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 Truck-Platooning Impacts on Flexible Pavements: Experimental and Mechanistic Approaches

2021 ◽  
Author(s):  
Aravind Ramakrishnan ◽  
◽  
Ashraf Alrajhi ◽  
Egemen Okte ◽  
Hasan Ozer ◽  
...  
Keyword(s):  
Permanent Deformation ◽  
Rest Period ◽  
Gaussian Mixture ◽  
Experimental Program ◽  
Fe Model ◽  
Equivalent Number ◽  
Number Of Cycles ◽  
Pavement Damage ◽  
Shift Model ◽  
The Impact

Truck platoons are expected to improve safety and reduce fuel consumption. However, their use is projected to accelerate pavement damage due to channelized-load application (lack of wander) and potentially reduced duration between truck-loading applications (reduced rest period). The effect of wander on pavement damage is well documented, while relatively few studies are available on the effect of rest period on pavement permanent deformation. Therefore, the main objective of this study was to quantify the impact of rest period theoretically, using a numerical method, and experimentally, using laboratory testing. A 3-D finite-element (FE) pavement model was developed and run to quantify the effect of rest period. Strain recovery and accumulation were predicted by fitting Gaussian mixture models to the strain values computed from the FE model. The effect of rest period was found to be insignificant for truck spacing greater than 10 ft. An experimental program was conducted, and several asphalt concrete (AC) mixes were considered at various stress levels, temperatures, and rest periods. Test results showed that AC deformation increased with rest period, irrespective of AC-mix type, stress level, and/or temperature. This observation was attributed to a well-documented hardening–relaxation mechanism, which occurs during AC plastic deformation. Hence, experimental and FE-model results are conflicting due to modeling AC as a viscoelastic and the difference in the loading mechanism. A shift model was developed by extending the time–temperature superposition concept to incorporate rest period, using the experimental data. The shift factors were used to compute the equivalent number of cycles for various platoon scenarios (truck spacings or rest period). The shift model was implemented in AASHTOware pavement mechanic–empirical design (PMED) guidelines for the calculation of rutting using equivalent number of cycles.

scholarly journals Effects of Various Antifouling Coatings and Fouling on Marine Sonar Performance

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 663 ◽  
Author(s):  
Bradley Donnelly ◽  
Ian Bedwell ◽  
Jim Dimas ◽  
Andrew Scardino ◽  
Youhong Tang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Transmission Loss ◽  
Fuel Efficiency ◽  
Peel Test ◽  
Acoustic Properties ◽  
Frictional Drag ◽  
Adhesive Properties ◽  
Adhesion Properties ◽  
Antifouling Coatings ◽  
The Impact

There is a rising imperative to increase the operational availability of maritime vessels by extending the time between full docking cycles. To achieve operational efficacy, maritime vessels must remain clear of biological growth. Such growth can cause significant increases in frictional drag, thereby reducing speed, range and fuel efficiency and decreasing the sensitivity of acoustic sensors. The impact that various stages of fouling have on acoustic equipment is unclear. It is also unclear to what extent antifouling techniques interfere with the transmission of acoustic signals. In this study, to examine this effect, neoprene samples were coated with three antifouling coatings, namely, Intersmooth 7460HS, HempaGuard X7 and Hempasil X3. Other neoprene samples were left uncoated but were imbedded with the biocide, 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) during the mixing and curing process. Uncoated nitrile samples that had varying levels of fouling from immersion in Port Phillip Bay, Australia, for 92, 156 and 239 days were also extracted. The acoustic properties of these samples were measured using an acoustic insertion loss test and compared to uncoated neoprene or nitrile to ascertain the acoustic effects of the applications of antifouling coatings as well as the fouling growth itself. A T-peel test was performed on all coated samples in an attempt to understand the adhesive properties of the coatings when applied to neoprene. It was found that the application of antifouling coatings had little effect on the transmission characteristics of the neoprene with approximately 1 dB loss. The embedment of DCOIT, however, has a chance of causing aeration in the neoprene, which can heavily hamper transmission. An assessment of the effect of the fouling growth found that light and medium fouling levels produced little transmission loss, whereas more extreme fouling lead to a 9 dB transmission loss. The adhesion properties of the coatings were investigated but not fully ascertained as tensile yielding occurred before peeling. However, various failure modes are presented and discussed in this study.

scholarly journals Multi-layered bird beaks: a finite-element approach towards the role of keratin in stress dissipation

2012 ◽  
Vol 9 (73) ◽  
pp. 1787-1796 ◽  
Author(s):  
Joris Soons ◽  
Anthony Herrel ◽  
Annelies Genbrugge ◽  
Dominique Adriaens ◽  
Peter Aerts ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Speckle Pattern ◽  
Young Modulus ◽  
Von Mises Stress ◽  
Fe Model ◽  
Element Approach ◽  
Von Mises ◽  
The Impact

Bird beaks are layered structures, which contain a bony core and an outer keratin layer. The elastic moduli of this bone and keratin were obtained in a previous study. However, the mechanical role and interaction of both materials in stress dissipation during seed crushing remain unknown. In this paper, a multi-layered finite-element (FE) model of the Java finch's upper beak ( Padda oryzivora ) is established. Validation measurements are conducted using in vivo bite forces and by comparing the displacements with those obtained by digital speckle pattern interferometry. Next, the Young modulus of bone and keratin in this FE model was optimized in order to obtain the smallest peak von Mises stress in the upper beak. To do so, we created a surrogate model, which also allows us to study the impact of changing material properties of both tissues on the peak stresses. The theoretically best values for both moduli in the Java finch are retrieved and correspond well with previous experimentally obtained values, suggesting that material properties are tuned to the mechanical demands imposed during seed crushing.

Investigation of Honeycomb Sandwich Composite Structure with Pre-Damage under Uniaxial Compression

2013 ◽  
Vol 658 ◽  
pp. 242-246
Author(s):  
Hui Min Yan ◽  
Bin Liu ◽  
Fei Xu ◽  
Ya Ge Liu
Keyword(s):  
Sandwich Structure ◽  
Failure Modes ◽  
Impact Damage ◽  
Adhesive Layer ◽  
Sandwich Composite ◽  
Adhesive Properties ◽  
Damage Level ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite ◽  
The Impact

In this paper, the failure modes of the honeycomb sandwich structure under uniaxial compressions after impact (CAI) are analyzed through experiments and Finite Element Method (FEM). Three cases of impact damage location, two cases of impact damage depth and adhesive properties are investigated by the comparisons of corresponding non-destructive structure. Several conclusions are drawn: the failure modes and the initial damage positions obtained from experiments and FEM simulations are almost the same; the location of impact damage may affect the overall loading capabilities of the sandwich structure, whose decreasing rate peaks when the damage is at the top surface and drops when the damage is at the marginal area; different adhesive layer property of interface may lead to the failure mode change, that is, instead of honeycomb core failure, interlaminar failure will occur when the fracture energy of the adhesive layer is low; the damage level and risky location of the structure will vary relevant to the impact energy.

Evaluation of Adhesive T-Joint Using Finite Element Analysis

2015 ◽  
Vol 786 ◽  
pp. 37-42 ◽  
Author(s):  
B. Izzawati ◽  
Mohd Afendi ◽  
S. Nurhashima ◽  
A. Nor ◽  
Abdul Rahman Abdullah ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Adhesive Layer ◽  
Effect Of Temperature ◽  
Fe Model ◽  
Stress Distributions ◽  
Adhesive Properties ◽  
Element Analysis ◽  
Parametric Studies ◽  
And Behavior

This study evaluates the effect of temperature upon adhesive properties and behavior of adhesively bonded T-joint. Finite element analyses established the effect of this parameter on the durability joint and stress distribution within the adhesive layer. A series of temperatures and stress analyses using finite element analysis (FEA) has been conducted in the T-joint configuration for this purpose. The parametric studies on the FE model revealed that stress distributions are sensitive to the changes in adhesive properties due to changes in temperature. In general, stresses were reduced with changes in the temperature which resulted in the ability of the adhesive layer to undergo plastic deformation.

scholarly journals Calibrated Numerical Approach for the Dynamic Analysis of Glass Curtain Walls under Spheroconical Bag Impact

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 154
Author(s):  
Alessia Bez ◽  
Chiara Bedon ◽  
Giampiero Manara ◽  
Claudio Amadio ◽  
Guido Lori
Keyword(s):  
Finite Element ◽  
Time History ◽  
Numerical Approach ◽  
Experimental Investigations ◽  
Fe Model ◽  
Computationally Efficient ◽  
Test Protocol ◽  
Time Histories ◽  
Design Calculations ◽  
The Impact

The structural design of glass curtain walls and facades is a challenging issue, considering that building envelopes can be subjected extreme design loads. Among others, the soft body impact (SBI) test protocol represents a key design step to protect the occupants. While in Europe the standardized protocol based on the pneumatic twin-tire (TT) impactor can be nowadays supported by Finite Element (FE) numerical simulations, cost-time consuming experimental procedures with the spheroconical bag (SB) impactor are still required for facade producers and manufacturers by several technical committees, for the impact assessment of novel systems. At the same time, validated numerical calibrations for SB are still missing in support of designers and manufacturers. In this paper, an enhanced numerical approach is proposed for curtain walls under SB, based on a coupled methodology inclusive of a computationally efficient two Degree of Freedom (2-DOF) and a more geometrically accurate Finite Element (FE) model. As shown, the SB impactor is characterized by stiffness and dissipation properties that hardly match with ideal rigid elastic assumptions, nor with the TT features. Based on a reliable set of experimental investigations and records, the proposed methodology acts on the time history of the imposed load, which is implicitly calibrated to account for the SB impactor features, once the facade features (flexibility and damping parameters) are known. The resulting calibration of the 2-DOF modelling parameters for the derivation of time histories of impact force is achieved with the support of experimental measurements and FE model of the examined facade. The potential and accuracy of the method is emphasized by the collected experimental and numerical comparisons. Successively, the same numerical approach is used to derive a series of iso-damage curves that could support practical design calculations.

Recent data on the causative agent of pale green dwarf (Acholeplasma laidlawii var. granulum incertae sedis) in Ukraine: pathogenicityand virulence factors and host reactions

2015 ◽  
Vol 2 (1) ◽  
pp. 30-34
Author(s):  
K. Korobkova ◽  
V. Patyka
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Proteolytic Enzymes ◽  
Physiological State ◽  
Plant Cells ◽  
Temporary Increase ◽  
Adhesive Properties ◽  
The Impact ◽  
Signaling Interactions ◽  
Pale Green

Contemporary state of the distribution of mycoplasma diseases of cultivated crops in Ukraine was analyzed. The changes of the physiological state of plant cells under the impact of mollicutes were investigated. It was demonstrated that there is temporary increase in the activity of peroxidase, catalase, polyphenoloxidase, phenylalanine-ammonia-lyase at the early stages of interaction. The adhesive properties are changed in the mollicutes under the impact of plant lectin; there is synthesis of new polypeptides. It was determined that the phytopathogenic acholeplasma is capable of producing a complex of proteolytic enzymes into the culture me- dium. It was concluded that when plant cells are infected with acholeplasma, a number of signaling interactions and metabolic transformations condition the recognition of pathogenesis and ensure the aggregate response of a plant to stress in the form of defense reactions. It was assumed that some specifi cities of the biology of phy- topathogenic acholeplasma determine their avoiding the immune mechanisms of plants and promote long-term persistence of mollicutes.

scholarly journals Bond Behaviour of Near-Surface Mounted Strips in RC Beams—Experimental Investigation and Numerical Simulations

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4362
Author(s):  
Renata Kotynia ◽  
Hussien Abdel Baky ◽  
Kenneth W. Neale
Keyword(s):  
Concrete Strength ◽  
Element Model ◽  
Steel Reinforcement ◽  
Reinforcement Ratio ◽  
Experimental Program ◽  
Fe Model ◽  
Bond Behaviour ◽  
Near Surface ◽  
Cfrp Laminates ◽  
Near Surface Mounted

This paper presents an investigation of the bond mechanism between carbon fibre reinforced polymer (CFRP) laminates, concrete and steel in the near-surface mounted (NSM) CFRP-strengthened reinforced concrete (RC) beam-bond tests. The experimental program consisting of thirty modified concrete beams flexurally strengthened with NSM CFRP strips was published in. The effects of five parameters and their interactions on the ultimate load carrying capacities and the associated bond mechanisms of the beams are investigated in this paper with consideration of the following investigated parameters: beam span, beam depth, longitudinal tensile steel reinforcement ratio, the bond length of the CFRP strips and compressive concrete strength. The longitudinal steel reinforcement was cut at the beam mid-span in four beams to investigate a better assessment of the influence of the steel reinforcement ratio on the bond behaviour of CFRP to concrete bond behaviour. The numerical analysis implemented in this paper is based on a nonlinear micromechanical finite element model (FEM) that was used for investigation of the flexural behaviour of NSM CFRP-strengthened members. The 3D model based on advanced CFRP to concrete bond responses was introduced to modelling of tested specimens. The FEM procedure presents the orthotropic behaviour of the CFRP strips and the bond response between the CFRP and concrete. Comparison of the experimental and numerical results revealed an excellent agreement that confirms the suitability of the proposed FE model.

scholarly journals 3D-printing on textiles – an investigation on adhesion properties of the produced composite materials

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Maryna Gorlachova ◽  
Boris Mahltig
Keyword(s):  
3D Printing ◽  
Adhesive Properties ◽  
Adhesion Properties ◽  
Practical Applications ◽  
3D Print ◽  
3D Objects ◽  
Textile Fabrics ◽  
Polylactide Acid ◽  
Polyamide 6.6 ◽  
Textile Sector

AbstractThe actual paper is related to adhesive properties of 3D objects printed on cotton textile fabrics. For practical applications of 3D prints in the textile sector, the adhesion of the printed object on the textile substrate is an important issue. In the current study, two different types of polymers are printed on cotton – polylactide acid (PLA) and polyamide 6.6 (Nylon). Altogether six cotton fabrics differing in structure, weight and thickness are evaluated. Also, the effect of washing and enzymatic desizing is investigated. For printing parameters, best results are gained for elevated process temperatures, intermediate printing speed and low Z-distance between printing head and substrate. Also, a textile treatment by washing and desizing can improve the adhesion of an afterwards applied 3D print. The presented results are quite useful for future developments of 3D printing applications on textile substrates, e.g. to implement new decorative features or protective functions.

scholarly journals The impact of molded pulp product process on the mechanical properties of molded Bleached Chemi-Thermo-Mechanical Pulp

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Claire Dislaire ◽  
Yves Grohens ◽  
Bastien Seantier ◽  
Marion Muzy
Keyword(s):  
Mechanical Properties ◽  
Water Uptake ◽  
Process Parameters ◽  
Manufacturing Process ◽  
Water Immersion ◽  
Young Modulus ◽  
Drying Time ◽  
Mechanical Pulp ◽  
Hygroscopic Properties ◽  
The Impact

AbstractThis study was carried out using bleached softwood Chemi-Thermo-Mechanical Pulp to evaluate the influence of Molded Pulp Products’ manufacturing process parameters on the finished products’ mechanical and hygroscopic properties. A Taguchi table was done to make 8 tests with specific process parameters such as moulds temperature, pulping time, drying time, and pressing time. The results of these tests were used to obtain an optimized manufacturing process with improved mechanical properties and a lower water uptake after sorption analysis and water immersion. The optimized process parameters allowed us to improve the Young’ Modulus after 30h immersion of 58% and a water uptake reduction of 78% with the first 8 tests done.

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