Material and component testing under combined torsional and axial loading

Cyclically loaded rotary power transmission elements, consisting of shafts and welded or mechanically connected power receiving elements such as gears, cams, coupling parts, gimbals, or welded shafts are essential components in many industries. For the design of the joints of such components, in particular laser or electron beam welded components, reliable fatigue strength values are often not  of the reasons for this is that in many applications these components are subjected to a superimposed bending or axial load in addition to the torsional load, which results in a complex multi-axial stress condition that has not been covered by the relevant regulations to date.

Fraunhofer IWS has a novel servohydraulic test system with which the load components torsion and axial tension / pressure can be fed independently into a test specimen. This allows components or component-like samples to be tested under load conditions that map the application with high accuracy. Torques up to ± 8 kNm can be applied at a maximum rotation angle of ± 50 ° via the rotary cylinder. In the axial direction, forces of up to ± 40 kN can be achieved with maximum distances of ± 50 mm. Samples and components with diameters of up to 320 mm and lengths of up to 1250 mm are suitable as test samples.

Service offer

With this system we offer, among others, the following test tasks:

  • Determination of strength and deformation characteristics under quasi-static torsional or torsional axial load on specimens and components
  • Determination of the service life and determination of fatigue strength characteristics (Wöhler curves) on test samples and components with pure torsional or combined torsional axial load
  • Lifetime tests and determination of fatigue strength characteristic values (Wöhler curves) for the design of multi-axially stressed welded joints (axial / radial round seams) under torsional or torsional axial load
  • Analyses on the failure mechanisms of multiaxially loaded, in particular welded test samples and components (damage analysis)