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It is an open question to confine an accurate ballistic limit curve (BLC) for Whipple shield above 7 km/s due to lack of experimental capability to launch gram-size spherical projectile in this velocity range.Numerical simulation was conducted by using AUTO-DYN-2D with Grüneisen EOS/Tillotson EOS and Steinberg-Guinan strength model.Both simulation results with the two EOSs show fluctuation,which contradicts the monotonic decreasing trend predicted by models and scaled laws.BLC obtained with Grüneisen EOS turns upward after 8.5 km/s and then it decreases from 9.5 km/s to 14.3 km/s,after which comes a sharp increase in linear trend.BLC obtained with Tillotson EOS turns upward after 8 km/s and it monotonically increases as a conic.Comparison between simulation results in this paper and surrogate experiments and scaled experiments validates the variation trend of results obtained with Tillotson EOS.Theoretical calculation and experimental research denote that the constitute material aluminum melts or even vaporizes under shock loading at impact velocities above 7 km/s.A debris cloud model containing molten particles and vaporized particles is founded to explain the fluctuation of BLC.Besides,it can be deduced from simulation results with Tillotson EOS that aluminum totally vaporizes at 300 GPa.