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- .MCD 20000 0
- .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 0.001000
- .CMD MARGIN 0
- .CMD LINELENGTH 78
- .CMD SET PRNCOLWIDTH 8
- .CMD SET PRNPRECISION 4
- .TXT 1 0 1 51
- a1,50,48,49
- ELASTIC BENDING IN A BEAM SUPPORTED AT BOTH ENDS
- .TXT 2 0 2 61
- a2,61,59,114
- Equations taken from Baumeister, Availone, and Baumeister,
- "Mark's Standard Handbook for Mechanical Engineers."
- .TXT 3 5 2 67
- a2,67,65,102
- A beam is supported at both ends. This document finds the maximum
- stress and deflection in the beam.
- .TXT 3 0 1 18
- a1,18,16,17
- Beam dimensions:
- .TXT 2 6 1 9
- a1,9,7,8
- Length:
- .EQN 0 19 1 11
- L:3*ft
- .TXT 2 -19 1 16
- a1,16,14,15
- Cross-section:
- .EQN 0 19 1 12
- H:.3*in
- .EQN 0 14 1 12
- W:.3*in
- .TXT 2 -39 1 13
- a1,13,11,12
- Point load:
- .TXT 2 6 1 9
- a1,9,7,8
- Weight:
- .EQN 0 19 1 13
- F:50*lbf
- .TXT 2 -19 2 15
- a2,15,13,24
- Distance from
- far end:
- .EQN 1 19 1 11
- a:2*ft
- .TXT 2 -25 1 23
- a1,23,21,22
- Beam characteristics:
- .EQN 1 25 4 18
- E:2.9*10^7*lbf/in^2
- .TXT 1 -19 2 13
- a2,13,11,25
- Modulus of
- elasticity:
- .TXT 4 -6 1 65
- a1,65,63,64
- Now compute the deflection and stress at points along the beam:
- .EQN 2 25 4 11
- I:W*H^3/12
- .TXT 1 -19 2 11
- a2,11,9,20
- Moment of
- inertia:
- .TXT 4 0 2 16
- a2,16,14,27
- Distance to
- neutral axis:
- .EQN 0 19 3 8
- c:H/2
- .TXT 4 -19 2 17
- a2,17,15,24
- Area of
- cross-section:
- .EQN 0 19 1 10
- A:W*H
- .TXT 3 -19 2 14
- a2,14,12,24
- Points along
- the beam:
- .EQN 0 19 1 13
- i:0;50
- .EQN 0 20 3 12
- x[i:i*L/50
- .TXT 5 -39 1 13
- a1,13,11,12
- Deflection:
- .EQN 2 0 5 68
- y[i:F*((L-a)*(x[i^3-a*(2*L-a)*x[i)-if(x[i>a,L*(x[i-a)^3,0L^4))/(6*L*E*I)
- .EQN 7 39 4 22
- xmax:\((a*(2*L-a))/3)
- .TXT 2 -39 1 30
- a1,30,28,29
- Point of maximum deflection:
- .EQN 2 4 1 17
- xmax=?ft
- .EQN 2 0 4 46
- ymax:F*((L-a)*(xmax^3-a*(2*L-a)*xmax))/(6*L*E*I)
- .EQN 4 0 1 18
- ymax=?in
- .TXT 2 -4 1 60
- a1,60,58,59
- Side view of beam (vertical dimension greatly exaggerated)
- .EQN 2 -11 8 77
- 0*in&ymax&y[i{1,1,6,70,l}@L&0*ft&x[i
- .TXT 9 4 1 28
- a1,28,26,27
- Stress and bending moment:
- .EQN 2 9 4 51
- M[i:F*(L-a)*x[i/L-if(x[i>a,F*(x[i-a),0*F*1L)
- .EQN 5 0 3 21
- Mmax:F*(L-a)*a/L
- .EQN 1 28 1 19
- Mmax=?in*lbf
- .EQN 3 -28 3 12
- S[i:M[i*c/I
- .EQN 4 0 3 16
- Smax:Mmax*c/I
- .EQN 0 28 4 22
- Smax=?lbf/in^2
- .TXT 5 -12 1 25
- a1,25,23,24
- Stress diagram for beam
- .EQN 2 -23 8 68
- Smax&0*psi&S[i{1,1,6,60,l}@L&0*ft&x[i
- .TXT 8 0 1 4
- a1,4,2,3
- --
- .TXT 2 -1 1 25
- a1,24,22,23
- UNIT DEFINITIONS (MKS)
- .TXT 3 0 1 13
- a1,12,13,11
- Base units
- .EQN 2 5 1 8
- m~1L
- .EQN 0 18 1 9
- kg~1M
- .EQN 0 18 1 10
- sec~1T
- .TXT 2 -41 1 24
- a1,23,26,22
- Derived units: Length
- .EQN 2 5 1 12
- cm~.01*m
- .EQN 0 18 1 13
- km~1000*m
- .EQN 0 18 1 13
- mm~.001*m
- .EQN 2 -36 1 14
- ft~.3048*m
- .EQN 0 18 1 14
- in~2.54*cm
- .EQN 0 18 1 11
- yd~3*ft
- .TXT 2 -41 1 22
- a1,21,23,20
- Derived units: Mass
- .EQN 2 5 2 14
- gm~10^-3*kg
- .EQN 1 18 1 17
- tonne~1000*kg
- .TXT 0 17 1 14
- a1,14,12,13
- (metric ton)
- .EQN 2 -35 1 19
- lb~453.59247*gm
- .TXT 0 24 2 42
- a2,42,40,63
- (use convention that lb represents
- pounds MASS; avoirdupois)
- .EQN 2 -24 3 9
- oz~lb/16
- .EQN 1 18 1 15
- ton~2000*lb
- .TXT 0 17 1 15
- a1,15,13,14
- ("short" ton)
- .EQN 3 -35 1 18
- slug~32.174*lb
- .EQN 1 0 4 18
- g~9.80665*m/sec^2
- .TXT 2 22 1 27
- a1,27,25,26
- (acceleration of gravity)
- .TXT 3 -27 1 38
- a1,37,41,36
- Derived units: Force, Energy, Power
- .EQN 2 5 4 18
- newton~kg*m/sec^2
- .EQN 5 0 1 12
- lbf~g*lb
- .TXT 0 17 1 16
- a1,15,13,14
- (pound force)
- .EQN 2 -17 1 12
- kgf~g*kg
- .TXT 0 17 1 19
- a1,18,16,17
- (kilogram force)
- .EQN 2 -17 1 18
- joule~newton*m
- .TXT 2 -5 1 26
- a1,25,38,24
- Derived units: Pressure
- .EQN 2 5 4 13
- Pa~newton/m^2
- .EQN 0 18 4 11
- psi~lbf/in^2
-