UNIT-I

Part A

1) What are the various phases of design process?2) List some factors that influence machine design.3) Define Principal plane andPrincipal stress.4) How is Factor of Safety defined for brittle and ductile materials?5) Define stress concentration and stress concentration factor.6) Define Notch sensitivity.7) What are the types of variable stresses?8) What are the various theories of failure?9) Give any four methods of reducing stress concentration.10) Define Hardness and Stiffness.11) Give any four examples for curved beams.12) What are CAD tools?13) State the advantages of CAD.14) What are the methods for optimization?15) Differentiate between hardness and toughness of materials.16) Define creep and resilience.17) Distinguish between different types of variable stresses.18) Explain endurance limit. 19) State the significance of S-N curve.20) What is the use of Goodman & Soderberg diagrams?

Part B

1) An electric motor weighing 500N is mounted on a short cantilever beam of uniform rectangular cross section .The weight of the motor acts at distance of 300mm from the support.The depth of the section is twice the width.Determine the cross section of the beam.The allowable stress in the beam is 40 N/ mm2.2) The stress state in a machine member is given as follows. σx= 20 Mpa; σy= 7Mpa;τxy

=4Mpa.Find the principal normal and shear stresses.Locate the angle of σ1andσ2 from x –axis. 3) A cantilever of span 250mm and 50mm diameter carries a vertical downward load of 3kN at free end along with a torque of 1000N-m and an axial pull of 15kN.Calculate the maximum normal stress at the top and bottom face of the fixed end.4) A steel member is subjected to a 3 dimensional stress system and the resulting principal stresses are 120N/mm2 tension, 80 N/mm2 and 40N/mm2 compression .If the proportional limit of the material in simple tension is 280N/mm2 and its Poisson’s ratio is 0.3, determine the factor of safety according to a) Maximum principal stress theory b) Maximum principal strain theory and c) Maximum shear stress theory.5) A bolt is subjected to a tensile load of 25 KN and a shear load of 10 KN. Determine the diameter of the bolt according to: a) Maximum principal stress theoryb) Maximum principal strain theoryc) Maximum shear stress theory Assume factor of safety as 2.5, yield stress in simple tension = 300N/mm2, Poisson’s ratio = 0.25.

6) A spherical pressure vessel with 400mm inner diameter is welded from steel plates. The vessel is subjected to internal pressure varying from 0 to 50bar.Assuming the ultimate tensile strength as 440Mpa, yield strength 240Mpa and factor of safety 3, calculate the plate thickness.

7) The bending stress in a machine part fluctuates between a tensile stress of 280N/mm2 and a compressive stress of 140N/mm2. What should be the minimum ultimate tensile strength of this part to carry this fluctuation indefinitely according to i) Goodman’s formula ii) Soderbergformula?Take

Factor of safety = 1.75. Assume that the yield point is never likely to be less than 55% of ultimate tensile strength or greater than 93% of it.

8) A crankshaft bearing is loaded as shown in fig. Determine maximum and minimum principle stresses and maximum shear stresses.

9) Determine the maximum and minimum normal stresses and maximum shear stresses at the crankshaft bearing as shown in fig.

10.Taking stress concentration with account find the maximum stress induced when aTensile load of 2OKN is applied toi) A rectangular plate 80mm wide and 12mm thick with a transverse hole of 16mmDiameter.ii) A stepped shaft of diameters 60 and 30mm with a filled radius of 6mm.

UNIT-II

Part-A

1) What is simple torsion?2) What is simple bending moment?3) Define the term critical speed.4) What are the types of keys?5) List the various failures that occur in sunk keys.6) What is the function of a coupling?7) Name any two types of the rigid and flexible couplings.8) What are the advantages of gear coupling?9) List out the types of stresses induced in a shaft.10) Write down the expression for Torsional Rigidity.11) Differentiate between Cotter joint and Knuckle joint.12) Where the muff couplings are used?13) What are the materials used for flange in flange coupling?14) Under what circumstances flexible couplings are used?15) What are advantages and disadvantages of hollow shaft?16) What are the disadvantages of rigid coupling?17) What is the effect of key way on performance of shaft?18) Explain the need for good surface finish in shafts.19) What are the types of rigidity?20) Name few shaft materials.

Part-B

1) A factory line shaft is 4.5m long and is to transmit 75kW at 200rpm.The allowable stress in shear is 49MPa and the maximum allowable twist is 1ο in a length of 20 diameters. Determine the required shaft diameter.2) An electric generator rotates at 200rpm and receives 300kW from the driving engine. The armature of the generator is 60cm long and located between bearings 120cm centre to centre. Owing to the combined weight of armature and the magnetic pull, the shaft is subjected to 9000kg acting at right angles to the shaft. The ultimate stress for the shaft is 448 N/mm2 and shear stress is 392N/mm2.Find the diameter of the shaft for a factor of safety of 6.3) A solid shaft is to transmit 1000kW at 120 rpm. Find the shaft diameter if the design shear stress is 80N/mm2.If the shaft is made hollow with internal diameter being 0.6 times the outside diameter, find thepercentageof saving in material.4) Design a muff or Sleeve coupling for a shaft to transmit 35kW at 350rpm.The safe shear stress for the steel shaft is 50N/mm2and for the cast iron muff it is 15N/mm2.The allowable shear and crushing stresses for the key material are 42N/mm2and 120N/mm2 respectively.5) The split muff coupling is to be designed to transmit 67.5kW at 180rpm.Determine the diameter of the solid shaft if permissible shear stress in the shaft is limited to 42MPa.Assuming that the two halves of the couplings are connected by 8 bolts, determine the diameter of each clamping bolt if the permissible tensile stress intensity for the bolt material is limited to 70N/mm 2.The co-efficient of friction is 0.3.6) A knuckle joint is to transmit a force of 140kN.Allowable stresses in tension,shear and compression are 75 N/mm2,65N/mm2and 140N/mm2 respectively. Design the joint.

7) Design a protective type flange coupling for the following requirements:Power to be transmitted = 10kwSpeed of shafts =960 rpm

Select suitable materials

8) Determine the dimensions of rectangular sunk key made up of mild steel for 80mm diameter mild steel shaft to transmit a torque of 135 N-m. Assume Shear strength =50 N/mm2 and Compression strength=120N/mm2.9) Design a shaft to carry a bending moment that varies from +500N-m to -200 N-m and a twisting moment that varies from +200N-m to +400N-m. The shaft material is C-45 steel. Design for a factor of safety of 2.10) A solid shaft is subjected to bending moment of 3.46 kN-m and a torsional moment of 11.5KN-m.The shaft is made of C-45 steel and factor of safety is 6.Find the diameter of shaft.

UNIT III

Part A

1) What are the purposes of screws?2) Define: Pitch& Lead.3) List some types of commonly used thread forms.4) What are the advantages of preloading?5) What are the general applications of welding?6) List the advantages of welding?7) What are the types of welded joints?8) Under what circumstances welded joints are used?9) Define butt and lap joint with applications.10) Draw the weld symbol for double U-joint and single V-joint.11) List any two merits of a butt joint and a lap joint.12) What are the two types of fillet weld?13) Explain briefly the surface preparation methods for welded joints.14) Name any two tests conducted to check the weld quality.15) Designate metric size bolt.16) List out the application areas of square, buttress and trapezoidal threads.17) What are the advantages of threads in the bolt formed by rolling over machining?18) List the criteria for selection of size of the welding rod.19) Differentiate between gas and arc welding20) What is bolt of uniform strength?

Part B

1) The cylinder head of a steam engine with 250mm bore is fastened by eight stud bolts made of 30C8 steel. Maximum pressure inside the cylinder is 1Mpa. Determine the bolt size and approximate tightening torque. Take 20% overload. Assume σy= 300MPa for bolt material.

2) A cast iron cylinder head is fastened to a cylinder of 500mm bore with 8 stud bolts. The maximum pressure inside the cylinder is 2MPa. The stiffness of head is thrice the stiffness of the bolt. What should be the initial tightening load so that the cylinder head is leak proof at maximum pressure? Also choose a suitable bolt for the above application.

3) Find the size of the weld for the connection shown in figure below; if the tensile load acting on the connection is 120kN. Assume permissible shear stress on the weld is 75Mpa.

4) A plate 100mm wide and 12.5mm thick is to be welded to another plate by means of two parallel fillet welds as shown in figure below. The plates are subjected to a load of 50kN. Find the length of the weld so that the maximum stress does not exceed 56N/mm2. (Do the calculations under static loading).

5) An eccentrically loaded plate is welded to a frame as shown in figure. Design the welded joint, if the tensile stress in the plate should not exceed 100N/mm2 and that in weld is 80N/mm2.

6).A plate of 150mm wide and 15mm thick is to be welded to another plate by means of two parallel fillet weld. The plates are subjected to a load of 80kN. Find the length of the weld so that the maximum stress does not exceed 75N/mm2. Assume static load.

7)A plate 60mm wide and 10mm thick is welded to another plate by two parallel fillet welds as shown in fig. Determine the safe load that the weld joint can carry. The allowable working stress in shear for weld material is 75N/mm2.

8) A head ofsteam engine cylinder 60cm diameter is subjected to a steam pressure of 1.3MPa.The head is held in place by 16,M36 bolts. A copper gasket is used to make the joint steam tight. Determine the probable stress in the bolt. The combine stiffness of assembly is 0.25.

9)A steel bolt M16x2 is 300mm long and carries an impact load of 5000N-mm. If the thread stops adjacent to the nut and E=2.1x105Mpa, Find a) The stress in root area b) The stress if shank area is reduced to root area.What can be inferred from the above ?

10) Describe the welding specification with its elements and sketches.

UNIT-IV

Part-A

1) What are the applications of springs?2) Classify helical springs.3) Define Belleville springs.4) What is the stiffness of spring ?5) What is the buckling of springs?6) What is surge in springs?7) What is a laminated leaf spring?8) What are the factors to be considered for designing fulcrum pin of the lever?9) What is spring index?10) How will you find whether the given helical spring is a compression spring or tension spring?11) Why Wahl’s factor is to be considered in the design of helical compression springs?12) For springs in series the spring rate is (stiffness) added reciprocally – Prove.13) What are the varioustypes of spring?14) What are conical spring?15) What are the requirements of spring while designing?16) State any two functions of springs.17) Write down the formula for shear stress of a helical spring.18) What are the end conditions of spring?19) What is meant by springs in parallel?20) What are the various spring materials?

Part-B

1) A gas engine valve spring is to have a mean diameter of 37.5mm.The maximum load it will have to sustain is 450 N with a corresponding deflection of 12.5mm.The spring is to be made of tempered wire andsince the material is to be subjected to repeated load &fatigue, a low working stress of 300N/mm2 will be used. Find the size for the wire and number of coils used. Take rigidity modulus as 0.8×105 N/mm2.

2) A helical spring made of C50 steel has an outside diameter of 80mm and a wire diameter of 12mm.The spring has to support a maximum axial load of 1kN.Determine the maximum shear stress and the total deflection. If the spring has 10.5 coils with ends ground flat.Determine also the factor of safety. Take G=0.89×105N/mm2.

3) A semi-elliptical spring has 10 leaves with two full length leaves extending 650mm.It is 65mm wide and is made of 7mm thick. Design a helical spring, with mean coil diameter 100mm, which will have approximately the same values of induced stress and deflection for any load.

4) Design a leaf spring for a truck to the following specifications. Maximum load on the spring- 140kN Number of springs- 4 Material for spring-Chromium Vanadium Steel Permissible tensile stress- 600N/mm2

Maximum number of leaves- 10 Span of spring- 1000mm Permissible deflection- 80mm Young’s modulus of the spring- 200kN/mm2

5) A torsion spring is wound from a round wire into coil with a mean diameter 40mm.The torsional moment applied onto the spring is 5N-m.Assume the spring index as 10.The permissible stress in the spring is 550N/mm2 and E=2.1×105 N/mm2.What must be the diameter of wire and the corresponding deflection in degrees? Take number of effective coils as 7.

6) A spring made from a wire of 1.25mm diameter and 750N/mm2 as its yield strength has a mean diameter of 12.5mm and 14 active coils. Find (i) Stiffness of spring (ii) Solid height assuming that the ends are squared and ground. Take the modulus of rigidity as 0.85×105 N/mm2

7) A helical spring is made from active wire of 8mm diameter and is of outside diameter 75mm. This spring has 6 numbers of active coils. If the permissible stress in shear is 350N/mm2 and the modulus of rigidity is 84kN/mm2. Find the axial load which the spring can take and the deflection produced.

8) A helical valve spring is to be designed for an operating load range of 90N to 135N.The deflection of the spring for this load range is 7.5mm. Assuming a spring index of 10,a permissible shear stress of 480N/mm2 for the material and the modulus of rigidity of 0.8x105N/mm2. Determine dimensions of spring.

9) A helical spring of rate 12N/mm is mounted on the top of another spring of rate 8N/mm.Find the force required to give a deflection of 50mm. If they are placed side by side, what will be the deflection due to the application of same load? Assume both are having same free length.

10) Design a tension spring for a spring balance when the maximum load to be weighed is 1.2KN. Length of scale is 90mm and the spring index is 6. The material has maximum permissible shear stress of 400N/mm2 and G=0.82x105N/mm2.

UNIT-V

Part-A

1) What are the types of rolling contact bearings?2) What is a bearing?3) List any six types of bearing materials.4) What is a journal bearing?5) State the theory of lubrication.6) Define Kinematic viscosity.7) What is the function of flywheel?8) How does the function of flywheel differ from that of governor?9) How is Sommerfield number calculated?10) What are the stresses induced in flywheel arms?11) Define the term “Dynamic Load Rating”.12) Define the term “Bearing Life”.13) State the relation between the Coefficient of fluctuation of Energy and Coefficient of

Steadiness.14) What are types of thrust ball bearing?15) What is nature of contact involved in a ball bearing element?16) Classify the roller bearing.17) What is basic static loading rating?18) Classify the types of bearings.19) What are the types of journal bearing depending upon nature of lubrication?20) Name the materials used for sliding contact bearing.

Part-B

1) Design a suitable ball bearing for an axial flow compressor to carry a radial load of 2.5kN and a thrust load of 1.3kN.The service imposes a light shock with shock factor 1.5 and bearing will be in use for 35 hours per week for 4 years. The speed of shaft is 900rpm and diameter of shaft is 45mm.Assume X=0.56 and Y=1.4.

2) Select a suitable ball bearing to support the overhung countershaft. The shaft is 60mm diameter and rotates at 1250rpm.The bearings are to have 99% reliability corresponding to a life of 4000hrs.The bearing is subjected to an equivalent radial load of 6000N.

3) Design a journal bearing for a centrifugal pump with the following data: Diameter of the journal=150mm Load on bearing=40kN Speed of journal=900 rpm.

4) A cast iron flywheel for a blanking press has a mean diameter of 1.5m.The normal operating speed of 275rpm slows down to 250rpm during punching operation. The required energy fluctuation is 6500J and the density of the cast iron is 7000kg/m3.Find cross sectional area of flywheel rim if the arms and the hub provide 7% of the flywheel effect.

5) A single cylinder I.C engine working on four stroke cycle develops 75kW at 360rpm.The maximum fluctuation of energy can be assumed to be 0.9 times the energy developed/cycle. If the total fluctuation of speed is not to exceed 1% and the maximum centrifugal stress in the flywheel is to be 5.5MN/m2, estimate the mean diameter and the cross sectional area of the rim. Flywheel is made of cast iron.

6) Determine the maximum tensile stress in the thin rim of a steel flywheel rotating at 600rpm.The mean radius of rim is 1500mm.The flywheel rim is 200mm thick and 300mm wide and each of the six spokes is constant in cross section area of 0.01m2. Also find the tensile stress in each spoke and rim due centrifugal force.

7) Select a roller bearing having a life of 10000 hrs for spindle of a drilling machine with journal of 50mm diameter and carrying an axial load 8000N at 500 rpm.

8) Select a suitable deep groove ball bearing for drilling machine spindle of 40mm diameter. Radial load is 2KN.Thrust is 1.5KN. Spindle speed is 3000rpm.Desired life is 3000 hrs.

9) The following data is given for a rim type flywheel made of grey CI:Mean radius of rim = 1 mThickness of rim =100mmWidth of the rim =200mmNumber of spokes =4Speed of rotation =720rpmMass density of flywheel=7200 kg/m3

Calculate the maximum tensile stress in the rim.

10) Design a journal bearing for a centrifugal pump with the following data: Diameter of the journal =75mm Load on each journal =11500kN Speed of journal =1140 rpm.