Rotating Bodies - Stress
Stress in a Rotating Disc
Stress in a rotating disc can be calculated as
σz = ω2 r2 ρ / 3
= v2 ρ / 3
= ( 2 π n / 60)2r2ρ / 3 (1)
where
σz = stress (Pa, N/m2)
ω = angular velocity (rad/s)
r = radius of disc (m)
ρ = density (kg/m3)
π = 3.14...
n= revolutions per minute (rpm)
Stress in a Rotating Ring
Stress in a rotating ring can be calculated as
σz = ω2ρ (r12+ r1 r2+ r2 2) / 3 (2)
where
r1 = outer radius of ring (m)
r2= inner radius of ring (m)
For a thin ring the equation can be simplified to
σz = ω2 ρ r 2 (3)
where
r = mean radius of ring (m)
Design Stress for materials used in Flywheels
| Material | Density (kg/m3) | Typical Design Stress (MPa) |
|---|---|---|
| Aluminum alloy | 2700 | |
| Birch plywood | 700 | 30 |
| Composite carbon fiber - 40% epoxy | 1550 | 750 |
| E-glass fiber - 40% epoxy | 1900 | 250 |
| Kevlar fiber - 40% epoxy | 1400 | 1000 |
| Maraging steel | 8000 | 900 |
| Titanium Alloy | 4500 | 650 |
| "Super paper" | 1100 | |
| S-glass fiber/epoxy | 1900 | 350 |
Related Topics
• Dynamics
Motion of bodies and the action of forces in producing or changing their motion - velocity and acceleration, forces and torque.
Related Documents
Centripetal and Centrifugal Acceleration Force
Forces due to circular motion and centripetal / centrifugal acceleration.
Flywheels - Kinetic Energy
The kinetic energy stored in flywheels - the moment of inertia.
Stress
Stress is force applied on cross-sectional area.
Stress in Thick-Walled Cylinders or Tubes
Radial and tangential stress in thick-walled cylinders or tubes with closed ends - with internal and external pressure.
Stress in Thin-Walled Cylinders or Tubes
Hoop and longitudinal stress thin-walled tubes or cylinders.
Stress, Strain and Young's Modulus
Stress is force per unit area - strain is the deformation of a solid due to stress.
Young’s Modulus of Elasticity – Values for Common Materials
Young’s Modulus (Elastic Modulus) of various materials, including metals, plastics, and composites. How stiffness and elasticity influence material performance in engineering applications.