Starting 9am -ish
School of Engineering • Dr Javier Munguia
Shaft-calculations & Design
Friday 24th Nov Tree Cluster
Design and Manufacturing II
MEC2007
• Shaft design considerations
• Materials
• Geometry
• Locating components
• Forces acting on a shaft
• Force types:
• Torque
• Bending stress
• Axial Forces
• Transverse/Shear forces
• Applying factors
All you need…
• Handout K
• Your Cross-section drawing
• Your main Forces (Handout Q)
Worked EXAMPLE
r

Cross section
plane at centre
of wheel
(contact Patch)
29.5mm
Wheel dimensions
on Main HANDOUT
Expected
fracture plane
Brake disk
centre plan
L
X
R
Distances summary:
L =Contact patch to fracture plane
X= Brake-disk middle plane to fracture plane
R =Wheel radius (202mm)
Bdisc= Brake disc diameter
D= large shaft diameter
d= small shaft diameter (bearing bore diameter)
D d
Distances L,X, D,
Bdisc and d depend
on your own Cross
section. YOU DEFINE
THESE!
Wheel radius
from central
axle to ground
Bdisc
Identify your forces
From Orthographic sketch:
Fz
Fy
Fx
Q
Forces summary:
Fx =Longitudinal force (along X axis)
Fy= Lateral force (along Y axis)
Fz =Vertical reaction force(along Z axis))
Q = Braking force (depending on YOUR Caliper)
Determine Forces
and Distances
ONLY APPLICABLE TO THIS DESIGN EXAMPLE
Distances summary:
L =61 mm
X= 45 mm
Bdisk= 172mm
R =202 mm
D= 48.5 mm
d= 39 mmL
X
R
D d
Forces summary:
From Handout Q:
Fx =517 N →(will be different for you!)
Fy= 517 N →(will be different for you!)
Fz =738 N →(will be different for you!)
From Handout T (page 5)
Q = 1034 N →(will be different for you!)
Identify the shaft loads, direction and type
a) Identify 4 main load types on the shaft:
• Torque (T)
• Bending Moments (MB)
• Axial Forces (FA)
• Shear Forces (FS) also called ‘Transverse
forces’
b) Decide whether each load is ‘mean’ or
‘alternating’
Torque Bending M FA FS
Fx
Fy
Fz
Q X ✓
✓ ✓ ✓X
XX ✓ ✓
X X✓ ✓
✓ ✓
Alternating
vs
mean loads
Calculations Submission
• Solve the 4 load cases for each
force via Hand calculations
Handout K
• Use calculations spreadsheet on
CANVAS