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- .MCD 25000 0
- .CMD SURFACEFORMAT rot=10 tilt=35 vScale=20 size=15,30 hide=n
- .CMD SKETCHFORMAT mag=1.000000,1.000000 center=0.500000,0.500000 size=15,30 box=y
- .CMD PLOTFORMAT logs=0,0 subdivs=1,1 size=5,15 type=l
- .CMD FORMAT rd=d ct=10 im=i et=3 zt=15 pr=3 mass length time charge
- .CMD SET ORIGIN 0
- .CMD SET TOL 0.001000000000000
- .CMD MARGIN 0
- .CMD LINELENGTH 78
- .CMD SET PRNCOLWIDTH 8
- .CMD SET PRNPRECISION 4
- .TXT 0 39 1 39
- a1,38,39,37
- Copyright (c) 1990 by Mathsoft, Inc.
- .TXT 0 61 1 36
- a1,35,78,34
- Indices for stiffness and moment:
- .TXT 1 -100 1 27
- a1,26,78,25
- TORSIONAL GEARED SYSTEMS
- .EQN 0 199 1 9
- rad~1
- .EQN 0 11 1 8
- s~1T
- .EQN 1 -110 1 19
- n:1;stations
- .EQN 0 29 1 25
- j:2;(stations+1)
- .TXT 1 -129 2 72
- a2,71,78,114
- This document determines the torsional-frequency curve and the first
- critical speed of geared torsional systems.
- .TXT 3 0 1 22
- a1,21,78,20
- number of stations:
- .EQN 0 22 1 14
- stations~3
- .TXT 0 25 1 14
- a1,13,39,12
- gear ratio:
- .EQN 0 14 1 10
- α:0.5
- .TXT 2 -61 1 56
- a1,55,78,54
- Enter the shaft material properties and rotor masses:
- .TXT 2 0 1 15
- a1,14,78,13
- stiffnesses:
- .TXT 0 22 1 22
- a1,21,39,20
- moments of inertia:
- .TXT 0 29 3 23
- a3,22,27,54
- frequency range and
- number of points to
- be plotted:
- .EQN 2 -49 11 16
- K[j:1*10^6*lb*in/rad,2*10^6*lb*in/rad,3*10^6*lb*in/rad
- .EQN 0 25 8 14
- J[n:1*lb*in*s^2,2*lb*in*s^2,3*lb*in*s^2
- .EQN 2 24 3 17
- ▀.min~300*rad/s
- .TXT 0 49 1 12
- a1,11,78,10
- Counters:
- .EQN 0 12 1 17
- k:0;points
- .EQN 0 18 1 25
- i:1;(stations-1)
- .EQN 1 13 4 31
- ▀[k:▀.min+k*(▀.max-▀.min)/points
- .EQN 1 -43 3 10
- ▐[k:▀[k^2
- .TXT 1 26 1 13
- a1,12,78,11
- Frequency:
- .EQN 1 -75 3 18
- ▀.max~1500*rad/s
- .EQN 2 59 3 25
- K[(gear):K[(stations+1)*α^2
- .TXT 1 -28 1 23
- a1,22,78,21
- Boundary conditions:
- .EQN 1 -31 1 13
- points~20
- .EQN 3 59 3 19
- J[gear:J[gear*α^2
- .TXT 2 -110 1 24
- a1,23,78,22
- position of the gear:
- .EQN 0 27 1 10
- gear~2
- .EQN 0 55 8 22
- ({4,1}÷TR[(1,k)÷aux[(i,k)÷Θ[(1,k)÷p[(1,k)):({4,1}÷-▐[k*J[1÷1÷1÷1)
- .TXT 7 29 1 20
- a1,19,78,18
- Torque equations:
- .EQN 2 -30 20 66
- ({4,1}÷TR[(i+1,k)÷aux[(i+1,k)÷Θ[(i+1,k)÷p[(i+1,k)):({4,1}÷TR[(i,k)-▐[k*J[((p[(i,k))+1)*aux[(i,k)÷if(i≈(gear-1),Θ[(i,k)/(1-▐[k*J[(p[(
- i,k)+1)/K[(p[(i,k)+1)),Θ[(i,k)+TR[(i,k)/K[(p[(i,k)+1))÷if(i≈(gear-1),Θ[(i,k),(Θ[(i,k)+TR[(i,k)/K[(p[(i,k)+1)))÷i+1)
- .TXT 6 -32 1 26
- a1,25,29,24
- Press [Ctrl-PgDn] twice
- .TXT 15 33 1 30
- a1,29,78,28
- Cubic spline interpolation:
- .EQN 0 33 2 13
- freq[k:▀[k
- .EQN 0 16 5 27
- torque1[k:-TR[(stations,k)/10^6
- .TXT 1 -131 3 72
- a3,71,78,153
- The critical speeds of the system correspond to those frequencies
- which result in zero in the torsional-frequency curve (torque in the
- last station):
- .EQN 1 82 1 37
- derivative:cspline(freq,torque1)
- .EQN 2 0 2 56
- Torsional_curve[k:interp(derivative,freq,torque1,▀[k)
- .EQN 1 -82 17 65
- &&Torsional_curve[k/(lb*in),0{1,1,15,44,l}@▀.max&▀.min&▀[k
- .EQN 1 159 2 17
- a:0*(lb*in)^2
- .EQN 1 -77 2 12
- vaux[0:0
- .EQN 0 14 1 23
- d:0;(points-1)
- .EQN 0 27 2 24
- torque2[d:torque1[(d+1)
- .EQN 3 -41 2 76
- vaux[(d+1):if((torque1[d*torque2[d)<a,if((vaux[d≈0),(d+1),vaux[d),vaux[d)
- .EQN 3 0 2 21
- index:vaux[points
- .TXT 3 0 1 60
- a1,59,78,58
- Linear interpolation to estimate first natural frequency:
- .EQN 2 0 5 71
- ▀.nat:▀[(index-1)+torque1[(index-1)/(torque1[index-torque1[(index-1))*(▀[(index-1)-▀[index)
- .TXT 5 -29 1 20
- a1,19,30,18
- Press [Ctrl-PgDn]
- .EQN 3 -14 3 21
- ▀.nat={18993}?rad/s
- .TXT 1 -39 2 34
- a2,33,78,64
- The first natural frequency in
- the given frequency range is:
- .TXT 25 5 1 19
- a1,18,16,17
- UNIT DEFINITIONS
- .TXT 0 24 1 23
- a1,22,25,21
- MKS (SI) unit system
- .TXT 3 -24 1 16
- a1,15,13,14
- I. Base units
- .EQN 1 5 1 8
- m~1L
- .EQN 0 18 1 9
- kg~1M
- .EQN 0 18 1 8
- s~1T
- .EQN 0 18 1 13
- Kelvin~1Q
- .TXT 2 -59 1 22
- a1,21,19,20
- II. Angular measure
- .EQN 1 5 1 9
- rad~1
- .EQN 0 18 3 15
- deg~π/180*rad
- .TXT 4 -23 1 29
- a1,28,26,27
- III. Derived units: Length
- .EQN 1 5 1 12
- cm~.01*m
- .EQN 0 18 1 13
- km~1000*m
- .EQN 0 18 1 13
- mm~.001*m
- .EQN 1 -36 1 14
- ft~.3048*m
- .EQN 0 18 1 14
- in~2.54*cm
- .EQN 0 18 1 11
- yd~3*ft
- .EQN 0 18 1 14
- mi~5280*ft
- .TXT 2 -59 1 25
- a1,25,23,24
- IV. Derived units: Mass
- .EQN 1 5 2 14
- gm~10^-3*kg
- .EQN 1 18 1 17
- tonne~1000*kg
- .EQN 0 18 1 19
- lb~453.59247*gm
- .EQN 2 -36 3 9
- oz~lb/16
- .EQN 1 18 1 15
- ton~2000*lb
- .EQN 1 18 1 18
- slug~32.174*lb
- .TXT 2 -41 1 25
- a1,24,22,23
- V. Derived units: Time
- .EQN 1 5 1 15
- minute~60*s
- .EQN 0 18 1 12
- h~3600*s
- .EQN 0 18 1 12
- day~24*h
- .EQN 2 -36 1 16
- year~365*day
- .TXT 2 -5 1 34
- a1,33,31,32
- VI. Derived units: Area, Volume
- .EQN 1 5 2 18
- hectare~10^4*m^2
- .EQN 0 36 2 17
- acre~4840*yd^2
- .TXT 3 -37 1 6
- a1,5,3,4
- ---
- .EQN 1 1 2 13
- L~(.1*m)^3
- .EQN 0 36 2 13
- mL~10^-3*L
- .EQN 2 0 2 22
- fl_oz~29.57353*cm^3
- .EQN 3 0 1 17
- gal~128*fl_oz
- .TXT 2 -41 1 45
- a1,44,42,43
- VII. Derived units: Velocity, Acceleration
- .EQN 1 5 3 10
- mph~mi/h
- .EQN 0 18 3 10
- kph~km/h
- .TXT 4 -19 1 6
- a1,6,4,5
- ----
- .EQN 1 1 4 16
- g~9.80665*m/s^2
- .TXT 1 22 1 27
- a1,27,25,26
- (acceleration of gravity)
- .TXT 4 -27 1 44
- a1,43,41,42
- VIII. Derived units: Force, Energy, Power
- .EQN 1 5 4 11
- N~kg*m/s^2
- .EQN 0 18 2 15
- dyne~10^-5*N
- .EQN 1 23 1 12
- lbf~g*lb
- .TXT 1 -1 1 15
- a1,15,13,14
- (pound force)
- .EQN 2 1 1 12
- kgf~g*kg
- .TXT 1 -1 1 19
- a1,18,16,17
- (kilogram force)
- .TXT 2 -41 1 7
- a1,6,4,5
- ----
- .EQN 1 1 1 9
- J~N*m
- .EQN 0 18 2 14
- erg~10^-7*J
- .EQN 0 23 1 16
- cal~4.1868*J
- .EQN 1 0 1 17
- kcal~1000*cal
- .EQN 1 -41 2 27
- BTU~1.05505585262*10^3*J
- .TXT 3 -1 1 7
- a1,6,4,5
- ----
- .EQN 1 1 3 7
- W~J/s
- .EQN 0 41 3 17
- hp~550*(ft*lbf)/s
- .EQN 1 -23 1 13
- kW~1000*W
- .TXT 2 22 1 23
- a1,23,21,22
- (standard horsepower)
- .TXT 2 -45 1 41
- a1,40,38,39
- IX. Derived units: Pressure, Viscosity
- .EQN 1 5 4 9
- Pa~N/m^2
- .EQN 0 18 4 11
- psi~lbf/in^2
- .EQN 0 18 2 22
- atm~1.01325*10^5*Pa
- .EQN 2 0 2 23
- torr~1.33322*10^2*Pa
- .EQN 2 0 2 24
- in_Hg~3.38638*10^3*Pa
- .TXT 3 -37 1 6
- a1,6,4,5
- ----
- .EQN 1 37 4 14
- St~10^-4*m^2/s
- .EQN 1 -36 1 14
- P~0.1*Pa*s
- .EQN 2 0 1 13
- cP~0.01*P
-