Investigation On The Numerical Evaluation Methods For Flat Blade Impacting Plate

Aero-engine should have good tolerance ability to protect rotor debris from breaking the casing. Chinese large aircraft turbofan engine must be verified through inclusive to obtain airworthiness certificate. In order to study aero-engine casing inclusive problem, in this paper, fan debris and aero-engine fan casing tolerance zone is simplified as flat metal blade and metal target. Respectively, the process of flat blade impact the metal plate and the numerical evaluation method, the process of blade impact the stiffened plate and the optimal structure for stiffeners were detailed discussed in this paper.This paper calculate the ballistic limit and residual velocity by establishing numerical simulation model of different projectile and plate structures, the results obtained great agreement with the experimental datas. During the impact process, the projectle impact the plate several times, and the target presents multiple failure modes. When the plate not penetrated, its deflection can be approximation obtained by empirical formula, when projectile breakdown the target, the relationship between residual velocity and initial velocity meet the Recht-Ipson equation. Potential energy method and K.A.Belkin ballistic formula used in engineer were authenticated by numerical simulation and penetration experiments too.Paper also established numerical model to simulate the process of flat blade impact stiffened plate using a modified constitutive model parameters of material TC4. Simulation results show different failure modes of stiffened plates.The simplified method of equivalent thickness calculating is feasible, and the same quality stiffeners can promote the resistance ability of the plate.Based on the numerical simulation, this paper analysis the ballistic limit and residual velocity of different stiffened plates in order to find ways to structure optimization.The reults show that:increase the numbers of stiffeners in the impact area can promote resistance ability; the stiffeners in the non-impact region show small enhance. Stiffener set into a fine high-type, can obtain better impact resistance ability. Replace"|" type stiffener by "T" type stiffener, can improve the plate's performance.