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1
Keller, J. B. "Impact With Friction." Journal of Applied Mechanics 53, no. 1 (1986): 1–4. http://dx.doi.org/10.1115/1.3171712.
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A theory of the impact or collision of two rigid bodies, taking account of friction, is presented. It determines how the direction of sliding varies during the impact, which must be known to calculate the direction of the frictional force and thence the frictional impulse. This is accomplished by analyzing the equations of motion of the bodies during the collision. The normal impulse is determined by using a coefficient of restitution. When the direction of sliding is constant throughout the collision, the theory agrees with that given by Whittaker, which is correct only in this case.
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Arya, V. S., B. Binu Aswathy, Pradeep Jyothi, Thomas Greena, A. Suminamol, and V. Aparna. "Impact of Side Friction on Urban Roads." Journal of Transportation Engineering and Traffic Management 1, no. 2 (2020): 1–9. https://doi.org/10.5281/zenodo.3953698.
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Urban roads in India operate under mixed traffic conditions. They are subjected to side friction factors such as slow-moving vehicles, interference of buses, pedestrian traffic, trading activities, frequent side roads, vehicles parked along the carriage way, entry and exit through approach road. But the side friction factors are not considered while designing roads as per IRC guidelines. Hence, the present work aims to determine the effect of side friction parameters on speed reduction. A road side friction index (RSFI) has been developed to quantify side frictions. Percentage speed reduction (PSR) from free flow speed was analysed to study impact of road side friction on speed. Level of service (LOS) is determined from the data collected.
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Huang, Ruoxi, Jiajing Li, and Jiatong Yu. "The Impact of China: U.S Trade Frictions on Chinese Enterprise Innovation." Academic Journal of Management and Social Sciences 9, no. 1 (2024): 25–32. http://dx.doi.org/10.54097/vhcrg319.
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The trade frictions between the United States and China has brought great uncertainty and risk to the global economic development environment. Using the panel data of Chinese listed firms from 2009 to 2023, the Difference in Difference (DID) panel model and mediation effect model are employed to study the impact of the US-China trade frictions on firms' innovation. The empirical results show that the US-China trade friction has a negative impact on R&D innovation of Chinese firms. Further research finds that US-China trade friction has a stronger negative effect on R&D innovation of non-state-owned firms and the central and western regions. Finally, this paper finds that US-China trade friction will reduce corporate technology innovation by exacerbating corporate financing constraints.
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Tiwari, Ashish. "The Role of Friction in Athletic Performance: A Descriptive Analysis." INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, no. 04 (2024): 1–5. http://dx.doi.org/10.55041/ijsrem31958.
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Friction is a fundamental force that has a substantial impact on athletic performance across all sports disciplines. This descriptive research investigates the varied impact of friction in building athletic skill. This study looks at how friction affects running, jumping, throwing, and other sports activities by examining static and kinetic frictional forces, as well as elements that influence frictional interactions. The research examines the interaction of athletes, footwear, surfaces, and equipment to explain how friction governs propulsion, stability, and efficiency in sports activity. The findings of this study have important significance for players, coaches, and sports scientists, as they provide avenues for optimizing training techniques, equipment design, and performance tactics for increased athletic achievement. Keywords Friction , Athletic Performance , Role , Descriptive Analysis , Surface Friction , Footwear Friction , Sports Science , Biomechanics , Performance Optimization , Surface Interaction , Traction , Stability , Movement Efficiency , Injury Prevention ,Training Strategies
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ANDERSON, KEN, and MARIA CURY. "Friction into Traction: A Case Study of Frictions in Strategic Ethnography." Ethnographic Praxis in Industry Conference Proceedings 2023, no. 1 (2023): 346–68. https://doi.org/10.1111/epic.12173.
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This case study highlights the transformative power of strategic ethnography in shaping frameworks that gain traction within organizations, facilitated by three frictions: research friction, analysis friction, and path‐to‐action friction. By embracing frictions as productive movements, we not only witnessed the profound impact of ethnographic research on the future of a product category but also experienced the convergence of previously competing divisions, fostering innovation, collaboration, and organizational growth. Through an analysis of these frictions, we distill lessons for applied ethnography and highlight the importance of embracing rather than avoiding frictions in today's business settings.
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Sun, Wuxiang, Yanwei Liu, Xuan Li, Zhi Xu, Zhaojun Yang, and Hu Huang. "An Inertial Impact Piezoelectric Actuator Designed by the Asymmetric Friction Principle and Achieved by Laser Texturing of the Driving Feet." Actuators 11, no. 8 (2022): 211. http://dx.doi.org/10.3390/act11080211.
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An asymmetric friction principle is newly proposed for the design of inertial impact piezoelectric actuators. There are two ways to achieve asymmetric frictions: either by tuning the positive pressure or by tuning the friction coefficient. Compared with tuning the positive pressure by an asymmetric structure, the structural parameters can be reduced by employing a symmetric structure and tuning the friction coefficient. In this study, an asymmetric friction inertial impact actuator was developed using a symmetric compliant mechanism (SCM), and the asymmetric frictions were realized by laser texturing of the driving feet at one end of the SCM. Four kinds of microstructures were initially fabricated on the driving feet, and their friction properties were experimentally tested. Accordingly, two kinds of microstructures, namely Ta and Tb microstructures, were selected. Output characteristics of the actuator with these two microstructures were measured and comparatively analyzed. The experimental results indicate that the actuator could achieve stable step motion, and the output characteristics were affected by the fabricated microstructure, as it determined the friction coefficient. The actuator with the Tb microstructure achieved a maximum speed of 2.523 mm/s, a resolution of 188 nm, a vertical loading capacity of 2 N and a horizontal loading capacity of 0.6 N, whereas the actuator with the Ta microstructure had a higher resolution of 74 nm. This study provides a novel idea for the design of asymmetric friction inertial impact actuators by tuning the friction coefficient.
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Alhasan, Ahmad, Omar Smadi, Georges Bou-Saab, Nacu Hernandez, and Eric Cochran. "Pavement Friction Modeling using Texture Measurements and Pendulum Skid Tester." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 40 (2018): 440–51. http://dx.doi.org/10.1177/0361198118774165.
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Pavement frictional behavior affects pavement performance in terms of vehicle safety, fuel consumption, and tire wear. Comprehending and interpreting pavement friction measurements is a challenging task, because of friction sensitivity to several uncontrollable factors. These factors include: pavement surface conditions, such as the type and thickness of contaminants and fluids on the surface and their interaction with friction forces; and the device operating conditions, such as sliding speed, material properties and geometry of the rubber slider used, and operating temperature. Despite the efforts to describe and quantify the impact of varying conditions on pavement friction, which ultimately will allow for a better harmonization of friction measurements, there is a need to better understand the link between the surface texture and physical friction measurements. In this paper, Persson’s friction model is used to analyze and understand the impact of surface texture on frictional behavior of dry pavement surfaces. The model was used to analyze 18 test locations, which were compared with the dry kinetic coefficients of friction (COF) estimated using a British pendulum tester (BPT). The results show that Persson’s friction model could predict the COF estimated from the BPT results with relatively high accuracy. In addition, the model could provide a profound explanation of the frictional forces mechanism. Finally, it was found that the mean profile depth (MPD) cannot provide a full picture of the frictional behavior. However, combining MPD with the Hurst exponent, texture measurements can potentially provide a full physical explanation of the frictional behavior for road surfaces.
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Han, Inhwan, and B. J. Gilmore. "Multi-Body Impact Motion with Friction—Analysis, Simulation, and Experimental Validation." Journal of Mechanical Design 115, no. 3 (1993): 412–22. http://dx.doi.org/10.1115/1.2919206.
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When a multi-body system collides with a single body or with another multi-body system, impact dynamics with friction should be considered. This paper presents a general computer oriented analysis of impact dynamics incorporating friction. The presence of friction between sliding contacts during the impact makes the problem difficult since the events such as reverse sliding or sticking, which may occur at different times throughout the impact, must be determined. The boundary representations of the bodies are used to solve for the velocities at the points of contact. Using this information and a classification of the modes of impact, the frictional impact with sliding contact problem is solved. Using a high speed video camera, the resulting computer strategy is experimentally verified. Simulation and experimental results agree.
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Wang, Yu, and Matthew T. Mason. "Two-Dimensional Rigid-Body Collisions With Friction." Journal of Applied Mechanics 59, no. 3 (1992): 635–42. http://dx.doi.org/10.1115/1.2893771.
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This paper presents an analysis of a two-dimensional rigid-body collision with dry friction. We use Routh’s graphical method to describe an impact process and to determine the frictional impulse. We classify the possible modes of impact, and derive analytical expressions for impulse, using both Poisson’s and Newton’s models of restitution. We also address a new class of impacts, tangential impact, with zero initial approach velocity. Some methods for rigid-body impact violate energy conservation principles, yielding solutions that increase system energy during an impact. To avoid such anomalies, we show that Poisson’s hypothesis should be used, rather than Newton’s law of restitution. In addition, correct identification of the contact mode of impact is essential.
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Cojocaru, Dorian, and Dan B. Marghitu. "Impact Behavior of a Rotating Rigid Body with Impact and Viscous Friction." Mathematical Problems in Engineering 2020 (November 3, 2020): 1–11. http://dx.doi.org/10.1155/2020/5471629.
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The impact between a rotating link and a solid flat surface is considered. For the impact, we consider three distinct periods: elastic period, elastoplastic period, and restitution period. A Hertzian contact force is considered for the elastic period. Nonlinear contact forces developed from finite element analysis are used for the remaining two phases. The tangential effect is taken into account considering a friction force that combines the Coulomb dry friction model and a viscous friction function of velocity. Simulations results are obtained for different friction parameters. An experimental setup was designed to measure the contact time during impact. The experimental and simulation results are compared for different lengths of the link.
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Stark, Nicole E. P., Andrew Calis, Matthew Wood, et al. "The Implications of Surface Friction on Snowsport Helmet Oblique Impact Kinematics." SAE International Journal of Transportation Safety 12, no. 2 (2024): 167–72. http://dx.doi.org/10.4271/09-12-02-0017.
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<div>Head injuries account for 15% of snowsport-related injuries, and the majority of head impacts occur against ice or snow, low-friction surfaces. Therefore, this study aimed to evaluate how surface friction affects snowsport helmets’ oblique impact kinematics. Ten helmet models were impacted using an oblique drop tower with a 45-degree anvil and NOCSAE headform, at three locations, two surface friction conditions, and a drop speed of 5.0 m/s. Our findings indicate that friction affects peak linear acceleration, peak rotational acceleration, and peak rotational velocity during helmet impacts, with changes in post-impact rotation and impact response varying by location. Surface friction affects head impact kinematics, underscoring the need for sport-specific lab testing and emphasizing the need for friction-specific and sport-specific testing, particularly for snowsports, where surface conditions like snow and ice can alter kinematics.</div>
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Ai, Wen-Yuan, Xander Nagels, and Miguel Vanvlasselaer. "Criterion for ultra-fast bubble walls: the impact of hydrodynamic obstruction." Journal of Cosmology and Astroparticle Physics 2024, no. 03 (2024): 037. http://dx.doi.org/10.1088/1475-7516/2024/03/037.
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Abstract The Bödeker-Moore thermal friction [1] is usually used to determine whether or not a bubble wall can run away. However, the friction on the wall is not necessarily a monotonous function of the wall velocity and could have a maximum before it reaches the Bödeker-Moore limit. In this paper, we compare the maximal hydrodynamic obstruction, a frictional force that exists in local thermal equilibrium, and the Bödeker-Moore thermal friction. We study the former in a fully analytical way, clarifying its physical origin and providing a simple expression for its corresponding critical phase transition strength above which the driving force cannot be balanced out by the maximal hydrodynamic obstruction. We find that for large parameter space, the maximal hydrodynamic obstruction is larger than the Bödeker-Moore thermal friction, indicating that the conventional criterion for the runaway behavior of the bubble wall may have to be modified. We also explain how to apply efficiently the modified criterion to particle physics models and discuss possible limitations of the analysis carried out in this paper.
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Sun, Wanting. "Analyzing the risk contagion effect of stock market and foreign exchange market in the context of Sino-US trade frictions based on the perspective of behavioral finance." SHS Web of Conferences 170 (2023): 02023. http://dx.doi.org/10.1051/shsconf/202317002023.
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For the empirical study in this paper, the trade friction variables represented by the effectively applied weighted average tariffs imposed by the U.S. on China and technical barriers to trade have a negative impact on the size of China's export trade, and the impact of technical barriers to trade has a lag. In the analysis of the impact of trade structure, from the perspective of technology intensity, the impact of Sino-US trade frictions on China's exports to the United States of low- and medium-technology industries is significantly greater than that of high-technology industries, mainly due to the high technology level of high-technology products, strict standard requirements, strong innovation capacity, the impact of trade frictions is not significant; from the perspective of product end-use, investment goods are significantly more affected by Sino-US trade frictions than consumer goods, and the impact on industrial manufactured products is much greater than primary products, the results of the difference is mainly affected by the nature of the product, export volume and the area of friction.
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Wu, Wangqing, Changsheng He, Yuanbao Qiang, Huajian Peng, and Mingyong Zhou. "Polymer–Metal Interfacial Friction Characteristics under Ultrasonic Plasticizing Conditions: A United-Atom Molecular Dynamics Study." International Journal of Molecular Sciences 23, no. 5 (2022): 2829. http://dx.doi.org/10.3390/ijms23052829.
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Understanding the properties of polymer–metal interfacial friction is critical for accurate prototype design and process control in polymer-based advanced manufacturing. The transient polymer–metal interfacial friction characteristics are investigated using united-atom molecular dynamics in this study, which is under the boundary conditions of single sliding friction (SSF) and reciprocating sliding friction (RSF). It reflects the polymer–metal interaction under the conditions of initial compaction and ultrasonic vibration, so that the heat generation mechanism of ultrasonic plasticization microinjection molding (UPMIM) is explored. The contact mechanics, polymer segment rearrangement, and frictional energy transfer features of polymer–metal interface friction are investigated. The results reveal that, in both SSF and RSF modes, the sliding rate has a considerable impact on the dynamic response of the interfacial friction force, where the amplitude has a response time of about 0.6 ns to the friction. The high frequency movement of the polymer segment caused by dynamic interfacial friction may result in the formation of a new coupled interface. Frictional energy transfer is mainly characterized by dihedral and kinetic energy transitions in polymer chains. Our findings also show that the ultrasonic amplitude has a greater impact on polymer–metal interfacial friction heating than the frequency, as much as it does under ultrasonic plasticizing circumstances on the homogeneous polymer–polymer interface. Even if there are differences in thermophysical properties at the heterointerface, transient heating will still cause heat accumulation at the interface with a temperature difference of around 35 K.
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Sun, Han, and Haim Baruh. "Analysis of Three-Dimensional Rigid-Body Impact with Friction." Dynamics 2, no. 1 (2022): 1–26. http://dx.doi.org/10.3390/dynamics2010001.
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This paper is concerned with the modeling and simulation of two- and three-dimensional impact in the presence of friction. Single impacts are considered, and the impact equations are solved algebraically. Impact generates impulsive normal and frictional forces and the direction of sliding can change during impact. A procedure is developed to estimate the change in direction of sliding during three-dimensional impact. The modes of impact, such as sliding, sticking, or change in direction of sliding, are classified for both two- and three-dimensional impact. Simulations are conducted to analyze the energy lost, change in impact direction, and stick-slip conditions, where different models for restitution are compared. A closed-form solution is developed to analyze the modes of sliding for two-dimensional impact.
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Avdhut, Gujar, and Awasare A. "Friction on Mechanical Mechanisms." Research and Reviews on Experimental and Applied Mechanics 7, no. 3 (2024): 34–38. https://doi.org/10.5281/zenodo.14274698.
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<em>Friction is a critical factor influencing the performance, efficiency, and longevity of mechanical systems. This paper presents a comprehensive study on the impact of friction within various mechanical mechanisms, encompassing both theoretical analysis and experimental validation. By analyzing frictional forces in components such as gears, bearings, and sliding mechanisms, we examine how friction affects energy consumption, wear, and mechanical efficiency. Our study utilizes analytical models alongside finite element simulations to predict the behavior of frictional interfaces under different operational conditions, including load, speed, and lubrication. Additionally, experiments are conducted to validate theoretical predictions and evaluate the effectiveness of various friction-reducing strategies, such as surface coatings, lubricants, and material modifications. The findings underscore the importance of friction management in optimizing mechanical design and offer insights into sustainable practices for prolonging the life of mechanical components. This research provides valuable data for engineers and designers seeking to enhance system performance while mitigating the adverse effects of friction.</em>
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Arakawa, Sota, Hidekazu Tanaka, and Eiichiro Kokubo. "Collisional Growth Efficiency of Dust Aggregates and Its Independence of the Strength of Interparticle Rolling Friction." Astrophysical Journal 939, no. 2 (2022): 100. http://dx.doi.org/10.3847/1538-4357/ac96e1.
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Abstract The pairwise collisional growth of dust aggregates consisting of submicron-sized grains is the first step of planet formation, and understanding the collisional behavior of dust aggregates is therefore essential. It is known that the main energy dissipation mechanisms are the tangential frictions between particles in contact, namely, rolling, sliding, and twisting. However, there is great uncertainty for the strength of rolling friction, and the dependence of the collisional growth condition on the strength of rolling friction was poorly understood. Here we performed numerical simulations of collisions between two equal-mass porous aggregates with various collision velocities and impact parameters, and we also changed the strength of rolling friction systematically. We found that the threshold of the collision velocity for the fragmentation of dust aggregates is nearly independent of the strength of rolling friction. This is because the total amount of the energy dissipation by the tangential frictions is nearly constant even though the strength of rolling friction is varied.
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Zhang, Wei, Kun Liu, Jian Zhou, Rongxin Chen, Ning Zhang, and Guofu Lian. "EXPERIMENTAL INVESTIGATION ON STRESS AND DIE-WALL FRICTIONAL CHARACTERISTICS OF METAL POWDER DURING HIGH-VELOCITY COMPACTION." Materiali in tehnologije 55, no. 2 (2021): 163–70. http://dx.doi.org/10.17222/mit.2019.300.
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In this study, to evaluate the change in the stress and die-wall frictional characteristics during high-velocity compaction (HVC), a metal powder was subjected to HVC with a heavy hammer based on the stress-testing technology and Janssen-Walker model. The changes in the green density, stress characteristics and coefficients of friction at different impact heights were investigated. The density of green compacts increased with the increase in the impact height. The stress in the upper and lower punches and the die wall showed repeated loading and unloading. The coefficient of friction of the die wall underwent three stages and was related to powder densification. As the height position along the side wall was increased, the coefficient of friction increased gradually. With an increased impact height, the coefficient of friction increased significantly in the incomplete-molding stage but remained constant in the complete-molding stage. This work expands the theoretical basis of densification processing of a metal powder during HVC.
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Kireenkov, Alexey. "58970 NEW MODELS OF THE COMBINED DRY FRICTION AND CONNECTED WITH THEM MECHANICAL EFFECTS(Contact, Impact, and Friction)." Proceedings of the Asian Conference on Multibody Dynamics 2010.5 (2010): _58970–1_—_58970–6_. http://dx.doi.org/10.1299/jsmeacmd.2010.5._58970-1_.
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Bhatt, V., and Jeff Koechling. "Three-Dimensional Frictional Rigid-Body Impact." Journal of Applied Mechanics 62, no. 4 (1995): 893–98. http://dx.doi.org/10.1115/1.2896017.
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We present an analysis of the rigid-body model for frictional three-dimensional impacts, which was originally studied by Routh. Using Coulomb’s law for friction, a set of differential equations describing the progress and outcome of the impact process for general bodies can be obtained. The differential equations induce a flow in the tangent velocity space for which the trajectories cannot be solved for in a closed form, and a numerical integration scheme is required. At the point of sticking, the numerical problem becomes ill-conditioned and we have to analyze the flow at the singularity to determine the rest of the process. A local analysis at the point of sticking provides enough information about the global nature of the flow to let us enumerate all the possible dynamic scenarios for the sliding behavior during impact. The friction coefficient, and the mass parameters at the point of contact, determine the particular sliding behavior that would occur for a given problem. Once the initial conditions are specified, the possible outcome of the impact can then be easily determined.
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ŁUKASZEWICZ, Andrzej, Jerzy JÓZWIK, and Kamil CYBUL. "IMPACT OF FRICTION COEFFICIENT VARIATION ON TEMPERATURE FIELD IN ROTARY FRICTION WELDING OF METALS – FEM STUDY." Applied Computer Science 19, no. 3 (2023): 17–27. http://dx.doi.org/10.35784/acs-2023-22.
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A mathematical model is presented for investigating the temperature field caused by the rotary friction welding of dissimilar metals. For this purpose, an axisymmetric, nonlinear, boundary value problem of heat conduction is formulated with allowance for the frictional heating of two cylindrical specimens of finite length made of Al 6061 aluminium alloy and 304 stainless steel. The thermo-physical properties of materials change with increasing temperature. It was assumed that the coefficient of friction does not depend on the temperature. The mechanism of heat generation due to friction on the contact surface with the temperature field of samples is considered. The boundary problem of heat conduction was reduced to the set of nonlinear ordinary differential equations at time t relative to the values of temperature T at the finite elements nodes. The numerical solution of the problem was obtained with the inverse 2nd order differentiation method implemented in COMSOL FEM system (finite element method), with time step ∆t=0.1 (s). The influence of various values of friction coefficient is presented.
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Tee, J. W., S. H. Hamdan, and W. W. F. Chong. "Predictive tool for frictional performance of piston ring-pack/liner conjunction." Journal of Mechanical Engineering and Sciences 13, no. 3 (2019): 5513–27. http://dx.doi.org/10.15282/jmes.13.3.2019.19.0445.
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Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.
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Li, Wenshan, Yong Huang, and Guangming Xie. "A Study on the Mechanism of Impact between Curved Bridge Segments Using Nonsmooth Dynamics." Shock and Vibration 2020 (December 17, 2020): 1–13. http://dx.doi.org/10.1155/2020/5217165.
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It has been observed in many previous earthquakes that impact often occurs between the main girders in curved bridges. An earthquake can result in deck-unseating leading to catastrophic destruction of the structure. In this paper, the nonsmooth multirigid body dynamics method and the set-valued formulation were used to model and analyze the mechanism of impact between the curved bridge segments. The analysis demonstrated that these impacts are the major cause of segment rotation. The main contribution of this paper is to use Newton’s impact law and Coulomb’s friction law to describe the interaction between the curved bridge segments in the form of a set-valued function and to express impacts with friction as a linear complementary problem. For frictionless and frictional contact, the paper considers the single-point and multipoint impacts using the linear complementary formula to detect the unique actual slip-stick conditions of these states. A variety of criteria for distinguishing each case are presented and the results provide the kinetic characteristics of each contact case. The analysis has shown that the impact between the segments of a curved bridge and the tendency of the segments to rotate (and thus detach) are related to the overall geometry, the coefficient of restitution, the coefficient of friction, and the preimpact conditions in the plane of motion. Finally, a theoretical relationship diagram of the impact, rotation slip, and stick condition of the curved bridge segments at the contact point is given. The presented results will be useful for the seismic design of curved bridges.
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Yin, Yan Guo, Xiang Nan Jiao, Tao You, Jian Wei Yu, Ming Hua Jiao, and Ting Xie. "Research on the Tribology Performance of Copper-Bismuth Bearing Material." Applied Mechanics and Materials 217-219 (November 2012): 322–25. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.322.
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Copper-based bearing material containing Bi was prepared by running powder metallurgy process, the influence of the content of Bi on the tribological performance of copper-based bearing materials was inspected and Bi’s impact on frictional wear performance of copper-based bearing materials was studied by a MM-200 frictional wear tester. The research shows that, Bi, with a lower melting point, tends to melt and separate out, in friction process which may reduce shear strength of the friction pair surface and improve the performance of antifriction and adhesiveness resistance. When Bi content gets higher to produce more brittle phases, which will fall off directly from the matrix, the antifriction and antiwear of friction pair will weaken.
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Tikhomirov, Victor, Aleksandr Gorlenko, Stanislav Volohov, and Mikhail Izmerov. "MAGNETIC FIELD IMPACT UPON TRIBOTECHNICAL CHARACTERISTICS OF SLIDING FRICTION PAIRS WITH RESPECT TO FRICTION SHOCK ABSORBERS." Bulletin of Bryansk state technical university 2020, no. 11 (2020): 4–11. http://dx.doi.org/10.30987/1999-8775-2020-11-4-11.
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The purpose of the work is to examine magnetic field impact upon properties of friction steel surfaces at “pin-disc” tests. The magnetic field impact upon a friction contact with the substantiation of the mechanism of its impact is proved experimentally, and also the results bringing to positive effects for friction pairs are emphasized. 
 The analysis of experiment results has shown that a friction factor can be increased by 88% as compared with the version without magnetic field impact upon friction pair. At that under the magnetic field impact wear intensity becomes less for about half, and also friction surfaces quality becomes better as compared with the tests without a magnetic field as there are no vivid traces of plowing that is explained with the wear particles elimination from the friction area under the magnetic field impact. 
 The investigation methods: the fulfillment of laboratory physical experiments with the use of the developed and patented laboratory plant according to the “pin-disc” scheme. 
 The investigation results and novelty: the magnetic field impact upon a value of friction force, a factor of slip and wear intensity of friction surfaces is determined. 
 The conclusion: it is possible to control a friction factor and wear intensity through the magnetic field impact upon a friction contact.
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Zhu, Qingyi. "The Impact of Sino-US Trade Friction on China's Manufacturing Industry." Lecture Notes in Education Psychology and Public Media 22, no. 1 (2023): 1–7. http://dx.doi.org/10.54254/2753-7048/22/20230201.
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Against the backdrop of rapid economic development and globalization, the trade environment for Chinas manufacturing industry to integrate into the global value chain has undergone changes. The trade frictions between China and the United States have escalated from time to time, and how to face the challenges has become a major issue. Based on the background of trade frictions between China and the United States, this article first introduces the current development status of Chinas manufacturing industry, and then conducts an in-depth analysis of the changes in international and domestic market demand for Chinas manufacturing industry. Secondly, it analyzes the part of the Entity List of the China-United States trade war that affects the Chinese market, and analyzes the impact of Sino-US trade friction on the integration of Chinas manufacturing industry and the global value chain. Finally, some suggestions are put forward for the Chinese manufacturing industry to cope with trade frictions between China and the United States, providing strategies for industry protection and the path to achieve the transition of the manufacturing industry in the global value chain.
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Wong, S. V., A. M. S. Hamouda, and M. S. J. Hashmi. "Kinematic Contact-Impact Algorithm with Friction." International Journal of Crashworthiness 6, no. 1 (2001): 65–82. http://dx.doi.org/10.1533/cras.2001.0163.
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Li, Zhenhua, Mutellip Ahmat, Quanyi Zhang, and Huafeng Zhou. "Analysis of Contact Characteristics of Rough Surface/Microporous For Flat Friction Pair." Journal of Physics: Conference Series 2459, no. 1 (2023): 012048. http://dx.doi.org/10.1088/1742-6596/2459/1/012048.
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Abstract The rough surface has serious friction, wear and thermal damage during the sliding friction process in engineering applications, which leads to the failure of the friction pair. The rough surface contact is simplified into a rough surface with fractal properties and an ideal plane. The interaction between the asperities of the contacting body and the coupling effect of frictional heat flow at the frictional interface is considered. The impact of contact pressure and temperature rise between microporous model and non porous model on rough surface was compared, as well as the impact of Sa on the area, contact pressure and temperature rise of the friction pair. The results show that in the process of uniform sliding friction, when the asperities pass through the micropores, the asperities are embedded in the edge of the micropores so that the peak contact pressure increases, cutting occurs, and the deformation is affected by the interaction between the micropores and the asperities. The position of the highest pressure point is not fixed due to the deformation of the asperity, which improves the force of the asperity, and the micro-hole reduces the contact zone, thereby reducing the contact of the asperity and the pressure extreme point and reducing the pressure.Micropores reduce the temperature and enhance the wear condition of the end face. Small surface roughness can decrease the risk of end face wear.
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Wang, Jian Xi, Wei Xiao, and Xiao Dong Zhang. "Effect of Wheel/Rail Friction on Rolling Contact Fatigue." Advanced Materials Research 160-162 (November 2010): 1636–40. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.1636.
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A numerical model is presented to analyze effect of wheel/rail friction on rolling contact fatigue. A three-dimension finite element model of rail is built up to investigate the rail stresses and strain around wheel/rail patch. Then, based on the critical plane concept, a new model was proposed to predict the rolling contact fatigue (RCF) crack initiation life under different wheel/rail frictions by using stress and strain on the critical plane as fatigue parameter. The numerical results obtained show that the wheel/rail friction coefficient has a great impact on the fatigue crack initiation life.and the curve of fatigue crack initiation life under different wheel/rail friction coefficient is roughly "S" type. The results are very useful in the wheel/rail friction management and determining grinding interval and grinding removal.
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Li, Xiao Guang, and Ping Zhao. "Study on Tribological Performances of Friction Plate on MW Wind Power." Applied Mechanics and Materials 217-219 (November 2012): 314–17. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.314.
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The effects of contact pressure and sliding velocity and different environment conditions on the frictional coefficient of friction plate on MW wind power were studied by fatigue testing machine. The results show that the coefficient of static friction and difference between static and dynamic reduced with the increase of sliding speed, and reduced first and then increased and then reduced with the increase of contact pressure, and the change of dynamic friction coefficient was relatively flat with velocity and pressure under dry friction. The impact of water on the triological performance was the large, followed by oil when considering environment factors. Water and pressure and oil were the main influencing factors in considering all factors comprehensively.
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WIERZCHOLSKI, Krzysztof, and Andrzej MISZCZAK. "IMPACT OF ADHESION AND VISCOSITY FORCES ON FRICTION VARIATIONS IN BIO-TRIBOLOGICAL SYSTEMS." Tribologia 278, no. 2 (2018): 139–51. http://dx.doi.org/10.5604/01.3001.0012.6987.
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The classical theory of lubrication holds that the lubricant dynamic viscosity increments cause the increments of hydrodynamic pressure, as well as friction forces and wear. In the case of high values of hydrodynamic pressure, it very often has a significant impact on the friction coefficient. New achievements in the field of micro-and nano-tribology provide for new hypotheses on the decrements and increments of the friction coefficient in the case of the lubricant viscosity increments. Experimental investigations have shown that, even in the case of decrements of the friction coefficient with the lubricant viscosity increments, such decrements are very often lower than simultaneous hydrodynamic pressure increments which results in the friction force increments with the lubricant viscosity increments. In biological friction nods, we can observe a varied impact of the biological lubricant viscosity on the friction force and friction coefficient values. The abovementioned impact is caused by the adhesion and cohesion forces occurring between the biological fluid particles flowing around the phospholipid bilayer on the superficial layer of the cartilage with varied wettability and hydrogen ion concentration. The wettability (We) and power hydrogen ion concentration (pH) have a significant impact on the physiological fluid or biological lubricant viscosity variations and, as a result, on the friction forces and friction coefficient. This paper describes the abovementioned impact and the process of friction forces and friction coefficients variations in biological friction nods.
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Osakue, Edward E., and Robert J. Rogers. "An Experimental Study of Friction During Planar Elastic Impact." Journal of Pressure Vessel Technology 123, no. 4 (2001): 493–500. http://dx.doi.org/10.1115/1.1408304.
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Low-speed oblique elastic impacts frequently occur in heat exchangers and other equipment having loosely supported tubes or pipes. In order to experimentally study friction during such impacts, a pendulum-type impact apparatus was developed. A hardened steel sphere at the end of the pendulum collides with a flat steel surface for a range of approach velocities and angles. The present investigation examined eight velocities from 8 to 93 mm/s and impact angles (measured from the common normal) of 0 to 75 deg for each velocity. The normal and tangential contact force waveforms were measured using a triaxial piezoelectric force transducer which was dynamically calibrated. As expected, the results show that the tangential force is less than the limiting Amontons-Coulomb friction predictions at low impact angles. Two regimes of stick-slip and gross-slip friction are clearly distinguished by a new friction parameter called the specific traction ratio. Tangential force reversal was observed at low impact angles, indicating local tangential oscillations. The stick-slip results are consistent with a partial-slip model where the contact zone has a central sticking region surrounded by a ring area undergoing slip.
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Wang, Ziping. "Study of the Impact of Sino-US Trade Friction on Oil Prices." International Journal of English Literature and Social Sciences 8, no. 4 (2023): 147–58. http://dx.doi.org/10.22161/ijels.84.25.
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Since 2017, Sino-US trade frictions have continued, while international crude oil prices have fluctuated sharply, and China's crude oil procurement is faced with greater risk of price fluctuations. This paper uses the EGARCH model to study the impact of Sino-US trade frictions on oil prices, and finds that intensified trade events significantly reduce oil price returns and increase the volatility of oil prices, but moderating trade events have no significant impact on oil prices. The impact of intensified trade events on oil prices has the feature of mean recovery. The yield of oil prices decreases most on the first day but recovers to the original level on the third day. Moreover, moderating trade events have no significant dynamic impact on oil prices. The research results of this paper show that there is a leverage effect on the impact of sino-US trade friction on oil prices, that is, negative news has a greater impact on the price than positive news. Further analysis shows that sino-US trade frictions affect oil prices mainly through the mechanism of market sentiment.
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Qiu, Ruiyang, and Ruihai Li. "Finite-time stability of spring-mass system with unilateral impact constraints and frictions." Modern Physics Letters B 34, no. 30 (2020): 2050341. http://dx.doi.org/10.1142/s0217984920503418.
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In this paper, a spring-mass system with impacts and frictions is formulated by the impulsive differential system. An energy-like Lyapunov function and an auxiliary step function are constructed to analyze the finite-time stability of such impact system with a time-varying external force and sliding friction as well as air resistance. We establish the sufficient conditions of finite-time stability for three cases of the spring-mass system, and present numerical simulations for each case to verify the validity of the theoretical results.
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Nagashima, Takaaki, Taichi Sato, and Kihachiro Tanaka. "59155 Simultaneous Vibration Control in Two Directions Using an Impact Damper System(Contact, Impact, and Friction)." Proceedings of the Asian Conference on Multibody Dynamics 2010.5 (2010): _59155–1_—_59155–9_. http://dx.doi.org/10.1299/jsmeacmd.2010.5._59155-1_.
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Burdzik, R., P. Folęga, B. Łazarz, Z. Stanik, and J. Warczek. "Analysis of the Impact of Surface Layer Parameters on Wear Intensity of Friction Pairs / Analiza Wpływu Parametrów Warstwy Wierzchniej Na Intensywność Zużycia Par Ciernych." Archives of Metallurgy and Materials 57, no. 4 (2012): 987–93. http://dx.doi.org/10.2478/v10172-012-0110-8.
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The study discussed in the paper consisted in testing the impact of surface layer parameters on wear intensity of friction pair components. The study was conducted having taken additional operational factors into consideration, namely the friction conditions (presence of lubricant) and the value of loads affecting the contact zone of the samples being tested. The study constituted laboratory tests of wear and were conducted by means of a T-01M type laboratory test stand used to experimentally analyse frictional cooperation of various materials used in structural components of motor vehicles. The friction pairs examined were previously operating in a pin-on-disk system under various conditions. The materials of the friction pairs tested at the stand were subjected to heat treatment and chemical processing in order to attain specific parameters of their surface layers. The studies conducted enabled determination of the abrasive wear values for the material samples tested having entailed the surface layer parameters and the factors related to operation of actual structural components used in automotive engineering. An additional advantage of the studies conducted was the possibility to establish actual coefficients of friction occurring in specific friction pairs. Establishing the actual values of friction coefficients for the materials of friction pairs under specific conditions and having taken the impact of the surface layer parameters into consideration enabled identification of the reasons for excessive surface wear. Hence a reference can be made between the stationary tests undertaken and actual components cooperating with one another in kinematic pairs of machines. The utilitarian premise resulting from the studies conducted is the necessity of paying particular attention to surface layer parameters while designing friction pairs for machines.
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Smith, John R., Jeffrey B. Lund, and Robert K. Galloway. "Friction on PDC Cutters at High Normal Stress." Journal of Energy Resources Technology 124, no. 3 (2002): 146–53. http://dx.doi.org/10.1115/1.1485745.
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The impact of frictional forces on the overall forces when drilling with a PDC bit has previously been implied by models and by single cutter and bit tests. This report describes new experiments to measure friction between three different bit surface materials and two different rocks over a wide range of normal stresses in up to four different fluids. Polished PDC cutters are shown to have lower frictional forces on the face of the cutter than standard cutters in both water and mineral oil. The measured friction coefficients were generally higher than reported in previous studies.
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Quan, Song, Guo Yong, Gong Jun, Xuedong Liu, Jin Yongping, and Yang Shuyi. "Effect of fish scale texture on friction performance for reciprocating pair with high velocity." Industrial Lubrication and Tribology 72, no. 4 (2019): 497–502. http://dx.doi.org/10.1108/ilt-09-2019-0398.
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Purpose This paper aims to study the frictional performance of reciprocating pair with high velocity by using hydrodynamic lubrication principle and fish scale textured piston model. Design/methodology/approach Based on the idea of function characteristic approximation and coordinate change, a mathematical representation model of imitating fish scale texture pit section is established. According to the principle of dynamic pressure lubrication of the textured fluid, a three-dimensional numerical model of flow field for fish scale texture is established without considering cavitation. Numerical analysis of the model carp scale texture unit by orthogonal experimental design and FLUENT software is carried out. Findings Effects of fish scale pit texture on friction properties for a reciprocating pair piston surface with high velocity (impact piston) are acquired. Effects of texture characterization parameters and flow rate on the surface friction performance for impact piston are found. Effects of different characteristic parameters combination of imitating fish scale texture on friction performance for impact piston surface are obtained. Originality/value The model is an effective tool to study the friction and wear of reciprocating pair with high velocity. The effects of fish scale textured piston pair supply a theory lead to design the reciprocating pair with better friction performance. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2019-0398
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Sekhar, S. Ravi, D. Govardhan, R. Karthikeyan, and Ram Subbaiah. "Influence of Process Parameters on Physical and Mechanical Parameters of Friction Surfaced Deposits on Low Carbon Steel." E3S Web of Conferences 184 (2020): 01005. http://dx.doi.org/10.1051/e3sconf/202018401005.
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Friction surfacing is the innovative technique employed for the reformation of a metal surface. Frictional heat produced between two interaction surfaces is utilized to deposit one metal above the other professionally. In this process, the quantity heat needed for depositing is essentially be influenced by on choice of process constraints such as friction force, revolving speediness of mechtrode, table speediness and reside duration. Stainless steel was selected for friction surfacing on mild steel in this experiment, the number of experiments were decided based on factorial design. Investigational task of friction surfacing was executed and the responses were quantified from the deposits which were accepted after thorough inspection. Through regression equations the impact of procedure features on each response was determined.
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Zhang, Yanlong, Rui Zhang, and Li Wang. "Oblique impact dynamic analysis of wedge friction damper with Dankowicz dynamic friction." Electronic Research Archive 32, no. 2 (2024): 962–78. http://dx.doi.org/10.3934/era.2024047.
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<abstract> <p>Aiming at the wedge friction damper for freight train bogie, considering Dankowicz dynamic friction, the mechanical model of a three-degree-of-freedom inclined impact vibration system with gap and dynamic friction, is simplified. The mechanical model of the system is established, the motion equation of the system is obtained, and the motion state and conditions of the system are analyzed. The Poincare map is constructed by selecting a fixed collision section, and the response of the system is solved by the fourth-order Runge-Kutta numerical method with variable step size. The transition process of the system motion and the phenomenon of sticking and chatter are analyzed by numerical simulation when the external excitation frequency changes. The results show that: 1) Under certain parameters, with the change of excitation frequency, the system undergoes periodic doubling bifurcation, inverse periodic doubling bifurcation, Grazing bifurcation and Hopf bifurcation, and there is a "periodic bubble" phenomenon in the system motion. When the system excitation frequency is between 3.35–3.55, 4.425–6.12, and 7.34–7.758, the system motion has chatter and sticking phenomena; when the system excitation frequency is between 1.75–3.24 and 3.92–4.425, the sticking phenomenon disappears, and only the chatter phenomenon exists. 2) When other parameters remain unchanged, and the mass ratio decreases from 1.15 to 0.85, nonlinear dynamic phenomena such as the transition between periodic bubbles and chaotic bubbles will be found. In this paper, the bifurcation and chaos characteristics of the impact vibration system of the wedge friction damper are studied, and the rich friction-induced vibration forms such as chatter and sticking are revealed, which provides a reference for improving the stability of vehicle operation and the selection of parameters in vehicle vibration reduction design in engineering practice.</p> </abstract>
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Badertscher, Jeff, Kenneth A. Cunefare, and Aldo A. Ferri. "Braking Impact of Normal Dither Signals." Journal of Vibration and Acoustics 129, no. 1 (2006): 17–23. http://dx.doi.org/10.1115/1.2346689.
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Dither control is a method of introducing high-frequency control efforts into a system to suppress a lower-frequency disturbance. One application of dither control is the suppression of automotive brake squeal. Brake squeal is a problem that has plagued the automotive industry for years. Placing a piezoceramic stack actuator in the piston of a floating caliper brake creates an experimental normal dither system. Many theoretical models indicate a reduction in the braking torque due to the normal dither signal. Using a Hertzian contact stiffness model, the loss in friction is due to lowering the average normal force. There are also theories that the dither signal eliminates the “stick-slip” oscillation causing an effective decrease in the friction force. Yet another theory indicates that the effective contact area is reduced, lowering the mean coefficient of friction. A particular approach considering a single-degree-of-freedom friction oscillator predicts a maximum friction reduction of 10%, occurring at the primary resonance of the system. This paper will concentrate on validating this claim by experimentally determining braking torque reduction for a variety of dither control signals. Several dither control frequencies were chosen at system resonances, while others were chosen at frequencies most likely to provide control of the system. These frequencies were chosen based on previous squeal suppression research. The results indicate that dither control frequencies at system resonances have a greater impact on the braking system’s performance. In general, dither control reduces braking torque by no more than 2%.
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Juste-Lorente, Óscar, Mario Maza, Mathieu Piccand, and Francisco J. López-Valdés. "The Influence of Headform/Helmet Friction on Head Impact Biomechanics in Oblique Impacts at Different Tangential Velocities." Applied Sciences 11, no. 23 (2021): 11318. http://dx.doi.org/10.3390/app112311318.
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Oblique impacts of the helmet against the ground are the most frequent scenarios in real-world motorcycle crashes. The combination of two factors that largely affect the results of oblique impact tests are discussed in this work. This study aims to quantify the effect of the friction at the interface between the headform and the interior of a motorcycle helmet at different magnitudes of tangential velocity. The helmeted headform, with low friction and high friction surface of the headform, was dropped against three oblique anvils at different impact velocities resulting in three different magnitudes of the tangential velocity (3.27 m/s, 5.66 m/s, 8.08 m/s) with the same normal component of the impact velocity (5.66 m/s). Three impact directions (front, left-side and right-side) and three repetitions per impact condition were tested resulting in 54 impacts. Tangential velocity variation showed little effect on the linear acceleration results. On the contrary, the rotational results showed that the effect of the headform’s surface depends on the magnitude of the tangential velocity and on the impact direction. These results indicate that a combination of low friction with low tangential velocities may result into underprediction of the rotational headform variables that would not be representative of real-world conditions.
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Stosiak, Michał, Mykola Karpenko, Adam Deptuła, et al. "Modelling and Experimental Verification of the Interaction in a Hydraulic Directional Control Valve Spool Pair." Applied Sciences 13, no. 1 (2022): 458. http://dx.doi.org/10.3390/app13010458.
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This study examined the impact of mechanical oscillation on a hydraulic directional control valve. Particular attention was paid to the oscillating movement of the spool of the hydraulic directional control valve resulting from this impact. Different models of fluid and mixed friction were considered. The models analysed accounted for the relative movement of the directional control valve body and the fact that it is kinematically excited by external mechanical oscillations. It was observed that the mixed friction model, where the frictional force is considered to be the sum of molecular forces acting in micro-areas of contact and drag forces in the fluid, was the best for describing the movement of the spool for a specific spool oscillation frequency. This model yielded significantly more consistency between the simulated and experimental results than the classic fluid friction model.
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Seon, Junghoon, and Sang Lyong Joo. "Starting Overnight Trading and Changes in Market Frictions: Focusing on KOSPI 200 Futures." Asia Europe Perspective Association 16, no. 4 (2019): 185–200. https://doi.org/10.31203/aepa.2019.16.4.09.
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This paper investigates the impact of starting overnight trading for KOSPI 200 futures on market frictions in regular trading hours. On November 16, 2009, Korea Exchange the extended trading hours by starting overnight trading via Chicago Mercantile Exchange GLOBEX system. Thus non-trading hours out of 24 hours is reduced from 17.75 hours to 6.75 hours. We utilize this event as a natural experiment to investigate whether market frictions in regular trading has changed due to the reduction in non-trading hours. Stoll(2000) points out that the more compensation is need to be paid to liquidity providers in the market, as market friction gets bigger. That is why market friction can be measured by trading costs that are paid for immediacy to liquidity providers. Since any factor that restricts trading activity and increases trading costs can be considered as market friction, we can regard periodical closures in an exchange as a factor of market friction. The existence of periodical closures itself restricts trading activity. The extension of trading hours via starting overnight trading might expand the opportunity of trading and, thus, affect market frictions. Using intraday data measured by a 60-minute interval, we examine changes in total frictions and it’s components, real friction and informational friction during KOSPI 200 furures’regular trading hours before and after the event. The real friction is defined as the component of trading costs that consume real resources of liquidity providers (e.g. order processing costs and inventory holding costs). Meanwhile the informational friction is defined as the components of trading costs that redistribute investors’wealth without consuming real resources of liquidity providers (e.g asymmetric information costs). We measure total friction as the sensitivity of trading costs to the absolute value of order imbalances. Real friction (informational friction) is measured by the sensitivity of trading costs to expected (unexpected) component of the absolute value of order imbalances. This method of measurement is based on information-based market microstructure theory including Hasbrouck (1991). According to the theory, the unexpected component of order flows is more likely to impound private information than the expected component. We divide a trading day into six 60-minute intervals and use Quoted Spread Ratio (QSR) and Effective Spread Ratio (QSR) in order to measure trading costs. The changes in market frictions that has occurred after the event can be summarized as follows: Total frictions and real frictions have decreased, but informational frictions has not changed. The reason for this result is deduced as follows: As overnight trading increases investors’trading opportunity, the need for closing positions before the market close in order to evade overnight portfolio risk and making trades reflecting accumulated information just after the market open has decreased. This lessen order imbalances and thus, reduces real costs of liquidity providers such as order processing or inventory holding components of spreads during regular trading session. As regular trading session’s informational environment like the arrival rate of informed traders and their trading activity are not affected by the increased trading opportunity via overnight, asymmetric information costs, and thus informational frictions are likely to be unaffected.
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Bevilacqua, M., FE Ciarapica, A. Forcellese, and M. Simoncini. "Comparison among the environmental impact of solid state and fusion welding processes in joining an aluminium alloy." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 234, no. 1-2 (2019): 140–56. http://dx.doi.org/10.1177/0954405419845572.
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The life-cycle assessment methodology was used to evaluate the environmental impact of friction stir welding of AA5754-H114 aluminium alloy sheets. Other works in literature considered the environmental impact of friction stir welding, but in this study the influence of different process parameters on midpoint category impacts were analysed. Friction stir welding was performed under different values of rotational and welding speeds. Moreover, pin tool wear and mechanical properties of joints were also evaluated. The pre- and post-processing stages were also considered. Raw materials, energy and all inputs associated with each stage of product life cycle were collected and evaluated to analyse the environmental impact index. The results showed that, irrespective of the rotational speed, the lowest welding speed investigated leads to the highest energy consumption and, consequently, to the highest values of the midpoint category impact. On the contrary, at the highest welding speed, the environmental impact assumes the lowest values. By concerning the rotational speed, its effect on the midpoint category impact is strongly reduced compared with the one given by the welding speed. A performance index, obtained by considering both the midpoint category impact and ultimate tensile strength of the joints, was also defined. Finally, the environmental sustainability of friction stir welding was compared with two different fusion welding technologies, namely gas tungsten arc welding and laser beam welding. The results showed that friction stir welding was characterized by midpoint category impacts much lower than those of the gas tungsten arc welding, while such discrepancies decreased with the laser beam welding.
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Liu, Caishan, Hongjian Zhang, Zhen Zhao, and Bernard Brogliato. "Impact–contact dynamics in a disc–ball system." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 469, no. 2152 (2013): 20120741. http://dx.doi.org/10.1098/rspa.2012.0741.
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This paper concerns a disc–ball system, in which a moving ball collides against a disc resting on a rough, fixed horizontal surface. The complexity in such a simple object is due to the presence of the line contact between the disc and the fixed plate, which significantly influences the impact-generated state of the disc. We deal with this problem in a uniform framework that encapsulates different structures of the mathematical model, including contacts, impacts, stick–slip in friction, as well as the transitions among different states of the variable-structure dynamics. We design specific experiments that provide useful information to help determine the macroscopic parameters in impact and friction. Other complicated cases concerned with the couplings between impacts and friction are theoretically and experimentally investigated. Excellent agreements between numerical and experimental results support our theoretical developments.
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Klüppel, Manfred, and Gert Heinrich. "Rubber Friction on Self-Affine Road Tracks." Rubber Chemistry and Technology 73, no. 4 (2000): 578–606. http://dx.doi.org/10.5254/1.3547607.
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Abstract A basic theoretical concept of rubber friction on rough surfaces is presented that relates the frictional force to the dissipated energy of the rubber during sliding stochastic excitations on a broad frequency scale. It is shown that this is of high relevance for tire traction and allows for a prediction of the likely level of friction of tread compounds on the basis of viscoelastic data. The impact of both, the frequency dependent loss- and storage modulus on the frictional force during sliding of tires on rough tracks, is demonstrated quantitatively for different sliding velocities. The effect of the surface roughness of road tracks is described by three characteristic surface descriptors, i.e., the fractal dimension and the correlation lengths parallel and normal to the surface. These descriptors can be obtained from a fractal analysis of the road texture via stylus- or laser measurements. In particular, it is shown that the applied model of rubber friction is in agreement with the classical friction data of Grosch, who found a broad maximum for the friction coefficient with increasing sliding speed. The broadness of the friction maximum is shown to be directly related to the broadness of the roughness scale of the surface.
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Pranata, Syendy, Sugiyarto Sugiyarto, and Erwanto Erwanto. "Pengaruh Variasi Waktu Gesek Pada Pengelasan Gesek (Friction Welding) Terhadap Kekuatan Impak Baja AISI 1045 Dengan Stainless Steel." Jurnal Inovasi Teknologi Terapan 1, no. 1 (2023): 114–20. http://dx.doi.org/10.33504/jitt.v1i1.73.
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The Friction Welding method is a welding method that utilizes heat energy caused by the friction of the two materials to be joined, the heat from the friction will cause the material to become semisolid or plastic. The purpose of this research was to determine the effect of variations in friction time and distance suppression carried out on impact strength and hardness tests using the Friction Welding method on AISI 1045 steel material connected to Stainless Steel 304. The method used is the Response Surface Method (RSM) to determine impact strength value of AISI 1045 steel which is connected to Stainless Steel 304 after the friction welding process is carried out. The variation used in this study is the variation of the pressure distance and friction time. The size of the impact test specimen is made according to the impact test standard, namely ASTM E23. The greatest impact test results were found in specimen number 6 with a pressing distance of 4.41 mm and a friction time of 5 minutes, namely 0.156 Joule/mm2. While the lowest impact value is found in specimen number 1 with a pressing distance of 2 mm and a friction time of 4 minutes, namely 0.038 Joule/mm2.
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Ye, Xueqi, Jie Zhang, and Ping Chen. "Impact of Interatomic Potentials on Atomic-Scale Wear of Graphene: A Molecular Dynamics Study." Lubricants 12, no. 7 (2024): 245. http://dx.doi.org/10.3390/lubricants12070245.
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Selecting an appropriate empirical interatomic potential is essential for accurately describing interatomic interactions and simulating the friction and wear of graphene. Four empirical potentials—Tersoff, REBO, AIREBO, and LCBOP—were employed in molecular dynamics simulations to study the wear process of graphene at the atomic scale. The frictional process of graphene was found to be divisible into three distinct phases: elastic deformation, plastic deformation, and wear. Using a progressively increasing load method, the critical load for each phase of graphene under four different empirical potentials was identified. Furthermore, the formation of Stone–Wales (SW) defects, bond distribution, bond breaking and healing, and wrinkle formation were analyzed in detail. Finally, a comparison was made with previous experimental results regarding friction coefficient and wear morphology.
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Srivastava, Kartik, and Ajay Kumar. "The Impact of Road Side Friction on the Traffic Flow of Arterial Roads in Varanasi." Engineering, Technology & Applied Science Research 13, no. 4 (2023): 11157–65. http://dx.doi.org/10.48084/etasr.5897.
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Varanasi's prominence as a cultural and historical center means it receives visitors from all over the world. The city's tourism industry is a boon to the local economy. Better transportation infrastructure is crucial to attracting more tourists and increasing revenue. Varanasi is currently experiencing terrible difficulties due to various roadside frictional activities. Vehicle ownership grows in tandem with population growth. The increase in the number of vehicles on the road significantly impacts the reliability of the transportation network since land availability is fixed. The various roadside frictional activities usually found in the streets of Varanasi are on-street parking, pedestrian crossing, and Non-Motorized Vehicles (NMVs). There are not enough legal on-street parking and segregated lanes for NMVs/slow-moving vehicles or demarcation for pedestrian movements in the old city of Varanasi. Vehicles in Varanasi are traditionally parked on the street due to the narrow carriageways. Slow-moving vehicles are forced to move with fast-moving vehicles, and pedestrian crossings affect traffic flow. Integrated movement of slow-moving vehicles and rapid-moving vehicles affects traffic speed, pedestrian crossings impact the Level of Service (LOS), and on-street parking results in the reduction of the effective carriageway width and, hence, road capacity. This paper aims to identify the impact of pedestrian crossings, NMVs, and on-street parking on the traffic flow, speed, capacity, and LOS of urban arterial roads in Varanasi. To achieve this objective, two case studies were considered: the base section (with minimum side friction) and the friction section (with maximum side friction). The videography method was used for data collection. Nine hours of data were collected from 9:30 am to 6:30 pm. The video was played on the screen for data extraction. The speed model was developed by using fundamental diagram methods. Speed-density curve was drawn using Greenshield’s model. The speed-flow curve was derived from the speed-density curve to estimate the capacity at the base and friction sections. Reduction in capacity was determined by comparing friction section capacity with base section capacity. V/C ratio of a particular road compared with the V/C value provided by IRC 106 to predict LOS. A correlation model was developed between the percentage reduction in capacity and road width. Increase in parking, the proportion of NMVs, and pedestrian crossing frequency reduce the traffic flow. It was observed that a 6.42% capacity loss occurs at a 7.00% reduction in effective width, and a 35.09% loss occurs at a 36.02% reduction in effective width. Roads with frictional activities found their LOS class affected up to LOS-E (for the Bhelupur section).