Mechanisms & Mechanical Design B.Tech Question Paper : vardhaman.org
College : Vardhaman College Of Engineering
Degree : B.Tech
Department : Aeronautical Engineering
Semester : IV
Subject : Mechanisms & Mechanical Design
Document type : Question Paper
Website : vardhaman.org
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Mechanisms & Mechanical Design Question Paper :
Four Year B. Tech IV Semester Regular/Supplementary Examinations June – 2014
(Regulations : VCE-R11)
(Aeronautical Engineering)
Date : 6 June, 2014
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
Related : Vardhaman College Of Engineering Power System Generation B.Tech Question Paper : www.pdfquestion.in/6356.html
All parts of the question must be answered in one place only
Unit – I :
1. a) Differentiate between Machines and Mechanisms. 5M
b) What is Link? Briefly explain the classification of Kinematic pairs. 10M
2. a) Sketch and explain Peaucellier Mechanism. 5M
b) List and Explain any three inversions of Four bar chain mechanism. 10M
Unit – II :
3. In a slider crank mechanism shown in Fig 1, the crank is 200 mm long and rotates at 40 rad/sec in a CCW direction. The length of the connecting rod is 800 mm. When the crankturns through 60o from Inner-dead centre. Determine
i. The velocity of the slider
ii. Velocity of point E located at a distance of 200 mm on the connecting rod extended.
iii. The position and velocity of point F on the connecting rod having the least absolute velocity
iv. The angular velocity of connecting rod. v. The velocity of rubbing of pins of crank shaft, crank and cross head having pins diameters 80,60 and 100 mm respectively. ig.1 15M
4. Explain the procedure to draw velocity and acceleration vector diagram for a slider crank mechanism shown in Fig.2 using Klein’s construction 15M
Unit – III :
5. In the toggle mechanism shown in Fig.3 the slider D is constrained to move in a horizontal path the crank OA is rotating in CCW direction at a speed of 180 rpm the dimensions of various links are as follows: OA = 180 mm, CB = 240 mm, AB = 360 mm and BD = 540 mm
Find using I centre method,
i) Velocity of slider
ii) Angular velocity of links AB, CB and BD 15M
6. a) A four bar mechanism has links AB = 300 mm, BC = CD = 360 mm and AD= 600 mm. Angle BAD=60o. Crank AB rotates in CW direction at a speed of 100rpm. Locate all the instantaneous centers and determine the angular velocity of link BC. 8M
b) The rotor of the turbine of a ship has a mass of 2500kg and rotates at a speed of 3200rpm
C.C.W when viewed from stern. The rotor has radius of gyration of 0.4m.Determine the gyroscopic couple and its effect when
i. The ship steers to left in a curve of 80m radius at speed of 15 knots (1 knot=1.86hm/h)
ii. The ship pitches 5o above and 5o below the normal position and the bow is descending with its maximum velocity. The pitching motion follows SHM with time period 40s
iii. The ship rolls and at this instant its angular velocity is 0.4 rad/s C.W from stern. Also find maximum angular acceleration during pitching 7M
Unit – IV :
7. Draw the cam profile for following conditions:
Follower type = roller follower, in-line; lift = 25mm; base circle radius = 20mm; roller radius = 5mm; out stroke with Uniform Acceleration and Retardation Motion (UARM) for 1200 cam rotation; dwell for 600 cam rotation; return stroke with UARM, for 900 cam rotation; dwell for the remaining period. Determine max. velocity and acceleration during out stroke and return stroke if the cam rotates at 1200 rpm in clockwise direction. 15M
8. Draw the cam profile for following conditions: Follower type = Knife edged, in-line; lift = 50mm; base circle radius = 50mm; out stroke with Simple Harmonic Motion (SHM), for 600 cam rotation; dwell for 450 cam rotation; return stroke with SHM, for 900 cam rotation; dwell for the remaining period. Determine maximum velocity and acceleration during out stroke and return stroke if the cam rotates at 1000 rpm in clockwise direction. 15M
Unit – V :
9. a) State and explain the Law of Gearing. 6M
b) In an epicyclic gear train, the internal gears A & B, and compound gears C & D rotate independently about the axis O. The gears E & F rotate on pins fixed to the arm G, and gear E meshes with A & C, and Gear F meshes with B & D. All the wheels have same module and number of teeth are TC=28, TD=26, TE=TF=18. Sketch the arrangement, find the number of teeth on A & B, if the arm makes 100rpm clockwise and A is fixed. Find the speed of gear B. 9M
10. a) A solid shaft is transmitting 1MW at 240 rpm. Determine the diameter of the shaft, if the maximum torque transmitted exceeds the mean torque by 20 %. Take maximum allowable shear stress as 60MPa. 6M
b) A helical spring is made from a wire of 6mm diameter and has outside diameter of 75mm. If the permissible shear stress is 350MPa and modulus of rigidity 84KN/mm2, find the axialload which the spring can carry and the deflection per active turn (Neglect effect of curvature).8