Shear Friction Research Articles

Effect of surface roughness on the interface behavior of clayey soils

Abstract This study investigates the effect of surface roughness on the interface behavior between clayey soils and structural materials, aiming to determine the necessary parameters for soil-structural interaction. The research site, located in one of Iraq’s seismically active regions, was selected for its significance. Experimental measurements were conducted using the SRT-6210 Digital Surface Roughness Tester to assess the roughness characteristics of steel and concrete samples. Four distinct roughness parameters were measured, and their correlation with shear parameters was analyzed. The shear behavior of clay-steel and clay-concrete interfaces was successfully described using the average roughness parameter (Ra), which exhibited the strongest correlation with shear parameters. Direct shear box and interface shear box tests were employed to identify soil’s shear strength parameters and evaluate interface shear strength parameters. The experimental findings highlight the significant influence of surface roughness on the shear strength parameters of clay-steel and clay-concrete interfaces. The interface shear strength, friction angle, and adhesion exhibited an increasing trend with roughness. Notably, shear strength increased by approximately 29.76% when concrete sample roughness was below 20 μm and by 32.8% when steel sample roughness was below 30 μm. Moreover, increasing surface roughness improved the interface friction angle of clay-steel and clay-concrete samples by about 37.95 and 36.3%, respectively. Additionally, an increase in roughness led to a rise in the adhesion of concrete and steel samples by approximately 26.24 and 32%, respectively. These findings emphasize the significance of surface roughness in optimizing the interface behavior between clayey soils and structural materials. The results have important implications for enhancing the design and performance of soil-structural systems.

Frictional Strength, Stability, and Potential Shear Heating on Icy Satellite Faults

AbstractWe determined the frictional strength and stability of polycrystalline ice and ice‐ammonia to constrain fault behavior on icy satellites such as Enceladus and Europa. Friction experiments including velocity steps and slide‐hold‐slide tests were conducted to measure the steady‐state coefficient of friction, velocity dependence and healing between temperatures of 98 and 248 K at a normal stress of 100 kPa. Rate‐state friction parameters determined from velocity steps provide stability values. The friction results are used to infer fault strength and frictional heating of an icy crust with depth for both a pure ice crust and one containing ammonia. We find a reduced coefficient of friction for an ammonia‐bearing crust and stronger velocity dependence in the presence of partial melt. The temperature dependence of fault stability maps a seismogenic zone with depth analogous to the synoptic model for terrestrial fault stability, where we find instability between 0.7 and 3.9 km with a return to stability from 4.6 km if we assume a 6 km ice shell. We consider the role of sliding velocity and fault thickness on localized frictional heating in both systems and estimate the depth of melt generation in an ammonia‐bearing crust. Our results imply that faults at conditions similar to icy satellites can be seismogenic.

Enhancing wear resistance of aluminum alloy by fabricating a Ti-Al modified layer via surface mechanical attrition treatment

The limited wear resistance of aluminum alloys hinders their application in lightweight equipment. Herein, we present the successful fabrication of a Ti-Al modified layer on the surface of aluminum alloy 2024 via surface mechanical attrition treatment (SMAT-Ti). Tribological assessments indicate an improvement in tribological performance. Specifically, the average friction coefficient and wear rate of the SMAT-Ti treated sample decreased by 49.1% and 81.9%, respectively, compared to untreated sample. Analysis of wear surfaces and molecular dynamics simulations demonstrate that the improvements observed can be attributed to the wear-resistant tribofilm formation. Furthermore, the integration of Ti particles beneath the subsurface facilitates the formation of HCP bands and dislocation locks. These microstructural changes obstruct frictional shear deformation and crack propagation, effectively reducing wear.

Study on Heat Transfer Characteristics of High-Speed Herringbone Gear in Meshing Process Under Oil Injection Lubrication

Abstract To quantify the relationship between the total frictional heat and the absorbed heat by the oil film in the herringbone gear transmission, this article investigates the lubrication status and thermal characteristics of the tooth meshing point under the fuel injection condition. First, the contact analysis of the herringbone gears is carried out—studying the variation pattern of the maximum pressure, highest temperature rise, and minimum film thickness of different oil films at various mesh points along the meshing line. Second, the friction coefficient and frictional power for the meshing points on the tooth surface are calculated to determine the ratio of oil film pressure to total pressure distribution. This completes the allocation of frictional power for the meshing points of the driving and driven gears. Finally, by comparing the total heat generated by frictional shear with the heat absorbed by the oil film, the numerical relationship between the two can be quantified.

Hemodynamical behavior analysis of anemic, diabetic, and healthy blood flow in the carotid artery

The influence of blood rheology on hemodynamic parameters is investigated using Computational Fluid Dynamics on blood flow through the human carotid artery. We performed three-dimensional modeling and simulation to study blood flow through the carotid artery, which is divided into internal and exterior parts with a decreased radius. The blood flow was classified as basic pulsatile to simulate the human heart's rhythmic pulses. For hemodynamic modeling viscosity of the fluid, the Carreau model was utilized with four distinct blood instances: Anemic, diabetic, and two healthy blood types. The boundary conditions with Carreau viscosity were applied using the Ansys Fluent simulator, and the governing equations were solved using the finite volume technique. Different time steps were tested for their impact on wall deformation, strain rate, blood velocity, pressure, wall shear, and skin friction coefficient. The hemodynamical parameters were calculated using many cross-sectional planes along the artery. Finally, the impact of the four types of blood cases listed above was investigated, and we discovered that each blood case has a substantial impact on blood velocity, pressure, wall shear, and strain rate along the artery.

Frictional shear stress-induced incomplete martensitic transformation in mono-crystalline B2-CuZr spherulites

An austenitic B2-CuZr phase, when deformed, can undergo a martensitic transformation (MT) that produces a martensitic B19′-CuZr phase, resulting in remarkable transformation-induced plasticity (TRIP) and shape memory effects in B2-structured alloys. However, the shear mechanism as well as the crystallographic characteristics, which underlie the MT and, in turn, the TRIP and shape memory effects, remain unclear and somewhat controversial. Here we report that a single shear on {110}B2<001>B2, along with {1 1 5.5}B2 being the habit plane, are responsible for the MT in B2-CuZr, where {110}B2 and <001>B2 are the shear plane and the shear direction, respectively. These were revealed by determining unambiguously the orientation relationship between B2 and B19′, co-existing in individual spherulites contained in a B2-CuZr-containing bulk metal glass-matrix composite (BMGC). This exotic microstructure, featuring a core-shell like distribution in each single spherulite in which all the 12 possible martensite (B19′) variants constitute the core and the parent B2 forms the shell, was made from an incomplete MT in originally mono-crystalline B2 spherulites of the as-cast BMGC when subjected to moderately applied frictional shear stresses upon mechanical grinding. Finite element analysis suggests that a core-shell like shear stress distribution inside a B2 spherulite, caused by the confinement of the stiffer glass matrix, may account for it. These results provide direct experimental evidence to elucidate the B2→B19′ MT and its variant selections under various stress states, and pave the way for developing ductile B2-structured alloys, including but not limited to, shape memory intermetallics, high entropy alloys and B2-containing composite materials.

Characterization of Interlaminar Friction during the Forming Processes of High-Performance Thermoplastic Composites

Friction is a pivotal factor influencing wrinkle formation in composite material shaping processes, particularly in novel thermoplastic composites like polyetheretherketone (PEEK) and low-melting polyaryletherketone (LM-PAEK) matrices reinforced with unidirectional carbon fibers. The aerospace sector lacks comprehensive data on the behavior of these materials under forming conditions, motivating this study’s objective to characterize the interlaminar friction of such high-performance thermoplastic composites across diverse temperatures and forming parameters. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were employed to analyze the thermomechanical behaviors of PEEK and LM-PAEK. These data guided friction tests covering room-to-forming temperatures. Horizontal pull-out fixed-plies tests were conducted to determine the friction coefficient and shear stress dependency concerning temperature, pressure, and pulling rate. Below the melting point, both materials adhered to Coulomb’s law for friction behavior. However, above the melting temperature, PEEK’s friction decreased while LM-PAEK’s friction increased with rising temperatures. These findings highlight the distinct responses of these materials to temperature variations, pulling rates, and pressures, emphasizing the need for further research on friction characterization around glass transition and melting temperatures to enhance our understanding of this phenomenon.

Improvement effects of knee-bracing friction dampers on cyclic behavior of steel joints in antique buildings

To inherit the unique characteristics of historical timber architecture, the steel antique building (SAB) imitating ancient Chinese timber structures has been constructed using contemporary steel materials and fabrication techniques. These buildings typically exhibit premature yielding cracks and weak energy dissipation at the beam ends under seismic loads. To improve the seismic performance of SABs, two different types of friction dampers were deployed at the knee-bracing region around beam-column joints in SABs. First, cyclic loading tests on dampers indicate that both shear friction dampers and rotational friction dampers exhibit full hysteretic behavior, demonstrating an excellent and stable energy dissipation capacity. The friction coefficient of dampers with brass pads was theoretically calculated to be 0.35. Second, the quasi-static test showed that failure of steel joint specimens with knee-bracing dampers primarily occurred at replaceable angles in the beam-column connection region, which demonstrates that the repairability of steel joints in SABs can be greatly improved without overcomplicated labor. Adding knee-bracing dampers effectively postpones damage to the replaceable angles, which improves the strength, stiffness, and energy dissipation capacity of the steel joints significantly. The shear damper exhibits a more pronounced improvement in the overall structural seismic performance compared to the rotational damper with the same frictional sliding force. Moreover, numerical simulations showed that the strength of the proposed joints with knee-bracing friction dampers decreases with an increase in the axial compression ratio, while increasing the thickness of angles or the sliding force of dampers can effectively improve the seismic performance of the steel joints in SABs.

Effect of surface texture on frictional energy dissipation under magnetic fluid lubrication used for semi-active nonlinear energy sink

The effect of surface texture on the efficiency of friction energy dissipation in a nonlinear energy sink (NES) was investigated. Analysis of variance (ANOVA) was employed to develop a quadratic regression model explicating the relationship between control factors (groove width, depth, and density) and responses (shear stress and friction coefficient) associated with rectangular groove surface texture. Response surface methodology (RSM) was utilized to optimize the control variables for increasing shear stress and friction coefficient between magnetic fluids (MFs) and groove texture. Prototype testing revealed that groove texture significantly enhanced friction energy dissipation efficiency, confirming the effectiveness of optimized texture for MF-NES.

Anti-sedimentation mechanism of rotary magnetorheological brake integrating multi-helix microstructure

Solving the sedimentation problem of magnetorheological (MR) fluids is the key to promoting the application of MR actuators for long-term storage. Current strategies for mitigating MR fluid sedimentation focus on improving the material constitution of MR fluids. However, the sedimentation is bound to emerge over time as a result of the density mismatch between carbonyl iron particles and carrier liquids. Therefore, more robust approach to solve the particle sedimentation should be considered, such as improving the robustness of the MR actuator. This paper proposes a novel anti-sedimentation MR brake (AS-MRB) that integrates a multi-helix microstructure on the shaft surface. The protrusion-shaped multi-helix microstructure applied a combination of shear stress, pressure, friction, and centrifugal force to MR fluids. Therefore, the AS-MRB can autonomously alter the internal flow state, thus performing the self-homogenization of sedimented particles. Remarkably, vortexes with axis displacement were generated in the MR working gap during the self-homogenization process. This phenomenon facilitated the mass transfer between different fluid layers, as confirmed by the speed reduction and torque test. To accurately describe the real-time rotational speed of the AS-MRB, an impact-introduced dynamic model of the shaft was also proposed. An inductance sensor-based test system was developed to characterize the volume fraction of the particle instantaneously, which is directly pertinent to the evaluation of the anti-sedimentation performance. Severely sedimented MR fluids were introduced into the AS-MRB for the performance evaluation in harsh conditions. The results show that the maximum volume fraction difference Δφmax of the sedimented MR fluid was decreased from 54.02 % to 2.46 % after the homogenization. The maximum shear stress τmax of the sedimented MR fluid was increased from 11.78 % to 80.7 % of that of the initial MR fluid. These demonstrate the strong anti-sedimentation performance of the AS-MRB. Consequently, this study has developed a unique method for solving the sedimentation problem of MR fluids and creates avenues for promoting the application of MR actuators in long-term storage.

Study on mechanical properties of nickel-based tungsten carbide cladding layer based on plasma cladding process

The Ni60+60%WC cladding layer was prepared on the surface of Q355 steel by plasma cladding process under different cladding currents. Through a metallographic microscope, microhardness test, shear strength test, and friction and wear test, the relationship between solidification structure and mechanical properties of Ni60+60%WC cladding layer was analyzed. Through experiments, it is concluded that when the current is 150-170 A, there is a good metallurgical bond between the cladding layer and matrix, and the bonding effect improves with the increase of the cladding current. The metallurgical bonding effect is poor when the current is 130 A or 140 A. When the cladding current is high, the hard tungsten carbide particles in the cladding layer show varying degrees of sinking phenomenon. Simultaneously, with the escalation of the cladding current, the tungsten carbide (WC) particles within the cladding layer decrease in size, and the ablation phenomenon becomes more obvious. When the cladding current is 130-160, the hardness of the obtained cladding layer increases to varying degrees compared to the matrix, with the highest hardness obtained with a current of 160 A. With an increasing distance from the cladding layer surface, there is an observed trend of hardness initially increasing and subsequently decreasing. In addition, as the cladding current goes up, the shear strength of the cladding layer goes down. The trend of abrasive resistance of cladding layers is the same as that of hardness. The abrasive resistance of the cladding layer increases with the increase of hardness.

Utilization of Plastic Waste in Reinforcing Sandy Soil for Sustainable Engineering Applications

Large quantities of polyethylene terephthalate (PET) plastic are discarded into the environment during production, application, and disposal. Although current clean-up strategies aim to mitigate the adverse impacts of PET pollution, efforts struggle to keep up with the escalating amount of PET waste. This accumulation of PET waste poses significant threats to ecosystems worldwide. One recycling method for PET plastic waste involves its utilization in soil reinforcement applications within civil engineering. By incorporating PET plastic waste to reinforce poor-quality sands, sustainable construction practices can be promoted in civil engineering infrastructures, addressing multiple aspects of sustainability, including engineering, economic, social, and environmental considerations. The experimental work conducted in this research involved sieve analysis, proctor compaction test, California Bearing Ratio (CBR) test, and direct shear box test. The sand was reinforced with varying percentages of PET plastic waste flakes, namely 5, 10, and 15 %, with respect to the weight of the soil sample taken for the test, and laboratory tests were performed on the samples. Including PET plastic flakes enhanced various soil properties, such as shear strength and friction angle. It also improved the CBR value of the composite, making it suitable for pavement construction. The reduction in dry density further supports the application of the composite in lightweight structures. In conclusion, the geotechnical material obtained from the soil-PET plastic waste composite can be utilized in various geotechnical projects, including landfills and slope stabilization.

Cyclic shear behavior of en-echelon joints under constant normal stiffness conditions

To reveal the mechanism of shear failure of en-echelon joints under cyclic loading, such as during earthquakes, we conducted a series of cyclic shear tests of en-echelon joints under constant normal stiffness (CNS) conditions. We analyzed the evolution of shear stress, normal stress, stress path, dilatancy characteristics, and friction coefficient and revealed the failure mechanisms of en-echelon joints at different angles. The results show that the cyclic shear behavior of the en-echelon joints is closely related to the joint angle, with the shear strength at a positive angle exceeding that at a negative angle during shear cycles. As the number of cycles increases, the shear strength decreases rapidly, and the difference between the varying angles gradually decreases. Dilation occurs in the early shear cycles (1 and 2), while contraction is the main feature in later cycles (3−10). The friction coefficient decreases with the number of cycles and exhibits a more significant sensitivity to joint angles than shear cycles. The joint angle determines the asperities on the rupture surfaces and the block size, and thus determines the subsequent shear failure mode (block crushing and asperity degradation). At positive angles, block size is more greater and asperities on the rupture surface are smaller than at nonpositive angles. Therefore, the cyclic shear behavior is controlled by block crushing at positive angles and asperity degradation at negative angles.

The friction-induced microstructures changes of 18Cr-8Ni austenitic stainless steels with different grain sizes

Abstract The friction and wear performance, wear morphology and friction-induced subsurface microstructural characteristics of 18Cr-8Ni austenitic stainless steels with coarse-grained (CG), heterogeneous ultrafine-grained (HUFG), and nano/ultrafine-grained (NG/UFG) microstructures after dry sliding wear under room temperature were studied. The results reveal that HUFG steel with a good match between hardness and plasticity exhibits the best wear performance, followed by CG steel, while NG/UFG steel with the highest hardness exhibits the poorest wear performance. From the element distribution map, the contents of O and Si in the delamination and wear debris are relatively high. O is relatively evenly distributed on the whole wear surface of HUFG steel, and there is a continuous oxide layer on its wear surface. After the wear test, the hardness increment near the wear surface of the CG sample is the largest, and the depth affected by sliding is the largest, followed by the HUFG sample, and those of the NG/UFG steel are the smallest. The repeated frictional shear stress causes the formation of cracks between the mechanical mixed layer and the plastic deformation layer, and the continuous expansion of cracks can help oxygen elements diffuse deeply, causing the deformation layer materials to fall off.

Detection of movement resistance and friction coefficient in the transport of building materials and construction materials

In the production of building materials and construction materials, continuously operating conveying equipment is commonly used, including roller conveyors. Roller conveyors are devices designed for horizontal, slightly ascending or descending transport of piece products moving on a system of rotating rollers of different shapes (cylindrical, conical, disc, pulley or according to the profile of the conveyed object). The rotating rollers are placed in the track frame (supporting structure), which can be either stable, relocatable or adjustable (height and length adjustable, so-called scissor conveyors). An analogue of the roller conveyor is the pulley conveyor, where instead of rollers, discs - pulleys are mounted on a non-rotating axis. Several discs are installed on the axis with gaps. The pulleys on adjacent axes overlap so that there is no continuous gap. The track is used for handling flat building parts and objects such as metal sheets, glass panes, furniture parts, etc. When transporting item building materials or bulk building materials placed in storage boxes which are transported on a powered roller track on pallets, a driving force is required depending on the angle of inclination of the roller track, the weight of the load, the number of rollers on which the load rests and the coefficient of shear friction during movement. The paper presents a laboratory device that has been designed to detect the adhesion force during the transport of piece loads by a roller conveyor. On the implemented device, it is possible to determine in laboratory conditions the amount of resistance to the movement of the load on the driven roller conveyor depending on the weight of the load. The paper presents measured values of the shear friction coefficient during the movement of a steel storage box on a driven roller track. In this paper, a driven roller track is used for laboratory tests, where the drive of the rollers is implemented by so-called short chains. In addition to horizontal tracks, this chain drive allows you to drive rising tracks with variable gradients or even rising curved tracks.

Parametric study of reinforced interlocking brick wall under cyclic loading

Mortarless interlocking brick walls are a new form of masonry structures that can be efficiently constructed. In this study, a detailed numerical model of an interlocking brick wall under quasi-static in-plane cyclic loading is generated and verified with laboratory test data. The influence of the vertical reinforcement placement methods, i.e., grouted vs. unbonded, and the influence of wall-to-brick size ratio are firstly investigated. Parametric studies are then carried out to quantify the influences of axial precompression level, shear span ratio and friction coefficient between bricks on the lateral load-carrying capacity, deformation capacity, and energy dissipation capability of the studied mortarless interlocking brick walls subjected to in-plane cyclic loading with analytical equations summarised for predicting the resistance performance of this type of mortarless interlocking brick walls under in-plane cyclic loading.

Application of computer simulation to model transient vibration responses of GPLs reinforced doubly curved concrete panel under instantaneous heating

In this article for the first time, with the aid of computer simulation, transient vibration responses of the concrete doubly curved panel exposed to immediate heating are reported owing to the significance of concrete panels used in civil applications. The substrate includes spring element, shear, torsion, and substrate-structure friction factor. A novel model of a two-parameter substrate is introduced in this research with enough flexibility to involve three forms of polynomial, sinusoidal, and cosinusoidal expansion with various terms in its stiffness. With the aid of Halpin-Tsai micromechanics and the well-known rule of mixtures, the material properties of the graphene nanoplatelet (GPLs) composites reinforced doubly curved concrete panels are modeled. As well as this, for accurate modeling of the current work, the thermal conductivity of each continuous GPLs layer along with thickness direction using mathematical simulation is presented. Finally, entropy, the constitutive heat conduction equation, the Heaviside unit step function, and thermal shock loading are used in the final governing equations. The Laplace transform is employed to solve the temporal variation of the system’s response, while its spatial response is determined with the aid of the harmonic differential quadrature approach (HDQA). For more verification of the current work results and due to the lack of research in the field of the transient response of thermally induced vibrations of the panel, the results of the current work are verified with a Machine learning algorithm. Then, in the results section, some recommendations for enhancing the transient vibrations of the present concrete structure will be thoroughly examined.

PHYSICAL PROPERTIES CORRESPONDING TO COMFORT FEEL OF BEDDING FABRICS

The market for bedding products in Thailand now offers a wide range of physical attributes (fiber types, structures, fabric densities, thicknesses, and weights) that produce a variety of tactile sensations and comfort qualities. This study investigated the comfort properties of bedding fabrics in Thailand. Twenty-one bedding fabric samples were collected and measured for their mechanical and surface properties based on the Kawabata evaluation system for fabric (KES-F) as well as the horizontal wicking test and abrasion resistance, air permeability, wrinkle recovery, and thermal resistance (Qmax). The primary hand value (HV) and total hand value (THV) were calculated using the Kawabata hand evaluation equation KN-201-LDY describing women's thin dress fabric, using 5 different properties from the KES-F (tensile, shear, bending, compression, and surface friction). The principle component analysis (PCA) and cluster analysis of the physical properties of fabric samples showed that the samples could be placed in 4 groups. The first group was mostly cotton woven samples. The second group consisted of 2 samples that were both knitted, while the third group was mostly mixed (M) fabric samples. The last group contained cotton and M cotton samples. The first cluster was considered to provide the best hand-feel characteristics of all 4 clusters, while the second cluster was considered the least desirable based on hand-feel. The findings of this study should assist the bedding textile sector in developing new products.

CFD simulation of drag-reducing fluids in a non-Newtonian turbulent pipe flow

The conveyance of fluids from one terminal to another incurs considerable expenses primarily due to the significant costs associated with addressing pressure losses arising from shear stresses and friction along the inner surface during the pumping operations within pipelines. This study was conducted with the objective of simulating turbulent flow in pipes containing drag-reducing fluids. This was achieved through the utilization of both RKE and RNG versions of a non-Newtonian model for low Reynolds numbers, based on the k-ε model, along with a non-Newtonian damping function. The outcomes were subsequently compared to simulations carried out by Pinho and experimental data sourced from the existing literature. To simulate the flow in pipelines, computational fluid dynamics (CFD) software was employed, which incorporated non-linear molecular viscosity and a damping function to accurately account for near-wall effects. In addition, this research entailed the optimization of C and C0 parameters in the damping function and the stress term, which quantifies the cross-correlation between fluctuating viscosity and the fluctuating rate of strain. Furthermore, non-Newtonian terms were incorporated into the equations for turbulent kinetic energy (k), dissipation rate (ε), and momentum transfer. The study involved a comprehensive comparison of model predictions with experimental data across various flow parameters, including friction factor, axial velocity, turbulent kinetic energy, and Reynolds shear stresses. The results revealed a significant enhancement in the model's ability to predict critical flow parameters, such as friction factor, mean axial velocity, and Reynolds stress profiles. Nevertheless, the model displayed some limitations in predicting turbulent kinetic energy. Notably, the average error in calculating the friction factor for the fluids under investigation was found to be 5.45%, marking a substantial improvement compared to the Pinho model, which exhibited an average error of 32.49%.

Investigating deformation and work hardening behaviour of stacked sheet metal specimens in compression test: Influence of friction and interfacial shear resistance

Investigating deformation and work hardening behaviour of stacked sheet metal specimens in compression test: Influence of friction and interfacial shear resistance