Zr-based amorphous alloy is a new type of metastable energetic material, which has been exploringly used to design shaped charge (SC) liners by scholars of the military industry. In order to know well how the stand-off distance influences jet penetration performance of liners made by such energetic materials against metal targets, SC static explosion tests were conducted under the same initiation and target conditions but different stand-off distances compared with copper liners. Test results indicate that the jet depth of penetration (DOP) of Zr-based amorphous alloy liners firstly increases slowly and then decreases sharply as the stand-off becomes larger. The optimum stand-off distance is 3.5 times of charge diameter (CD) and the corresponding maximum DOP is about 2.68 CD against the 45# steel plate. The perforation area varies with the stand-off distance. It reaches the maximum when the stand-off is 3.5 CD and the corresponding perforation diameter is about 42mm, also the penetration hole is nearly circular. The jet DOP of Zr-based amorphous alloy liner is smaller than that of copper liner’s while the perforation area is the opposite. The former DOP is about 55.7% of the latter and the former perforation area is about 2.8 times of latter when the stand-off distance is 3.5 CD.
A method for constructing multi-scroll chaotic systems based on shift transformation is presented. Firstly a proper unstable linear system is selected, and the phase space is divided into several parts by a series of parallel interfaces. Then shift transformations of the linear system are implemented so that each space region is dominated by the corresponding new system. Finally the whole system is obtained using a proper nonlinear function based on signum functions. According to this method new multi-scroll chaotic systems with arbitrary odd number scrolls can be constructed, furthermore, some existing chaotic systems can also be modified into multi-scroll systems. Numerical simulations verify the feasibility of the proposed method.
The tracking control of chaotic Chen system is realized using a nonlinear single-input controller. According to the structure characteristic of the Chen system, proper feedback form is selected and an adaptive single-input controller is designed, which makes the Chen system track a certain variable of the Rossler system with unknown parameters. The Lyapunov direct method is applied to prove that the error signal asymptotically approaches zero. Numerical simulations show that the proposed control method is feasible, and the identification of unknown parameters can be realized.
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