Numerical investigation of penetration performance of non-ideal segmented-rod projectiles

The design of a segmented-rod projectile is often simplified into an ideal one in theoretical analysis for the convenience of modeling of its performance. But the actual performance of non-ideal segmented-rod projectiles over the impact velocity range in practical applications was rarely explored. AUTODYN numerical code is used to investigate the influence of the component design upon the penetration performance of non-ideal segmented-rod projectiles over a wide range of impact velocities, which can be used to guide the optimal design of weaponry segmented-rod projectiles.     

Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates

Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate, which have been included in material models to improve the reliability of numerical simulations of the material and structural responses under impact and blast loads. The strain-rate effects on the dynamic compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated. It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects, which, as a non-strain-rate factor, may greatly enhance the compressive strength of these materials. Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials, and thus may over-estimate the structural resistance to impact and blast loads, leading to non-conservative design of protective structures.     

Left-handed materials in magnetized metallic magnetic thin films

INTRODUCTION Veselago (1968) showed that if both the permit- tivity ε and the magnetic permeability μ of a material are negative, the propagation direction of an elec- tromagnetic (EM) wave will be opposite to its energy flow direction. Such media are called left-handed materials (LHMs) since the electric field E, magnetic field H, and wave vector k in these media form a left-hand triplet of vectors, instead of a right-hand triplet observed in conventional materials. For a long time, …     

Parental training and involvement in sexuality education for students who are deaf

The study examined whether schools for the deaf were providing services to assist parents in communicating with their children about sexuality (including sexual signs) and whether parents were involved in the sexuality education curriculum within their child's school. The Sexuality Curriculum Questionnaire for Educators of Students Who Are Deaf (Getch & Gabriel, 1998) was completed by 71 educators teaching sexuality curricula in schools for the deaf across the United States. Results indicated that parents were more likely to be involved in approval and development of their children's sexuality education than to receive assistance with sexuality education from the schools. Although the level of parental participation in curriculum development and approval is encouraging, the number of parents actually participating in curriculum development and approval remains low.