scholarly journals Numerical Simulation of Projectile Penetration into Laminated Transparent Armour

2020 ◽  
pp. 16-28
Author(s):  
I.F. Kobylkin ◽  
V.V. Shakirzyanova
Keyword(s):  
Single Layer ◽  
Adhesive Layer ◽  
Current Layer ◽  
Laminated Glass ◽  
Total Thickness ◽  
Glass Panel ◽  
Tensile Stresses ◽  
Glass Panels ◽  
The Impact ◽  
Subsequent Layer

The paper shows that the main reasons behind a laminated glass panel failing while penetrated by a high-velocity projectile are the high stresses in the region affected by the projectile and tensile stresses at the interface that are caused by the glass layers bending. For all the glass layers but the frontal one, intense fracturing does not start at the interface with the previous layer but at the interface with the subsequent layer, in the region of the tensile stresses generated by the current layer bending. The fracturing propagates towards the impact. A low-strength adhesive layer between glass layers inhibits and even stops the fracture-inducing wave propagating from the previous layer into the subsequent one. Analysis of the projectile deceleration plots in laminated glass panels of the same total thickness showed that the projectile undergoes more dramatic deceleration in a single-layer barrier and in barriers consisting of fewer layers.

scholarly journals Simple Laminated Glass Panels with Embedded Point Connection under Short-Term Load

2021 ◽  
Vol 1203 (2) ◽  
pp. 022079
Author(s):  
Michaela Zdražilová ◽  
Zdeněk Sokol ◽  
Martina Eliášová
Keyword(s):  
Bearing Capacity ◽  
Glass Structure ◽  
Structure Design ◽  
Laminated Glass ◽  
Glass Panel ◽  
Short Term ◽  
Load Bearing Capacity ◽  
Ongoing Research ◽  
Load Bearing ◽  
Glass Panels

Abstract Glass is a very attractive material for contemporary architecture. The trend is to achieve a maximum transparency of structures; therefore it becomes common to use glass as a material for load-bearing structural elements. Glass facades, roofs, beams or columns are widely used in buildings. The problematic part of a glass structure design is the connection between the glass pieces or between the glass elements and substructures from another material (e.g. steel, concrete etc.). The connection must be capable of bearing the stresses performing during the lifetime period and it should be as unobtrusive as possible at the same time. The ongoing research at the Faculty of Civil Engineering of the Czech Technical University in Prague is focused on an embedded laminated point connection for glass structures. Within this research, the real-scale glass panels were tested. The samples consisted of two glass plies bonded with the EVA foil. For the undrilled ply, the float glass was used in all cases. The thermally toughened or the heat strengthened glass was used for the pre-drilled ply. There was one embedded steel countersunk bolt with HDPE liners placed in each corner of the sample. During the experiment, the samples were horizontally placed using the embedded bolts. The load-bearing capacity of the six tested specimens was determined. The load was applied in several loading and unloading cycles until the collapse of the first embedded connection. If the glass panel failed before the connection, the sample was completely unloaded and then the load was gradually increasing until the collapse of the connection. Vertical deflection and the stresses at two different points were measured during the loading cycles. The humidity and the temperature were also monitored. The experiment showed the way of collapse and a short-term load-bearing capacity of a laminated glass panel with four embedded point connections.

A Numerical Study of the Impact Response of Laminated Glass Panels

2005 ◽  
Author(s):  
William Keith Rule
Keyword(s):  
Numerical Study ◽  
Spall Strength ◽  
Float Glass ◽  
Laminated Glass ◽  
Data Sets ◽  
Data Set ◽  
Explicit Finite Element ◽  
Glass Panels ◽  
Technical Interest ◽  
The Impact

This paper describes a study that was undertaken to simulate impacts on laminated float glass/polycarbonate/float glass panels using the Johnson-Holmquist (JH-2) model for brittle materials and the EPIC explicit finite element code. The simulation results are compared with observed impact results obtained by others. The JH-2 model was originally successfully calibrated to treat impact on thick monolithic glass slabs. In this study recent spall strength data for glass reported in the literature was used to revise the JH-2 model for application to thin laminated glass panels — a system of wide technical interest. The JH-2 coefficients developed were further validated by comparison with an additional independent data set obtained from the literature involving glass rod impact data. A good fit to both data sets considered was produced suggesting that the revised JH-2 coefficients proposed are reasonable.

scholarly journals Windblown Sand-Induced Degradation of Glass Panels in Curtain Walls

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Yuxi Zhao ◽  
Rongcheng Liu ◽  
Fan Yan ◽  
Dawei Zhang ◽  
Junjin Liu
Keyword(s):  
Visible Light ◽  
Mass Loss ◽  
Effective Area ◽  
Area Ratio ◽  
Light Transmittance ◽  
Relative Mass ◽  
Impact Time ◽  
Windblown Sand ◽  
Glass Panels ◽  
The Impact

The windblown sand-induced degradation of glass panels influences the serviceability and safety of these panels. In this study, the degradation of glass panels subject to windblown sand with different impact velocities and impact angles was studied based on a sandblasting test simulating a sandstorm. After the glass panels were degraded by windblown sand, the surface morphology of the damaged glass panels was observed using scanning electron microscopy, and three damage modes were found: a cutting mode, smash mode, and plastic deformation mode. The mass loss, visible light transmittance, and effective area ratio values of the glass samples were then measured to evaluate the effects of the windblown sand on the panels. The results indicate that, at high abrasive feed rates, the relative mass loss of the glass samples decreases initially and then remains steady with increases in impact time, whereas it increases first and then decreases with an increase in impact angle such as that for ductile materials. Both visible light transmittance and effective area ratio decrease with increases in the impact time and velocities. There exists a positive linear relationship between the visible light transmittance and effective area ratio.

Design of a Robust Memristive Spiking Neuromorphic System with Unsupervised Learning in Hardware

2021 ◽  
Vol 17 (4) ◽  
pp. 1-26
Author(s):  
Md Musabbir Adnan ◽  
Sagarvarma Sayyaparaju ◽  
Samuel D. Brown ◽  
Mst Shamim Ara Shawkat ◽  
Catherine D. Schuman ◽  
...  
Keyword(s):  
Unsupervised Learning ◽  
Recognition Task ◽  
Single Layer ◽  
Process Variations ◽  
Spike Timing ◽  
System Level ◽  
Design Parameters ◽  
Digital Pulse ◽  
Neuromorphic System ◽  
The Impact

Spiking neural networks (SNN) offer a power efficient, biologically plausible learning paradigm by encoding information into spikes. The discovery of the memristor has accelerated the progress of spiking neuromorphic systems, as the intrinsic plasticity of the device makes it an ideal candidate to mimic a biological synapse. Despite providing a nanoscale form factor, non-volatility, and low-power operation, memristors suffer from device-level non-idealities, which impact system-level performance. To address these issues, this article presents a memristive crossbar-based neuromorphic system using unsupervised learning with twin-memristor synapses, fully digital pulse width modulated spike-timing-dependent plasticity, and homeostasis neurons. The implemented single-layer SNN was applied to a pattern-recognition task of classifying handwritten-digits. The performance of the system was analyzed by varying design parameters such as number of training epochs, neurons, and capacitors. Furthermore, the impact of memristor device non-idealities, such as device-switching mismatch, aging, failure, and process variations, were investigated and the resilience of the proposed system was demonstrated.

scholarly journals Analysis of actinic flux profiles measured from an ozonesonde balloon

2015 ◽  
Vol 15 (8) ◽  
pp. 4131-4144 ◽  
Author(s):  
P. Wang ◽  
M. Allaart ◽  
W. H. Knap ◽  
P. Stammes
Keyword(s):  
Atmospheric Chemistry ◽  
Low Cost ◽  
Green Light ◽  
Single Layer ◽  
Radiative Transfer Model ◽  
Cloud Base ◽  
Transfer Model ◽  
Actinic Flux ◽  
Clear Sky ◽  
The Impact

Abstract. A green light sensor has been developed at KNMI to measure actinic flux profiles using an ozonesonde balloon. In total, 63 launches with ascending and descending profiles were performed between 2006 and 2010. The measured uncalibrated actinic flux profiles are analysed using the Doubling–Adding KNMI (DAK) radiative transfer model. Values of the cloud optical thickness (COT) along the flight track were taken from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) Cloud Physical Properties (CPP) product. The impact of clouds on the actinic flux profile is evaluated on the basis of the cloud modification factor (CMF) at the cloud top and cloud base, which is the ratio between the actinic fluxes for cloudy and clear-sky scenes. The impact of clouds on the actinic flux is clearly detected: the largest enhancement occurs at the cloud top due to multiple scattering. The actinic flux decreases almost linearly from cloud top to cloud base. Above the cloud top the actinic flux also increases compared to clear-sky scenes. We find that clouds can increase the actinic flux to 2.3 times the clear-sky value at cloud top and decrease it to about 0.05 at cloud base. The relationship between CMF and COT agrees well with DAK simulations, except for a few outliers. Good agreement is found between the DAK-simulated actinic flux profiles and the observations for single-layer clouds in fully overcast scenes. The instrument is suitable for operational balloon measurements because of its simplicity and low cost. It is worth further developing the instrument and launching it together with atmospheric chemistry composition sensors.

Effect of Adhesive Thickness on the Impact Toughness of Butt-Joints

2011 ◽  
Vol 230-232 ◽  
pp. 1350-1354 ◽  
Author(s):  
Min You ◽  
Jing Rong Hu ◽  
Xiao Ling Zheng ◽  
Ai Ping He ◽  
Cun Jun Chen
Keyword(s):  
Impact Toughness ◽  
Adhesive Layer ◽  
Curing Temperature ◽  
Curing Time ◽  
Optimum Thickness ◽  
Adhesively Bonded ◽  
Butt Joints ◽  
Notched Specimen ◽  
Adhesive Thickness ◽  
The Impact

The effect of the adhesive thickness on the impact toughness of the adhesively bonded steel joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness increases when the adhesive thickness increased then it decrease as the adhesive thickness increase. When the curing time is set as a constant, the higher the curing temperature is, the lower the impact toughness of the joint. The optimum thickness of the adhesive layer for the specimen of impact toughness test cured at 60 C for 1 h is 0.6 mm and it is 0.4 mm to 0.6 mm for the specimen cured 1 h at temperature of 90 C or higher than it. It is recommended using the notched specimen to decrease the testing deviation.

scholarly journals Experimental and Numerical Peeling Investigation on Aged Multi-Layer Anti-Shatter Safety Films (ASFs) for Structural Glass Retrofit

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 162
Author(s):  
Silvana Mattei ◽  
Luca Cozzarini ◽  
Chiara Bedon
Keyword(s):  
Young Modulus ◽  
Adhesive Layer ◽  
Experimental Program ◽  
Fe Model ◽  
Structural Glass ◽  
Adhesive Properties ◽  
Test Protocol ◽  
Adhesion Properties ◽  
The Impact ◽  
Pet Films

Anti-shatter safety films (ASFs) are often used for structural glass applications. The goal is to improve the response of monolithic elements and prevent fragments from shattering. Thus, the main reason behind their use is the possibility to upgrade safety levels against the brittle failure of glass and minimize the number of possible injuries. However, the impact response of glass elements bonded with Polyethylene terephthalate (PET)-films and pressure sensitive adhesives (PSAs) still represents a research topic of open discussion. Major challenges derive from material characterization and asymmetrical variability under design loads and ageing. In particular, the measurement of interface mechanical characteristics for the adhesive layer in contact with glass is a primary parameter for the ASF choice optimization. For this reason, the present paper presents an experimental campaign aimed at calibrating some basic mechanical parameters that provide the characterization of constitutive models, such as tensile properties (yielding stress and Young modulus) for PET-film and adhesive properties for PSA (energy fracture and peel force). In doing so, both tensile tests for PET-films and peeling specimens are taken into account for a commercially available ASF, given that the peeling test protocol is one of most common methods for the definition of adhesion properties. Moreover, an extensive calibration of the Finite Element (FE) model is performed in order to conduct a parametric numerical analysis of ASF bonded glass solutions. Furthermore, a Kinloch approach typically used to determine the fracture energy of a given tape by considering a variable peel angle, is also adopted to compare the outcomes of calibration analyses and FE investigations on the tested specimens. Finally, a study of the effect of multiple aspects is also presented. The results of the experimental program and the following considerations confirm the rate dependence and ageing dependence in peel tests.

scholarly journals Numerical Evaluation of Slender Glass Panel with Complex Geometry Subjected to Static Load and Soft-body Impact

2021 ◽  
Author(s):  
Marcin Kozłowski
Keyword(s):  
Static Load ◽  
Complex Geometry ◽  
Design Practice ◽  
Glass Panel ◽  
Soft Body ◽  
In Situ Experiments ◽  
Glass Panels ◽  
Current Standards

Current standards and glass codes of design practice require that glazing used in architectural applications has to be resistant to, in addition to typical loads, also accidental events, in particular human impact, without showing damage that is disproportionate to the original cause. A case study was performed of an indoor glass lantern in a public building made from slender two-side supported glass panels with a complex geometry (36 ventilation holes). The paper provides structural assessments and results of in-situ experiments including static loading and soft body impact. Results from numerical simulations of impact loading on the glass panels complementing the experimental results are also presented.

scholarly journals Forensic Engineering Analysis of Dynamic Forces Created by Pedestrians Impacting Plate Glass at Different Speeds

2015 ◽  
Vol 32 (1) ◽  
Author(s):  
Michael Kravitz
Keyword(s):  
Impact Load ◽  
Building Code ◽  
Engineering Analysis ◽  
Glass Panel ◽  
Impact Speed ◽  
Dynamic Forces ◽  
Exit Door ◽  
Forensic Engineering ◽  
Pedestrian Impact ◽  
The Impact

This paper examines the effect of a pedestrian inadvertently impacting a glass panel adjacent to a glass exit door. The glass panel was full length and unmarked, violating the local building code and building commissioner directives. The defense argued that the old building code, to which the college building was constructed, was “grandfathered” and there was no violation. Initial witness and plaintiff statements indicated that the plaintiff was running when he struck the panel, which shattered and caused the plaintiff to incur injuries. The plaintiff testified later, in deposition, that he was walking when he struck the glass. The court needed to establish liability percentage, which is common in civil cases, and it was necessary to determine at what pedestrian impact speed the glass panel would break. The analysis used Timoshenko’s theory of vibration plates, Roark’s stress strain formulas, ergonomics, and human factors to estimate the impact load and stresses on the glass panel that caused failure.

Toward a Novel SMA-reinforced Laminated Glass Panel

2016 ◽  
pp. 87-120
Author(s):  
Chiara Bedon ◽  
Filipe Amarante dos Santos
Keyword(s):  
Laminated Glass ◽  
Glass Panel
Sign in / Sign up

Export Citation Format

Share Document