The damage tolerance for pipe/rod bar in the auxiliary power units （APUs） support system is studied. The main objective is to study whether planes can safely land when the fatigue crack appears on the bar. Firstly, ...The damage tolerance for pipe/rod bar in the auxiliary power units （APUs） support system is studied. The main objective is to study whether planes can safely land when the fatigue crack appears on the bar. Firstly, the stress intensity factors （K~） of two bar structures are computed, and the iso-stress intensity factor （iso-Kl） model is presented. The model uses the finite element model （FEM） instead of the parameters of material to com- pute the crack propagation. Then, the general relations between Kt vs crack size are obtained for different mate- rials, inner to outer diameter ratios （D^n/Dout） and external crack propagation angles （0）. Finally, the FEM anal- ysis results are input to the ANSYS parametric design language（ANSYS-APDL） software. And the fatigue life of damaged bar is estimated under the condition of loading spectrum.展开更多
文摘The damage tolerance for pipe/rod bar in the auxiliary power units （APUs） support system is studied. The main objective is to study whether planes can safely land when the fatigue crack appears on the bar. Firstly, the stress intensity factors （K~） of two bar structures are computed, and the iso-stress intensity factor （iso-Kl） model is presented. The model uses the finite element model （FEM） instead of the parameters of material to com- pute the crack propagation. Then, the general relations between Kt vs crack size are obtained for different mate- rials, inner to outer diameter ratios （D^n/Dout） and external crack propagation angles （0）. Finally, the FEM anal- ysis results are input to the ANSYS parametric design language（ANSYS-APDL） software. And the fatigue life of damaged bar is estimated under the condition of loading spectrum.
