Topography Modeling of Surface Grinding Based on Random Abrasives and Performance Evaluation

The surface morphology and roughness of a workpiece are crucial parameters in grinding processes.Accurate prediction of these parameters is essential for maintaining the workpiece’s surface integrity.However,the randomness of abrasive grain shapes and workpiece surface formation behaviors poses significant challenges,and accuracy in current physical mechanism-based predictive models is needed.To address this problem,by using the random plane method and accounting for the random morphology and distribution of abrasive grains,this paper proposes a novel method to model CBN grinding wheels and predict workpiece surface roughness.First,a kinematic model of a single abrasive grain is developed to accurately capture the three-dimensional morphology of the grinding wheel.Next,by formulating an elastic deformation and formation model of the workpiece surface based on Hertz theory,the variation in grinding arc length at different grinding depths is revealed.Subsequently,a predictive model for the surface morphology of the workpiece ground by a single abrasive grain is devised.This model integrates the normal distribution model of abrasive grain size and the spatial distribution model of abrasive grain positions,to elucidate how the circumferential and axial distribution of abrasive grains influences workpiece surface formation.Lastly,by integrating the dynamic effective abrasive grain model,a predictive model for the surface morphology and roughness of the grinding wheel is established.To examine the impact of changing the grit size of the grinding wheel and grinding depth on workpiece surface roughness,and to validate the accuracy of the model,experiments are conducted.Results indicate that the predicted three-dimensional morphology of the grinding wheel and workpiece surfaces closely matches the actual grinding wheel and ground workpiece surfaces,with surface roughness prediction deviations as small as 2.3%.

Unveiling three-dimensional sea surface signatures caused by internal solitary waves:insights from the surface water ocean topography mission

Internal solitary waves(ISW),characterized by large amplitude and long propagation distance,are widespread in global oceans.While remote sensing images have played an essential role in studying ISWs,they mainly exploit two-dimensional image information.However,with the launch of the surface water ocean topography(SWOT)satellite on December 16,2022,a unique opportunity has emerged to capture wide-swath three-dimensional ISW-induced sea surface information.In this study,we examine ISWs in the Andaman Sea using data from the Ka-band Radar Interferometer(KaRIN),a crucial sensor onboard SWOT.KaRIN not only provides backscattering satellite images but also employs synthetic aperture interferometry techniques to retrieve wide-swath two-dimensional sea surface height measurements.Our observations in the Andaman Sea revealed the presence of ISWs characterized by dark-bright strips and surface elevation solitons.The surface soliton has an amplitude of 0.32 m,resulting in an estimation of ISW amplitude of approximately 60 m.In contrast to traditional two-dimensional satellite images or nadir-looking altimetry data,the SWOT mission’s capability to capture threedimensional sea surface information represents a significant advancement.This breakthrough holds substantial promise for ISW studies,particularly in the context of ISW amplitude inversion.

Study of the ability of SWOT to detect sea surface height changes caused by internal solitary waves

Surface Water and Ocean Topography(SWOT)is a next-generation radar altimeter that offers high resolution,wide swath,imaging capabilities.It has provided free public data worldwide since December 2023.This paper aims to preliminarily analyze the detection capabilities of the Ka-band radar interferometer(KaRIn)and Nadir altimeter(NALT),which are carried out by SWOT for internal solitary waves(ISWs),and to gather other remote sensing images to validate SWOT observations.KaRIn effectively detects ISW surface features and generates surface height variation maps reflecting the modulations induced by ISWs.However,its swath width does not completely cover the entire wave packet,and the resolution of L2/L3 level products(about 2 km)cannot be used to identify ISWs with smaller wavelengths.Additionally,significant wave height(SWH)images exhibit blocky structures that are not suitable for ISW studies;sea surface height anomaly(SSHA)images display systematic leftright banding.We optimize this imbalance using detrending methods;however,more precise treatment should commence with L1-level data.Quantitative analysis based on L3-level SSHA data indicates that the average SSHA variation induced by ISWs ranges from 10 cm to 20 cm.NALTs disturbed by ISWs record unusually elevated SWH and SSHA values,rendering the data unsuitable for analysis and necessitating targeted corrections in future retracking algorithms.For the normalized radar cross section,Ku-band and four-parameter maximum likelihood estimation retracking demonstrated greater sensitivity to minor changes in the sea surface,making them more suitable for ISW detection.In conclusion,SWOT demonstrates outstanding capabilities in ISW detection,significantly advancing research on the modulation of the sea surface by ISWs and remote sensing imaging mechanisms.

Influence of high-speed milling parameter on 3D surface topography and fatigue behavior of TB6 titanium alloy

High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality.In order to optimize the machining parameters in high-speed milling TB6 titanium alloy,experiments of high-speed milling and fatigue were conducted to investigate the effect of parameters on 3D surface topography and fatigue life.Based on the fatigue fracture,the effect mechanism of surface topography on the fatigue crack initiation was proposed.The experiment results show that when the milling speed ranged from 100 m/min to 140 m/min,and the feed per tooth ranged from 0.02 mm/z to 0.06 mm/z,the obtained surface roughness were within the limit（0.8 μm）.Fatigue life decreased sharply with the increase of surface equivalent stress concentration factor.The average error of fatigue life between the established model and the experimental results was 6.25%.The fatigue cracks nucleated at the intersection edge of machined surface.

Running-in Test and Fractal Methodology for Worn Surface Topography Characterization

Studying and understanding of the surface topography variation are the basis for analyzing tribological problems,and characterization of worn surface is necessary.Fractal geometry offers a more accurate description for surface roughness that topographic surfaces are statistically self-similar and can be quantitatively evaluated by fractal parameters.The change regularity of worn surface topography is one of the most important aspects of running-in study.However,the existing research normally adopts only one friction matching pair to explore the surface topography change,which interrupts the running-in wear process and makes the experimental result lack authenticity and objectivity.In this paper,to investigate the change regularity of surface topography during the real running-in process,a series of running-in tests by changing friction pairs under the same operating conditions are conducted on UMT-II Universal Multifunction Tester.The surface profile data are acquired by MiaoXAM2.5X-50X Ultrahigh Precision Surface 3D Profiler and analyzed using fractal dimension D,scale coefficient C and characteristic roughness Ra ＊based on root mean square（RMS） method.The characterization effects of the three parameters are discussed and compared.The results obtained show that there exists remarkable fractal feature of surface topography during running-in process,both D and Ra ＊increase gradually,while C decreases slowly as the wear-in process goes on,and all parameters tend to be stable when the wear process steps into the normal wear process.Ra ＊illustrates higher sensitivity for rough surface characterization compared with the other two parameters.In addition,the running-in test carried with a set of identical surface properties is more scientific and reasonable than the traditional one.The proposed research further indicates that the fractal method can quantitatively measure the rough surface,which also provides an evidence for running-in process identification and tribology design.

Fatigue life prediction of workpiece with 3D rough surface topography based on surface reconstruction technology

The fatigue performance of a workpiece depends on its surface quality.In traditional fatigue life prediction,the effect of surface quality is commonly accounted for by using empirical correction factors,which is imprecise when safety is of great concern.For surface quality,the surface topography is an important parameter,which introduces stress concentration that reduces the fatigue life.It is not feasible to test the stress concentration of different surface topographies.On the one hand,it is time-consuming and high-cost,and on the other hand,it cannot reflect the general statistical characteristics.With the help of surface reconstruction technology and interpolation method,a more efficient and economic approach is proposed,where FE simulation of workpiece with the reconstructed surface topography is used as a foundation for fatigue life prediction.The relationship between surface roughness(Sa)and fatigue life of the workpiece is studied with the proposed approach.

Erosion and erosion-corrosion of Al-brass alloy: Effects of jet velocity, sand concentration and impingement angle on surface roughness

Effects of jet velocity,sand concentration and impingement angle on the surface roughness of Al-brass alloy were investigated after erosion and erosion?corrosion tests.The tests were performed using a jet impingement rig.The eroded surfaces were characterized using2-D and3-D surface profilometery and scanning electron microscopy(SEM).The results showed that there was an increase in the surface roughness of the erosion?corrosion samples as sand concentration was increased to1,5and10g/L at jet velocities of9,6and3m/s,respectively.However,the surface roughness decreased with a further increase in sand concentration.This decrease in the surface roughness was attributed to the higher work hardening of the surface,rebounding or blanketing effect and very high frequency of the impacts at the higher sand concentrations.The surface roughness increased as the jet velocity increased.The results also showed that the change in the surface roughness with impingement angle was not significant at two jet velocities of3and6m/s.However,at a higher jet velocity of9m/s,formation of ripples on the erosion surfaces at oblique angles resulted in a higher surface roughness as compared with the normal impingement angle.

Surface Topography and Roughness of High-speed Milled AlMn1Cu

The aluminum alloy AlMn1Cu has been broadly applied for functional parts production because of its good properties. But few researches about the machining mechanism and the surface roughness were reported. The high-speed milling experiments are carried out in order to improve the machining quality and reveal the machining mechanism. The typical topography features of machined surface are observed by scan electron microscope（SEM）. The results show that the milled surface topography is mainly characterized by the plastic shearing deformation surface and material piling zone. The material flows plastically along the end cutting edge of the flat-end milling tool and meanwhile is extruded by the end cutting edge, resulting in that materials partly adhere to the machined surface and form the material piling zone. As the depth of cut and the feed per tooth increase, the plastic flow of materials is strengthened and the machined surface becomes rougher. However, as the cutting speed increases, the plastic flow of materials is weakened and the milled surface becomes smoother. The cutting parameters （e.g. cutting speed, feed per tooth and depth of cut） influencing the surface roughness are analyzed. It can be concluded that the roughness of the machined surface formed by the end cutting edge is less than that by the cylindrical cutting edge when a cylindrical flat-end mill tool is used for milling. The proposed research provides the typical topography features of machined surface of the anti-rust aluminum alloy AlMn1Cu in high speed milling.

GENERALIZED SIMULATION MODEL FOR MILLED SURFACE TOPOGRAPHY-APPLICATION TO PERIPHERAL MILLING

Based on analyzing various factors influencing milled surface topography, firstly, a generalized model for milled surface topography is proposed. Secondly, using the principles of transformation matrix and vector operation, the trajectory equation of cutting edge relative to workpiece is derived. Then, a three dimensional topography simulation algorithm is constructed through dividing the workpiece into regular grids. Finally, taking the peripheral milling process as an example, the generalized model is simplified, and the corresponding simulation examples are given. The results indicate that it is very efficient for the generalized model to be used to analyze and simulate the peripherally milled surface topography.

Bending strength and fracture surface topography of natural fiber-reinforced shell for investment casting process

In order to improve the properties of silica sol shell for investment casting process, various contents of cattail fibers were added into the slurry to prepare a fiber-reinforced shell in the present study. The bending strength of fiber-reinforced shell was investigated and the fracture surfaces of shell specimens were observed using SEM. It is found that the bending strength increases with the increase of fiber content, and the bending strength of a green shell with 1.0 wt.% fiber addition increases by 44% compared to the fiber-free shell. The failure of specimens of the fiber-reinforced green shell results from fiber rupture and debonding between the interface of fibers and adhesive under the bending load. The micro-crack propagation in the matrix is inhibited by the micro-holes for ablation of f ibers in specimens of the f iber-reinforced shell during the stage of being fired. As a result, the bending strength of specimens of the fired shell had no significant drop. Particularly, the bending strength of specimens of the fired shell reinforced with 0.6wt.% fiber reached the maximum value of 4.6 MPa.

Effect of Surface Topography on Stress Concentration Factor

Neuber rule and Arola-Ramulu model are widely used to predict the stress concentration factor of rough specimens. However, the height parameters and effective valley radius used in these two models depend strongly on the resolution of the roughness-measuring instruments and are easily introduce measuring errors. Besides, it is difficult to find a suitable parameter to characterize surface topography to quantitatively describe its effect on stress concentration factor. In order to overcome these disadvantages, profile moments are carried out to characterize surface topography, surface topography is simulated by superposing series of cosine components, the stress concentration factors of different micro cosine-shaped surface topographies are investigated by finite element analysis. In terms of micro cosine-shaped surface topography, an equation using the second profile moment to estimate the stress concentration factor is proposed, predictions for the stress concentration factor using the proposed expression are within 10% error compared with the results of finite element analysis, which are more accurate than other models. Moreover, the proposed equation is applied to the real surface topography machined by turning. Predictions for the stress concentration factor using the proposed expression are within 10% of the maximum stress concentration factors and about 5% of the effective stress concentration factors estimated from the finite element analysis for three levels of turning surface topographies under different simulated scales. The proposed model is feasible in predicting the stress concentration factors of real machined surface topographies.

3D Evaluation Method of Cutting Surface Topography of Carbon / Phenolic (C/Ph) Composite

3D evaluation method of cutting surface topography for C/Ph composites was established.The cutting surface was measured by Talyscan 150,using 3D non-contact measurement.Through the results of 2D and 3D roughness evaluating for C/Ph composite and Duralumin,the 2D evaluation method of the cutting surface topography of C/Ph composite loses a lot of information,the characteristics of the surface topography of C/Ph composite can be comprehensively and authentically evaluated only by 3D evaluation method.Furthermore,3D amplitude and spatial parameters were adopted to evaluate the surface.The results show that： the topography of the C/Ph composite is anisotropic,there are more valleys in the machined surface of C/Ph than that of duralumin,and there are not obvious feeding textures for C/Ph,which indicates the machining mechanism is different from the metal.In conclusion,the topography of the C/Ph composite cutting surface is anisotropic;the cutting surface of C/Ph composite needs 3D evaluation method.

Choice of reference surfaces for machined surface roughness in milling of SiC_p/Al composites

In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was measured by OLS3000 Confocal laser scanning microscope. The 3D measured data of machined surface topography were analyzed by the area power spectrum density. The result shows that the texture of machined surface topography in milling of Si Cp/Al composites is almost isotropic. This is the reason that the values of Rq at different locations on the same machined surface are obviously different. Through the comparison of performance of different filtering methods, the robust least squares reference surface can be used to extract the surface roughness of SiC p/Al composites effectively.

Effect of electrochemical polishing time on surface topography of mild steel

The variation in altitude density function （ADF） of the surface topography of mild steel during electrochemical polishing （ECP） was investigated, and the mechanism of the variation of surface roughness with polishing time was analyzed. The results show that the variation trend of ADF with polishing time is flat-steep-flat; the variation of surface roughness results in the different distri- butions of surface current density, and there is a fine surface smoothness in the special period of ECP from 4 to 8 s.

A 3D evaluation method of cutting surface topography of carbon/carbon(C/C) composite

This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughness of C/C composite and Duralumin, the 2D evaluation method of the cutting surface topography of C/C composite loses a lot of information, and the characteristics of the surface topography of C/C composite can be comprehensively and authentically evaluated only by the 3D evaluation method. Furthermore, 3D amplitude and spatial parameters are adopted to evaluate the surface and the results show that： the topography of the C/C composite is anisotropy and there are no obvious feeding textures but abrupt peaks and valleys on surface of the C/C composite, which indicates that the machining mecha- nism is different from that of the metal. In conclusion, The C/C composite surface is evaluated using a 3D evaluation method, the roughness error is small, and the unique topography characteristics earl be au- thentically evaluated.

Implant surface features as key role on cell behavior

It has been recognized that physical and chemical properties of biomaterial surfaces mediate the quality of extracellular matrix(ECM)that may affect cell behaviors.In nature,ECM is a heterogeneous three-dimensional superstructure formed by three major components,glycosaminoglycan,glycoconjugate,and protein,that anchors cellular compartments in tissues and regulates the function and the behavior of cells.Changes in the biointerface alter the quality of ECM and morphology through cell surface receptors,which,in turn,enable it to trigger specific cell signaling and different cellular responses.In fact,a number of strategies have been used to improve the functionality of surfaces and direct cell behavior through precisely designed environments.Herein,we aimed to discuss,through a science-based viewpoint,the biomaterial surface features on cell behavior and analyze the impact of cell physical modification on dental implant development.

Surface Topography of Fine-grained ZrO_2 Ceramic by Two-dimensional Ultrasonic Vibration Grinding

The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding（WTDUVG）. By AFM images, the surface topography and the micro structure of the two-dimensional ultrasonic vibration grinding ceramics were especially analyzed. The experimental results indicate that the surface roughness is related to grinding vibration mode and the material removal mechanism. Surface quality of WTDUVG is superior to that of conventional grinding, and it is easy for two-dimensional ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.

3D surface topography formation in ultra-precision turning

The generation process of 3D surface topography in ultra-precision turning is analyzed, as the result of superimposing between actual roughness surface,waviness surface and geometrical form texture surface. From the viewpoints of machine technical system and manufacturing process,factors influencing on roughness surface, waviness surface and geometrical form texture surface in ultra-precision turning are discussed further.The 3D topography of ideal roughness surface and actual surface affected by cutting vibration are simulated respectively.

The Characteristics of the Surface Topography of Excimer Laser Processed Al_2O_3 Ceramic

Surface of Al 2O 3 ceramic was processed by an excimer laser and the characteristics of topography were examined based on the application of the microelectromechanical system(MEMS). It is indicated that the statistic parameters of surface topography processed by the excimer laser have an obvious regularity. The arithmetic-mean value R a and the root-mean square value R q change with the changing of processing parameters in the same step and trend, and there is a quantitative relation between them.A simplified model is proposed for the excimer laser processing surface profile, whose results of the analysis and calculation agree basically with the experimental data. Furthermore,the surfaces processed by excimer laser are greatly flat. Skewness root-mean-square value Z· q changed little with the change of the technological parameters. The above characteristics depend on the processing principle of excimer laser, quite different from the cutting processing.

Effect of Pb content on the surface topography and corrosion resistance of hot dip Zn-Al-Mg coatings

In this study,the effect of Pb content on the surface morphology and salt spray corrosion resistance of hot dip Zn-AI-Mg coatings was investigated. The results showed that the coating surface easily formed small grains of zinc spangle structures and that the salt spray con＇osion resistance of the coating decreased when Pb content was greater than 0.01%. The microstructure and energy dispersive spectrum analysis of surface and cross-sectional areas was performed by scanning electron microscopy. Pb content present in the coating was analyzed by glow discharge spectrum. The results showed that the distribution of Pb in the coating was not uniform. The Pb content was segregated on the surface and at the cross-section of the Zn-A1-MgZn2 ternary eutectic structure,especially,on the surface of the Zn-A1-MgZn2 ternary eutectic structure.