2013] 4.38) What is meant by eccentric loading of springs? 4.39) The extension springs are in considerably less that the compression springs. Why? [AU, Nov / Dec –2011] 4.40) Explain buckling of compression springs. 4.41) What is meant by surge in springs? [AU, Nov / Dec – 2008, 2012] 4.42) What is surge in springs? [AU, May / Jun - 2013] 4.43) Explain surge in coil springs. 4.44) Estimate the equivalent stiffness of springs in parallel and in series.
3. 3. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 66 4.45) What are the purposes of using concentric springs? [AU, Apr / May – 2015] 4.46) What are the applications of concentric springs? [AU, Apr / May – 2010] 4.47) When two concentric springs of stiffness 100 N/mm and 50 N/mm respectively are subjected to an axial load of 750 N, what will be the deflection of each spring? [AU, Nov / Dec – 2007] 4.48) Explain briefly leaf springs. [AU, Nov / Dec - 2009] 4.49) What are the advantages of the leaf springs? 4.50) What is semi - elliptical leaf springs? 4.51) What is meant by semi elliptical leaf springs? [AU, May / Jun – 2014] 4.52) What is meant by nipping in leaf springs? 4.53) What is nipping of leaf spring? [AU, Nov / Dec – 2015, May / Jun – 2016] 4.54) What is master leaf and how are the lengths of various leaves determined? 4.55) Why are leaf springs made in layers instead of a single plate? 4.56) What is a lever? [AU, Nov / Dec –2011] 4.57) What is a flywheel? For what purpose is it used? 4.58) What is the use of flywheel? [AU, Nov / Dec - 2008, May / Jun - 2012] 4.59) What is the function of a flywheel? [AU, Apr / May – 2011, Nov / Dec –2012] 4.60) What is the main function of a flywheel in an engine? [AU, Nov / Dec –2011] 4.61) What is the purpose of flywheel that is used in an IC engine? [AU, Nov / Dec –2013] 4.62) How does the function of flywheel differ from that of governor? [AU, May / Jun – 2012, Nov / Dec –2012] 4.63) What is the purpose of the flywheel? [AU, Nov / Dec – 2015] 4.64) Write the difference between flywheel and governor. 4.65) Specify the types of flywheel. 4.66) Define co-efficient of fluctuation of speed. [AU, Nov / Dec –2011] 4.67) Define Co-efficient of fluctuation of speed in flywheel. [AU, May / Jun - 2013] 4.68) Define (a) Coefficient of fluctuation of speed (b) Coefficient of fluctuation of energy. [AU, Nov / Dec –2014] 4.69) Define the term 'fluctuation of speed' and 'fluctuation of energy'. [AU, May / Jun – 2016] 4.70) Define the term co-efficient of steadiness. [AU, Nov / Dec – 2009, 2011]
4. 4. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 67 4.71) Define the term "fluctuation of energy". [AU, May / Jun – 2014] 4.72) Define co-efficient of fluctuation of energy. [AU, Nov / Dec - 2009] 4.73) What type of stresses is produced in a disc flywheel? [AU, Nov / Dec - 2010] 4.74) Explain briefly the stresses induced in a flywheel. 4.75) Explain how the size of the flywheel can be determined. 4.76) At what angle of the crank the twisting moment is maximum in the crankshaft? [AU, Nov / Dec –2011] 4.77) What is the use of connecting rod? 4.78) Why is I-section preferred for the connecting rod? 4.79) Why I section is chosen for the connecting rod of I.C engines? [AU, Nov / Dec – 2015] 4.80) Sketch the cross section of connecting rod at mid-span. 4.81) Why is piston end of a connecting rod kept smaller than the crank pin end? [AU, Nov / Dec - 2010] 4.82) Under what force, the big end bolts and caps are designed? [AU, Nov / Dec –2011] 4.83) What type of external forces act on connecting rod? [AU, Nov / Dec –2012] PART - B 4.84) Design a spring for a balance to measure 0 to 1000 N over a scale of length 80 mm. The spring is to be enclosed in a casting of 25 mm diameter. The approximate number of turns is 30. The modulus of rigidity is 85 KN/mm2. Also calculate the maximum shear stress induced. 4.85) One helical spring is nested inside another; the dimensions are as tabulated below. Both the springs have the same free length and carry a total load of 2500 N. Outer spring Inner springs Number of active coils 6 10 Wire diameter 12.5 mm 9mm Mean coil diameter 100 mm 70 mm Determine the i) Maximum load carried by each spring
5. 5. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 68 ii) Total deflection of each spring iii) Maximum stress in each spring TakeG = 83 GPa. 4.86) Design a spring for a spring loaded safety valve for the following conditions. Operating pressure 10 bar. Diameter of the valve seat 100mm. Design shear stress for the spring material is 400 N/mm2. Modulus of rigidity is 8.00 x 104N/mm2. The spring is to be kept in a casing of 120 mm inner diameter and 350mm long. The spring should be at maximum lift to 6mm, when the pressure is 11 bar. 4.87) A spring loaded safety valve for a boiler is required to blow-off at a pressure of 1.5 N/mm2. The diameter of the valve is 60 mm. Design a suitable compression spring for the safety valve, assuming the spring index to be 6 and 25 mm initial compression. The maximum lift of the valve is 15 mm. The shear stress in the spring material is to be limited to 450 MPa. Take G = 0.84 * 105MPa. 4.88) A spring for a spring balance is to elongate 100mm, when subjected to a load of 20Kgf. Assume that the mean diameter of the coil is to be 6 times the diameter of the wire and the maximum stress to be induced is limited to 40 Kgf/mm2. Determine the diameter for the wire, for the coil and the number of coils required and length of spring. Modulus of rigidity G.=0.8 x104Kgf/mm2. 4.89) Design and draw a valve spring of a petrol engine for the following operating conditions: Spring load when the valve is opened = 400 N Spring load when the valve is closed = 250 N Maximum inside diameter of spring = 25 mm Length of the spring when the valve is opened = 40 mm Length of the spring when the valve is closed = 50 mm Maximum permissible shear stress = 400 MPa 4.90) Design a helical spring for a spring loaded safety valve of the following conditions:
6. 6. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 69 Diameter of valve seat = 65mm Operation pressure = 0.7N/mm2 Maximum pressure when the valve blows freely = 0.75N/mm2 Maximum lift of the valve when the pressure rises from 0.7 to 0.75N.mm2 = 3.5mm Maximum allowable stress = 550MPa Modulus of rigidity = 84kN/mm2 Spring index = 6 Draw a neat sketch of the free spring showing the main dimensions. [AU, Nov / Dec - 2012] 4.91) A safety valve of 60 mm diameter is to blow off at a pressure of 1.2 N/mm2 . It is held on its seat by a closed coil helical spring. The maximum lift of the valve is 10 mm. Design a suitable compression spring of C = 5 and providing an initial compression of 35 mm.  = 500 MPa, G = 80 KN/mm2 . Calculate the a) Diameter of the spring wire b) Mean coil diameter c) Number of active turns d) Pitch diameter of the coil. [AU, May / Jun – 2013, 2016] 4.92) Design a helical tension spring for a spring loaded safety valve for the following conditions. Diameter of valve seat = 65 mm. Operating pressure = 0.7 N/mm2 Maximum pressure = 0.75 N/mm2 . Maximum lift of the valve when the pressure ranges from 0.7 to 0.75 N/mm2 is 3.5 mm. = 550 MPa , G = 84 KN/mm2 , C = 6 4.93) Design a close-coiled helical spring of silicon-manganese steel for the valve of an IC engine capable of exerting a net force of 65N when the valve is open and 54N
7. 7. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 70 when the valve is closed. The internal and external diameters are governed by space limitations, as it has to fit over bushing of 19 mm outside diameter and go inside a space of 38 mm diameter. The valve lift is 6 mm. [AU, Nov / Dec - 2010] 4.94) A helical compression spring is used to absorb the shock. The initial compression of the spring is 30 mm and it is further compressed by 50 mm while absorbing the shock. The spring is to absorb 250 J of energy during the process. The spring index can be taken as 6. The spring is made of patented and cold drawn steel wire with ultimate strength of 1500 N/mm and modulus of rigidity of 81370 N/mm2 . The permissible shear stress for the spring wire should be taken as 30% of the ultimate tensile strength. Design the spring and calculate [AU, Nov / Dec - 2009] 4.95) A helical compression spring is used to absorb the shock. The initial compression of the spring is 30 mm and it is further compressed by 50 mm while absorbing the shock. The spring is to absorb 250 J of energy during the process. The spring index can be taken as 6. The spring is made of patented and cold drawn steel wire with ultimate strength of 1500 N/mm and modulus of rigidity of 81370 N/mm2 . The permissible shear stress for the spring wire should be taken as 30% of the ultimate tensile strength. Design the spring and calculate : [AU, Nov / Dec - 2009] (i) Wire diameter (ii) Mean coil diameter (iii) Number of active turns (iv) Pitch of the turns 4.96) A close-coiled helical compression spring has plain ends and is to fit over a 25 mm diameter rod. When a compressive force of 100 N is applied to the spring it compresses by 50 mm. If the spring has a preferred wire diameter of 4 mm, and the spring material has a maximum allowable shear stress of 180 MN/m2 and a modulus of rigidity of 81 GN/m2 , determine [AU, May / Jun – 2014] (i) The mean coil diameter of the spring. (ii)The diametrical clearance between the spring and the rod. (iii) The number of coil in the spring (iv) The solid length of the spring.
10. 10. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 73 4.110) Design a helical compression spring for a maximum load of 1000 N for a deflection of 25 mm using the value of spring index as 5. The maximum permissible shear stress for spring wire is 420 MPa and modulus of rigidity is 84 kN/mm2 . [AU, Nov / Dec – 2007] 4.111) Design a closed coiled helical compression spring for a service load ranging from 2.5 KN to 3KN. The deflection for this load range is 6mm. Use a spring index of 5. Take the shear yield strength as 700 N/mm2 and modulus of rigidity as 8 x 104N/mm2. Factor of safety is not to be less than 1.3. Also check the spring of buckling. 4.112) Design a closed coiled helical compression spring for a service load ranging from 2.5 KN to 3KN. The deflection for this load range is 6mm. Use a spring index of 5. Take the shear yield strength as 700 N/mm2 and modulus of rigidity as 8 * 104 N/mm2 . Factor of safety is not to be less than 1.3. Also check the spring of buckling. 4.113) Design a closed coiled helical compression spring for a service load ranging from 2.25 KN to 2.75KN. The deflection for this load range is 6mm. Use a spring index of 5. Take the permissible shear stress intensity as 420 N/mm2 and modulus of rigidity as 84 x 103 N/mm2. Neglect the effects of stress concentration. Draw a fully dimensioned sketch of the spring, showing the details of the finish of the end coils. [AU, Nov / Dec – 2012] 4.114) Design and draw a valve spring of a petrol engine for the following operating conditions: Spring load when the valve is open = 400 N Spring load when the valve is closed = 250 N Maximum inside diameter of the spring = 25 mm Length of the spring when the valve is open = 40 mm Length of the spring when the valve is closed = 50 mm Maximum permissible shear stress = 400 MPa. [AU, Apr / May – 2011]
11. 11. R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2016 – NOV 2016 ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 74 4.115) A helical spring is made from a wire of 6mm diameter and outside diameter of 70mm. the spring has 6 numbers of active coils. If the permissible stress in shear is 300N/mm2 and the modulus of the rigidity is 80kN/mm2 , find the axial load which the spring can take and the deflection produced. [AU, May / Jun - 2012] 4.116) A helical spring is made from a wire of 8 mm diameter and is of outside diameter 75 mm. The spring has 6 numbers of active coils. If the permissible stress in shear is 350 N/mm2 and the modulus of rigidity is 84 kN/mm2 . Find the axial load, which the spring can take and the deflection produced. [AU, Nov / Dec – 2015] 4.117) A helical torsion spring of mean diameter 600 mm is made of a round wire of 6 mm diameter. If a torque of 6 Nm is applied on the spring, find the bending stress induced and the angular deflection of spring in degrees. Take C = 10, E = 200 KN/mm2 . The number of effective turns may be taken as 5.5. 4.118) A concentric spring for an aircraft engine valve is to exert a maximum force of 5 KN under a axial deflection of 40mm. Both the springs have the same free length, same solid length and are subjected to equal maximum shear stress of 500 N/mm2. If the spring index for both the springs is 6, find the (a) load shared by each spring (b) main dimensions of both the springs, and (c) number of active coils of each spring. Assume G = 0.8 x 105N/mm2 and diametral clearance to be equal to the difference between the wire diameters. 4.119) A concentric spring is used as a valve spring in a heavy duty engine. It consists of two helical compression springs having the same free length and same solid length. The composite spring subjected to a maximum force of 6000N and the corresponding deflection is 50mm. The maximum torsional shear stress induced in spring is 800 N/mm2 . The spring index of each spring is 6. Assume the same material for two springs and the modulus of rigidity of the spring is 8137 N/m2 . The diametral clearance between the coils is equal to the difference between the wire diameters. Calculate [AU, April / May – 2010] (i) The axial force transmitted by the spring. (ii) Wire and mean coil diameters of each springs (iii) Number of active coils in each springs