| The modern turbine engine is operating at a high speed. The fan blade would shed due to birdsstrike, FOD, HCF and LCF fatigue and material defects etc. If the fan blade is not contained in theengine, it may lead to catastrophic accident. To improve the thrust weight ratio, stiffened fan casing isutilized for mitigating fan blade out events. Therefore, it is of great significance for studying thecontainment capability of the metal with stiffened structure of the metal casing.In this paper, with the research on civil engine casing containment, stiffened aluminum alloy plateballistic impact tests and numerical simulations are carried out as well as the stiffened structuraloptimization. The main contents are as follows:(1)On the basis of the civil engine casing structure and relevant standards, stiffened aluminumspecimens are designed for the ballistic impact tests. The test process, the fracture, the critical speedand strain response are analyzed after the tests, where the results indicate that ribs can effectivelyimprove the impact resistance of target.(2)On the basis of the impact tests, numerical model is established with the help of LS-DYNAsoftware, the material and its parameters used in the simulation model are determined according tomaterial data. By comparison and analysis of between the finite element simulation and tests, itdemonstrates that numerical simulation agrees well with the tests.(3)The optimal size of ribs is obtained using self-programmed genetic algorithm of MATLAB bycyclically calling ANSYS/LS-DYNA software with the identified FE model. The results show theoptimization ability and convergence speed of genetic algorithm are so good that it is a practicalcalculation method for impact resistance optimization of stiffened plates.The results of impact tests and the computing models of simulation in this paper have a certainreferential value in the design of the case containment, and also provide a feasible method for theoptimization calculation of stiffened plate. |
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