Stress in ThinWalled Cylinders or Tubes
Hoop and longitudinal stress thinwalled tubes or cylinders.
When a thinwalled tube or cylinder is subjected to internal pressure a hoop and longitudinal stress are produced in the wall.
For the thin walled equations below the wall thickness is less than 1/20 of tube or cylinder diameter.
Hoop (Circumferential) Stress
The hoop stress is acting circumferential and perpendicular to the axis and the radius of the cylinder wall. The hoop stress can be calculated as
σ_{h} = p d / (2 t) (1)
where
σ_{h} = hoop stress (MPa, psi)
p = internal pressure in the tube or cylinder (MPa, psi)
d = internal diameter of tube or cylinder (mm, in)
t = tube or cylinder wall thickness (mm, in)
Longitudinal (Axial) Stress
For a cylinder closed closed in both ends the internal pressure creates a force along the axis of the cylinder. The longitudinal stress caused by this force can be calculated as
σ_{l} = p d / (4 t) (2)
where
σ_{l} = longitudinal stress (MPa, psi)
Example  Stress in a Thin Walled Tube
The pressure in a thin walled tube with diameter 0.3 m and thickness 0.001 m is 1000 kPa (10 bar).
The hoop stress can be calculated
σ_{h} = (1000 kPa) (0.3 m) / (2 (0.001 m))
= 150000 kPa
= 150 MPa
The longitudinal stress can be calculated
σ_{h} = (1000 kPa) (0.3 m) / (4 (0.001 m))
= 75000 kPa
= 75 MPa
Note that typical maximum allowable stress for carbon steel pipes is below 135 MPa.
Related Topics

Mechanics
Forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more. 
Statics
Loads  forces and torque, beams and columns.
Related Documents

Fixed Pipes  Stress vs. Change in Temperature
Temperature changes introduces stress fixed pipes. 
Process Pipes  Allowable Stress vs. Temperature
Allowable wall stress in pipes according ASME M31.3. 
Rotating Bodies  Stress
Stress in rotating disc and ring bodies. 
Rotating Shafts  Torque
Torsional moments acting on rotating shafts. 
Stress
Stress is force applied on crosssectional area. 
Stress in ThickWalled Cylinders or Tubes
Radial and tangential stress in thickwalled cylinders or tubes with closed ends  with internal and external pressure. 
Stress, Strain and Young's Modulus
Stress is force per unit area  strain is the deformation of a solid due to stress.