Study on stability of double corsair's main stand
The structure safety is numerically studied on main support of the huge pirate ship by use of finite element method (FEM). In order to the elements meshed successfully, the equivalent treatment is used for the complex structure. The static, structure instability and model analyses are carried out. The static and stability safe coefficient are 6.12 and 19, respectively, which are more than the demand in national standard. The model analysis indicates that the swing frequency is 0.08 Hz, and can be kept off the natural frequency.
Dynamic Stability of the Stiffened Plates Subjected to Solid-fluid Impact
Dynamic stability of the stiffened plates subjected to solid-fluid impact is calculated with finite element method.That is helpful for the dynamic stability of the bulkheads in underwater explosion.Some factors are analyzed,including stiffened plates and the thickness of the stiffened plates,the magnitude and the shape of the initial imperfection,the impact pulse width,the pulse load,the edge conditions,the distributions of the stiffeners and the thickness of the plate.Some suggestions are presented according to these factors,which are helpful to the engineering design.
Simulation study of high power microwave generation by virtual cathode oscillation in coaxial vircator
Summary form only given, as follows. We have numerically simulated the high power microwave generation by virtual cathode oscillation in a coaxial vircator with 3 dimensional PIC code Magic. It is noted that the coaxial vircator has the advantage of an enhancement of power efficiency and gaining of narrow bandwidth frequency. The study is focused on the design of a diode structure for a coaxial vircator suitable for Chundoong IREB pulser (Max. 600 kV, 85 kA, 60 ns). It consists of a center annular cathode, a cylindrical meshed-anode and a reflector. The simulation results showed that the coaxial vircator can indeed be operated at the selected frequency with the narrow bandwidth and the microwave output power strongly depends on the position and geometry of the reflector. From this simulation results we expect that the maximum microwave output power will be obtained by the reflector of 4 cm in width and also 4 cm in distance away from the IREB, where the resonant frequency of microwave from coaxial vircator is simulated to be 6.577 GHz.