Rotating Bending Test Machine (RBTM)

Rotating Bending Test Machine (RBTM)

When using high-strength materials it is very important to consider not only the fatigue strength but also the presence of surface defects when determining the fatigue life of components.

The IABG Rotating Bending Test Machine allows the time and cost saving determination of the fatigue strength of high-strength materials, such as those used in the manufacture of springs and stabilizer bars.

Purpose of the rotating bending test

  • Comparison of fatigue strength before the raw material is processed to become the final product.
  • Material optimisation (e.g. type of material, heat treatments, shot peening parameters, scatter reduction, etc.)
  • Discovery of cracks, inclusions or similar discontinuities in the material to determine the materials quality
  • Assessment of the surface quality

Advantages compared to other existing test machines

  • Clamping of test bar is not necessary due to the utilisation of special purpose bearings
  • High test frequency
  • Tests a large and therefore representative material volume
  • Short assembly and test specimen exchange time
  • Reliable and low maintenance

Typical results

  • „„Fatigue strength in the finite-life fatigue strength area
  • „„Fatigue life
  • „„Scatter along an S/N curve (Wöhler line)
  • „„Distribution of material defects in material volume

Typical users

  • „„Manufacturers of high strength steels
  • „„Wire manufacturers for the spring and stabilizer bar industry
  • „„Manufacturers of Springs and stabilizer bars
  • „„Generally all manufacturers producing steel of high purity

Technical Data

  • Test specimens: processed and unprocessed cylindrical bars or pipes (also for stepped shafts)
  • Diameter of bar / pipe: d = 10 to 30 mm
  • Length of bar / pipe: L = 60 d + 140 mm (or special sample shapes)
  • Test frequency: f = 5 to 50 Hz (variable)
  • Power consumption: < 1 kW
  • Properties: no outward vibration, very quiet
  • Weight / measurements of machine: ca. 1000 kg, L = 2600 mm, W = 1000 mm, H = 1500 mm
  • Load conditions: load transfered over convex, non-wearing plastic bushings
  • Load (stress) and strain measurements
  • max. bending moment: Mmax = 3,6 kNm