Verification of stress hypotheses (WP 130)

Verification of stress hypotheses (WP 130)

verification of the Rankine yield criterion and the Tresca yield criterion

CodeWP130

Description:

  • Stress hypotheses are applied in the science of the strength of materials when calculating comparative stresses where unequal stresses are combined.
  • The following stress hypotheses, taking into account material properties, have been tried and proven in practice: Rankine yield criterion (direct stress hypothesis), von Mises yield criterion (change of shape hypothesis) and Tresca yield criterion (shear stress hypothesis).
  • The experimental unit WP 130is used to verify these comparative stress hypotheses on test specimens made of various metals.
  • For the purpose, a multi-axial stress state is produced at a point on the specimen and the resulting deformation is measured.
  • The specimen is clamped on one end to the fixed frame.
  • A loading plate is clamped to the specimen on the other end.
  • A weight is attached on the outer circumference of the plate.
  • A balance weight compensates for the dead-load of the plate and the applied weight.
  • As a result, only direct and shearing stress occur at a point on the test specimen and shear forces are avoided.
  • The loading plate has a graduation grid enabling weights to be attached at 15° increments.
  • This permits purely bending moment and twisting as well as combined load moments to be achieved.
  • Diametrically opposite the weight, measuring points are provided on the loading plate to measure the deformation.
  • This enables the deformation at the point of maximum deflection to be measured.
  • The various elements of the experiment are clearly laid-out and housed securely in a storage system.

Technical Details:

Specifications:

  • experiments verifying comparative stress hypotheses from the science of the strength of materials
  • 7 different load combinations of bending and torsion
  • loading of the test specimen without shear force by compensation for the influence of dead-load
  • test specimens made of steel, copper, brass, aluminium
  • generation of load moments by means of weight and lever arm
  • measurement of the deformation at the point of maximum deflection
  • storage system to house the components

Technical Data:

  • Specimens:
    • length: 49mm
    • clamping length: 11,5mm
    • specimen diameter in measuring cross-section: Ø 4mm
  • Weights to place load on specimens:
    • 1x 2N (hanger), 1x 1N, 1x 2N, 1x 4N, 2x 8N
  • Weights to compensate for the load and the loading plate:
    • 1x1N, 2x2N, 1x4N, 2x8N
  • Lever arm: 100mm:
  • Deformation:
    • measuring range: 0…10mm
    • graduation: 0,01mm

Dimensions & Weight:

  • L x W x H: 390x330x360mm
  • Weight: approx. 17kg
  • L x W x H: 720x480x178mm (storage system)
  • Weight: approx. 10kg (storage system)

Learning Objectives/Experiments:

  • generation of multi-axial loads on test samples made of ductile metals:
    • steel, copper, brass, aluminium
  • generation of various load moments:
    • pure bending moment
    • pure twisting moment
    • combined bending moment and twisting moment
  • determination of the yield point
  • verification of the Rankine yield criterion
  • verification of the Tresca yield criterion
  • representation in Mohr’s circle of stresses and strains

Scope of delivery:

  • 1 experimental unit
  • 1 set of specimens (4x St, 4x Cu, 4x Al, 4x brass)
  • 1 set of weights (loading)
  • 1 set of weights (compensation)
  • 1 hexagon socket wrench
  • 1 storage system with foam inlay
  • 1 set of instructional material

Features:

  • verification of the Rankine yield criterion and the Tresca yield criterion
  • multi-axial loads of test specimens made of ductile metals by pure bending, pure torsion or a combination of the two
  • loading of the test specimen without shear force by compensation for the influence of dead-load

Accessories:

Optional:

  • WP130.01 Set of 4 bending and torsion specimens, Al, Cu, St, CuZn
  • WP 130.21 Set of 4 bending and torsion specimens, Al
  • WP 130.22 Set of 4 bending and torsion specimens, Cu
  • WP 130.23 Set of 4 bending and torsion specimens, St
  • WP 130.24 Set of 4 bending and torsion specimens, CuZn
  • WP 300.09 Laboratory trolley

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