Surface Texture Parameters Research Articles

The preliminary study of the forecasting model between surface texture and various material parameters for the ISO 10844 test track

Pavement surface texture is an essential factor in influencing the sound emission of vehicles, and reducing noise pollution would be a big issue for all humans. According to the Economic Commission for Europe (ECE) R-117 requirement, all the vehicle tires vending in Europe should pass noise accreditation after September 2009, and the pavement surface of the test track should follow ISO 10844. The Mean Profile Depth (MPD) is adopted to be the texture parameter of the test track surface in ISO 10844. the MPD of the Test track should be controlled at specific intervals, and the material design should be a big challenge of pavement Engineering. This study aims to establish an MPD prediction function with material properties for pavement Engineers. In material, there were two fine aggregates, three gradation curves, three air voids of the specimen, and 18 mixture designs adopted in this study. There were three specimens in each mixture design; the total specimen number was 54 for MPD measurement. Fifty-four laboratory test specimens were compacted using a Superpave gyratory compactor (SGC). A High-Definition Pavement Texture Machine (HDPTM) measured the specimen surface MPD. The parameters in this study included fineness module (FM), fine aggregate angularity (FAA), air void (AV) of the specimen, and Gyration number (G) of SGC. Gene Expression Programming (GEP) was adopted to build a prediction model between MPD and various parameters. Based on the results of this study, the best MPD forecasting model using FAA, FM, and AV, the R2 of is 0.74, meaning the best MPD forecasting model could be a very nice tool to help pavement engineers to do MPD quality control on the test track for ISO 10844. In addition, GEP was an excellent method to discover the nonlinear relationship between MPD and various parameters of asphalt concrete, and it was worthy of further study.

Key topographic parameters driving surface adhesion of Porphyromonas gingivalis

Dental implant failure is primarily due to peri-implantitis, a consequence of bacterial biofilm formation. Bacterial adhesion is strongly linked to micro-/nano-topographies of a surface; thus an assessment of surface texture parameters is essential to understand bacterial adhesion. In this study, mirror polished titanium samples (Ti6Al4V) were irradiated with a femtosecond laser (fs-L) at a wavelength of 1030 nm (infrared) with variable laser parameters (laser beam polarization, number, spacing and organization of the impacts). Images of 3-D topographies were obtained by focal variation microscopy and analyzed with MountainsMap software to measure surface parameters. From bacteria associated with peri-implantitis, we selected Porphyromonas gingivalis to evaluate its adhesion on Ti6Al4V surfaces in an in vitro study. Correlations between various surface parameters and P. gingivalis adhesion were investigated. We discovered that Sa value, a common measure of surface roughness, was not sufficient in describing the complexity of these fs-L treated surfaces and their bacterial interaction. We found that Sku, density and mean depths of the furrows, were the most accurate parameters for this purpose. These results provide important information that could help anticipate the bacterial adhesive properties of a surface based on its topographic parameters, thus the development of promising laser designed biofunctional implants.

Scale effects on surface texture characterisation of ultra-precision diamond milling

Surfaces with nanometric texture, machined by ultra-precision diamond milling (UPDM), have wide applications for their functionalities. Surface texture characterisation is crucial for their quality evaluation and it would vary in the measurement data processing under various scales, which is termed scale effects. However, the scale effects have not been comprehensively studied. In this work, we focus on the scale effects on surface texture characterisation of UPDM. Firstly, a series of experiments were conducted at different material removal rates to produce surfaces with nanometric texture. Secondly, a discrete wavelet transform (DWT)-based method was employed for surface filtering and surface texture parameters (Sa, Sq, and Sz) were evaluated according to ISO standards. Thirdly, power spectral density (PSD) analysis and surface filtering comparison were performed to realize a scale observation. Furthermore, the effects of the filtering scale, the sampling scale, and the subarea scale on surface texture characterisation were investigated. Finally, the results showed that surface topographies were governed by various machining factors which resulted in multi-scale topographical components. The PSD analysis enabled discrimination of the multi-scale topographical components to the underlying machining factors. The DWT-based method achieved a relatively small deviation (<4%) for surface filtering as compared to the zero-order Gaussian regression filter. The filtering scale affected the filtered topographical components and it visualised and differentiated those components with the machining mechanisms. The sampling scale determined the filtered components to yield an impact on the characterisation results and Sz was more sensitive to this effect than Sa and Sq. The subarea scale influenced the probability distributions and statistical values of surface texture parameters within its contained components and it indicated that the increased material removal rate resulted in a deterioration of surface uniformity.

Studies on the corrosion behavior of aluminum alloy in solid/molten salt hydrate phase change material based on fractal theory

The corrosion behavior of Al7075 in the solid and molten states of phase change material were investigated based on fractal theory in conjunction with electrochemical impedance spectroscopy. Results indicated that the surface texture parameters were properly used to describe the corrosion degree as well as identify the different pitting stages. Pitting conformed with Weibull distribution. The statistical parameters Skewness and Kurtosis had a good linear relation with fractal dimension (Ds). Additionally, there was linear relationship between Ds and DEIS based on EIS spectra, due to the fractal geometry of Al7075 electrodes that induced time-constant dispersion and resulted in CPE behaviors.

Fast three-dimensional simulation based on data constraints and methods to improve the realism of knitted sweaters

The purpose of this research is to use the methods of data constraints for parametric design and three-dimensional simulation of knitted sweaters to achieve the purpose of enhancing the simulation effect. First, based on the basic plates of knitted sweaters as a reference, the parameters of the curve parts of the plates were constrained, and the constraint relationships were applied to build the parametric design models. After entering the user parameters, the changed plates can be obtained. On this basis, the transformation of flat plates to three-dimensional surfaces was carried out. The triangular grid mapping relationships between two-dimensional plates and three-dimensional surfaces were constructed, and the physical properties were further specified for the mesh particles. When the surface texture parameters of the two-dimensional plane are designed, the three-dimensional surface will change accordingly. In addition, this research put forward the stitching and matching methods of the seams of knitted sweaters. The joint size was equally divided, and the number of coils was converted into the number of triangular mesh. Point-to-point mesh was used to realize the accurate counterpoint fusion of coils. The feasibility of parametric and virtual design methods was verified by taking an example, which provides ideas for the computer-aided design of knitted sweaters and promotes the improvement of production efficiency without wasting raw materials.

Vibration characteristics of turbocharger rotor system considering internal thread texture parameters of semi-floating ring bearing

The internal thread texture causes changes in the dynamic characteristics of the oil film of the semi-floating ring bearing, which affects the amplitude of vibration and operating life of the turbocharger rotor system. Based on the fluid lubrication theory, the oil film governing equation of a semi-floating ring bearing with surface texture parameters is derived. The effects of the texture depth, position, and number of turns of the internal thread on the dynamic characteristics of the bearing oil film, such as the maximum pressure, load-carrying capacity and stiffness damping, are analyzed. Taking a type of turbocharger as an example, a hydrodynamic model is established to analyze the oil film lubrication in the semi-floating ring bearings, and the dynamic characteristic of the oil film is analyzed by computational fluid dynamics method. The results show that the maximum pressure, bearing capacity, and stiffness damping coefficient of oil film increase firstly and then decrease with the increase of texture depth and the number of thread turns in the range of journal rotation speed from 1000 to 20,0000 r/min. Compared with the non-texture bearings, the dynamic characteristics coefficients of the oil film such as bearing capacity and stiffness damping increase the most, when the depth of texture is 0.006 mm and the number of thread turns is 9. Secondly, the dynamic characteristic coefficient of oil film is improved when the texture is distributed in the middle than on both sides. The thread texture with appropriate parameters can suppress the rotor system vibration amplitude. The conclusion can provide a reference for the design of textual parameters of semi-floating ring bearings.

Influence of surface characteristics of cement pavement on ice-concrete adhesion

Breaking the adhesion between ice- and pavement is crucial for road de-icing. This study investigates the impact of concrete pavement surface characteristics on ice-pavement adhesion. To achieve this, 20 cement concrete specimens with different combinations of 10 surface textures and 2 wettability surface characteristics were prepared. The water contact angle (WCA) and six texture parameters were determined using the sessile drop and tangent line methods, as well as the sand patch and laser texture scanner techniques. To evaluate the ice–concrete adhesion, shear strength measurements obtained through interlayer shear instrument testing were utilized. In our analysis, we examined the relationship between ice adhesion strength and several factors, including the freezing temperature (T), water wettability, and surface texture parameters. A partial least squares (PLS) model was built to comprehensively analyze the effects of different factors on ice-concrete adhesion. The results indicate that improving hydrophobicity, as demonstrated by an increase in WCA from 20.4° to 119.4°, and raising the freezing temperature were both effective approaches for significantly reducing ice-concrete adhesion. The effects of different texture parameters on hydrophilic and hydrophobic concrete were significantly different. Specifically, for ordinary concrete, the ratio of the surface area (Sr) and the mean texture depth (MTD) demonstrated a positive correlation with ice adhesion strength. For hydrophobic surfaces, the MTD exhibited the greatest correlation with adhesion, followed by Sr. However, skewness (Rsk) also had a significant effect on the ice adhesion of hydrophobic concrete, and ice adhesion preferred valley-texture concrete. Finally, the PLS model results showed that the order of influence on ice-concrete adhesion was: Sr > WCA > MTD > T > Rsk. Based on our findings, we suggest three approaches for reducing ice adhesion to concrete surfaces: implementing semicircular or trapezoidal groove textures, reducing the surface energy of the concrete, and introducing the valley texture surfaces. This study focuses on the influence of surface characteristics of concrete pavements on ice adhesion and provides guidance on designing concrete surfaces for effective road de-icing.

Wetting model of rough solid surfaces and the effect of aggregate properties on epoxy resin binder-aggregate interface wetting

In order to study the effect of aggregate characteristics on the wetting of epoxy resin binder-aggregate interface, based on the Wenzel model and Cassie model, this paper established a new wetting model of the irregular rough surface. The model regularizes the rough solid surface and can calculate the wetting depth and apparent contact angle between different irregular rough solids and liquids. The texture parameters of aggregates, the surface tension of test liquids and the contact angles of different liquids-aggregates were tested by laser confocal tester and optical contact angle measuring instrument. It was found that the surface texture parameters of different aggregates were quite different. The relative error between the apparent contact angle calculated by the prediction model and the contact angle measured by the test was less than 15 %, indicating that the prediction model had excellent prediction effect. Through the analysis of the wetting model, it is found that the surface tension of the test liquid, the lithology of the solid aggregate, the surface roughness and the texture structure are the important control parameters affecting the wetting. The surface morphology of rough solid can be designed by changing the resolution k and depth H of micropores, so as to control the wettability of solid aggregate surface and epoxy resin aggregate.

Assessing the technological quality of abrasive water jet and laser cutting processes by geometrical errors and a multiplicative indicator

Technological quality is an important factor in industry processes. In this study an original index for assessing the technological quality for laser and abrasive water jet cutting was proposed. Developed MCTQ index links the most important features of quality assessment. The carried out tests allowed for the determination of the technological quality assessment based on the evaluation of dimensional and shape accuracy, analysis of the perpendicularity error of the cut edge, measurements of the surface texture parameters, and analysis of microscopic images. The results for both cutting technologies showed that the magnitude of the deviation of the analyzed geometric features increases with the thickness of the sheet. In the case of the laser jet cutting, the occurrence of surface defects were mainly affected by the molten material blow out from the kerf by the associated gas through the upper cutting zone. Straightness deviation, is mainly shape errors in case of the abrasive water jet cutting process. A proposed multiplicative indicator of cutting technological quality provides a relative measure for comparing the results of the cutting process among themselves.

Optimisation of Imaging Confocal Microscopy for Topography Measurements of Metal Additive Surfaces

Additive manufactured surfaces, especially metal powder bed fusion surfaces, present unique challenges for measurement because of their complex topographies. To address these measurement challenges, optimisation of the measurement process is required. Using a statistical approach, sensitivity analyses were performed on measurement settings found on a commercial programmable array scanning confocal microscope. The instrument measurement process parameters were compared by their effects on three quality indicators: the areal surface texture parameter Sa, measurement noise, and number of non-measured points. An analysis was performed using a full factorial design of experiments for both the top and side surfaces of test surfaces made from Inconel 718 and Ti-6Al-4V using powder bed fusion. The results indicated that measurements of metal additive surfaces are robust to changes in the measurement control parameters for Sa, with variations within 5% of the mean parameter value for the same objective, surface, and measured area. The number of non-measured points and the measurement noise were more varied and were affected by the choice of measurement control parameters, but such changes could be predicted by the statistical models. The contribution offered by this work is an increased understanding of imaging confocal microscopy measurement of metal additive surfaces, along with the establishment of good practice guidance for measurements.

Impacts of Particle Shape, Skeletal Porosity and Density on the Settling Velocity of Gravel‐Size Coral Debris

AbstractKnowledge of the hydrodynamic behavior of carbonate bioclasts is essential for solving coastal morphodynamic problems in marine carbonate depositional environments. Marine carbonate grains are produced within the sedimentary system itself and are deformed by subsequent hydrodynamics, resulting in particle densities, sizes and shapes that are distinct from those of terrigenous sediments. In this study, we investigated the shapes and settling characteristics of gravel‐size natural coral debris collected from the coasts of Okinawa Prefecture, Japan. Based on the shape parameters and settling velocities obtained using image analysis techniques and settling tube experiments, respectively, a correlation model for predicting the settling velocity of coral gravel particles was developed by extending the previous formula of Dietrich (1982, https://doi.org/10.1029/wr018i006p01615) over particle Reynolds number values ranging from 384.23 to 4439.76. The model determines the settling velocity as a function of particle nominal diameter, form, roundness, and surface texture parameters that were selected after examining several other shape descriptors. Compared with other models, the proposed model showed better settling velocity predictive skills for coral gravel particles classified into four shape types. The proposed model also determines how the drag coefficient of coral gravel particles should be modified from that for spherical particles, by accounting for the abovementioned coral gravel particle shape parameters. The obtained data set of settling velocity and modification of the drag coefficient can be used for quantitative interpretation of suspension, transport, and sedimentation processes in marine carbonate depositional environments.

Influence of Contour Scan Variation on Surface, Bulk and Mechanical Properties of LPBF-Processed AlSi7Mg0.6.

Metal additive manufacturing technologies have great potential for future use in load-bearing aerospace applications, requiring a deeper understanding of mechanical performance and influencing factors. The objective of this study was to investigate the influence of contour scan variation on surface quality, tensile and fatigue strength for laser powder bed fusion samples made of AlSi7Mg0.6 material and to create high-quality as-built surfaces. The samples were produced with identical bulk and different contour scan parameters to accommodate the investigation of the impact of as-built surface texture on mechanical properties. The bulk quality was evaluated by density measurements according to Archimedes' principle and tensile testing. The surfaces were investigated using the optical fringe projection method, and surface quality was assessed by the areal surface texture parameters Sa (arithmetic mean height) and Sk (core height, derived from material ratio curve). Fatigue life was tested at different load levels, and the endurance limit was estimated based on a logarithmic-linear relation between number of cycles and stress. All samples were found to have a relative density of more than 99%. Surface conditions distinctive in Sa and Sk were successfully created. The resulting mean values of the ultimate tensile strength σult are between 375 and 405 MPa for 7 different surface conditions. It was confirmed that the influence of contour scan variation on bulk quality is insignificant for the assessed samples. Regarding fatigue, one as-built condition was found to perform as well as surface post-processed parts and better than the as-cast material (compared to literature values). The fatigue strength at the endurance limit for 106 cycles is between 45 and 84 MPa for the three considered surface conditions.

Study on the Matching of Surface Texture Parameters and Processing Parameters of Coated Cemented Carbide Tools

Placing micro-textures on a tool surface can play an anti-wear and friction-reducing role and capture impurities and improve the tool-chip friction state, thus improving the cutting performance of the tool and the quality of the workpiece. To ensure the processing quality in the micro-texture-coated tool-cutting process, the process parameters and micro-texture parameters are limited to smaller parameters, which reduces the processing efficiency and increases the cost. Aiming at this problem, this paper designs orthogonal experiments of the cutting process and micro-texture parameters, builds an experimental platform for milling titanium alloy with a micro-texture-coated ball-end milling cutter, analyzes the influence of cutting parameters on tool milling performance and workpiece quality, establishes a high fitting prediction model, and optimizes parameters. The results show that the cutting parameters significantly affect the milling force, tool wear, and workpiece surface roughness, which are in the first response level, and the micro-texture parameters, which are in the second response level. It is proven that micro-texture has anti-wear and anti-friction effects, and it is found that micro-texture parameters affect the evaluation index by changing the distribution state of the micro-texture. It is found that the multiple linear regression model fits better. Parameter optimization results are: v = 159.4232 (m/min), ap = 0.211 (mm), f = 0.06 (mm/r), micro-pit diameter D = 62.3429 (μm), distance from blade L = 121.5184 (μm), and micro-pit spacing L1 = 235.6443 (μm). It provides some guidance for the selection of micro-texture parameters and cutting parameters on a micro-texture-coated tool.

Effect of compound pit textures on the friction and wear of thrust cylindrical roller bearings under starved lubrication

PurposeThis study aims to investigate the effect of compound pit textures on the tribological properties of thrust cylindrical roller bearings (TCRBs) using several parameters, such as compound type, pit diameter, pit depth and pit area density.Design/methodology/approachThe surface texture parameters of the shaft washer (WS) raceway include pit diameter (D; 100, 300 and 500 µm), pit depth (H; 10 and 20 µm) and pit area density (S; 10%, 13% and 18%). Pits were produced on the WS of the TCRBs using laser marking equipment. The friction and wear performances of compound pit-textured TCRBs under starved lubrication conditions are studied using a friction and wear test rig. The influence mechanisms of the compound pit texture on the friction and wear properties of TCRBs are discussed through real tests and discussions.FindingsCompared with nontextured bearings, the average coefficient of friction (ACOFs) and wear loss of TCRBs with single/compound pit textures are reduced when rotating under starved lubrication. D has the greatest effect on the COFs curve. When D = 300 µm, H = 10 µm and S = 10%, the ACOF and wear loss are the lowest, that is, 0.0207 and 3.38 mg, respectively. Under the same lubrication conditions, compared with the nontextured bearing group, the COF and wear loss are reduced by 41.4 and 59.6%, respectively.Originality/valueThis study provides a useful reference for the raceways of textured TCRBs.

A theoretical and experimental investigation into surface generation in ultra-precision diamond milling

Ultra-precision diamond milling (UPDM) provides a promising generation of high-quality surface up to sub-micrometric form accuracy and nanometric surface roughness. Prior to its machining process, the investigation on surface generation would be beneficial to achieve desired quality with reduced cost and boosted productivity. However, few studies discussed this issue so far. In this study, a theoretical and experimental investigation into surface generation was carried out in UPDM. Firstly, a geometric model was built up considering the material removal process between the milling tool and the workpiece. Secondly, surface generation process was elaborated according to the developed model. Finally, UPDM experiments were performed on a typical brass material at different cutting conditions and surface texture parameters were characterized according to ISO 25178-2. Autocorrelation function (ACF) analysis was employed for a detailed evaluation of surface generation. The results showed that the static factors (cutting parameters) as well as the dynamic factors (material effects and spindle vibration), which were associated with the cutting conditions, yielded a great influence on surface generation. Surface texture characterization indicated that there was a good consistence between simulation and experiment, demonstrating the feasibility of the proposed method. ACF analysis indicated that, with the increased feedrate/step ratio, surface generation approximately achieved a transition from the periodical surface (dominated by cutting residuals) to the random surface (determined by multiple components). Significantly, this study draws up a fundamental understanding toward surface generation in UPDM.

Influence mechanism of laser defocusing amount on surface texture in direct metal deposition

Direct metal deposition is a promising additive manufacturing, but the surface quality of as-built parts has been a prominent issue limiting its immediate application. The laser beam exerts different influence mechanisms on the surface texture of the top surface and sidewalls, which are the main contour surfaces of as-built parts during multi-axis deposition. In this paper, the deposition height deviation and the deposition height instability were proposed to characterize the surface texture on the top surface, and the surface maximum height was used for the sidewalls. The correlation between the laser defocusing amount and the surface texture parameters was quantitatively studied. Results show that the deposition height deviation under the positive laser defocusing state is smaller than that under the negative laser defocusing state, although the laser defocusing distance is the same. The deposition height presents a self-stable phenomenon under the positive laser defocusing state. The surface quality on sidewalls is better under the negative laser defocusing state than that under the positive laser defocusing state. In addition, the influence mechanism of the laser defocusing amount was analyzed on the formation of multiple overlapped tracks on the top surface. Three formation mechanisms of adhered protrusions on sidewalls were revealed through a high-speed camera, namely particle adhesion, powder adhesion, and agglomeration adhesion. The research can be utilized to guide the dynamic adjustment of the laser defocusing amount to improve the forming quality. • The deposition height presents a self-stable phenomenon under the positive laser defocusing state. • The surface maximum height is suitable to characterize the surface texture on sidewalls. • A large laser defocusing distance under the NLDS is preferred to obtain a better surface quality on sidewalls. • Adhered protrusions are categorized into particle adhesion, powder adhesion, and agglomeration adhesion.

Study on the Influence of Surface Texture Parameters of Oil Production Screw Motor Rotor on the Tribological Properties of Its Friction Pair

By researching the influence of micro-groove texture on the surface tribological properties of the stator and rotor pair of oil production hydraulic motors, this paper aims to reduce the frictional resistance moment of the spiral pair of hydraulic motors, and further solve the problem of the difficult restart of the pump of a certain type of hydraulic-driven screw pump. According to the spiral pair of screw motors, a metal-rubber flat plate reciprocating friction model is established, and rectangular micro-grooves with different texture angles and depths are machined on the surface of the metal specimen. A combination of finite element simulation and tribological tests is used to carry out a study on the influence of different texture parameters on the friction performance of the hydraulic motor spiral pair. The results showed that at a certain texture angle, the friction coefficient of each specimen basically increases with the texture depth. When the texture depth is constant, the friction coefficient increases first and then decreases with the increase of the texture angle. The texture angle is the main factor affecting the friction coefficient. Under the same test conditions, the friction coefficient of the textured specimen can be reduced by 20.2% compared with the untextured specimen. In the metal-rubber contact pair of the stator and rotor of the hydraulic motor, the friction reduction mechanism of the texture mainly transport the lubricating medium through the micro-grooves to improve the lubricating conditions. Samples with a reasonable design of texture parameters can effectively reduce the friction coefficient of the friction pair without reducing the service life of the hydraulic motor, which is conducive to the smooth restart of the oil production system of the hydraulically driven screw pump.

Study on skid resistance and skid-resistance durability of polymer modified cement mortar based on surface texture properties

In this paper, the effects of the three polymer emulsions-EVA, XSBRL, and SBR, on the skid resistance and skid-resistance durability of cement mortar were investigated based on the surface texture properties of the specimens. The surface texture properties include texture roughness and texture abrasion resistance, which were evaluated by 3D surface texture parameters. Using close-up photography and reverse engineering techniques, texture data was retrieved from the surface of the specimen to determine the 3D texture parameters. The friction coefficient tester and the wet track abrasion tester were used to verify the surface texture roughness and texture abrasion resistance, respectively. The results show that the polymer content increment can significantly improve the surface texture roughness, which is beneficial to enhancing the skid resistance of cement mortar. The varying surface texture roughness improvement effects of the various polymer emulsions are the main reason for the variation in the skid resistance of the three PCMs. EVA provides the best skid resistance by effectively improving the surface texture height (Sa), symmetry (Ssk), and core material volume (Vmc) of the cement mortar. In contrast, XSBRL enhances skid resistance by increasing the surface texture sharpness (Sku), slope (Sdq), top material volume (Vmp), and surface area (Sdr), with slightly less improvement. SBR is the least effective in improving the surface texture parameters of the cement mortar and therefore has the worst skid resistance. The three polymer emulsions increased the texture abrasion resistance of cement mortar. E-PCM was the highest texture abrasion resistance, followed by X-PCM, and S-PCM was the poorest. The Vmc may have a role in the variation in texture abrasion resistance, as the more peak core material volume there is, the more material is available for abrasion. Therefore, polymer emulsions can enhance the skid resistance and skid-resistance durability of cement mortar by improving the texture properties, with E-PCM being the most enhancement effect.

Nanoscale 3D Spatial Analysis of Zirconia Disc Surfaces Subjected to Different Laser Treatments

We propose the application of morphological, fractal and multifractal analysis to differentiate surface patterns on zirconia-based ceramics after laser treatments. Furthermore, we introduce two new approaches for ceramic surfaces: the Moran correlogram, which complements the spatial autocorrelation analyses, and the Otsu binarization algorithm, which was used to identify the lacunar points in the lacunarity analysis. First, the AFM (Atomic Force Microscope) topographies revealed that samples have significant differences in terms of spatial features. Quantitatively, spatial surface texture parameters indicated that all laser treatments reduced the superficial isotropy of the Zirconia disc. Moran’s correlograms revealed a decrease in the short-range correlation in all treated samples. The Minkowski functionals (MFs) indicated a reduction in the amount of matter in the peaks, especially for the sample with Nd-YAG laser treatment. The estimated fractal dimension (FD) pointed out that all laser treatments weakened the surface complexity of the Zirconia disc. On the other hand, clear fingerprints of multifractal behavior in all the samples were detected, where the highest degree of multifractality was computed for the samples with CO2 laser treatment. Finally, our findings suggested that the morphological changes caused by laser treatments on the surfaces of zirconia discs can be monitored and differentiated through the parameters proposed here.

Using 3D road texture measurements for tyre/road noise modell

When investigating the generation of rolling noise, profound knowledge of the tyre/road interaction is inevitable. Research projects addressing the road surface influence on the noise generation are commonly based on standardized road surface texture parameters, e.g. mean profile depth or spectral analysis of surface profiles. Such quantities are calculated from line texture measurements or equally sized parts of 3D-road surface samples. AIT has recently developed a high-speed continuous 3D texture scanner which provides heightened spatial information down to 60µm. This allows the determination of a multitude of additional parameters of road surface geometries. In this paper, comparisons of line texture, statistical analyses of the variability of 3D texture parameters on real road sections, as well as basic statistical models to investigate correlations between these parameters and coupled Close-Proximity Method (CPX) measurements will be described.