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Effect of Shot Peening on Low Cycle Fatigue Life of Compressor Disc of a Typical Fighter Class Aero-Engine

2013; Elsevier BV; Volume: 55; Linguagem: Inglês

10.1016/j.proeng.2013.03.233

1877-7058

B. D. Sahoo, R. K. Satpathy, Kartik Prasad, Shahnawaz Ahmed, Vikas Kumar,

Surface Treatment and Residual Stress

This investigation deals with the study of a compressor disc made of α-β titanium alloy of a typical fighter aero-engine having a TBO (Time Between Overhaul) of 550 hours and TTL (total technical life) of 1500 hours. In general, the failure of most of compressor discs is attributed to low cycle fatigue (LCF) due to the presence of residual tensile stresses at the dovetail slots. In the present study, shot peening was carried out to introduce compressive residual stress at the dove tail slots in order to enhance fatigue life of the disc. The local stress at the longitudinal and transverse edge of the slot generally increases upto 450 MPa and 230 MPa, respectively, during service. In the present study, the introduced residual compressive stresses measured by XRD technique on the slot and face of the disc has been found to be of the order 650 MPa & 770 MPa, respectively. Stress controlled LCF tests (R=0.1, maximum stress = 85% Yield Strength, frequency = 0.33 Hz) have been conducted at room temperature. The LCF life of shotpeened disc was observed to be nearly three times as compared to that of unpeened disc. Following this surface treatment, life of the disc has been revised from 800 to 1500 hours, thereby eliminating the need of disc replacement at operating units. This has improved the reliability and serviceability of the fleet.