Investigation of Laser Shock Peening on Aero-Engine Compressor Rotor Blade

Abstract

Compressor rotor blade is one of the critical parts of aero-engine. Because of the complex structure and bad work environment, it often went wrong. More over, the trouble of blade can result in serious accident of engine even the aircraft. But the conventional shot peening strengthen method couldn’t take ideal effect, so a new method, laser shock peening on aero-engine compressor rotor blade was studied in this paper. The principle of laser shock peening strengthening was presented first, and the appropriate shock parameters of a certain type blade are fixed on by modeling. The parameters were as follows: laser pulse width is 20ns, output energy is 25J, the spot diameter is 8mm, and peak value is at GW level, and the laser peak value power is bigger than material dynamic yield intensity. Based on these parameters, an experiment was performed by shocking the blade through a repeated Nd: glass LASER supplied by Jiangsu University. Through contrastive performance test, an analysis on the high frequency fatigue life and surface rigidity of the blade fore and after laser shock was performed. The result was concluded that laser shock peening can significantly increase the high frequency fatigue life of aero-engine compressor rotor blade, and enhance the surface rigidity to increase the performance of contuse resistance. At last the reasons were analyzed from two aspects: laser shock can impart compressive residual stress on blade and reduce the size of crystal grain. Surface compressive residual stress can change the blade distribution of load when working; and reduce the size of crystal grain can bring in more crystal interface, for the more interface the crystal has the higher dislocation moving resistance and yield stress is produced.