Question

Part A

Q1: The crank OP of a mechanism as shown in figure below rotates uniformly at 60 rpm counter-clockwise. Various links have following dimensions: OP = 50 mm; RQ= 200 mm; RS = 200 mm; PR = 300 mm a) Make appropriate scale to draw position diagram using graphical method. b) Find the linear velocities (mm/sec) and angular velocities (rad/sec) for all links and draw velocity diagram. c) Find the tangential accelerations (mm/sec) and radial acceleration (mm/sec) and angular accelerations (rad/sec) for all links and draw acceleration diagram. d) Identify total number of links, number of full joints (Revolute and sliding joints), number of lower pairs and number of turning pairs for the mechanism. Note: Show all drawing work and scales to get full credit Р 30° +150 mm 350 mm R - = S fo Q

Answer 1

a-

b-

25 mm: 1cm 301 3 R

Velocity dicegram- 100mmis=1cm VE So 4 . V3

=) Ws = 0.45 rad is » 2 given link op rotates in Go opm. counter clockcoise direction 2 KN Wp3 60 link p = op: Somm Link 3 = PPR300 mm links 4 = RQ-200mm link 5 = RS-200mm 60 W2 = 2X60 =) W2 = 2x W2= 6.28gad ls Op=8= 50 mm ķa la xop - V2 = 6:28x50 V2= 314.16 mmis from velouty diagram (Attes scale cowersim) V3=285 mm is wy=90 mmis Vs = 90 mmis Vo Il mm/s augulas velouties W3= V3 W3= 285 =) W3= 0.95 radis 300 90 wy=0.45 rad is PR vy Wy= Ra Wys 200 Wsi Ws- 90 200 Ws= VS RS Kaise mmis and V6 = 11 now auceleration analysis -> for example an bar=a8 at tangential au" 90+ radiat aceleration at augulas acceleration at and ar both perpendicalar to each other 98=8w² Resaltant a=Jastat² J
c-

scale - 394.184 mmisedriem o'q! s! a6 las 02 Die az 75 ४। ais acceleration diagram

ar (from diagram Tangondial at acceleratim angalar aceleration link-2 W+cmstant d=0 Radial acceleratim ay=wop a=66.28350 90= 1971,92 mm Sec? at d= cat W. PR 13= 800:19 PR are are des liork-3 Atz=23. PR W3 = 0.95 rad/s 802.1950t3 mm/sec2 (from diagram) 800:19_7.66 300 yad /s2 1537.37 dy = aru 200 aty=xy RG ( 95% 300 98=270.75 mmisec? = wil.RG =0.45² x200 arey = 40.5 mm/sec? 075 . W}.RS link-u Wy=0.45radis dy=7.68 rad /s2 aty= 1537.3) mmisecz link-5 ds = 15 37.31 200 Xu=7.68 radise alt5=25Rs alts=1537.31 -0.45²x200 45= 0.4. Sradis mml seca 025=40.5 mm/sec link-6 to=0 (sliding only) eincar acceleration in sliding direction Ag = 394.184 mm/s2 No. Of links =) L=6 No.of joints Revolute Joints=5 = turning pairs Sliding Joints = 1 Total=6 No. of lower pairs = 6
please ignore 5%-10% error due to scale consideration.