scholarly journals Significance of Adhesion Theories in Area of Flexible Bonded Structural Joints in Construction Sector

2021 ◽  
Vol 1203 (2) ◽  
pp. 022081
Author(s):  
Barbora Nečasová
Keyword(s):  
High Surface ◽  
High Strength ◽  
Bonded Joints ◽  
Test Results ◽  
Surface Polarity ◽  
Adhesive Properties ◽  
Basic Principles ◽  
Structural Bonding ◽  
The One ◽  
The Impact

Abstract The issue of bonding has been a part of humanity throughout its history. The greatest development in this area occurred in the second half of the 20th century and the issue of bonding has gained a lot of interest from the scientific community. Over the past 80 years, there has been a significant increase in scientific research and grants aimed at defining adhesion. We now know that examining the adhesion of materials, determining the adhesive properties or simply evaluating the test results and assessing the failure of the test specimens is not possible without understanding the basic principles and theories of bonding, i.e. adhesive joining. The presented paper is focused on the description of fundamental adhesion theories and their usage in the field of structural bonding in construction industry. The importance of understanding to adhesive properties of used products is demonstrated on an example of four different surfaces in combination with representatives of high strength flexible adhesive systems intended for façade applications. Representatives with high surface polarity, medium-high polarity and low polarity were deliberately selected. The one-way ANOVA was performed to analyse the impact of surface adhesive properties on adhesion of bonded joints. It was confirmed that the riskiest is bonding of polymer-based materials. For all selected materials it was concluded that the hypotheses of the adsorption theory, which, to some extent, also includes the assumptions of other adhesive theories, seem to be the most fundamental for the presented researched area.

Physical Simulation for Evaluating Heat-Affected Zone Toughness of High and Ultra-High Strength Steels

2013 ◽  
Vol 762 ◽  
pp. 711-716 ◽  
Author(s):  
Risto O. Laitinen ◽  
David A. Porter ◽  
L. Pentti Karjalainen ◽  
Pasi Leiviskä ◽  
Jukka Kömi
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Physical Simulation ◽  
Energy Requirement ◽  
High Strength Steels ◽  
High Strength ◽  
Coarse Grained ◽  
Test Results ◽  
Ultra High Strength Steels ◽  
The Impact

Physical simulation of the most critical sub-zones of the heat-affected zone is a useful tool for the evaluation of the toughness of welded joints in high-strength and ultra-high-strength steels. In two high-strength offshore steels with the yield strength of 500 MPa, the coarse grained, intercritical and intercritically reheated coarse grained zones were simulated using the cooling times from 800 to 500 °C (t8/5) 5 s and 30 s. Impact and CTOD tests as well as microstructural investigations were carried out in order to evaluate the weldability of the steels without the need for expensive welding tests. The test results showed that the intercritically reheated coarse grained zone with the longer cooling time t8/5=30 s was the most critical sub-zone in the HAZ due to the M-A constituents and coarse ferritic-bainitic microstructure. In 6 mm thick ultra-high-strength steel Optim 960 QC, the coarse grained and intercritically reheated coarse grained zones were simulated using the cooling times t8/5 of 5, 10, 15 and 20s and the intercritical zone using the cooling times t8/5 of 5 and 10 s in order to select the suitable heat input for welding. The impact test results from the simulated zones fulfilled the impact energy requirement of 14 J (5x10 mm specimen) at -40 °C for the cooling times, t8/5, from 5 to 15 s, which correspond to the heat input range 0.4-0.7 kJ/mm (for a 6 mm thickness).

Test of Adhesion and Shear Strength of Polyurethane Adhesives to Cement-Bonded Particleboard

2015 ◽  
Vol 1100 ◽  
pp. 185-188
Author(s):  
Barbora Nečasová ◽  
Pavel Liška ◽  
Jiří Šlanhof
Keyword(s):  
Shear Strength ◽  
Experimental Measurements ◽  
Bonded Joints ◽  
Test Results ◽  
Mechanical Joints ◽  
Structural Bonding ◽  
Bonded Composite ◽  
Polyurethane Adhesives ◽  
Cladding Material

This research case was carried out to examine the possibility of usage of cement-bonded composite particleboards as a sheathing of a vented façade system with bonded joints. The potential of bonded joints in combination with composite cladding material was studied and described in more detail as well as verified through experimental measurements. For the purpose of tests spruce timber profiles were chosen for the load bearing substructure. Three types of industrial adhesives intended for structural bonding were selected. The article is focused on the preparation as well as on the subsequent experimental verification of the substructure bonding retention to the cladding and the determination of shear strength under tensile stress at a temperature of (20.0 ± 3) oC and a relative humidity of (55.0 ± 10) %. The test results proved the fact that bonded joints are more than suitable equivalent to the mechanical joints. Furthermore, the series of tests verified the suitability of use of the chosen adhesives in combination with cement-bonded particleboard.

scholarly journals Development of a Flexible Lightweight Hydraulic-Pneumatic Flywheel System for Wind Turbine Rotors

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 162
Author(s):  
Laurence Alhrshy ◽  
Clemens Jauch ◽  
Peter Kloft
Keyword(s):  
Wind Turbine ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Test Results ◽  
Mechanical Loads ◽  
Conventional Steel ◽  
Simulation Results ◽  
The One ◽  
The Impact ◽  
Wind Turbine Rotor

In this paper, the design of a flexible piston accumulator for application in a hydraulic-pneumatic flywheel system in a wind turbine rotor is presented. The flywheel system enables a wind turbine to vary the inertia of its rotor blades to control the power output and, most importantly, to influence the vibratory behaviour of wind turbine components. The method used for designing the flexible accumulator is based on the one hand on test results of a flexible piston accumulator prototype, and on the other hand, on simulation results of a model of a flexible piston accumulator. As a result, a design of flexible piston accumulators for application in the flywheel system is implemented and compared with the design of conventional steel accumulators. Due to the proposed design of the flywheel system, the impact on the mechanical loads of a wind turbine is analysed. The simulation results show that the new design of the piston accumulators causes a lower impact on the mechanical loads of the wind turbine than a previously published design of piston accumulators. It is further shown that the considered wind turbine can take on the flywheel system without the need for reinforcements in the rotor blades.

Wooden Facade with Bonded Joints - Experimental Test

2015 ◽  
Vol 1122 ◽  
pp. 23-27 ◽  
Author(s):  
Barbora Nečasová ◽  
Pavel Liška ◽  
Jiří Šlanhof
Keyword(s):  
Relative Humidity ◽  
Siberian Larch ◽  
Experimental Measurements ◽  
Bonded Joints ◽  
Test Results ◽  
Adhesive Systems ◽  
Adhesive Bonds ◽  
Mechanical Joints ◽  
Structural Bonding ◽  
Cladding Material

A research case focused on vented wooden façade system with bonded joints is presented in this paper. The potential of bonded joints is studied and described in more detail and verified through experimental measurements. For the purpose of tests spruce timber profiles were chosen for the load bearing substructure and Siberian larch façade sheeting for the cladding. Three types of industrial adhesives intended for structural bonding were selected. The article is focused on the preparation as well as on the subsequent experimental verification of substructure bonding retention to the cladding. The adhesive bonds were tested both in tension as well as in shear at a temperature of (293.15 ± 3) K and a relative humidity of (55 ± 10) %. The test results proved the fact that bonded joints are more than suitable equivalent to the mechanical joints. During the tests appeared some differences in stability and failure behaviour between the adhesive systems as well as within the sheeting material. Additionally, the suitability of selected group of adhesives in combination with Siberian larch cladding material as well as with the timber substructure was confirmed.

scholarly journals The Global Experience of Deployment of Energy-Efficient Technologies in High-Rise Construction

2018 ◽  
Vol 33 ◽  
pp. 01017 ◽  
Author(s):  
Natalia D. Potienko ◽  
Anna A. Kuznetsova ◽  
Darya N. Solyakova ◽  
Yulia E. Klyueva
Keyword(s):  
Energy Efficient ◽  
Building Design ◽  
Basic Principles ◽  
High Rise ◽  
Analytical Review ◽  
Compositional Interpretation ◽  
The One ◽  
Structural Levels ◽  
The Impact

The objective of this research is to examine issues related to the increasing importance of energy-efficient technologies in high-rise construction. The aim of the paper is to investigate modern approaches to building design that involve implementation of various energy-saving technologies in diverse climates and at different structural levels, including the levels of urban development, functionality, planning, construction and engineering. The research methodology is based on the comprehensive analysis of the advanced global expertise in the design and construction of energy-efficient high-rise buildings, with the examination of their positive and negative features. The research also defines the basic principles of energy-efficient architecture. Besides, it draws parallels between the climate characteristics of countries that lead in the field of energy-efficient high-rise construction, on the one hand, and the climate in Russia, on the other, which makes it possible to use the vast experience of many countries, wholly or partially. The paper also gives an analytical review of the results arrived at by implementing energy efficiency principles into high-rise architecture. The study findings determine the impact of energy-efficient technologies on high-rise architecture and planning solutions. In conclusion, the research states that, apart from aesthetic and compositional interpretation of architectural forms, an architect nowadays has to address the task of finding a synthesis between technological and architectural solutions, which requires knowledge of advanced technologies. The study findings reveal that the implementation of modern energy-efficient technologies into high-rise construction is of immediate interest and is sure to bring long-term benefits.

scholarly journals Impact Performance of Steel Fiber-Reinforced Self-Compacting Concrete against Repeated Drop Weight Impact

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 91
Author(s):  
Sallal R. Abid ◽  
Murali Gunasekaran ◽  
Sajjad H. Ali ◽  
Ahmed L. Kadhum ◽  
Thaar S. Al-Gasham ◽  
...  
Keyword(s):  
Steel Fiber ◽  
Impact Resistance ◽  
High Strength ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Self Compacting Concrete ◽  
Impact Performance ◽  
Free Falling ◽  
The Impact

The self-compacting concrete (SCC) was invented to overcome the compaction problems in deep sections, owing to its perfect workability characteristics. Steel fibers when used with SCC would affect the required fluidity characteristics but improve its impact resistance. In this research, an experimental work was conducted to evaluate the impact response of micro-steel fiber-reinforced SCC, under flexural impact. A 5.47 kg free-falling mass was dropped repeatedly from 100 mm height on the top center of 270 mm-length beam specimens. Eight mixtures with two design grades of 30 and 50 MPa were prepared to distinguish the normal and high-strength SCCs. The distinguishing variable for each design grade was the fiber content, where four volumetric contents of 0%, 0.5%, 0.75%, and 1.0% were used. The test results showed that the impact resistance and ductility were significantly improved due to the incorporation of micro-steel fibers. The percentage improvements were noticeably higher at failure stage than at cracking stage. For the 30 MPa mixtures, the maximum percentage improvements at cracking and failure stages were 543% and 836%, respectively. Weibull’s linear correlations with R2 values of 0.84 to 0.97 were obtained at the failure stage, which meant that the impact failure number followed the Wiebull distribution.

Evaluation of Mechanical Properties of Jute and Kevlar Fiber Reinforced Materials

2018 ◽  
pp. 169-175 ◽  
Author(s):  
B. Rajesh ◽  
M. L. S. Devakumar
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Impact Strength ◽  
Testing Machine ◽  
High Strength ◽  
Impact Testing ◽  
Test Results ◽  
Kevlar Fiber ◽  
The Impact

The purpose of this paper is to investigate the mechanical properties of kevlar fiber and jute fiber reinforcement. Nowadays the composite materials are widely used materials. Having wide range of applications due to its light weight, high strength and low cost. These composite materials are now being explored in applications of aerospace and automotive industries. In the present work, the composite material is prepared with intermediate aramid fabric layer (Kevlar) which is high strength fiber and it is combined with jute fabric reinforced epoxy composite to increase the strength of kevlar. This composite material is tested for mechanical properties like flexural, tensile & impact strength are calculated with UTM (universal testing machine) for flexural, tensile tests and impact testing is done with impact testing machine. Through this test results the impact strength of the composite material is calculated. The energy dissipation by impact test of jute and kevlar fabric composite and strength of fibers will be analyzed by scanning electron microscopy (FESEM). Thermo gravity analysis (TGA) and differential thermal analysis (DTA) is carried out. Through these test results it can conclude that the jute can be combined with the kevlar where the impact is primary considerations like bulletproof vests, automobile bodies, tyres etc. The usage of jute in all kevlar applications will increase the strength of kevlar by reducing the usage of Kevlar and cost will be minimized.

Influence of Freeze-Thaw Cycles on Bonded Interface Performance between CFRP and High Strength Concrete

2014 ◽  
Vol 638-640 ◽  
pp. 1516-1520 ◽  
Author(s):  
Lei Hong ◽  
Run Min Duo ◽  
Su Yan Wang ◽  
Lu Xi Li
Keyword(s):  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Bonded Joints ◽  
Test Results ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Reinforced Polymer

The bonded joints between carbon fiber reinforced polymer (CFRP) and high strength concrete subjected to different freeze-thaw cycles were studied and the results were analyzed. The test results indicate that with the increase of freeze-thaw cycles, effective bond length, ultimate bond load and ultimate global slip response will decrease. But it has little effects on initial stripping load. The failure modes change from adhesive debonding to shear failure of concrete.

scholarly journals Experimental Characterization of the Initial Shear Strength of Composite Masonry including AAC Blocks and DPC Layers

2021 ◽  
Vol 13 (22) ◽  
pp. 12749
Author(s):  
Martijn Vanheukelom ◽  
Rajarshi Das ◽  
Hervé Degée ◽  
Bram Vandoren
Keyword(s):  
Shear Strength ◽  
Concrete Block ◽  
Friction Angle ◽  
Test Results ◽  
Mortar Joint ◽  
A Value ◽  
Aerated Concrete ◽  
The One ◽  
The Impact

Modern masonry structures, apart from having a load-bearing function, are more and more subjected to additional non-structural requirements related to, e.g., thermal insulation and moisture control. This has respectively led to the introduction of thermal break layers, in practice often executed using autoclaved aerated concrete (AAC) blocks, and damp proof courses (DPC) in masonry walls. These modifications have an impact on the mechanical characteristics of the masonry, such as the shear strength. In this paper, an extensive experimental campaign is therefore conducted on masonry triplets to investigate the initial shear strength of concrete block and clay brick masonry, including AAC blocks. The impact of the the presence of a polyethylene DPC layer is also studied. Moreover, the position of the DPC membrane is varied, i.e., directly on top of the brick (which is generally not recommended yet common in construction practice) and in the middle of the mortar joint. In total, 138 shear tests were performed according to the EN 1052-3 standard, with low to moderate precompression levels. The test results focus on the differences in friction angle, shear modulus, and friction coefficient. It is concluded that the presence of an AAC block decreases the initial shear strength to a value which is lower than the one assumed by Eurocode 6. Moreover, when adding a DPC membrane, the shear strength is reduced even further to almost zero, in particular when the membrane is not put in the middle of the mortar joint.

scholarly journals Effectiveness of Death Penalty Against Crime of Abuse of Narcotics Agents or Statutory RI Number 35 of 2009 Concerning Narcotics Law as Viewed From The Principles of Justice And Humanity

2018 ◽  
Vol 1 (3) ◽  
pp. 651
Author(s):  
Yuke Sinayangsih ◽  
Umar Ma'ruf
Keyword(s):  
Law Enforcement ◽  
Death Penalty ◽  
Deterrent Effect ◽  
Public Prosecutor ◽  
Basic Principles ◽  
The Public ◽  
Court Proceedings ◽  
Principles Of Justice ◽  
The One ◽  
The Impact

In the process of law enforcement, the public prosecutor in demanding and Judge deciding cases narcotic crime in particular is not arbitrary impose the death penalty. Death penalty if that is the legal facts in the examination in the court proceedings indicates decent offender sentenced to death, for example: consideration of the type categorized as narcotics or weight considerations of narcotics to be sold or distributed. Narcotics law enforcement has become a concern for legislators us and see the impact of drug abuse. No doubt the legislators also provides severe criminal purpose that is the death penalty in order to provide a deterrent effect for the offender dealers or drug dealers. Although the death penalty is still ongoing and has not been abolished in Indonesia, people differ in responding as the number of countries that abolished the death penalty. On the one hand, there are groups of people expressed support that the death penalty is still needed in Indonesia moreover legally still recognized. Meanwhile, on the other hand there are groups of people who want the death penalty abolished. They argue that the provisions which apply the death penalty in Indonesia is not in accordance with the basic principles of the fundamentals of this country, namely 1945.Keywords: Criminal Die; Abuse Of Narcotics; Principle Of Justice And Humanityity

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