Tangential Friction Force Research Articles

Development and Investigation of a Grasping Analysis System with Two-Axis Force Sensors at Each of the 16 Points on the Object Surface for a Hardware-Based FinRay-Type Soft Gripper.

The FinRay soft gripper achieves passive enveloping grasping through its functional flexible structure, adapting to the contact configuration of the object to be grasped. However, variations in beam position and thickness lead to different behaviors, making it important to research the relationship between structure and force. Conventional research using FEM simulations has tested various virtual FinRay models but replicating phenomena such as buckling and slipping has been challenging. While hardware-based methods that involve installing sensors on the gripper and the object to analyze their states have been attempted, no studies have focused on the tangential contact force related to slipping. Therefore, we developed a 16-way object contact force measurement device incorporating two-axis force sensors into each of the 16 segmented objects and compared the normal and tangential components of the enveloping grasping force of the FinRay soft gripper under two types of contact friction conditions. In the first experiment, the proposed device was compared with a device containing a six-axis force sensor in one segmented object, confirming that the proposed device has no issues with measurement performance. In the second experiment, comparisons of the proposed device were made under various conditions: two contact friction states, three object contact positions, and two object motion states. The results demonstrated that the proposed device could decompose and analyze the grasping force into its normal and tangential components for each segmented object. Moreover, low friction conditions result in a wide contact area with lower tangential frictional force and a uniform normal pushing force, achieving effective enveloping grasping.

Influence of two kinds of clearance joints on the dynamics of planar mechanical system based on a modified contact force model

This study takes the slider-crank mechanism with revolute joint and translational joint as the research object and studies the contact force model of the clearance joint and the influence of the hybrid clearance joints on the nonlinear dynamic behavior of the mechanism. A modified contact force model is established based on the simplified elastic oscillator model, which can be used as a normal force in clearance joint. In the new contact force model, the component n of the indentation depth can be arbitrarily selected and it can support the calculation of contact force for both fully elastic recovery, non-elastic recovery and fully inelastic recovery. Based on the LuGre friction model, the tangential friction model of the clearance joint is given. Thus, the normal force and tangential force during the dynamic contact of the clearance joint are formed. Combining Lagrange’s equations of the first kind with the modified normal force and tangential friction force, the dynamic equations of the multi-body system with clearance joints are established. The Baumgarte stabilization method is used to improve the numerical stability. The correctness of the dynamic prediction model in the mechanism with clearance joint is verified by experiment. The dynamic analysis of the slider-crank mechanism with mixed clearance joints shows that the revolute clearance joint has a greater influence on the mechanism than the translational clearance, and the revolute clearance joint plays a leading role in the dynamic response.

Flow behavior during solder/Cu column friction plunge micro-welding

PurposeThe author proposed a friction plunge micro-welding (FPMW) method and applied it to column grid array packaging to realize the connection of copper columns without precision molds assisted positioning. The purpose of this paper is to study the flow behavior of the solder undergoing frictional thermo-mechanical action during the FPMW and to determine the source of the solders in the micro-zones with different microstructure characteristics near the solder/Cu column friction interface.Design/methodology/approachThree kinds of Sn58Bi/SAC305 and SAC305/Pb90Sn composite solder samples were designed to study the flow behavior of the solder during FPMW using Bi and Pb as tracer elements.FindingsThe results show that most of the solders in the position occupied by the copper column was softened and plasticized during the welding process and was extruded to side of the copper column, flowing axially, circumferentially and radially along a trajectory similar to a conical spiral line. Under the drive of the tangential friction force and the radial hold-tight force, the extruded out visco-plastic solders fully mixed with the visco-plastic solders on the sides of the copper column, and bonded with the solders that deformed plastically on the periphery, so that a stir zone and a dynamic recrystallization zone finally evolved. The outside plastically deformed solders evolved into a thermo-mechanical affected zone.Originality/valueThe flow behavior of the solder during the FPMW was determined, as well as the source of the solders in micro-zones with different microstructure characteristics.

Frequency response variability in friction-damped structures due to non-unique residual tractions: Obtaining conservative bounds using a nonlinear-mode-based approach

Under static dry friction, the tangential friction force (residual traction) is non-unique within the Coulomb’s limits. The actual value of the residual traction depends on the load history and is generally unknown. This phenomenon can lead to a large variability of the vibration response if at least one but not all contacts are permanently sticking and there is coupling between tangential displacements and normal forces. In the present work, a method is developed that allows obtaining conservative upper and lower bounds of the frequency response. Focusing on primary resonances with well-separated modes, a Nonlinear-Mode-based approach is pursued. First, bounds of the nonlinear modal properties, specifically the amplitude-dependent modal frequency, damping ratio and deflection shape are computed. Then, interval arithmetic is applied to the closed-form expression governing the amplitude-frequency curves for a given harmonic excitation force. The method is numerically demonstrated for a planar structure coupled with two Jenkins-type contact elements. It is shown that for this system, the bounds of the modal properties can be simply obtained from the frictional limit cases (barely sticking contact), so that a potentially costly numerical optimization is not needed. It is concluded that the obtained frequency response bounds are indeed conservative but not overly conservative, and the method is computationally highly efficient as it relies on analytical developments. The developed method of Nonlinear-Mode-based forward propagation seems attractive also for other sources of uncertainty and experimentally identified bounds.

Pounding responses of a base-isolated liquid storage tank under bidirectional earthquakes

ABSTRACT The probability of seismic pounding of sliding isolation liquid storage tank (LST) is high. Considering normal impact force and tangential friction force at the location of pounding under bidirectional earthquake, a 3-D calculation model of sliding isolation LST is established based on finite element method. Pounding dynamic responses under unidirectional and bidirectional earthquakes are comparatively investigated, and frequency domain analysis is also conducted. Finally, mitigation measure for adverse effect caused by the pounding is proposed. Results show that the influence of concrete nonlinearity on the pounding is very significant. Dynamic responses are significantly increased due to the pounding, and the maximum tensile stress of tank wall reaches to 2.510MPa under ChiChi earthquake, which exceeds the concrete tensile strength. Besides, pounding causes the high frequency response. Reasonable rubber cushion design can ensure that the maximum displacement of the sliding isolation LST is limited by the moat wall and the failure probability caused by the pounding is decreased.

Experimental investigation on acoustic emission in fretting friction and wear of bolted joints

Fretting between bolted interfaces may change the dynamic characteristics of structures under vibration loading. The acoustic emission (AE) technique has been successfully used to investigate friction and wear mechanisms between different kinds of contact pairs. This paper experimentally investigates the AE signals of a bolted joint structure during friction and long-time fretting wear to explore the relationship between AE characteristics and interface fretting behaviors. A test apparatus dedicated to the study of fretting behaviors of bolted joints together with an AE acquisition system is used to carry out the experimental tests. Relative displacement, tangential friction force and the related AE waveform features are obtained simultaneously to better relate acoustic emission signals with hysteresis loops. The effects of external excitation amplitude and fretting wear cycles are investigated. The frequency signatures of the individual burst acoustic emission event under different excitation amplitudes and wear stages are analyzed. Results show that AE events mainly occur in the micro-slip and the gross-slip regime, and AE technique is more sensitive to the transition point from micro-slip to gross-slip regime. As the external excitation amplitude increases, the value of most AE parameters is gradually increased. As the fretting wear cycles increase, evolutions of bolt preload, frictional coefficients, and AE parameters first show a significant change and then become asymptotically stable. Furthermore, the frequency intensity and range will increase with the increase of excitation amplitude and decrease with the wear cycles.

An analytical solution of the rope-sheave contact in static conditions based on a bristle model

This paper presents an analytical solution for the rope-sheave contact problem in static conditions, also applicable to belt-pulley problems and similar mechanisms. The rope is assumed under constant and unequal loads at the two ends, as in an elevator when the brake is acting on the drive sheave and the weights of the cabin and counterweights are different. The rope is assumed to behave as a rod without bending stiffness. Assuming a bristle model for the rope-sheave contact and Coulomb friction, the balance of forces in a differential slice of the rope is used to obtain a closed-form solution for the axial force field and the normal and tangential contact force fields. This analytical solution is found first in the case of a bristle model with tangential flexibility but axially rigid. Then, the model is extended to axially flexible bristles, that allows the rope to sheave relative penetration. The solution is valid until one cross-section of the rope achieves the saturated tangential friction force. The value of the axial load when this condition is met is identified. If the high-load further increases, the rope in contact with the sheave is separated in two areas, the area next to the low-load remains fully stuck to the sheave while the area next to the high-load shows exactly the saturated friction force. This paper calculates the angle of separation between the two areas and the axial force field and normal and tangential contact force fields, being all these functions piece-wisely defined. Finally, the paper presents numerical results for a particular example of all the analytical solutions.

Modeling of a detailed bow spring centralizer description in stiff-string torque and drag calculation

Flexible bow spring centralizers are commonly used in the drilling industry to ensure a good centralization of casings inside the borehole. A bow spring centralizer consists of multiple bows evenly spaced around the tubular. They are attached to the casing at multiple locations via connections or rings, and run-in hole such that the bows are sliding against the borehole. To provide a good centralization, the bows must be stiff enough to push the casing away from the borehole. Also, it must be flexible enough to avoid large contact forces and consequently friction forces that can cause excessive drag. This paper aims to present a theoretical model for bow-spring centralizers and its implementation in a stiff-string torque and drag model based on the finite element method.Our modeling approach assumes that the flexible centralizer bows are identical. Each bow acts independently from the others and could be in contact with the borehole or not, depending on the lateral displacement and orientation of the centralizer. The bow force follows a power law based on a constant stiffness and a stiffness power coefficient that are computed based on test measurements provided by the manufacturer.When introduced in a stiff-string torque and drag model, the contact forces are computed on each individual bow. For drag forces, the bows are assumed to be non-rotating inside the borehole, so the axial friction force at a bow spring is related to the algebraic sum of all bow contacts. When the casing is rotating inside the centralizer, a tangential friction force is generated between the casing and bow spring rings. It is related to the resultant contact force i.e., the vector sum of all bow contacts.An example of the calibration for a bow-spring centralizer is studied in this paper. The theoretical bow-spring model showed its capacity to have a good interpretation of the measurements. It also showed the importance of specifying the testing condition with regards to the possible clearance between the casing and centralizer rings. The finite element torque and drag model is firstly validated against another model. When applied to a case study of running in hole a casing string with bow-spring centralizers, the model shows its effectiveness to describe the casing centralization along the wellbore as well as the tension variations at the surface.

Maximizing tangential frictional forces effects in bidimensional collisions: a study of the tangent restitution coefficient through a video analysis approach

In this work we used the video analysis technique to investigate the contribution of the friction forces to the dynamic of a series of oblique collisions of a basketball against the floor’s surface. This contribution was evaluated through the tangent restitution coefficients associated to these collisions, which, in general, presented values distinct from the unit, proving, thus, its importance. Additionally, the appreciably values bigger than unity obtained for this quantity quantitatively confirms the physical scenario suggested in a previous work by some of the authors [1] which is governed by the torques transmitted to the ball during the successive collisions and characterized by variations on the magnitudes and even on the directions of the friction forces. To support this dynamic we considered a ball of relatively sizeable radius and mass, and launched with a certain spin velocity. Also, in order to increase the friction coefficient, the floor’s surface was covered with a rough and rubberized material.

Tribological performance of thermal sprayed coatings under abrasive conditions

In this work, the tribological behaviour of thermally sprayed titanium and chromium ceramic-based coatings was investigated under abrasive conditions. Their structure was studied by a scanning electron microscope (SEM), while their hardness was evaluated using a microhardness tester. To study the strength of these ceramic coatings under abrasion conditions, reciprocating sliding experiments were carried out in a high-precision (10 mN resolution, 1000 Hz data acquisition) pin-on-disk apparatus and by using a Ø6 mm corundum ball to generate high contact pressures (1.5 GPa). To thoroughly investigate the friction evolution of the tribo-system, three-dimensional mapping of the tangential friction forces (triboscopy) was performed. Following the abrasion experiments, the wear of these coatings was measured using confocal microscopy. The obtained friction and wear results were compared to state-of-the-art materials and coatings that are currently being used in various industrial applications. From this comparison, it was found that the titanium and chromium ceramic-based coatings have comparable if not better tribological properties for the given conditions. The main wear mechanism was mainly two-body abrasion due to the surface roughness of the counter-material, as well as three-body abrasion due to the formation of debris at the interface.

Self-powered multifunctional body motion detectors based on highly compressible and stretchable ferroelectrets with an air-filled parallel-tunnel structure

The new kind of ferroelectret electroactive polymers for flexible film sensors represent an attractive opportunity for self-powered wearable devices, which could offer sustainable and convenient health care services for people without the problem of energy supply. However, due to the mechanical heterogeneity, obtaining ferroelectrets with both a high longitudinal and transverse piezoelectric response is still a great challenge, which limits its multifunctional sensing application, especially in body motion tracking. Herein, we develop an air-filled parallel tunnel ferroelectret-based self-powered body motion detectors. Ascribed to the high mechanical compression and tensile properties of the specially designed parallel tunnel void structure and excellent charge storage stability of the fluorinated polyethylene propylene (FEP) electret film, these laminated films exhibit many fascinating merits, including ultrahigh longitudinal piezoelectric response (piezoelectric coefficient of 6200 pC/N, pressure sensitivity of 1950 pC/kPa), wide pressure detection range (0.03–62 kPa), remarkable transverse piezoelectric response (tensile sensitivity of 1600 pC/mm), long-term durability (1,08,0000 cycles), and superior friction force detection capability. This is the first work, to our knowledge, that ever use one kind of piezoelectric mechanism in a single ferroelectret-based sensor to achieve longitudinal stress, transverse stress, and tangential friction force sensing. Furthermore, on the basis of such sensors and machine learning algorithms, we designed an intelligent gesture recognition system for future human-machine interaction applications. Looking forward, our material design methodologies offer an approach to the self-powered flexible multifunctional sensor with great prosperity in household healthcare, smart mobile medical electronics, and humanoid robots.

Dynamic investigation and alleviative measures for the skidding phenomenon of lubricated rolling bearing under light load

The skidding phenomenon occurs during the operation of rolling bearing under the light load owing to the design error, which will intensify the surface damage and lead to noise and abnormal vibration. In this study, a skidding dynamics model of lubricated rolling bearing is established considering the interactions between the roller and races, as well as the cage. The effect of lubricant on the dynamic characteristics of the rolling bearing is characterized as the lubricating oil stiffness, central film thickness, time-varying friction coefficient between the roller and race, passing flow resistances of rollers, and resistance torques. In addition, the nonlinear contact and structure deformations of rollers are formulated. For mitigating the skidding phenomenon of the roller under light load, the effect of roller number, inside radius of the hollow roller, density and viscosity of the lubricant, interference fit, and radial load are analyzed. The results indicate that the skidding phenomenon of the roller is induced by the lesser tangential roller-race friction forces and larger passing flow resistances of rollers. It is helpful to intensify the interactions at the roller-race interface or/and decrease the running resistance by reducing the roller number, decreasing the lubricant density, or choosing the correct viscosity of the lubricant. Besides, the effect of interference fit and increasing radial load is significant on the premise of not changing the design parameters of the rolling bearing.

Study on Wear Characteristics of Revolute Clearance Joints in Mechanical Systems.

The existence of clearance causes contact-impact forces in joints, which lead to surface wear and incessant material loss of the joint surface during the motion of mechanisms. In this work, the wear characteristics of dry revolute clearance joints in planar mechanisms are studied using a computational methodology. The normal contact force model and the tangential friction force model are established to describe the contact-impact in clearance joints. Then, the dynamic wear model based on the Archard’s wear model is established to predict the wear characteristics of clearance joints in mechanisms. The dynamic wear depths of clearance joints are obtained in two steps. The first step is the dynamics analysis of mechanisms to obtain the contact and sliding characteristics between the bearing and journal in the clearance joint. The second step is the dynamic wear depth analysis of clearance joints based on dynamic Archard’s wear model. Finally, a planar slider-crank mechanism with two revolute clearance joints between the connecting rod and its adjacent links is used as the implement example. Different case studies are performed to investigate the wear characteristics of clearance joints in mechanical systems.

A biomimetic remora disc with tunable, reversible adhesion for surface sliding and skimming

Remora suckerfish (Echeneis naucrates) can perform skimming and sliding motions on the surfaces of moving hosts to optimize adhesion positions. We found that remora achieve skimming and sliding motions through coordinated movement of the suction disc’s lamellae and lip locomotion through live animal observations. We implemented an integrated biomimetic remora suction disc based on morphological and kinematic data of biological remoras. With soft actuators enabling ‘compression–rotation’ and ‘compression–extension’, the biomimetic disc controls the disc lip and lamellar movement under driving with only one degree of freedom, and can switch freely between three states: zero, low-friction, and robust adhesion. Then we investigate the effects of the biomimetic suction-disc soft-lip material, preload, and lamellar movement on the tangential friction force (both forward and backward) under different adhesion states. This biomimetic suction disc with a low-modulus soft lip can adhere to a smooth surface under 0.1 N preload and achieve normal adhesion-force and tangential frictional-force control ranges spanning ∼10−1 to ∼102 N and ∼10−1 to ∼101 N, respectively. The results reveal how remora disc achieved fast, tunable adhesion for skimming and sliding on surfaces. Furthermore, we demonstrate a bio-inspired robot capable of attachment, detachment, skimming, and sliding motions with the aiding of simple biomimetic pectoral-fin flapping. This study lays a foundation for future integrated applications of underwater adhesion robots and related biomechanical exploration.

Endothelial Mechanosensors for Atheroprone and Atheroprotective Shear Stress Signals.

Vascular endothelial cells (ECs), derived from the mesoderm, form a single layer of squamous cells that covers the inner surface of blood vessels. In addition to being regulated by chemical signals from the extracellular matrix (ECM) and blood, ECs are directly confronted to complex hemodynamic environment. These physical inputs are translated into biochemical signals, dictating multiple aspects of cell behaviour and destination, including growth, differentiation, migration, adhesion, death and survival. Mechanosensors are initial responders to changes in mechanical environments, and the overwhelming majority of them are located on the plasma membrane. Physical forces affect plasma membrane fluidity and change of protein complexes on plasma membrane, accompanied by altering intercellular connections, cell-ECM adhesion, deformation of the cytoskeleton, and consequently, transcriptional responses in shaping specific phenotypes. Among the diverse forces exerted on ECs, shear stress (SS), defined as tangential friction force exerted by blood flow, has been extensively studied, from mechanosensing to mechanotransduction, as well as corresponding phenotypes. However, the precise mechanosensors and signalling pathways that determine atheroprone and atheroprotective phenotypes of arteries remain unclear. Moreover, it is worth to mention that some established mechanosensors of atheroprotective SS, endothelial glycocalyx, for example, might be dismantled by atheroprone SS. Therefore, we provide an overview of the current knowledge on mechanosensors in ECs for SS signals. We emphasize how these ECs coordinate or differentially participate in phenotype regulation induced by atheroprone and atheroprotective SS.

Effect of track curvature on the microstructure evolution and cracking in the longitudinal section of lower gauge corner flow lips formed in rails

The microstructure of the flow lips formed at the lower corner of gauge face in the longitudinal section of worn high rails serving in curved tracks has been investigated. The radii of the curved tracks are 1500 m (S1, sharper curve) and 4000 m (S2, milder curve). Sharper curves result in a higher angle of attack (AOA) between rail-wheel thus leading to higher lateral contact forces as well as tangential frictional forces thus facilitating plastic flow. Such conditions favour formation of flow lips where rail material flows from the rail upper gauge face to the lower corner of the gauge face. A combination of optical microscopy (OM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and nano-indentation hardness measurements have been used for the characterization of the flow lip. It is observed that the outermost region of the flow lip consists of a uniformly present white etching layer (WEL) followed by an intermittently present brown etching layer (BEL) where the WEL and BEL thickness is less for milder curves. The WEL has the highest hardness and consists of fine grains of ferrite and particles/fine fragments of cementite. The BEL is relatively softer than WEL and has a similar appearance to WEL, but patches of lamellar structure appear with increasing depth from the outer edge. Beyond the BEL region, layers of deformed pearlitic structure are observed, and a more intact pearlitic structure is observed at a much lower depth for the milder curve than the sharper curve. For both the curvatures at a given depth, the hardness of pearlite bears a Hall-Petch type of relationship to the pearlitic interlamellar spacing. However, the alignment of the deformed microstructure is heavily dependent on the curvature. It has been found to align almost parallel (4°–10°) to the rail longitudinal axis for the milder curvature and at around 21°–35° for the sharper curvature. Cracks originate from the brittle WEL region due to contact fatigue whereas crack propagation is driven by bending stresses. Cracks have been found to move parallel to the alignment of the deformed pearlite along longitudinal direction for the milder curvature. Alignment of pearlite also motivates the crack propagation trajectory for the sharper curvature and hence the crack moves at an angle between 21° and 35° with the longitudinal direction but becomes almost perpendicular after a distance. Shallow cracks travelling parallel to the rail outer edge in S2 can result in spalling of the rail material leading to wear, whereas for sharper curves, cracks run deeper into the railhead. Thus, the tendency for rail failure through 'Reverse Transverse Fracture' – which involves crack initiation at the lower gauge corner and propagation into the railhead – increases with the sharpness of the rail curvature.

Stick-slip motion in the contact between soft elastomer and spherical hard steel indenter: Model explanation of superplasticity mode in metal samples with grain boundary defects

We describe the laboratory facilities that were developed to study the contact phenomena. Developed equipment can be used to measure the forces between two contacting bodies and to analyze the evolution of the contact area. We also present the results of the experiment concerning indentation of the steel sphere into the hardened gelatin solution with following movement of the sphere in tangential direction with constant velocity. It is shown that at tangential displacement (shift) system exhibit stationary stick-slip mode of motion with “stiction spike” at the beginning of the indenter motion. Also, at the beginning of movement, when the contact between gelatin and indenter is strong due to their interaction, we observe the damage of the gelatin surface (the crack propagates from the surface into the gelatin body). This fracture weakens the contact and decreases the tangential friction force. In stationary dynamic stick-slip mode the surface of the gelatin remains undamaged. Similar mechanism of the grain boundary slips in nanostructured metals cause the superplasticity phenomena.

Numerical and experimental study on dynamics of the planar mechanical system considering two revolute clearance joints

AbstractDue to assembly, wear and manufacturing errors and clearance in the joints are inevitable. When the clearance is introduced into a mechanical system, the impact force in the clearance joint will cause undesirable vibration of the system. In this paper, the dynamic responses of the mechanical system with two revolute clearance joints are studied using computational and experimental methodology. The clearance joint is considered as force constraint. The normal contact force and tangential friction force between the journal and bearing in a clearance joint are modeled using a nonlinear contact force model considering energy loss and a modified Coulomb friction model considering a dynamic friction coefficient, respectively. A planar slider‐crank mechanism with two revolute clearance joints is used to implement the study. The dynamic responses obtained from numerical simulation are compared with the experimental test. Numerical simulations and experimental tests for different clearance sizes and crank speeds are presented and discussed, respectively. The simulation results agree quite well with those of the experiment for different cases, which proves the accuracy and efficiency of the computational method for dynamics analysis of the mechanical system with two revolute clearance joints in this study. The investigation indicates that the clearances in revolute joints significantly affect the dynamic characteristics of mechanical systems, which must be considered in the precision analysis, design, and control of multibody systems, especially for high‐speed machinery.

On the Effect of Friction on Tibiofemoral Joint Kinematics

The effect of friction on nonlinear dynamics and vibration of total knee arthroplasties is yet to be investigated and understood. This research work aims at studying the influence of friction on nonlinear dynamics, friction-induced vibration, and damage of tibiofemoral joints. For this purpose, a spatial dynamic knee model is developed using an asymmetric nonlinear elastic model accounting for knee joint ligaments and a penalty contact model to compute normal contact stresses in the joint while contact detection is treated such that the associated computational time is reduced. Several friction models are considered and embedded in the dynamic model to estimate tangential friction forces in the knee joint. External loads and moments, due to the presence of all soft tissues, e.g., muscles and hip-joint reaction forces, applied to the femoral bone are determined using a musculoskeletal approach. In the post-processing stage, damage, i.e., wear and creep, are estimated using three wear models and an empirical creep formulation, respectively. In addition, a FFT analysis is performed to evaluate likely friction-induced vibration of tibiofemoral joints. Mesh density analysis is performed and the methodology is assessed against outcomes available in the literature. It can be concluded that friction influences not only the tribology, but also dynamics of the knee joint, and friction-induced vibration is likely to take place when the friction coefficient increases.

THE PHENOMENON OF INK DUSTING TAKING INTO ACCOUNT THE SURFACE ROUGHNESS OFFSET PRINTING PLATE

The paper investigates the influence of the mechanics of a friction printing pair on ink dusting in the printing process, taking into account the surface roughness of the printing plate. The aim of the study is to determine the influence of the surface roughness of the printing plate on the deformation of the deckle, as well as on the value of the total force in the area of the printed contact, the relative gear ratio and the relative speed of sliding of the deckle along the surface of the cylinder, which directly affects the dusting of the ink. It was found that when studying the mechanics of a printed pair, the influence of the microgeometry of the contacting surfaces on the parameters under study was not taken into account. The influence of microprotrusions of the surface roughness of the printing plate on the deformation of the deckle in the area of the printed contact has been substantiated and established. To determine the introduction of surface roughness irregularities, a discrete roughness model is used, presented as a set of identical spherical segments. To determine the influence of the surface roughness of the printing plate on the friction force arising in the contact zone, a calculation scheme is proposed that differs from analogs. A method is developed for calculating the parameters of a friction pair in the printing process, taking into account the roughness. Expressions are obtained for determining the total moment of tangential friction forces in the sliding sections when spherical irregularities are introduced. According to the proposed technique, the corresponding graphical dependences of the gear ratio on different parameters of the friction printed pair are shown. The advantages of this study in comparison with analogs are that at certain values of the parameters of the friction pair, taking into account the surface roughness of the printing plate, also at known values of the mechanical characteristics and thickness of the deckle, it is possible to determine the change in the length of the deckle of a given composition, which is necessary in the printing process. The proposed calculation method, which is carried out without taking into account the pressure in the printed contact zone, allows predicting the quality of printed impressions and the amount of ink involved in the formation of ink dusting, as well as correctly adjusting the printing press before the printing process.