Effect Of Roughness Research Articles

Drive-By Identification of Joint Bridge Damage and Surface Roughness Based on Sensitivity Analysis of Residual Contact Point Deflections

Drive-by inspection of bridge damage using a passing vehicle’s dynamic response has great potential in bridge damage identification. Among the current drive-by methodologies, the methods based on bridge modeling have been proposed for the quantitative identification of bridge damage and bridge surface roughness. However, the coupling of bridge damage and unknown surface roughness increases the difficulty of the identification problem and most previous studies conduct the identification task of bridge damage or bridge surface roughness separately. In this paper, a novel method is proposed for the identification of joint bridge damage and bridge surface roughness based on the residual bridge deflections from the front and rear wheels contact points of an instrumented passing vehicle. The vehicle–bridge interaction is analyzed using a half-car model of a four degrees of freedom (4-DOF) with front and rear vehicle wheels. First, the vehicle–bridge unknown forces and displacement of the vehicle axles are identified by the generalized Kalman filter under unknown input (GKF-UI) proposed by the authors. The sensors can be installed conveniently on the vehicle body due to GKF-UI. Then, the residual bridge deflections from the front and rear vehicle wheels contact points are utilized to eliminate the effect of road surface roughness. Afterward, bridge structural damage is identified based on the sensitivity analysis of residual bridge deflections from the front and rear contact points with [Formula: see text]1-norm regularization. Finally, bridge road surface roughness is estimated based on the identified unknown forces and updated bridge model with damage. The results of numerical identification examples demonstrate the effectiveness of the proposed method for the identification of joint bridge damage and surface roughness.

Assessment of the influence of roughness, concrete adhesion and scale effect on the shear strength of concrete-gneiss rock interfaces

Assessment of the influence of roughness, concrete adhesion and scale effect on the shear strength of concrete-gneiss rock interfaces

Predicting fatigue failure in five‐axis machined ball‐end milled components through FKM local stress approach

AbstractComponents created with five‐axis machining show a multi‐scale surface character due to cusps created on the surface and feed and tool marks within the cusps. Therefore, it becomes difficult to incorporate the effects of surface character on fatigue life for such components. In this work, an Forschungskuratorium Maschinenbau (FKM) guideline is adapted to develop a fatigue prediction model which considers cusps as notches and marks within the cusps as surface roughness (characterized by parameter R10z). The assessment uses stresses obtained from an finite element analysis model to predict the fatigue life of components whilst considering stress concentration, stress gradient, mean stress, and surface roughness effects. When cusps are regarded as surface roughness within the conventional FKM approach, fatigue life is considerably underestimated. In comparison, fatigue life predictions that take into consideration the roughness within cusps and treat cusps as stress‐raising notches are closer to experimental life.

TXRF capability of metallic contamination analysis on rough silicon wafers

AbstractTotal X-Ray Fluorescence (TXRF) is a non-destructive technique for the characterization of metallic contaminants on bare silicon wafers. TXRF is sensible to roughness leading to a diffraction phenomenon. In this study, the effects of roughness on TXRF analysis were evaluated with various rough silicon wafers produced by microelectronic processes of grinding, wet cleaning and chemical mechanical polishing. TXRF parameters rise as roughness increases, starting from 3 nm RMS (Root Mean Square) roughness. On spectra, characteristic Si (silicon wafer) and W (TXRF anode) peaks widen. Secondary peaks, sum/escape peaks appear, inducing interferences with Al, Cu, Zn and background noise increases as well. Through intentionally contaminated grinded wafers (RMS 12 nm) by spin-coating at selected concentrations, it was observed that most of the elements are quantified at 1 × 1012 at/cm2. At concentrations of 1 × 1010 at/cm2 and 1 × 1011 at/cm2, only few elements are quantified due to the elevated background noise and interferences. Graphical abstract

Effect of Nanoscale Surface Roughness and Electron-Phonon Interaction on Vibrational Modes of Cadmium Telluride Using Resonant Raman Spectroscopy.

This study investigates the combined effects of nanoscale surface roughness and electron-phonon interaction on the vibrational modes of cadmium telluride (CdTe) using resonant Raman spectroscopy. Raman spectra simulations aided in identifying the active phonon modes and their dependence on roughness. Our results reveal that increasing surface roughness leads to an asymmetric line shape in the first-order longitudinal optical (1LO) phonon mode, attributed to an increase in the electron-phonon interaction. This asymmetry broadens the entire Raman spectrum. Conversely, the overtone (second-order longitudinal optical [2LO]) mode exhibits a symmetrical line shape that intensifies with roughness. Additionally, we identify and discuss the contributions of surface optical phonon mode and multiphonon modes to the Raman spectra, highlighting their dependence on roughness. This work offers a deeper understanding of how surface roughness and electron-phonon scattering influence the line shape of CdTe resonant Raman spectra, providing valuable insights into its vibrational properties.

Dynamics of acoustically levitated ice impacts on smooth and textured surfaces: Effects of surface roughness, elasticity, and structure

Atmospheric ice collisions on exposed outdoor infrastructure are a rarely explored surface design challenge. A primary obstacle to realistic ice particles in the laboratory setting is freezing a droplet without a solid surface present and then allowing it to impact a substrate without physical intervention. Using acoustically levitated ice formation with subsequent release onto a controlled area, a third class of ice-countering system called “ice-impacting” is introduced. Stainless steel 316 (SS), epoxy resin-coated (ER), and laser-textured (LT) surfaces with known surface roughness, hardness, and structural characteristics were subjected to 40 ice droplet impacts each. The impact effect on surface properties and the effect of these properties on solid-solid interfacial impact dynamics, in turn, were examined using an analysis framework based on fundamental conservation laws. Elasticity was the most significant factor in droplet behaviour as the ER surface exhibited rebounding for 78 % of impacts, nearly double the rates of the stainless steel surfaces. However, surface roughness also played a role, particularly for droplets with rotational motion, as immobilization occurred for 66 % of impacts on the rougher LT surface. Moreover, the nanostructures on that textured surface resulted in droplet redirection perpendicular to the surface directionality. In contrast, the other surfaces experienced no consistent change in rebound angle. Elasticity also affected momentum retention: the ER surface had a translational restitution coefficient of 0.32 compared to 0.17 for the SS/LT surfaces. Surface roughness was a predominant aspect of energy retention, as the LT surface had a translational-to-rotational energy transfer coefficient of 0.07 (0.23 for the smoother surfaces), resulting in an overall energy retention coefficient of 0.09 compared to 0.28 for the SS and ER surfaces on average. The results show that the interplay between elasticity, roughness, and structure at a dynamic solid-solid interface must be considered to optimize their effectiveness when designing ice-countering surfaces.

Influence of roughness and temperature on the emissivity of molybdenum in RTPV system

In this paper, the effect of different surface roughness and temperature on molybdenum's emissivity was studied. We measured and analyzed the emissivity of molybdenum with surface roughness ranging from 5 to 103 nm at 25, 600, 800, and 1030 °C. The emissivity of molybdenum increases with the temperature and surface roughness. For molybdenum with a flat surface, the emissivity is relatively low within the temperature range of 600–1000 ℃, with an average emissivity of less than 0.1. Whereas for samples with large roughness, the average emissivity is greater than 0.1 and changes significantly with temperature. Considering the cutoff wavelength of 2.2 μm for InGaAs cell, the proportion of the spectrum emitted by the samples at 600 ℃ in the 1–2.2 μm is around 10 %. At 1030 °C, the proportion reaches 44.1 % for the flat molybdenum and gradually declines with the surface roughness. Moreover, the effect of the surface roughness of molybdenum on the radioisotope thermophotovoltaic (RTPV) system was analyzed. The results show that a molybdenum emitter with larger roughness can improve the conversion efficiency of the RTPV system.

Surface roughness influence on the behaviour of biocomposite adhesive joints

While research has explored surface treatment effects on adhesive joints made by synthetic composites or metals, there is a lack of research on biocomposite adhesive joints. This work aims to explore the effects of the surface roughness, induced by a sandblasting treatment, on the Mode-I-behaviour of adhesive joints made by flax/epoxy composites. This work focuses on the roughness induced by a variation of the sandlasting pressure. Roughness measurements were carried out on biocomposite adherents for three pressures (5, 6 and 7 bar). A finite element model (FEM) of a double cantilever beam (DCB) with a cohesive description (cohesive zone model, CZM) of the adhesive was proposed. In a macroscopic way, the roughness effect is represented by the change in the CZM parameters, accordingly, an identification procedure for different roughness level, was proposed. Comparisons between experimental Mode-I tests and FE simulations reveal a significant correlation between surface roughness and joint behaviour. A roughness mean depth R≈3μm, induced by a sandblasting pressure of 5 bar, appear to maximize the bonding strength (+16.6% with respect to 7 bar pressure-induced roughness R≈4μm). The Mode-I fracture energy decreases with the increasing of the roughness mean depth R (−33% between 5 and 7 bar conditions). These results provide critical insights for optimizing manufacturing processes of flax/epoxy composite adhesive joints in industries striving for sustainable solutions.

Effect of Surface Roughness on Fatigue Strength in Martensitic Stainless Steel

Effect of Surface Roughness on Fatigue Strength in Martensitic Stainless Steel

Effect of Surface Roughness on Range Straggling at Low Energy Ions Bombardment

Effect of Surface Roughness on Range Straggling at Low Energy Ions Bombardment

Study on transient cavitation performance of centrifugal pump based on the influence of rough impeller

This study employs numerical simulation to investigate the transient flow and cavitation performance of centrifugal pumps with rough impellers, validating the numerical method with experimental data. Initially, the effect of blade roughness on the external characteristics of centrifugal pumps is examined. Subsequently, the study specifically addresses the impact of roughness on internal flow characteristics during cavitation, including vapor volume distribution, three-dimensional vortex structures, and vorticity distribution in the impeller channel. Furthermore, the influence of blade roughness on local energy loss is analyzed using entropy production theory. Finally, several monitoring points are arranged in the impeller channel to assess pressure pulsation effects. The results show that blade roughness generally reduces the head and efficiency of centrifugal pumps. During the non-cavitation and cavitation incipient stages, roughness marginally increases the head, with a maximum increase in only 0.1%. Impeller roughness causes vacuole collapse and vortex structure enlargement, disrupting the stable flow path within the channel. Blade roughness also escalates energy loss within impeller components, particularly under full cavitation conditions, where the impeller's entropy production accounts for up to 50%. Pressure pulsation results reveal that while blade roughness can slightly suppress cavitation, it also disturbs the flow field pressure. These insights provide guidance and data support for mitigating roughness and cavitation, the two primary instability factors in centrifugal pump operations.

Effect of sample dimensions on the stiffness of PA12 Lattice materials fabricated using Powder Bed Fusion

Powder Bed Fusion fabrication techniques, including selective laser sintering, have made the fabrication of lattice meta-materials consisting of periodic cells formed by interconnected struts possible. It is generally observed that cell size has a strong influence on the lattice’s effective Young’s modulus, following in the case of typical polymers used for printing a trend of the smaller the softer. However, there is no clear understanding of the origin of the effective elastic modulus reduction with lattice cell size. In this paper, an integrated study is performed to unravel the reasons behind this effect. The analysis performed encompasses mechanical characterization (compression tests and nanoindentation), microstructure characterization (X-ray tomography, DSC, SAXS, and WAXS), and numerical analysis of the effect of defects (FFT and Finite element simulations of cells with roughness and defects) of PA12 printed single cells of different sizes and full lattice specimens containing many cells. It is found that the effect of porosity and roughness is not enough to explain the reduction of the effective elastic modulus with the cell size, suggesting that this effect is necessarily a combination of the defects, incomplete melting of particles and the changes of PA12 nanostructure induced by the different printing conditions as function of full specimen size . The results of the micro- and nanostructure characterization validate this assumption.

Towards personalized microfluidics: 3D printing of high-performance micropumps by control and optimization of fabrication-induced surface roughness

Additive fabrication technologies are very attractive for use in the realization of customized medical diagnostic and point-of-care devices in the rapidly growing field of personalized healthcare. However, non-idealities in additive manufacturing processes, such as the enhanced roughness that is inherent to many such processes, limit the use of these fabrication technologies in real products. In this work, the effect of additive fabrication-induced surface roughness on fluid flow within material extrusion (MEX) 3D-printed microfluidic devices is modeled and experimentally validated. An optimization process to eliminate such effects in functional 3D-printed devices is developed. By the resulting careful model-driven optimization, high-performance printed glass and Acrylonitrile butadiene styrene (ABS) valveless micropumps are demonstrated in this work for the first time. Water flow rates of 210 µl min−1 and 140 µl min−1 for the ABS and the glass micropumps respectively, and a maximum working backpressure of 978 Pa at an actuation signal of 68 Hz and 120 Vpp are achieved, attesting to the viability of additive fabrication to realize functional microfluidic devices.

The effect of surface roughness and wettability on the adhesion and proliferation of Saos-2 cells seeded on 3D printed poly(3-hydroxybutyrate)/polylactide (PHB/PLA) surfaces

The aim of this work is to explore the effect of surface characteristics of the 3D printed scaffolds on their suitability for Saos-2 cells growth. Two promising materials for bone tissue engineering were examined, both containing poly(3-hydroxybutyrate)/poly(d,l-lactide) plasticized blend and one of them filled with bioactive tricalcium phosphate. The surface free energy (SFE) of samples was determined by contact angle measurement with four liquids. For non-filled sample the water contact angle (WCA) was 74° and its SFE was 40 mN m−1. The composite sample exhibited substantially decreased WCA, 61°. Moreover, the addition of the tricalcium phosphate caused doubling of the polar component of the SFE which increased by a total of 13%. 3D printed surfaces prepared by fused deposition modeling method showed a profound increase of WCA due to the increase in their surface roughness which was analyzed by confocal microscopy. The change in wetting properties strongly affected the behavior of Saos-2 cells on printed surfaces. The number of cells as measured by DNA quantification linearly decreased with increasing surface WCA. The highest number of cells was observed on the pressed samples and 3D printed surfaces made of simple lines and a grid with 50 μm gap between lines. The favored surfaces exhibit WCA under 80° which is important information for the future design of the scaffolds.

Cold Plasma for the Modification of the Surface Roughness of Microparticles.

Cold plasma treatment is commonly used for sterilization. However, another potential of cold plasma treatment is surface modification. To date, several efforts have been directed toward investigating the effect of cold plasma treatment in modifying the surfaces of films. Here, the impact of suspension properties and parameters of cold plasma treatment on the changes of surfaces of monodisperse polymeric microparticles is tested. The plasma treatment did not touch the surface chemistry of the monodisperse polymeric microparticles. The concentration of suspensions of 1 mg/mL was determined to relate to a stronger effect of the plasma treatment on the roughness of the microparticles. Microparticles with an average diameter of 20 μm show a roughness increase with the plasma treatment time. However, a plasma treatment time longer than 15 min damages the microparticles, as observed in particles with an average diameter of 20 and 50 μm. We finally prototyped monodisperse microparticles to deliver drugs to the nasal mucosa by studying the effect of roughness in their (undesired) self-adhesion and (desired) adhesion with tissue. A moderate roughness, with an average peak-to-valley distance of 500 nm, appears to be the most effective in reducing the detachment forces with nasal tissue by up to 5 mN.

Accurate and Robust Static Hydrophobic Contact Angle Measurements Using Machine Learning.

We present a machine learning (ML) approach to static contact angle measurement, trained on a large data set (>7.2 million) of half drop contours based on solutions to the Young-Laplace equation where the contact angle is known a priori (removing all sources of error from human input). The data set included the effects of surface roughness, gravity, the size of drop relative to the image, and reflections of the drop on the surface. The presented ML model (valid for contact angles >110°), in combination with a new automated image and contour processing approach, is shown to be more accurate than other methods when benchmarked against an experimental data set, with an estimated error of 1°. The ML model is also 2 orders of magnitude faster at predicting contact angles than Young-Laplace fitting (the current best practice approach). The accuracy and speed of the presented approach provides a viable pathway toward robust and reproducible high-throughput contact angle analysis. This approach, Conan-ML, is open-source and provided for the use and development of new approaches to goniometry.

Mesoscale modeling of new-to-old concrete interface under combined shear and compressive loads

A mesoscale model of new-to-old concrete interface under combined shear and compressive loads is established, and a parameter study is conducted to evaluate the influence of interface roughness, bond strength, and fracture energy. The mesoscale model is numerically generated using a random aggregate technique, in which the number of aggregates is calculated using the Fuller grading curve and Walraven formula and the aggregates are randomly placed using the Monte Carlo simulation. The concrete damaged plasticity model is employed to simulate the mechanical behaviors of new and old mortars, as well as the interfacial transition zone between the mortar and aggregate. The linear elastic model is utilized to simulate the behavior of aggregates, while the cohesive-friction model is employed to represent the behavior of new-to-old concrete interface. The effect of interface roughness, bond strength, and fracture energy on the interface shear strength and post-peak shear strength using the double-shear test specimens is investigated. The results indicate that increasing the roughness of old concrete surface leads to significant increases in both the interface shear strength and post-peak shear strength, but the larger interface roughness is not necessarily better. As the interface bond strength increases, the interface shear strength remains the same, whereas the post-peak shear strength shows a large increase with the lower interface roughness. Moreover, the interface fracture energy imparts the minimal influence on the interface shear strength and post-peak shear strength, but the higher interface fracture energy can improve the overall constitutive behavior of new-to-old concrete interface if the roughness of old concrete surface is low. The numerical mesoscale model presented can provide the theoretical guidance and technical support for effective design and construction of new-to-old concrete interface and structures.

Study of the contact angle and roughness effects on mercury intrusion porosimetry (MIP) analysis in natural/real carbonate rocks using massive pure minerals and synthetic carbonate rocks

Studying pore networks in rocks is critical for understanding reservoir properties, with mercury intrusion porosimetry (MIP) being a key laboratory method. MIP involves capillary intrusion of mercury, with intrusion pressure (P) related to capillary diameter (d) by the Washburn equation, incorporating mercury properties like contact angle (θ) and surface tension (γ). While a constant contact angle of 140° is typically assumed for MIP, it can vary based on rock mineralogy and surface roughness. This study aims to analyze how contact angle variations and surface roughness affect MIP analysis of carbonate rocks. Initially, contact angle data was obtained for calcite, dolomite, and quartz with varying roughness levels. Synthetic rocks were then constructed using these minerals. MIP was performed using the typical 140° contact angle and a calculated contact angle from the Cassie model, which considers surface composition fraction. Natural rock MIP analysis followed, with contact angles varying due to mineral composition and roughness. The study found higher contact angles than the standard 140°, affecting pore size distributions up to 30%. Natural rock pore network curves were adjusted based on synthetic rock data analysis. These findings emphasize the need for accurate contact angle selection in MIP for precise pore distribution analysis and contribute to the further study of carbonate rocks.

Effects of surface roughness parameters on the shear strength of AA 6061-T6 aluminium alloy in structural adhesive bonding applications

This study aims to investigate the effects of the surface roughness of an aluminium substrate on the adhesive joint strength of aluminium–aluminium specimens prepared using epoxy and methyl methacrylate adhesives for shear strength tests. Aluminium surfaces were mechanically abraded using silicon carbide (SiC) papers with different grit sizes in two different modes. The evaluated bonding performance characteristics included the maximum bonding strength and residual strength of the adhesive joints after their exposure to various environmental conditions. The results demonstrated that excellent adhesion characteristics were obtained at the optimum SiC grit size (grit-80) regardless of the adhesive type. In addition, the topographical and morphological properties of the aluminium surfaces were studied before and after mechanical abrasion via surface profilometry and scanning electron microscopy, respectively. A possible mechanism was proposed to explain the observed shear strength changes and respective modes of fracture after sample exposure to air, de-ionised water, and aqueous salt solutions.

Analysis of Thermoelastic Contact of Gas-Lubricated Rough Sealing Faces.

Friction and wear are the main failure sources of face seals. When the surfaces of sealing rings exhibit greater roughness, the level of friction might increase and lead to sealing failure. Therefore, in this paper, based on the elastic contact hypothesis of rough and wavy surfaces and the influence of temperature on the elastic modulus of materials, a thermoelastic contact lubrication model of a gas-lubricated end seal is established. The novelty and advantage of this study is that it takes the effect of surface roughness into consideration during thermoelastic analysis of gas-lubricated seals. The film pressure, temperature, contact force and deformation of a gas spiral groove-faced seal are numerically determined. The influence of surface roughness on the contact distribution, deformation and temperature of the end-face seal at different speeds and pressures is analyzed. The film thickness increases as the rotational speed increases from 1 rpm to 2000 rpm, while the contact pressure sharply decreases from 0.25 kPa to 0. The analysis shows that the roughness contact mainly happens on the inner side of the rings due to convergent distortion of the seal faces, which easily causes partial wear of the seal faces. Moreover, it can also be found that the spiral grooves on the sealing surface can produce obvious hydrodynamic pressure effect due to the function of shear speed when the speed increases to 2000 rpm, while the film temperature increases from 293.3 K to about 306 K. The greater surface roughness results in a larger temperature rise under low-rotational-speed and lower-seal-pressure conditions, which further increases the risk of severe wear or even failure of the seal faces.