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1 – 10 of over 6000Hakan Keskin, Musa Atar, Süleyman Korkut and Derya Sevim Korkut
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types…
Abstract
Purpose
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types of varnishes. The finding obtained would benefit the manufacturers of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
Design/methodology/approach
For this purpose, test samples were prepared from Scotch pine, Oriental spruce, and Uludağ fir woods that met the requirements of ASTM D 358. The samples were impregnated with Imersol Aqua using short‐, medium‐, and long‐term immersion techniques according to ASTM D 1413 and the manufacturer's instructions. After impregnation, surfaces were coated with synthetic, acrylic, polyurethane, and water‐based varnishes in accordance with ASTM D 3023 standards. After the varnishing process, the adhesion strength of the samples was determined in accordance with ASTM D 4541.
Findings
It was also found that among the wood samples, the adhesion strength was highest in Scotch pine and lowest in Uludağ fir. The synthetic varnish produced the highest adhesion strength, whereas polyurethane and acrylic varnishes had the lowest adhesion strength. The adhesion strength was highest after medium‐term immersion and lowest after long‐term dipping. The highest adhesion strength (4.299 MPa) was produced by a combination of Scotch pine, medium‐duration immersion, and the use of a wood‐based varnish. The lowest adhesion strength (2.090 MPa) resulted from the combination of Uludağ fir, long‐term immersion, and a water‐based varnish.
Research limitations/implications
Impregnating woods using materials with appropriate water repellent, biotic, and abiotic effects before the application of varnishes and paints is important for long‐term protection against photochemical degradation, dimensional changes, biological factors, and fire.
Practical implications
The effect of a varnish on surface adhesion strength can determine the usefulness of the varnish.
Originality/value
Improving surface adhesion of some varnishes via medium‐term impregnation with Imersol Aqua impregnation should be used on Scotch pine, Oriental spruce, and Uludağ fir woods which could be used in the manufacturing of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
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Jiajun Zhou, Mengling Wu, Chun Tian, Zewang Yuan and Chao Chen
The purpose of this study is to investigate the adhesion characteristics of the wheel–rail under water and large sliding conditions. This is carried out by conducting a series of…
Abstract
Purpose
The purpose of this study is to investigate the adhesion characteristics of the wheel–rail under water and large sliding conditions. This is carried out by conducting a series of tests on a full-scale roller rig. The measured data provides an experimental base for conducting further theoretical research.
Design/methodology/approach
The influence of the slip ratio, rolling speed and the axle load on the adhesion coefficient between the wheel and the rail is analyzed under wet conditions using a full-scale roller rig.
Findings
From the research, it is found that the adhesion coefficient–slip ratio curve varies from the traditional theoretical description under water and large sliding conditions. Moreover, it is also observed that after the adhesion coefficient reaches the saturation point, the adhesion coefficient does not decrease, but continues to increase as the slip ratio increases.
Originality/value
The adhesion improvement phenomenon in this paper may provide new ideas for designing anti-skid control and braking system mechanisms for trains.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0236/
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Chun Tian, Gengwei Zhai, Mengling Wu, Jiajun Zhou and Yaojie Li
In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface, this study aims to analyze the…
Abstract
Purpose
In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface, this study aims to analyze the utilization of wheel-rail adhesion coefficient under different medium conditions and propose relevant measures for reasonable and optimized utilization of adhesion to ensure the traction/braking performance and operation safety of trains.
Design/methodology/approach
Based on the PLS-160 wheel-rail adhesion simulation test rig, the study investigates the variation patterns of maximum utilized adhesion characteristics on the rail surface under different conditions of small creepage and large slip. Through statistical analysis of multiple sets of experimental data, the statistical distribution patterns of maximum utilized adhesion on the rail surface are obtained, and a method for analyzing wheel-rail adhesion redundancy based on normal distribution is proposed. The study analyzes the utilization of traction/braking adhesion, as well as adhesion redundancy, for different medium under small creepage and large slip conditions. Based on these findings, relevant measures for the reasonable and optimized utilization of adhesion are derived.
Findings
When the third-body medium exists on the rail surface, the train should adopt the low-level service braking to avoid the braking skidding by extending the braking distance. Compared with the current adhesion control strategy of small creepage, adopting appropriate strategies to control the train’s adhesion coefficient near the second peak point of the adhesion coefficient-slip ratio curve in large slip can effectively improve the traction/braking adhesion redundancy and the upper limit of adhesion utilization, thereby ensuring the traction/braking performance and operation safety of the train.
Originality/value
Most existing studies focus on the wheel-rail adhesion coefficient values and variation patterns under different medium conditions, without considering whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train. Therefore, there is a risk of traction overspeeding/braking skidding. This study analyzes whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train and whether there is redundancy. Based on these findings, relevant measures for the reasonable and optimized utilization of adhesion are derived to further ensure operation safety of the train.
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Jiajun Zhou, Chao Chen, Chun Tian, Gengwei Zhai and Hao Yu
To authenticate the existence and principles of the adhesion recovery phenomenon under water pollution conditions, an innovative circumferential rail–wheel adhesion test rig was…
Abstract
Purpose
To authenticate the existence and principles of the adhesion recovery phenomenon under water pollution conditions, an innovative circumferential rail–wheel adhesion test rig was used. The study conducted extensive tests on the adhesion characteristics under large sliding conditions.
Design/methodology/approach
Experiments were conducted to investigate the influence of speed, axle load and slip on adhesion recovery. Based on the experimental results, the adhesion recovery transition function was re-fitted.
Findings
The study reveals that the adhesion recovery phenomenon truly exists under water conditions. The adhesion coefficient shows an increasing trend with the growth of the slip ratio. Moreover, at the current speed and axle load levels, the adhesion recovery is directly proportional to the square of the slip ratio and inversely proportional to the axle load.
Originality/value
The phenomenon of adhesion recovery and the formulated equations in this study can serve as an experimental and theoretical foundation for the design of braking and anti-skid control algorithms for trains.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2023-0379/
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Powder lubrication is widely used in industrial production, but most of the research that analyze the wear process and speculate on the wear mechanism of the tested specimens…
Abstract
Purpose
Powder lubrication is widely used in industrial production, but most of the research that analyze the wear process and speculate on the wear mechanism of the tested specimens lacks reliability, and it is difficult to reveal the essence of the friction and wear process. The purpose of this paper is using the optical in situ observation method to observe the condition of the powder lubrication layer in real time and dynamically, and directly obtain the morphology change of the specimen during the whole wear process, which is helpful to the establishment of new tribological basic theories such as friction and wear mechanism and lubrication theory.
Design/methodology/approach
Mechanical model of powder lubrication is established considering asperity and powder layer, and the influence of adhesion effect on load and friction force is analyzed. The finite difference method is used to solve the above physical model, and the influence of the adhesion effect on load and friction force is analyzed. The total load and friction of the friction pair are composed of two parts: fluid and asperity. Based on the optical in situ observation method to build a test platform. The interface of the adhesion stage was observed by SEM.
Findings
When the film thickness ratio is less than 1, the local damage and diffusion of the powder layer are basically completed and the adhesion stage is entered. At this time, the asperity is not fully loaded, the powder layer is loaded by 50%, the asperity is less loaded, the deformation is small and the possibility of plastic flow is reduced. However, in the adhesion stage, the friction force is basically generated between asperity, and the friction force ratio of the asperity is 80%. Heavy load and surface roughness of the specimen are the necessary conditions for the powder adhesion period.
Practical implications
In this paper, the failure process of the powder layer at the friction interface with different roughness and load is studied based on the optical in situ observation method. Second, the contact surface with the micro-convex body and powder layer is simulated, and the influence of adhesion effect on the mechanical properties of the real contact surface in the process of powder lubrication is analyzed, thus providing theoretical guidance for mechanical processing, workpiece operation and lubrication design.
Originality/value
Mechanical model considering asperities and powder layer powder lubrication was established to analyze the influence of the adhesion effect on load and friction. Based on the optical in situ observation method to build a test platform. The tests found that the failure process of the powder lubricating layer includes five stages: powder complete stage, local failure stage, local failure diffusion stage, powder adhesion stage and complete failure stage.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2022-0322/
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Yuqi Yang, Bing Wu, Guanwen Xiao and Quan Shen
The purpose of this study is to develop a 3D wheel-rail adhesion model under wet condition, which considers the generated surface roughness topography and the traditional braking…
Abstract
Purpose
The purpose of this study is to develop a 3D wheel-rail adhesion model under wet condition, which considers the generated surface roughness topography and the traditional braking procedure for high-speed trains.
Design/methodology/approach
Wheel-rail adhesion has an important effect on the braking ability of railway vehicle. Based on the deterministic mixed lubrication approach, the model was solved to get the adhesion characteristics of the train during braking. The elastic deformation was calculated with the discrete convolution and fast Fourier transform method. The simulation results of adhesion coefficient were compared with the experimental values. The wheel-rail adhesion characteristics of train braking at several different initial speeds were investigated. The effects of the time-step length and roughness orientation on the contact load ratio were also discussed.
Findings
The results show that the adhesion coefficient of the numerical model is in good agreement with the experimental results. At the instant of braking, the adhesion coefficient drops to a lower adhesion level, the value of adhesion coefficient is lower than 0.06, especially at a higher speed (200, 300 and 400 km/h).
Originality/value
It can provide a better understanding of the low adhesion phenomenon of train braking under wet condition.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2023-0040/
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The purpose of this study is to investigate surface treatments and fiber types on adhesion properties polylactic acid (PLA) three-dimensional (3D) parts printed on woven fabrics.
Abstract
Purpose
The purpose of this study is to investigate surface treatments and fiber types on adhesion properties polylactic acid (PLA) three-dimensional (3D) parts printed on woven fabrics.
Design/methodology/approach
The cotton, flax and jute fabrics were exposed to alkali, hydrogen peroxide, stearic acid and ionic liquid treatments to modify surface characteristics before PLA 3D printing. The modification efficiency was assessed with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analyses. Then, fused deposition modeling (FDM) printer and PLA filament were used for 3D printing onto the untreated and treated fabrics. The adhesion strength between the fabrics and PLA 3D parts were tested according to DIN 53530 via universal tensile tester.
Findings
The fabric structure is effective on adhesion force and greater values were observed for plain weave fabrics. Maximum separation forces were obtained for alkali pretreated fabrics among jute and cotton. Hydrogen peroxide treatment also increased adhesion forces for jute and cotton fabrics while decreasing for flax fabrics. Stearic acid and ionic liquid treatments reduced adhesion forces compared to untreated fabrics. Treatments are effective to alter adhesion via changing surface chemistry, surface morphology and fabric physical properties but display different effects related to fabric material.
Originality/value
This study provides experimental information about effects of different fiber types and surface treatments on adhesion strength of PLA 3D parts. There is limited research about comprehensive observation on 3D printing on cellulosic-woven fabrics.
Wenliang Zhu, Wenjian Zhu, Shubin Zheng and Na Wu
The purpose of this paper is to develop an improved adhesion model to better reproduce the low adhesion condition of the anti-skid control for rail vehicles under braking…
Abstract
Purpose
The purpose of this paper is to develop an improved adhesion model to better reproduce the low adhesion condition of the anti-skid control for rail vehicles under braking condition.
Design/methodology/approach
In view of the low adhesion characteristics for rail vehicles under braking conditions, the Polach adhesion model was improved based on the sliding power and sliding energy. The wheel–rail low adhesion model suitable for braking condition was given. The analysis of braking anti-skid control under emergency braking condition was carried out through the co-simulation, and compared with the test data; the effectiveness and practicability of the improved low adhesion model were verified.
Findings
The results showed that the improved adhesion model is simple and efficient and the parameters involved are less, and it can be directly applied to the real-time simulation of anti-skid control in the process of train braking.
Originality/value
This paper can provide a theoretical reference for the reasons of change and improvement of adhesion between wheel and rail caused by the adjustment of braking force under anti-skid control, which can fulfill a need to the study of sliding energy on the contact surface, the removal effect of pollutants on the wheel–rail surface and the improvement and recovery of adhesion caused.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0244/
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Nils Grimmelsmann, Mirja Kreuziger, Michael Korger, Hubert Meissner and Andrea Ehrmann
Composites combining two or more different materials with different physical and chemical properties allow for tailoring mechanical and other characteristics of the resulting…
Abstract
Purpose
Composites combining two or more different materials with different physical and chemical properties allow for tailoring mechanical and other characteristics of the resulting multi-material system. In relation to fiber-reinforced plastic composites, combinations of textile materials with 3D printed polymers result in different mechanical properties. While the tensile strength of the multi-material system is increased compared to the pure 3D printed material, the elasticity of the polymer layer can be retained to a certain degree, as the textile material is not completely immersed in the polymer. Instead, an interface layer is built in which both materials interpenetrate to a certain degree. The purpose of this study is to investigate the adhesion between both materials at this interface.
Design/methodology/approach
This paper gives an overview of the parameters affecting the interface layer. It shows that both the printing material and the textile substrate influence the adhesion between both materials due to viscosity during printing, thickness and pore sizes, respectively. While some material combinations build strong form-locking connections, others can easily be delaminated.
Findings
Depending on both materials, significantly different adhesion values can be found in such 3D printed composites.
Practical implications
This makes some combinations very well suitable for building composites with novel mechanical properties, while other suffer of insufficient connections.
Originality/value
For the first time, the dependence of the polymer-textile adhesion force was evaluated according to the distance between both compound partners. It was shown that this value is of crucial interest and must thus be taken into account when producing printed polymer-textile composites.
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The purpose of this paper is to present a design of climbing robot with magnetic wheels which can move on the surface of steel bridge. The locomotion concept is based on adapted…
Abstract
Purpose
The purpose of this paper is to present a design of climbing robot with magnetic wheels which can move on the surface of steel bridge. The locomotion concept is based on adapted lightweight magnetic wheel units with relatively high attractive force and friction force.
Design/methodology/approach
The robot has the main advantages of being compact (352 × – 215 × – 155 mm), lightweight (2.3 kg without battery) and simple mechanical structure. It is not only able to climb vertical walls and follow circumferential paths, but also able to pass complex obstacles such as bolts, steps, convex and concave corners with almost any inclination regarding gravity. By using a servo as a compliant joint, the wheel base can be changed to enable the robot to overcome convex corners.
Findings
The experiment results show that the climbing robot has a good performance on locomotion, and it is successful in negotiating the complex obstacles. On the other hand, the limitations in locomotion of the robot are also presented.
Originality/value
Compared with the past researches, the robot shows good performance on overcoming complex obstacles such as concave corners, convex corners, bolts and steps on the steel bridge. Magnetic wheel with the characterization of compact size and lightweight is able to provide bigger adhesion force and friction coefficient.
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