scholarly journals Friction Coefficient of Load-Bearing Elements of Building Technical Facilities

2021 ◽  
Vol 1203 (2) ◽  
pp. 022008
Author(s):  
Leopold Hrabovský ◽  
Peter Michalik
Keyword(s):  
Friction Coefficient ◽  
High Reliability ◽  
Circular Cross Section ◽  
Vertical Movement ◽  
Friction Coefficients ◽  
Measuring Device ◽  
Load Bearing ◽  
Construction Design ◽  
Wide Range ◽  
Compression Springs

Abstract The engineering activities in construction are a set of a wide range of activities that are performed, for example, for the purpose of the installation or mandatory replacement or modernisation of lifts. On the territory of the Czech Republic, there are standards that strictly prescribe what is required to repair and replace on an existing lift in order to ensure the greatest possible safety when riding the lift, but also the high reliability and dependability of the lift. Polyurethane lift belts were developed and used for the vertical movement of lifts at the turn of the millennium. Due to patent rights, they were reserved solely for selected manufacturers of lifts. The classic ropes with a circular cross-section are currently being replaced more and more frequently in construction engineering by flat ropes or belts due to their undisputed advantages. This paper describes the construction design and implemented equipment on which it is possible to determine, in the laboratory, the value of the rope friction coefficient in the given type of traction disc grooves. To be specific, this paper describes the friction coefficient determined in a laboratory, in dry and clean conditions, of a flat rope with a polyurethane sheath on the circumference of the traction disc. The friction coefficient values were acquired indirectly, i.e. by measuring the tractive forces in the approaching and receding rope branches on the rotating traction disc powered by an electric drive. The friction coefficient was determined from the measured values of both tractive forces during the course of a single experimental measuring through a calculation from Euler’s relation. The value of the receding force was obtained using two methods that differ from each other in the manner of attachment (by a screw or compression springs) of the end of the rope to the load-bearing construction of the measuring device. The information obtained from the experimental measurements made it possible to compare the measured values of the rope friction coefficients with the values given by the manufacturers and to make the conclusion that the method used to determine the friction coefficients and the set of laboratory activities and procedures for determining the friction coefficients on the testing equipment is suitable and usable in practice.

scholarly journals Study on Road Friction Database for Automated Driving - Fundamental Consideration of Measuring Device for Road Friction Database -

2021 ◽  
Author(s):  
Tetsunori Haraguchi ◽  
Ichiro Kageyama ◽  
Yukiyo Kuriyagawa ◽  
Tetsuya Kaneko ◽  
Motohiro Asai ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Traffic Safety ◽  
Surface Condition ◽  
Automated Driving ◽  
Friction Coefficients ◽  
Measuring Device ◽  
The Road ◽  
Road Friction ◽  
Road Friction Coefficient ◽  
Fundamental Consideration

This research deals with the possibility for construction of the database on the braking friction coefficient for actual roads from the viewpoint of traffic safety especially for automated driving such as level 4 or higher. In an automated driving such levels, the controller needs to control the vehicle, but the road surface condition, especially the road friction coefficient on wet roads, snowy or icy roads, changes greatly, and in some cases, changes by almost one order. Therefore, it is necessary for the controller to constantly collect environment information such as the road friction coefficients and prepare for emergencies such as obstacle avoidance. However, at present, the measurement of the road friction coefficients is not systemically performed, and a method for accurately measuring has not been established. In order to improve this situation, this study examines a method for continuously measurement for the road friction characteristics such as μ-s characteristics.

The Research on Dynamic Friction Tester of Pavement

2010 ◽  
Vol 40-41 ◽  
pp. 711-716
Author(s):  
Deng Feng Li ◽  
Li Min Guan ◽  
Qi Ming Zhang ◽  
Cai Xia Zhao
Keyword(s):  
Friction Coefficient ◽  
System Design ◽  
Control Method ◽  
High Reliability ◽  
Low Cost ◽  
Skid Resistance ◽  
Dynamic Friction ◽  
Slip Ratio ◽  
Measuring Device ◽  
Friction Tester

As to the pavement test, with the slip-based control method, a new pavement mobile type of measuring device was designed to obtain the continuous friction coefficient parameters in this paper. The operation principles and the concrete completion methods of slip ratio control were introduced in detail. 89C52 was adopted as the center chip to achieve the system design of hardware and software. After the pavement tests, the prototype is of high reliability, low cost, and simple operation, meanwhile, meets the requirements of pavement skid resistance.

scholarly journals Developing Smart Measurement Device to Measure Kinetic Friction Coefficients of Bi-Tilt Isolator

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
Friction Coefficient ◽  
Image Correlation ◽  
Kinetic Friction ◽  
Measurement Device ◽  
Friction Coefficients ◽  
Measuring Device ◽  
Contact Surfaces ◽  
Relationship Of ◽  
The Relationship ◽  
Smart Measurement

A sliding vibration isolation system, affected by a kinetic friction force, provides a flexible or energy dissipation system for a structure. The kinetic friction coefficient of the contact surfaces between the moving parts changes with the relative moving velocity of the two contact surfaces. In this study, a smart measuring device is proposed to measure the kinetic friction coefficients of materials. The Arduino boards Arduino Nano, Arduino MPU-9250, and Arduino SD modules were combined to create this proposed smart device and mounted on three aluminum extrusions constructed as a horizontal platform. Then, varying amounts of steel gaskets were applied to adjust the various slopes for sliding tests. The time history of the acceleration and displacement responses of test object movements in the sliding process were respectively, recorded and detected by this proposed smart measuring device and the digital image correlation method (DIC). Statistical analyses of all test responses were used to derive the relationship of velocity to kinetic friction coefficient. Test and analysis results showed that (1) the relationship of velocity to kinetic friction coefficient for the conditions of mild lubrication and no lubrication displayed a trend of first decreasing and then increasing with increasing speed, respectively and (2) the relationship of velocity to kinetic friction coefficient for the condition of full lubrication revealed that the kinetic friction coefficient decreased with increasing speed. Test results demonstrated that this proposed smart measurement device, which is low in price and easy to assemble, can easily measure the kinetic friction coefficient of a material under various lubrication conditions.

scholarly journals Study on the Road Friction Database for Automated Driving: Fundamental Consideration of the Measuring Device for the Road Friction Database

2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Ichiro Kageyama ◽  
Yukiyo Kuriyagawa ◽  
Tetsunori Haraguchi ◽  
Tetsuya Kaneko ◽  
Motohiro Asai ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Traffic Safety ◽  
Surface Condition ◽  
Automated Driving ◽  
Friction Coefficients ◽  
Measuring Device ◽  
Friction Characteristics ◽  
The Road ◽  
Road Friction ◽  
On The Road

This study deals with the possibility of construction of a database on the braking friction coefficient for actual roads from the viewpoint of traffic safety, especially for automated driving, such as level 4 or higher. At these levels of automated driving, the controller needs to control the vehicle. However, the road surface condition, especially the road friction coefficient on wet roads and snowy or icy roads, changes greatly, and in some cases, changes by almost one order. Therefore, it is necessary for the controller to constantly collect environment information, such as the road friction coefficients, and prepare for emergencies, such as obstacle avoidance. However, at present, the measurement of the road friction coefficients is not systemically performed, and a method for accurately measuring has not been established. In order to improve this situation, this study examines a method for continuous measurement of the road friction characteristics, such as the μ-s characteristics. It is shown that the μ-s characteristics are continuously measured using the MF generally used in tire engineering, and the friction characteristics identified from the results are sufficiently satisfactory.

scholarly journals New Equation for Predicting Pipe Friction Coefficients Using the Statistical Based Entropy Concepts

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 611
Author(s):  
Yeon-Woong Choe ◽  
Sang-Bo Sim ◽  
Yeon-Moon Choo
Keyword(s):  
Friction Coefficient ◽  
Accurate Determination ◽  
Mean Velocity ◽  
Friction Coefficients ◽  
Flow Discharge ◽  
Comparison Results ◽  
Flow Loss ◽  
Key Variables ◽  
New Equation

In general, this new equation is significant for designing and operating a pipeline to predict flow discharge. In order to predict the flow discharge, accurate determination of the flow loss due to pipe friction is very important. However, existing pipe friction coefficient equations have difficulties in obtaining key variables or those only applicable to pipes with specific conditions. Thus, this study develops a new equation for predicting pipe friction coefficients using statistically based entropy concepts, which are currently being used in various fields. The parameters in the proposed equation can be easily obtained and are easy to estimate. Existing formulas for calculating pipe friction coefficient requires the friction head loss and Reynolds number. Unlike existing formulas, the proposed equation only requires pipe specifications, entropy value and average velocity. The developed equation can predict the friction coefficient by using the well-known entropy, the mean velocity and the pipe specifications. The comparison results with the Nikuradse’s experimental data show that the R2 and RMSE values were 0.998 and 0.000366 in smooth pipe, and 0.979 to 0.994 or 0.000399 to 0.000436 in rough pipe, and the discrepancy ratio analysis results show that the accuracy of both results in smooth and rough pipes is very close to zero. The proposed equation will enable the easier estimation of flow rates.

scholarly journals Theoretical Studies of the Interaction between Screw Surface and Material in the Mixer

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 962
Author(s):  
Andrzej Marczuk ◽  
Vasily Sysuev ◽  
Alexey Aleshkin ◽  
Petr Savinykh ◽  
Nikolay Turubanov ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
High Efficiency ◽  
Animal Feed ◽  
Structural Features ◽  
Power Demand ◽  
Friction Coefficients ◽  
Length Unit ◽  
Mixing Chamber ◽  
Size Of Particles ◽  
The Impact

Mixing is one of the most commonly used processes in food, animal feed, chemical, cosmetic, etc., industries. It is supposed to provide high-quality homogenous, nutritious mixtures. To provide appropriate mixing of materials while maintaining the process high efficiency and low energy consumption it is crucial to explore and describe the material flow caused by the movement of mixing elements and the contact between particles. The process of mixing is also affected by structural features of the machine components and the mixing chamber, speed of mixing, and properties of the mixed materials, such as the size of particles, moisture, friction coefficients. Thus, modeling of the phenomena that accompany the process of mixing using the above-listed parameters is indispensable for appropriate implementation of the process. The paper provides theoretical power calculations that take into account the material speed change, the impact of the material friction coefficient on the screw steel surface and the impact of the friction coefficient on the material, taking into account the loading height of the mixing chamber and the chamber loading value. Dependencies between the mixer power and the product degree of fineness, rotational speed of screw friction coefficients, the number of windings per length unit, and width of the screw tape have been presented on the basis of a developed model. It has been found that power increases along with an increase in the value of these parameters. Verification of the theoretical model indicated consistence of the predicted power demand with the power demand determined in tests performed on a real object for values of the assumed, effective loading, which was 65–75%.

scholarly journals The Comprehensive Autistic Trait Inventory (CATI): development and validation of a new measure of autistic traits in the general population

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael C. W. English ◽  
Gilles E. Gignac ◽  
Troy A. W. Visser ◽  
Andrew J. O. Whitehouse ◽  
James T. Enns ◽  
...  
Keyword(s):  
Factor Analysis ◽  
General Population ◽  
Measurement Invariance ◽  
High Reliability ◽  
Predictive Ability ◽  
Autistic Traits ◽  
Autism Spectrum ◽  
Autism Spectrum Quotient ◽  
Sensory Sensitivity ◽  
Wide Range

Abstract Background Traits and characteristics qualitatively similar to those seen in diagnosed autism spectrum disorder can be found to varying degrees in the general population. To measure these traits and facilitate their use in autism research, several questionnaires have been developed that provide broad measures of autistic traits [e.g. Autism-Spectrum Quotient (AQ), Broad Autism Phenotype Questionnaire (BAPQ)]. However, since their development, our understanding of autism has grown considerably, and it is arguable that existing measures do not provide an ideal representation of the trait dimensions currently associated with autism. Our aim was to create a new measure of autistic traits that reflects our current understanding of autism, the Comprehensive Autism Trait Inventory (CATI). Methods In Study 1, 107 pilot items were administered to 1119 individuals in the general population and exploratory factor analysis of responses used to create the 42-item CATI comprising six subscales: Social Interactions, Communication, Social Camouflage, Repetitive Behaviours, Cognitive Rigidity, and Sensory Sensitivity. In Study 2, the CATI was administered to 1068 new individuals and confirmatory factor analysis used to verify the factor structure. The AQ and BAPQ were administered to validate the CATI, and additional autistic participants were recruited to compare the predictive ability of the measures. In Study 3, to validate the CATI subscales, the CATI was administered to 195 new individuals along with existing valid measures qualitatively similar to each CATI subscale. Results The CATI showed convergent validity at both the total-scale (r ≥ .79) and subscale level (r ≥ .68). The CATI also showed superior internal reliability for total-scale scores (α = .95) relative to the AQ (α = .90) and BAPQ (α = .94), consistently high reliability for subscales (α > .81), greater predictive ability for classifying autism (Youden’s Index = .62 vs .56–.59), and demonstrated measurement invariance for sex. Limitations Analyses of predictive ability for classifying autism depended upon self-reported diagnosis or identification of autism. The autistic sample was not large enough to test measurement invariance of autism diagnosis. Conclusions The CATI is a reliable and economical new measure that provides observations across a wide range of trait dimensions associated with autism, potentially precluding the need to administer multiple measures, and to our knowledge, the CATI is also the first broad measure of autistic traits to have dedicated subscales for social camouflage and sensory sensitivity.

scholarly journals Constructing a biomimetic robust bi-layered hydrophilic lubrication coating on surface of silicone elastomer

Friction ◽  
2021 ◽  
Author(s):  
Luyao Gao ◽  
Xiaoduo Zhao ◽  
Shuanhong Ma ◽  
Zhengfeng Ma ◽  
Meirong Cai ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Composite Layer ◽  
High Load ◽  
Silicone Elastomer ◽  
Aqueous Lubrication ◽  
Low Friction ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Lubrication Performance ◽  
Wide Range

AbstractSilicone elastomers-based materials have been extensively involved in the field of biomedical devices, while their use is extremely restricted due to the poor surface lubricity and inherent hydrophobicity. This paper describes a novel strategy for generating a robust layered soft matter lubrication coating on the surface of the polydimethylsiloxane (PDMS) silicone elastomer, by entangling thick polyzwitterionic polyelectrolyte brush of poly (sulfobetaine methacrylate) (PSBMA) into the sub-surface of the initiator-embedded stiff hydrogel coating layer of P(AAm-co-AA-co-HEMA-Br)/Fe, to achieve a unified low friction and high load-bearing properties. Meanwhile, the stiff hydrogel layer with controllable thickness is covalently anchored on the surface of PDMS by adding iron powder to provide catalytic sites through surface catalytically initiated radical polymerization (SCIRP) method and provides high load-bearing capacity, while the topmost brush/hydrogel composite layer is highly effective for aqueous lubrication. Their synergy effects are capable of attaining low friction coefficient (COFs) under wide range of loaded condition in water environment with steel ball as sliding pair. Furthermore, the influence of mechanical modulus of the stiff hydrogel layer on the lubrication performance of layered coating is investigated, for which the COF is the lowest only when the modulus of the stiff hydrogel layer well matches the PDMS substrate. Surprisingly, the COF of the modified PDMS could remain low friction (COF < 0.05) stably after encountering 50,000 sliding cycles under 10 N load. Finally, the surface wear characterizations prove the robustness of the layered lubricating coating. This work provides a new route for engineering lubricious silicon elastomer with low friction, high load-bearing capacity, and considerable durability.

New Approach for Versatile Self Piercing Riveting: Joining System and Auxiliary Part

2021 ◽  
Vol 883 ◽  
pp. 3-10
Author(s):  
Fabian Kappe ◽  
Mathias Bobbert ◽  
Gerson Meschut
Keyword(s):  
Boundary Conditions ◽  
Research Work ◽  
High Load ◽  
Continuous Increase ◽  
New Approach ◽  
Load Bearing ◽  
Mechanical Joining ◽  
Wide Range ◽  
Riveting Process

The increasing use of multi-material constructions lead to a continuous increase in the use of mechanical joining techniques due to the wide range of joining possibilities as well as the high load-bearing capacities of the joints. Nevertheless, the currently rigid tool systems are not able to react to changing boundary conditions, like changing the material-geometry-combination. Therefore research work is crucial with regard to versatile joining systems. In this paper, a new approach for a versatile self-piercing riveting process considering the joining system as well as the auxiliary joining part is presented.

Developing low-cost methane gas concentration measuring device

2021 ◽  
pp. 54-59
Author(s):  
Md. Mahidy Hossain ◽  
Nadim Khandaker
Keyword(s):  
Promising Result ◽  
Low Cost ◽  
Measurement Techniques ◽  
Health And Safety ◽  
Modern Science ◽  
Methane Content ◽  
Measuring Device ◽  
Methane Generation ◽  
Methane Gas ◽  
Wide Range

In every aspect of Engineering more advanced, efficient and progressive solutions are required. The modern age of science requires innovative minds. The field of environmental engineering is also advancing with modern science and technology innovations. Measuring of methane concentration and flow rate is nothing new, yet a complicated process. The need for more accurate measurement is a necessity in proper operation of bio digesters for methane generation. The traditional process of the measuring methane content in biogas is time consuming yet complicated. The need for development and application of methane measurement techniques is not only limited to biogas but has other monitoring value as well in other health and safety applications in built environments. Winsen Electronics and Hanwei Electronics are two of the leading sensor-manufactures of China who are providing a wide range of gas detecting sensors that are locally available in Bangladesh and yet has not been applied to methane content measurement in biogas operations. In This paper we are reporting on the application of a purpose-built propane, butane detector for methane gas detection within the range of accuracy for it to be applied in methane detection in a biogas stream. This paper, reports on application and calibration of the methane detecting sensor MQ-4 with promising result. Based on the study we postulate that the sensor can be used to detect methane for an on-line monitoring of many environmental, industrial purposes such as bio digesters, integrated waste management facility. The cost of fabrication of the sensor system is only $18 making it a viable sensor with respect to cost for application in Bangladesh.

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