In order to promote the effective improvement of thrust-to-weight ratio of new generation of large aeroengines

the research on autofrettage mechanism of high-strength aluminum alloy pipe fittings for aero-engine weightreduction requirements was carried out. It is a feasible way to reduce the weight of aero-engines that using effectively strengthened high-strength aluminum alloy pipe fittings to replace stainless steel high-pressure pipe fittings in the low temperature section of aero-engine on a large scale. To obtain the mathematical model of the high-pressure autofrettage process of aviation pipeline，the strengthening mechanism of high-pressure pipeline autofrettage process was researched and Bauschinger effect

strain aging and strain hardening based on the triple shear unified failure criterion were considered. The bilinear kinematic hardening model was used to analyze the elasto-plastic behavior of the pipeline during the hardening process and the evolution of the residual stress distribution. Based on ANSYS

the fatigue strength of reinforced aluminum alloy pipe and stainless steel fittings were simulated and analyzed under rated conditions. Finally

pulse fatigue experiments were done to verify that it is feasible to replace existing stainless steel fittings with strengthened aluminum alloy pipe fittings.