Ballistic test of double-layer metal casing of aero-engines

In order to study the containment of double-layer metal-structured casing of aero-engines under blade`s impact，the ballistic test of double-layer titanium alloy laminated target plates with different clearances was carried out by using a sliding-bore gun test system.The process of blade penetration into target plate was recorded by high-speed camera system，and the damaged targets were recovered.The penetration resistance and failure modes of different laminated target plates were studied.Through 28 effective ballistic tests，it was found that： compared with the test results of the combination with the same thickness of the inner （attack surface） and outer target plate，the larger gap indicated the worse anti-penetration ability of the target plate；compared with the test results of the combination without the gap，the anti-penetration ability of the combination with the thinner inner target plate was better than that of the combination with the same thickness of the inner and outer target plates.The ballistic test was simulated numerically by commercial finite element software ANSYS/LS-DYNA.The finite element simulation results were in good agreement with the test results.It was found that the anti-penetration ability of the combination with thinner inner target was stronger than that of the combination with thicker inner target，and both of them were stronger than that of the combination with the same thickness of inner and outer targets；in the case of no clearance，the ballistic limit increased with the increase of blade angle of attack，but the angle of attack of the sudden increase of velocity curve was different.The dimensionless target thickness determined the failure mode of the blade impacting the double-layer targets.