Residual Stress Determination


The measurement of residual stress is vital in the field of welding, stress relieving, and other manufacturing processes that may introduce such stresses. Accurate measurement of residual stress and its variation with depth provides insight into the stability of the component. The PolyU Aviation Services Research Centre (ASRC) has developed a verified method for measuring residual stress in aero engine parts.

  • Residual Stress Determination 0
  • Residual Stress Determination 1
  • Residual Stress Determination 2
Technical name of innovation
Residual stress determination by incremental hole drilling and back calculation
Commercialisation opportunities
Provision of professional services
Problem addressed

After repair, stress relief of aero engine parts may not fully remove all stress, so it is crucial to test both the part and the repair process to establish whether the repair has been successful. This is especially important for high-temperature repairs.

  • Verification of results via an in-house 4-point bending test.
  • Verification of results via X-ray diffraction of surface stresses.
  • First locally established residual stress test rig.
Key impact
  • Allows local industries to get a benchmark measure of residual stress without overseas costs.
  • Provides fast feedback on heat treatment and stress reliving processes. Results are non-certified, but high confidence of accuracy due to round robin testing and parallel verification through other means and modelling.
  • Stress measurements in scrap aero engine parts
  • Residual stress in automotive and rolling stock parts
The Hong Kong Polytechnic University (PolyU)

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