26 research outputs found
Review of Concrete Structures Strengthened with FRP Against Impact Loading
Recent global terrorism activities and threats imposed prominent danger to the public civil infrastructure, and thus blast and impact resistance design of structures has become an indispensable requirement in the design processes. Fiber reinforced polymer (FRP) can be used as an excellent material to improve the blast and impact resistance of structures. Up to now most studies concentrate on blast-resistance of FRP strengthened structures. The number of studies about impact resistance of structures strengthened with FRP is very limited and the findings in these studies are controversial. Since structures under blast and impact loadings do not necessarily behave the same, it also is important to understand the performance of FRP strengthened structures subjected to impact loads. This study aims to provide an overview of the impact resistance of structures strengthened with FRP, which include reinforced concrete (RC) beams, RC slabs, RC columns and masonry walls. This study also reviews the dynamic properties of FRP materials. Although some issues still need to be investigated and clarified, it would be suggested that FRP can be used to strengthen and protect structures against impact events or terrorism activities. © 2016 Institution of Structural Engineers
A Simple Analytical Model for Ballistic Impact in Composites
The analytical models already developed by Smith and Roylance for impact in yarns and impact in textiles have been used, together with a new failure criterion based on the energy that crosses each yarn, to build a simple analytical model of impact in textiles. This model has been checked with Dyneema armours and predicts accurately the residual velocity of Fragment Simulating Projectiles. The model has been completed with a delamination equation taken from Beaumont in order to include the composite characteristics of delamination. The result is a very simple model which simulates accurately the impact of a FSP into a composite armour with very few seconds of calculation in a personal computer.Les modèles analytiques développés par Smith et Roylance concernant l'impact de projectiles sur des fils et des tissus ont servi de base pour créer un modèle analytique simple avec un critère de fracture nouveau. Ce modèle a été contrasté avec des résultats expérimentaux et complété avec un modèle de délamination déjà utilisé par Beaumont dans sa thèse doctorale. Le résultat final est un modèle analytique très simple capable de simuler l'impact sur un matériau composite en quelques secondes de calcul avec une bonne précision
Novel polymer-ceramic composites for protection against ballistic fragments
For the first time, internally reinforced aggregate polymer ceramic composites were evaluated against fragment simulating projectiles (FSPs) of various calibers to investigate their ballistic impact response. Samples were prepared by mechanically mixing B4C and cBN over a range of ratios and combinations with either thermosetting phenolic or epoxy resin and aramid pulp. Dry mixtures were then molded in a closed die using a heated platen press. The resulting tiles were then mounted as ‘‘strike faces’’ to an aramid backing material using an epoxy resin. Backed targets were tested in a fully instrumented firing range against 5.56 mm FSPs to test ballistic limit. A further series of tests using 7.62, 12.5, and 20 mm FSPs was conducted to examine round deformation across a range of fragments calibers. Round deformations were measured after impact and plotted against shot velocity. It was found that the polymer ceramic composite materials were effective round deformers and, like sintered ceramic strike faces, demonstrated improved ballistic performance at an equivalent areal density and impressive multihit capability
Modeling ballistic impact on textile materials - Chapter 7
Abstract: Modeling the damage response of materials to ballistic impact has received a great deal of attention, with particular focus on its applications in the defense and aerospace industries. With the constant advances in material science leading to high performance applications of damage response technology, predicting the ballistic resistance and behavior of protective materials subjected to impacts is the subject of much research. This chapter reviews the various techniques used to model the response of textile materials to ballistic impact