We introduce a method for learning to generate the surface of 3D shapes. Our approach represents a 3D shape as a collection of parametric surface elements and, in contrast to methods generating voxel ...grids or point clouds, naturally infers a surface representation of the shape. Beyond its novelty, our new shape generation framework, AtlasNet, comes with significant advantages, such as improved precision and generalization capabilities, and the possibility to generate a shape of arbitrary resolution without memory issues. We demonstrate these benefits and compare to strong baselines on the ShapeNet benchmark for two applications: (i) autoencoding shapes, and (ii) single-view reconstruction from a still image. We also provide results showing its potential for other applications, such as morphing, parametrization, super-resolution, matching, and co-segmentation.
•This paper reviews surface texture metrology literature for metal additively manufactured parts.•AM processes and materials used in the literature are presented.•The types of surfaces, measurement ...technologies and strategies employed are analysed.•Data processing, filtering and surface characterisation are discussed.
A comprehensive analysis of literature pertaining to surface texture metrology for metal additive manufacturing has been performed. This review paper structures the results of this analysis into sections that address specific areas of interest: industrial domain; additive manufacturing processes and materials; types of surface investigated; surface measurement technology and surface texture characterisation. Each section reports on how frequently specific techniques, processes or materials have been utilised and discusses how and why they are employed. Based on these results, possible optimisation of methods and reporting is suggested and the areas that may have significant potential for future research are highlighted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
A new contact stiffness model for the rough surface with different machining textures is established. The studied surface consists of regular surface machining texture in the global scale and ...stochastic micro-asperities in the local scale. The proposed model improves upon previous work that considers only the effect of stochastic asperities and completely ignores that of the machining textures generated by different machining methods. The analytical expression to calculate the contact stiffness of the studied textured surface is derived and numerical results are obtained via the finite element method. A high-precision test bench to measure the interface contact stiffness of the workpiece with different surface textures is designed. The measured results and simulated results are directly compared to demonstrate the validity of the proposed method. The effects of different texture types and surface roughness values on the contact stiffness of the proposed textured surface are analyzed. The proposed method provides a research basis for the accurate calculation of nonlinear contact stiffness and dynamic characteristics of the surface with complex texture topography.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the ...availability of ultrashort laser pulses, LIPSS have gained an increasing attraction during the past decade, since these structures can be generated in a simple single-step process, which allows a surface nanostructuring for tailoring optical, mechanical, and chemical surface properties. In this study, the current state in the field of LIPSS is reviewed. Their formation mechanisms are analyzed in ultrafast time-resolved scattering, diffraction, and polarization constrained double-pulse experiments. These experiments allow us to address the question whether the LIPSS are seeded via ultrafast energy deposition mechanisms acting during the absorption of optical radiation or via self-organization after the irradiation process. Relevant control parameters of LIPSS are identified, and technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.
Inspired by the surface of shells in natural world, six bionic multi-scale composite surface textures were designed. Numerical simulation was carried out to investigate the mechanism for influences ...of the texture geometric parameters and service conditions on lubrication characteristics. The results revealed that the bionic surface enhanced the load-carrying capacity and reduced the friction coefficient. Groove combinations offered a better lubrication performance than wavy combinations. The texture geometric parameters showed significant influence on the frictional characteristics. For all texture shapes, the load-carrying capacity increased approximately linearly with the rotational speed and decreased with the water film thickness. The results would help guide effective texture design to improve the lubrication performance of axial piston pump friction pairs under marine environments.
•Six bionic multiscale composite textures of different depths were designed.•The effect of model parameter on the lubrication characteristics was investigated.•The improvement of the lubrication performance of bionic surfaces was verified.•Develop theoretical guideline for texture optimal design in marine environment.
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The purpose of the paper is to investigate the effect of surface modification on the friction characteristics of sliding bearings. This paper reviews the previous studies on the influences of surface ...texture, coating materials and lubricant additives on the performance of the sliding bearings. Through the theoretical models and simulation experiments between different friction couple, the researchers found that under the condition of fluid lubrication, the surface modification design can significantly improve the friction characteristics of the surface of the friction couple, which has attracted the wide attention of researchers. The development status and latest progress in improving the surface properties of friction couple are introduced mainly from the geometrical characteristics of surface texture, the matrix of surface coating materials and the types of lubricating additives. Among them, the geometric features of texture mainly include texture shape, scale, parameters, position and combination form. The types of coating material substrates mainly include iron-based alloys and aluminum-based alloys. Lubricating oil additives mainly include ionic liquids and nanoparticles. Finally, the existing problems and future development directions of surface modification are pointed out.
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As machine learning becomes more popular in the precision engineering sector, the need for large datasets of measurement data increases. Due to the often manual, user dependent and labour-intensive ...measurement processes, collecting a large amount of data is often infeasible. It would, therefore, be desirable to collect a small amount of data on which to train a model to generate synthetic data that is representative of the real measurement data. To this end, we present an approach to numerical surface texture generation based on a progressively growing generative adversarial network. We show that by encoding height data into grayscale values within an image, the network can create realistic synthetic surface data both qualitatively and quantitatively. The proposed approach is general to any encoded surface; we demonstrate the model trained on two example datasets consisting of surfaces from different manufacturing processes and measured with different techniques. We finally present an extension to the generator model which automatically categorises the produced surfaces, allowing a surface of a desired category to be generated. Finally, we calculate the distributions of areal surface texture parameters for each type of surface and show that there is good agreement between the synthetic and real data.
•By encoding height data in grayscale images, generative adversarial networks (GANs) can be used to produce synthetic measurement data•A progressively growing GAN (PGGAN) is shown to produce convincing synthetic texture data for different manufacturing processes and measurement techniques•The PGGAN can be extended to produce synthetic surface texture data of a variety of different surface categories from a single model together with the appropriate classification label•Analysis of the distributions of ISO areal amplitude and spatial parameters shows good representation of the real surfaces by the generator model
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Six types of micro-textures with different diameters and area densities are produced on the surfaces of the TC11 alloy. The wear characteristics of the textured and untextured surfaces are ...investigated at 500°C. It is found that the regular textured surface enhances the amount of oxygen adsorbed on the material surfaces, which promotes the formation of more tribo-oxides on the textured surface compared to the untextured samples, and thus significantly enhances the anti-wear ability of the TC11 alloy. A micro-dimpled structure with relatively small-diameter and high-density is likely to improve the tribological properties of TC11 alloy at 500°C.
Titanium alloys are very attractive for applications in many industrial sectors because of their unique physical, mechanical, chemical and corrosion properties. However, titanium alloys are characterized by poor tribological behavior. This study aims at revealing the mechanisms of how surface texturing affects the dry sliding wear behavior of the TC11 alloy at 500°C. Six types of micro-textures with different diameters and area densities were produced on the surfaces of the TC11 alloy. The wear characteristics of the textured and untextured surfaces were investigated at 500°C. It was found that the regular textured surface can enhance the amount of oxygen adsorbed, which promotes the formation of more tribo-oxides on the textured surface compared to the untextured, and thus significantly enhances the anti-wear ability of the TC11 alloy. A micro-dimpled structure with relatively small diameter and high density of dimples is likely to improve the tribological properties of TC11 alloy at 500°C. Display omitted
•Micro-textures were produced on the surfaces of the TC11 alloy.•The tribological property was improved significantly by surface texture at 500°C.•Micro-textures lead to the enhanced amount of oxygen adsorbed on the surface.•Surface pattern influences the formation of tribo-oxides and its hardness.•A small diameter and dense texture would improve anti-wear ability at 500°C.
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•The fluid flow characteristics inside the micro cavities are obtained.•Effects of operating conditions and structural parameters on the fluid features are investigated.•The lubrication mechanisms of ...the micro interface are elaborated.
The paper aims to reveal the micro interface lubrication regimes of water lubricated bearing. Typical micro cavities are explored through computational fluid dynamic analysis. Streamline, pressure, eddy viscosity and kinetic energy distribution are obtained in the micro cavities. Influences of operating conditions and dimensionless structural parameters on fluid features are explored with detailed information. Velocity vectors as well as pressure contours are acquired inside the cavity. Analysis elaborates the micro interface lubrication mechanisms as well as the changing rules of lubrication performances with structural parameters for the cavity. Experimental data verifies the correctness of the lubrication model and the lubrication regimes. The micro interface lubrication mechanisms are revealed and they apply to bearings with different dimensions. Research results lay solid foundation for further optimal design of surface topography of such bearings.
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