An analytical model for perforation of ceramic/multi-layered planar woven fabric targets by blunt projectiles

An analytical model has been developed in this paper for perforation of ceramic/multi-layer woven fabric targets by blunt projectiles. In previous Chocron–Galvez analytical model the semi-angle of ceramic conoid is constant and the strain rate effects are also neglected in the stress–strain behavior of the yarns and only strain energy absorbed by the yarns is considered.     

An analytical model for composite sandwich panels with honeycomb core subjected to high-velocity impact

In this paper, an analytical model for perforation of composite sandwich panels with honeycomb core subjected to high-velocity impact has been developed. The sandwich panel consists of a aluminium honeycomb core sandwiched between two thin composite skins. The solution involves a three-stage, perforation process including perforation of the front composite skin, honeycomb core, and bottom composite skin. The strain and kinetic energy of the front and back-up composite skins and the absorbed energy of honeycomb core has been estimated. In addition, based on the energy balance and equation of motion the absorbed energy of sandwich panel, residual velocity of projectile, perforation time and projectile velocity have been obtained and compared with the available experimental tests and numerical model. Furthermore, effects of composite skins and aluminium honeycomb core on perforation resistance and ballistic performance of sandwich panels has been investigated.     

Urban modernization and heritage in the historic centre of Santiago de Chile (1818–1939)

ABSTRACT

Architecture and urban heritage have been decisive in the modernization of the historical centre of Santiago de Chile. As early as the first half of the nineteenth century they added value to this area of the capital. Public authorities, with the support of regulations, identified valuable urban heritage, incorporating it into urban transformations. For various practical or historical reasons, buildings and public spaces were preserved and eventually reused, giving birth to a renewed idea of planning, which took advantage of this existing heritage. The incorporation of new typologies into the colonial urban fabric, together with the conservation of traditional buildings and public spaces, produced memorable places, both in the republican and modern city. They enriched the urban practices and the city landscapes, offering a valuable continuity with the colonial and republican past. The integration of old and new stimulated the emergence of an urbanism of quality. This article focuses on three specific moments of that peculiar modernization process: the consolidation of the original colonial grid (1818–1846), Vicuña Mackenna’s Transformation Plan (1872–1875) and Santiago's first official Urbanization Plan (1939).     

A new analytical model of normal penetration of projectiles into the light-weight ceramic–metal targets

In this paper based on Zaera and Sanchez-Galvez [4] model, a new analytical model has been presented for penetration of deformable projectiles into ceramic–metal targets. By considering erosion and flattening of projectile tip, the one-dimensional equation of motion has been established. The momentum equation has been employed to describe the fragmented ceramic conoid. Considering work hardening material behavior, energy conservation equation has also been used for modeling the deformation of back-up metallic plate. Semi-angle of ceramic conoid is modified based on Wilson and Hetherington [8] experiments. The ballistic limit and residual velocity of projectile predicted by new analytical model have a good agreement with the experimental results.