Research on the influence of the form of stiffened structure on the containment capability of auxiliary power unit casing

To study the impact of stiffened structural forms on the high-speed impact resistance and damage modes of GH4169 reinforced auxiliary power unit (APU) casing, a series of high-speed impact simulations were conducted in ANSYS/LS-DYNA software, based on the Johnson-Cook constitutive model and failure model. The simulation results show that as the number of reinforcing ribs increases, the remaining kinetic energy of the projectile decreases, and the energy absorbed by the target plate gradually increases. This is mainly because the reinforcing ribs change the failure form of the target plate, causing a larger range of plastic deformation and thus increasing energy absorption. At the same time, studies have been made on the damage morphology and impact process of the target plate under different impact speeds of the projectile. It has been found that the failure modes of the target plate are different under different impact speeds. The reinforcing ribs can guide the failure form of the target plate towards longitudinal shear failure, which can absorb more energy. Therefore, the use of reinforced design enhances the energy absorption capacity of the APU casing when subjected to blade impacts, helping to improve the containment performance of the APU casing.