Stress and strain analysis on a thick-walled cylinder (FL 140)

Stress and strain analysis on a thick-walled cylinder (FL 140)

direct stresses and strains of a thick cylinder under internal pressure



  • In contrast to thin-walled vessels, when designing thick-walled vessels allowance must be made for an uneven distribution of stresses through the thickness of the wall.
  • The stress state in a thick-walled vessel under internal pressure is triaxial.
  • The direct stresses and strains occur: radial, circumferential, hoop and axial.
  • Since the stresses and strains occurring in a vessel are not measured directly, they are determined by measuring strains on the surface.
  • Strain gauges are employed to record the strains electrically and the stresses and strains are determined from those measurements.
  • The FL 140experimental unit is used to investigate direct stresses and strains occurring on a thick-walled cylinder subjected to internal pressure.
  • The oil-filled cylinder is made up of two halves, and is sealed on both sides.
  • Internal pressure is generated inside the vessel with a hydraulic pump.
  • A pressure gauge indicates the internal pressure. An eccentric groove is cut between the two halves of the cylinder, in which the strain gauges are mounted at various radial points.
  • Additional strain gauges are mounted on the inner and outer surfaces of the cylinder.
  • Radial, hoop and axial strains are measured, enabling the strain state to be fully recorded.
  • The measuring amplifier FL 152displays the recorded signals as measured value readouts.
  • To assist and visualise evaluation of the experiment, the measured values can be imported into the application software.
  • Mohr’s circle for stress and strain analysis is used to represent the triaxial stress state in the cylinder wall graphically.
  • The direct stresses and strains are calculated from the measured strains, applying the appropriate law of elasticity.

Technical Details:


  • investigation of the stresses and strains in a thick-walled cylinder under internal pressure
  • two-part cylinder with flat groove
  • strain gauge application at various radial points in the groove and on the cylinder surface
  • hermetically sealed hydraulic system, maintenance-free to generate pressure
  • hydraulic system with hydraulic pump and manometer
  • FL 152 measuring amplifier required
  • software for analysing measured values in FL 152

Technical Data:

  • Aluminium cylinder
    • length: 300mm
    • diameter: Ø=140mm
    • wall thickness: 50mm
    • internal pressure: max. 7N/mm2(70bar)
  • Strain gauge application
    • 11 strain gauges: half-bridges, 350 Ohm
    • gauge factor: 2,00 ±1%
    • supply voltage: 10V
  • Pressure gauge
    • 0…100bar
    • accuracy: class 1,0

Dimensions & Weight:

  • L x W x H: 700x350x330mm
  • Weight: approx. 32kg

Learning Objections/Experiments:

  • measurement of elongations by strain gauges
  • application of Mohr’s circle for the triaxial stress state
  • determination of the distribution of direct stress in
    • radial, tangential and axial direction
  • investigation of correlations between elongation, pressure and stress in the triaxial stress state

Scope of Delivery:

  • 1 experimental unit
  • 1 set of instructional material


  • cylinder with strain gauge application on surface and in wall
  • triaxial stress state in cylinder wall


  • Required: FL 152 multi-channel measuring amplifier
  • Optional: WP 300.09 Laboratory trolley

Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.