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<p>High pressure turbine disks are critical components of aeroengines. The failure of such component is strictly forbidden for safety reasons. This component must meet the certification requirements in terms of fatigue life to initiation as well as crack growth life via damage tolerance approach. Fastener holes are highly stressed areas. The cold expansion process is used in aeronautical industry on fastener holes in order to introduce compressive residual stress around the hole up to 4&#xa0;mm beneath the surface. This residual stress will prevent early crack initiation and reduce the crack growth rates. The residual stress field must be characterized and modeled in order to take into account the beneficial effect of cold expansion on the crack growth rates. Two different models including a three dimensional finite element model and a reconstructed residual stress model by the eigenstrain theory have been created. Indeed, these models aim to study the distribution of the residual stress field around an <i>Inconel718</i> cold expanded hole. The three dimensional finite element model was established to simulate the actual split-sleeve cold expansion process and the reaming/chamfering operations. The results reveal that the residual stress varies through the thickness at different cross sections perpendicular to the hole axis of the sample. The eigenstrain study was applied to the same sample, subject to cold expansion treatment. The eigenstrain distribution was calculated using limited experimental strain measurement by neutron diffraction. The results reveal that the distribution of the residual stress field along the radial direction of the expanded hole is in good agreement with the numerical model, however, this simplified model is, by essence, unable to predict the residual stress variation through the thickness of the sample. Finally, the experimental data obtained by neutron diffraction were compared with those derived from simulation approaches.</p>

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Modelisation and numerical simulation on the residual stress induced by cold expansion of fastener holes located in nickel based superalloy aircraft engine disks

  • 期刊论文

  • 发表日期：

    2026年3月24日

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  • Moad Fatmi,
  • Manuel François,
  • Carl Labergere,
  • Emmanuel Fessler,
  • Stéphane Pierret

摘要

High pressure turbine disks are critical components of aeroengines. The failure of such component is strictly forbidden for safety reasons. This component must meet the certification requirements in terms of fatigue life to initiation as well as crack growth life via damage tolerance approach. Fastener holes are highly stressed areas. The cold expansion process is used in aeronautical industry on fastener holes in order to introduce compressive residual stress around the hole up to 4 mm beneath the surface. This residual stress will prevent early crack initiation and reduce the crack growth rates. The residual stress field must be characterized and modeled in order to take into account the beneficial effect of cold expansion on the crack growth rates. Two different models including a three dimensional finite element model and a reconstructed residual stress model by the eigenstrain theory have been created. Indeed, these models aim to study the distribution of the residual stress field around an Inconel718 cold expanded hole. The three dimensional finite element model was established to simulate the actual split-sleeve cold expansion process and the reaming/chamfering operations. The results reveal that the residual stress varies through the thickness at different cross sections perpendicular to the hole axis of the sample. The eigenstrain study was applied to the same sample, subject to cold expansion treatment. The eigenstrain distribution was calculated using limited experimental strain measurement by neutron diffraction. The results reveal that the distribution of the residual stress field along the radial direction of the expanded hole is in good agreement with the numerical model, however, this simplified model is, by essence, unable to predict the residual stress variation through the thickness of the sample. Finally, the experimental data obtained by neutron diffraction were compared with those derived from simulation approaches.