Optimum Selection Analysis of Composite Cap Cone

An in-depth analysis was conducted on the dynamic strength design optimization of carbon fiber composite cap cones in aircraft engines subjected to bird body impacts. Initially, the top, 1/4, 1/2, 3/4, and root positions of the cap cone’s generatrix were designated as the impact sites. The analysis of bird impacts revealed that the 1/2 position along the generatrix is the most hazardous impact location. Subsequently, considering the thickness of the composite material cap cone as a variable and accounting for its high-speed rotational state, a bird impact analysis was performed at the most critical impact location. Additionally, a comparative study on the bird impact performance of the composite material cap cone under rotating and non-rotating conditions was conducted. The study indicates that, under identical conditions, the cap cone in rotation experiences more severe damage than in a non-rotating state, necessitating a cone thickness of 7 mm or greater; Subsequently, a bolt strength analysis model was established to thoroughly examine the impact of varying cone side thicknesses on the load applied to connecting bolts, and to assess bolt strength. The findings suggest that excessive bolt loads can also constrain the optimization of the cap cone; hence, finding the optimal balance between bolt quantity and strength is essential in design. Lastly, the study discussed the weakening of local stiffness in the composite material cap cone post-impact, noting a 12% decrease in its elastic mode frequency and the emergence of asymmetric vibration modes. This phenomenon could potentially lead to dynamic unbalanced loads, thus necessitating further evaluation in the optimization process of the cap cone.