direct stresses and strains of a thick cylinder under internal pressure

Description:

• 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:

Specification:

• 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

Features:

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

Accessories:

• 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.