scholarly journals Experimental Research on Load Capacity, Treatment of Adhesively Bonded Surface and Failure Process of Structural T-joint

2016 ◽  
Vol 64 (2) ◽  
pp. 473-479
Author(s):  
Miroslav Müller
Keyword(s):  
Surface Treatment ◽  
Mechanical Treatment ◽  
Load Capacity ◽  
Failure Process ◽  
Adhesive Bond ◽  
T Joints ◽  
Limit Values ◽  
Epoxy Adhesives ◽  
Two Component ◽  
The Impact

In this paper the mechanical behaviour of structural two-component epoxy adhesives in T-joints is experimentally investigated. The aim of this study is to analyse the impact of the adhesive bonded surface treatment on the maximum force required to cause destruction, i.e. bearing capacity of T-joints bonded with various adhesives. Experimental results showed that the type of the adhesive affected the limit values of a force required for the destruction of the adhesive bond. The effect of the bonded surface treatment was also confirmed. From the results of experiment it was proved on five tested two-component epoxy adhesives that the negative effect of the peeling forces can be reduced by mechanical treatment of the adhesive bonded surface e.g. blasting. When there is applied an unsuitable mechanical treatment of adhesive bonded surface, the decrease of the force required for the destruction of the bond was up to about 98%.

scholarly journals Effect of incorrect mix ratio on strength of two component adhesive Butt-Joints tested at elevated temperature

2018 ◽  
Vol 244 ◽  
pp. 01019
Author(s):  
Jakub Szabelski
Keyword(s):  
Elevated Temperature ◽  
Material Properties ◽  
Mixed Type ◽  
Epoxy Adhesive ◽  
Future Research ◽  
Butt Joints ◽  
Adhesive Material ◽  
Epoxy Adhesives ◽  
Two Component ◽  
The Impact

The aim of this study was to determine the impact of the incorrect mix ratio on the strength of joints bonded with a commercial epoxy adhesive compo-sition. The performance of cold-cured as well as accelerated cured butt joints was monitored at elevated temperature conditions. The obtained data was subjected to statistical analysis to show the correlation between joint strength at high temperature and incorrect mix ratio. The degradation of adhesive material properties with increase of hardener ratio in adhesive material was observed, as well as the change in failure type from mixed type to clearly cohesive (for inadequate volume of harde-ner) or adhesive (for excessive amount of hardener). Surprisingly insufficiency of hardener doesn’t affect the strength of joint in such manner. General recommend-dation were drawn for the preparation of two-component epoxy adhesives for joints to be used in elevated temperature, particularly when uncertainty regarding the correct resin/hardener mix ratio and future research was planned.

Investigation on the Load Capacity and Failure Process of T-Joint by Experiments and Numerical Method

2011 ◽  
Vol 328-330 ◽  
pp. 1317-1321
Author(s):  
Ping Hu ◽  
Qi Shao ◽  
Qian Nie ◽  
Wei Dong Li
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Failure Process ◽  
Adhesive Layer ◽  
Zone Model ◽  
T Joints ◽  
Damage And Failure ◽  
Automotive Structures ◽  
In The Beginning

Adhesive bonded T-joint is commonly applied in the manufacture of automotive structures. The objective of this work is the analysis of the load capacity of the adhesive-bonded T-joints under tension load and the influence causing by some parameters of adherend on the damage of T-joint. Thus, a series of tests were carried out and the balanced joint and the imbalanced joint concepts were proposed to illustrate the influence. And the results show that the imbalanced joints suffered greater stress concentration than the balanced one. Furthermore, by increasing the stiffness of adherends , one can increase the load capacity of a balanced joint. Meanwhile, in order to simulate the damage and failure processes in this type of joint, the cohesive zone model (CZM) based analysis was carried out using finite element method in ABAQUS. One can observed that only the upper end of adhesive layer transmits the load in the beginning.

scholarly journals RESEARCH ON MECHANICAL PROPERTIES OF SINGLE-COMPONENT EPOXY DESIGNED FOR BONDING OF STRUCTURAL JOINTS

2015 ◽  
Author(s):  
Miroslav MÜLLER
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Surface Treatment ◽  
Adhesive Bonding ◽  
Adhesive Bond ◽  
Single Component ◽  
Point Of View ◽  
Transportation Industry ◽  
Lap Shear ◽  
The Impact

An adhesive bonding technology is among the basic methods of bonding. However, it is limited by several factors, e.g. a treatment of bonded surface. Structural adhesives are chemicals. It follows that there are significant differences in the mechanical properties among particular types. The aim of the research was to evaluate the mechanical properties of single-component epoxy adhesives used in the transportation industry. The effect of a surface treatment of the steel surface on bond strength was also evaluated. The tested sets were mutually compared using Anova F-test from the point of view of the influence on mechanical properties (the tensile strength of adhesives, the elongation of adhesives, the adhesive bond tensile lap-shear strength, the elongation of the adhesive bond, the impact strength and hardness). The results confirm the assumption about the different behaviour of one-component epoxy. An important part of the experiment was to evaluate the influence of the surface treatment on the bond strength. From the result of experiments it can be concluded that the adhesive SP492 (p = 0.1898) and B5103-3 (p = 0.4263) are resistant to different types of tested treatment of the bonding surface.

scholarly journals Research on Influence of Loading Speed of Structural Two-component Epoxy Adhesives on Adhesive Bond Strength

2016 ◽  
Vol 149 ◽  
pp. 340-345 ◽  
Author(s):  
Miroslav Müller ◽  
Petr Valášek ◽  
Alessandro Ruggiero ◽  
Roberto D’Amato
Keyword(s):  
Bond Strength ◽  
Adhesive Bond ◽  
Epoxy Adhesives ◽  
Two Component ◽  
Adhesive Bond Strength

scholarly journals Effect of Saline Environment on Mechanical Properties of Structural Adhesive Bonds

2016 ◽  
Vol 64 (5) ◽  
pp. 1609-1617 ◽  
Author(s):  
Miroslav Müller
Keyword(s):  
Saline Solution ◽  
Adhesive Bond ◽  
Degradation Process ◽  
Inorganic Filler ◽  
Adhesive Bonds ◽  
Saline Environment ◽  
Epoxy Adhesives ◽  
Two Component ◽  
Adhesive Bond Strength ◽  
Structural Adhesive

This study brings new pieces of knowledge about a utilization of an inorganic filler in an area of steel adhesive bonds exposed to a degradation environment. The filler in the form of glass beads with a fraction size 90 ± 20 μm was used within the research. The aim of the research was to evaluate an influence of the degradation environment on a strength of structural two‑component epoxy adhesives and a composite material. A preparation of adhesive bonds and a process of testing of the adhesive bonds were in accordance with the modified standard ČSN EN 1465. The degradation environment in a form of 5 % saline solution was used within this experiment. Adhesive bonded testing samples were subjected to a cyclic loading of the saline solution. The adhesive bonds with the filler reached up to 16 % higher adhesive bond strength than the unfilled adhesive bonds. The bonds adhesive bonded with the tested composite adhesive better resisted to the degradation process of ca. 9 %. The cyclic exposure, i.e. dipping of the testing samples into the saline solution and consequent drying significantly decreases the strength of the adhesive bond (up to 67 % in 6 weeks).

scholarly journals Oxidative Stress Biomarkers in Urine of Metal Carpentry Workers Can Be Diagnostic for Occupational Exposure to Low Level of Welding Fumes from Associated Metals

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3167
Author(s):  
Flavia Buonaurio ◽  
Maria Luisa Astolfi ◽  
Daniela Pigini ◽  
Giovanna Tranfo ◽  
Silvia Canepari ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Occupational Exposure ◽  
Oxidation Products ◽  
Control Group ◽  
Welding Fumes ◽  
Oxidative Stress Biomarkers ◽  
Limit Values ◽  
Stress Biomarkers ◽  
Specificity And Sensitivity ◽  
The Impact

Urinary concentrations of 16 different exposure biomarkers to metals were determined at the beginning and at the end of a working shift on a group of workers in the metal carpentry industry. Five different oxidative stress biomarkers were also measured, such as the oxidation products of RNA and DNA metabolized and excreted in the urine. The results of workers exposed to metals were compared to those of a control group. The metal concentrations found in these workers were well below the occupational exposure limit values and exceeded the mean concentrations of the same metals in the urine of the control group by a factor of four at maximum. Barium (Ba), mercury (Hg), lead (Pb) and strontium (Sr) were correlated with the RNA oxidative stress biomarker, 8-oxo-7, 8-dihydroguanosine (8-oxoGuo), which was found able to discriminate exposed workers from controls with a high level of specificity and sensitivity. The power of this early diagnostic technique was assessed by means of the ROC curve. Ba, rubidium (Rb), Sr, tellurium (Te), and vanadium (V) were correlated with the level of the protein oxidation biomarker 3-Nitrotyrosine (3-NO2Tyr), and Ba, beryllium (Be), copper (Cu), and Rb with 5-methylcytidine (5-MeCyt), an epigenetic marker of RNA damage. These effect biomarkers can help in identifying those workers that can be defined as “occupationally exposed” even at low exposure levels, and they can provide information about the impact that such doses have on their health.

scholarly journals Research of the Technical Seismicity Due to Blasting Works in Quarries and Their Impact on the Environment and Population

2021 ◽  
Vol 11 (5) ◽  
pp. 2118
Author(s):  
Jan Feher ◽  
Jozef Cambal ◽  
Blazej Pandula ◽  
Julian Kondela ◽  
Marian Sofranko ◽  
...  
Keyword(s):  
Particle Velocity ◽  
Normative Values ◽  
Internal Environment ◽  
Negative Effects ◽  
Vibration Acceleration ◽  
Limit Values ◽  
Vibration Intensity ◽  
Timing Interval ◽  
Millisecond Timing ◽  
The Impact

Vibrations caused by blasting works have an impact not only on buildings but also the internal environment of the buildings. If these buildings are situated in the surroundings of quarries, the citizens can perceive these vibrations negatively. By applying an appropriate millisecond timing interval, it is possible to lower the intensity of vibrations to the levels that the citizens will not perceive as negative effects inside the buildings. The limit values for this vibration intensity have not been defined to date. For the protection of the building from the vibrations, normative values of the particle velocity and frequency were determined. Hygienic standards for the inhabitants of the housing were applied, which assessed the impact of the vibration on humans through the measurement of the vibration acceleration in the housing. In this article, the results of the research carried out in Trebejov Quarry are presented. The experimental blasts carried out in Trebejov Quarry proved that the reduction in the vibration intensity under the value 2 mm.s−1 led to the satisfaction of the inhabitants.

scholarly journals Sub-Chronic Effects of Slight PAH- and PCB-Contaminated Mesocosms in Paracentrotus lividus Lmk: A Multi-Endpoint Approach and De Novo Transcriptomic

2021 ◽  
Vol 22 (13) ◽  
pp. 6674
Author(s):  
Luisa Albarano ◽  
Valerio Zupo ◽  
Davide Caramiello ◽  
Maria Toscanesi ◽  
Marco Trifuoggi ◽  
...  
Keyword(s):  
De Novo ◽  
Sea Urchins ◽  
Transcriptome Assembly ◽  
Paracentrotus Lividus ◽  
Marine Biota ◽  
De Novo Transcriptome Assembly ◽  
De Novo Transcriptome ◽  
Limit Values ◽  
The Impact ◽  
Endpoint Approach

Sediment pollution is a major issue in coastal areas, potentially endangering human health and the marine environments. We investigated the short-term sublethal effects of sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) on the sea urchin Paracentrotus lividus for two months. Spiking occurred at concentrations below threshold limit values permitted by the law (TLVPAHs = 900 µg/L, TLVPCBs = 8 µg/L, Legislative Italian Decree 173/2016). A multi-endpoint approach was adopted, considering both adults (mortality, bioaccumulation and gonadal index) and embryos (embryotoxicity, genotoxicity and de novo transcriptome assembly). The slight concentrations of PAHs and PCBs added to the mesocosms were observed to readily compartmentalize in adults, resulting below the detection limits just one week after their addition. Reconstructed sediment and seawater, as negative controls, did not affect sea urchins. PAH- and PCB-spiked mesocosms were observed to impair P. lividus at various endpoints, including bioaccumulation and embryo development (mainly PAHs) and genotoxicity (PAHs and PCBs). In particular, genotoxicity tests revealed that PAHs and PCBs affected the development of P. lividus embryos deriving from exposed adults. Negative effects were also detected by generating a de novo transcriptome assembly and its annotation, as well as by real-time qPCR performed to identify genes differentially expressed in adults exposed to the two contaminants. The effects on sea urchins (both adults and embryos) at background concentrations of PAHs and PCBs below TLV suggest a need for further investigations on the impact of slight concentrations of such contaminants on marine biota.

Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Electric Vehicles ◽  
Thermal Load ◽  
Load Capacity ◽  
Maximum Load ◽  
Induction Machines ◽  
Electric Machines ◽  
Model Parameters ◽  
Dynamic Operating ◽  
The Impact

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.

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