Characteristics and mechanisms of turboshaft engine axial compressor casing containment

To investigate the containment characteristics and mechanisms of axial compressor blade and casing in turboshaft engine,experimental and simulation research is conducted on Titanium alloy axial compressor blades and stainless steel simulator casings in this paper.Experiments for four thicknesses(from 0.8 mm to 1.4 mm)of casings are presented on high-speed spin tester.Perforation,ricochet with and without failure of the casings are obtained in test results.Three obvious bulges or dishing region are observed,petaling failure occurs in the first bulge or the third deformation region.Parabolic and elongated dimples are observed at the fracture surface.Finite Element(FE)models with calibrated Johnson-Cook material behavior law are built and analyzed by using explicit dynamic software for a better understanding on the containment behavior.Good agreement is obtained between the experimental observations and numerical predictions.The evolution of the impact force,energy absorption,temperature increase and the cracks’propagation are analyzed.Three force peaks occur in the impact process.Energy analysis reveals that penetration condition of ricochet with failure leads to most internal energy of the casing.

Penetration of disk fragments following impact on thin plate

To investigate the ballistic resistance and failure pattern of aeroengine casing following the impact of disk fragments, and to determine the optimum case structure, the phenomena of a 1/3rd disk fragment impact on single and double-layered thin plate targets were simulated using nonlinear dynamical analysis software MSC.Dytran. Strain rate effect was introduced in a Johnson-Cook (JC) material model for the disk fragment and the plate. Impact modeling was based on the Arbitrary Lagrange-Eulerian method, and simulated using explicit finite element method (FEM). Simulation results showed that the major failure pattern of the plate is shearing and tensile fracture with large plastic deformation. It was also concluded that the ballistic limit velocity increases with the standoff distance when it is beyond a certain value, and that greater resistance is obtained when the front plate has either a proportionately low or high thickness. The impact resistance of a double-layered plate may exceed that of a single plate if the thicknesses and standoff distance of the two plates are set appropriately.