Corneliu Cismasiu

The paper reports experimental and numerical simulation of ballistic impact problems on thin composite laminated plates reinforced with Kevlar 29. Ballistic impact was imparted with simulated fragments designed in accordance with STANAG-2920 on plates of different thickness. Numerical modelling was developed and used to obtain an estimate for the limit perforation velocity V50 and simulate failure modes and damage. Computations were carried out using a commercial code based on nite differences and values obtained are compared with the experimental data to evaluate the performance of the simulation. Good correlation between computational simulation and experimental results was achieved, both in terms of deformation and damage of the laminates. Future work is advanced to include the interposition of an outer ceramic layer as well as examining the influence of dry-wet and temperature cycles on the mechanical strength of the plates and their temporal evolution under accelerated ageing.

Superelasticity, a unique property of shape memory alloys (SMAs), allows the material to recover after withstanding large deformations. This recovery takes place without any residual strains, while dissipating a considerable amount of energy. This property makes SMAs particularly suitable for applications in vibration control devices. Numerical models, calibrated with experimental laboratory tests from the literature, are used to investigate the dynamic response of three vibration control devices, built up of austenitic superelastic wires. The energy dissipation and re-centering capabilities, important features of these devices, are clearly illustrated by the numerical tests. Their sensitivity to ambient temperature and strain rate is also addressed. Finally, one of these devices is tested as a seismic passive vibration control system in a simplified numerical model of a railway viaduct, subjected to different ground accelerations.

Being able to efficiently mitigate the effects of blast loads on structures, sacrificial cladding solutions are increasingly used to protect structural elements from the effects of accidental explosions and/or terrorist attacks. The present study analyses the loss of effectiveness of a deterministically designed sacrificial cladding when variability in the material properties and uncertainties in the mechanical model are considered. The results of an experimental campaign are used to validate the numerical models that allow the deterministic design of a sacrificial cladding which successfully improves the blast resistant capabilities of a given structural element. Nonetheless, it is shown that, taking into account the probabilistic variability of key parameters is of vital importance when designing sacrificial cladding solutions, since, when not properly designed for the structural element it intends to protect, adding a sacrificial cladding might negatively impact its blast resistant capabilities. Additionally, it is concluded that the deterministic approach might be against safety. In the reported case study, when comparing the admissible charge weight yielding from the deterministic and probabilistic approaches, one verifies that the former allows a higher charge weight.

This paper investigates the dynamic behaviour of cable-supported glazing façades
subjected to medium-level air blast loads. Preliminary numerical studies are carried-out in
SAP2000 by means of a geometrically refined and simplified lumped-mass finite-element
numerical model, in order to assess the major effects of the design blast load in the main
façade components. As shown, both the glass panels and the cable system are able to
properly accommodate the incoming impulsive loads, typically involving extreme ...

In densely built urban areas, explosive events produce blast waves that interact strongly with surrounding structures, resulting in amplified pressures and highly variable injury patterns. These complex interactions challenge conventional blast models and emphasize the need for improved, rapid injury estimation methods to support effective emergency response and mitigation. To address this need, the present study develops predictive equations for the rapid estimation of TNT blast-induced human injuries in urban environments, with particular emphasis on densely built areas characterized by complex street geometries. These equations were derived through regression analysis of an extensive dataset of simulated blast events with varying charge sizes, placed in three representative urban scenarios characterized by distinct street layouts and topographic conditions. The numerical simulations were performed using validated finite-volume Computational Fluid Dynamics models implemented in the GPU-accelerated commercial software Viper::Blast. The proposed equations allow the delineation of primary and secondary injury zones. Primary injuries are associated with overpressure effects on air-filled organs, while secondary injuries result from debris and projectiles and are directly correlated with predicted damage to masonry elements and glazing. Tertiary and quaternary injuries, which are respectively related to body displacement and impact, burns, inhalation hazards, and psychological effects, are not addressed in the present research. Results show that the urban fabric strongly influences both the extent and the shape of the injury zones. In contrast, terrain topography, provided that slopes remain relatively moderate, has only a minimal effect. Overall, the predictive equations offer a rapid yet reliable tool for quantifying blast-related injuries in urban environments. They support risk assessment, mitigation planning, and emergency response strategies for both accidental and deliberate explosions.

The paper reports on numerical simulation of impact problems on fiber reinforced plastic composite laminated plates reinforced with Kevlar 29. The ballistic impact caused by STANAG-2920 projectile is analyzed to obtain an estimate for the V50 and the global damage. All estimate have been carried out using the finite difference numerical code AUTODYN-3D, are compared with the experimental data to illustrate the performance of the simulation. Good correlation between resulting simulations and experimental results is demonstrated both in terms of deformation and damage of the laminates and ballistic performance.

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