Papers by Author: Xiao Dong He

Abstract: This study presents an effective methodology for the optimum design of two-component armor. The armor consists of two plates: one is boron carbide ceramic and the other is kevlar/epoxy composites. The effect of the thickness of two plates on the ballistic limit velocities of the armor was investigated by Florence model. A finite element model was created using MSC.DYTRAN to simulate the impact of a rigid projectile on the composite armor. The optimum thickness of the ceramic and composite was obtained by evaluating the ballistic resistance efficiency.

Abstract: High silicon electrical steel prepared by EB-PVD was subjected to high temperature rapid thermal annealing and subsequent pack rolling. The phase composition and Fe configurations were characterized by X-ray diffraction and Mössbauer spectroscopy. The results show that the as-deposited, as-annealed and as-rolled samples mainly consist of DO₃ ordering phase and the as-deposited electrical steel is composed of six kinds of Fe sites corresponding to 333.8KOe, 319KOe, 302 KOe, 284 KOe, 249 KOe, 196 KOe, respectively, while the Fe site corresponding to 196 KOe hasn’t been found in the other two samples. Moreover, the other two samples show a larger Fe site occupancy corresponding to 284 KOe.

Abstract: The effect of pressures on microstructure and properties of as-deposited high silicon electrical steel by EB-PVD during hot pressing was studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the phase composition and morphology; the density and electrical resistivity were measured using the bottle method and four-probing method, respectively. It was found that the density increased from 7.25×10³ kg/m³ to 7.5 ×10³ kg/m³, while the electrical resistivity decreased from 85µΩ•cm to 75µΩ•cm with the increase of the pressure from 30 MPa to 60 MPa.

Abstract: The composite material has high strength-to-weight, stiffness-to-weight ratios and it has the layer designing property to satisfy special mechanical requirement. Nowadays, the marine produce industry makes efforts to use composites for marine propeller to improve the hydrodynamic and structural performance. In this paper, the authors use FEA coupled CFD to design the layer sequence of composite propeller and develop ANSYS subroutine to simulate resin flow in the mould. The composite propeller is produced by RTM (resin transfer molding) and tested to measure the performance of composite propeller. Compared to the same size aluminum propeller, the composite propeller saves 39% weight and has less noise.