Study On The Effect Of Arc Contact Surface And Laser Hardening On Fretting Fatigue Life

Fretting damage is a very common construction in the forms of damage. Studies have shown thatfretting fatigue would reduce the life of components by30%or more. With the development of theuse of titanium alloy in aeronautics structure, the problem of fretting damage has become more acuteand actually one of the main obstacles to its application. Therefore, the study of fretting fatiguebehavior, and using the appropriate measures for protection, such as improve the structural design,and to find effective methods of surface modification to improve the fretting fatigue life of titaniumalloy for aerospace applications has important significance.This paper first studied the SWT life prediction model based on critical plane method, andproposed further amendments to this model. Finite element analysis and experimental data wereintegrated to get two modified parameters. Then the life prediction model was established. Comparedwith related experiments, the modified model was verified to be more accurate and reliable.Anti fretting fatigue design method based on the structure of arc contact was put forward. In thispaper, finite element method was used to research the stress field in the micro region with the changeof arc contact radius. Then the appropriate radius was determined. Six sets of test pieces weredesigned and processed to completed the arc contact experiments. The results showed that the frettingfatigue life of the arc contact structure was significantly higher than the plane to plane contact. In twoconditions, the experimental life value were increased by108.45%and44.09%. This verified thefeasibility of arc contact structure design. On the other hand, the proposed life prediction model wasused to predict the fretting fatigue life of arc contact structure. The theory analysis and experimentalresearch comparison showed that the life prediction error is small, indicated the applicability of lifeprediction model.Anti fretting fatigue design method based on surface hardening process was advanced. Six sets ofplane-plane contact structure specimens were processed by laser hardening. Then the fretting fatiguetests were completed. The results showed that the fretting fatigue life of plane-plane contact structurewas increased by110.78%and17.56%in two conditions after laser hardening process. And themodified life prediction model was used to the specimens after laser hardening process. To improvethe accuracy of life prediction, the relationship between hardness and elastic modulus was introduced,and the influence of surface hardness to the fretting fatigue life was studied. The results showed thatthe error of life prediction model was small, and the life prediction model was proved to be valid.