The response of glass window systems to blast loadings: An overview

The failure of glass windows in terrorist bombing attacks and accidental explosion incidents has been cited as one of the major causes to the vast casualties. Many studies have been carried out to investigate the response and vulnerability of glass windows against blast loadings. These include laboratory and field tests that have been carried out to experimentally study glass window performance under explosion scenarios and development of analytical and numerical models to analyze and predict glass window responses. This article reviews literatures on the studies of the response of glass window systems to blast loadings. Over 100 papers and documents that are available in the open literature are reviewed. The background and history of the studies on the topic are also briefed. Understandings about the dynamic material properties of glass and available material models are summarized. Popularly used analysis methods and design standards for monolithic and laminated glass windows are outlined, and their accuracies are discussed. Recent studies including analytical solution, numerical simulation, and experimental investigations on glass window systems are summarized. Mitigation measures for blast-resistant windows are also briefly discussed

Troublesome trade-offs: balancing urban activities and values when securing a city-centre governmental quarter

Background Homeland security measures increasingly affect urban life and activities. Standoff distance, which prevents unscreened vehicles from approaching within a certain distance of a building, is a widely applied measure when protecting buildings against attacks with vehicle-borne improvised explosive devices. This measure both is rather inexpensive and has few negative externalities when implemented in rural areas. Unfortunately, sites with protection needs often are situated in city centres. Methods We apply the so-called Security Function Framework to illuminate the externalities or the ‘troublesome trade-offs’ between protecting a high-value site against vehicle-borne improvised explosive devices and protecting other urban values. Results This paper demonstrates that standoff creates challenges for other important values, such as functional office spaces for all employees, deliveries and emergency vehicle access. Simultaneously, standoff creates opportunities for reinforcing social-responsibility requirements, such as accessibility for pedestrians and environmental considerations. Conclusions Security measures can have both negative and positive externalities and planning might alleviate some of the negative ones

Eine Fliessgelenktheorie hoeherer Ordnung fuer raeumliche Stabtragwerke (zugleich ein Beitrag zur historischen Entwicklung)

TIB: ZA 4628(32) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Development of EOS data for granular material like sand by using micromodels

Detonations in soil can occur due to several reasons: e.g. land mines or bombs from the Second World War. Soil is also often used as a protective barrier. In all cases the behaviour of soil loaded by shock waves is important. The simulation of shock wave loaded soil using hydro-codes like AUTODYN needs a failure model as well as an equation of state (EOS). The parameters for these models are often not known. The popular material law for sand from Laine and Sandvik [1], e.g., is a first approximation, but it can only be used for dry sand with a certain grain grading. The parameters porosity, grain grading, and humidity have a big influence on the material behaviour of cohesive soils. Micro-mechanic models can be used to develop the material behaviour of granular materials. EOS data can be obtained by numerically loading micro-mechanically modelled grains and measuring the density under a certain pressure in the finite element model. The influence of porosity, grain grading, and humidity can be easily investigated. EOS data are determined in this work for cohesive soils depending on these parameters

Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations

Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction

Windows and glazing systems exposed to explosion loads: Part 2 – Safety improvement strategies

International terrorism has increased the interest in the dynamic behavior of windows under explosion loads. Windows are usually the first elements exposed to blast loading causing serious secondary threats as they can break up in sharp shards which are accelerated inwards. The University of the German Armed Forces, Munich, FOI the Swedish Defence Research Agency, and TNO Defence, Security and Safety conducted studies to assess the lethality of these shards. These results are presented in Part 1 of this paper in two parts. In Part 2, the authors discuss safety improvement and hazard mitigation strategies for window systems. First, general safety strategies to counter blast threats are discussed. Then, balanced design principles are presented leading to a significant reduction of stresses in the window panels by allowing larger elastic-plastic deformation of the total window frame system. By using elastic-plastic, i.e., dissipative, support elements blast energy is dissipated and the load transferred to the main structure is controlled and reduced