Kinds Of Textures Research Articles

Microstructure evolution of interface and matrix during the preparation of SiCf/Ti60 composites

In this paper, continuous SiC fiber-reinforced Ti60 (SiCf/Ti60) composites were fabricated by preparing SiCf/Ti60 precursor wires from matrix-coated fibers and hot isostatic pressing (HIP) consolidation. The microstructures of the precursor wires and composites were investigated using XRD, SEM, EPMA, EBSD, and TEM, which led to the microstructure evolution of the composites. The conclusions of this study are as follows. 1. A reaction layer (RL) with a thickness of approximately 0.1 μm already exists at the interface of the precursor wires during the preparation. The HIP process accelerates the diffusion of the carbon coating with the Ti60 matrix, resulting in an increase in the thickness of the RL to approximately 0.5 μm. This layer is primarily composed of fine-grained TiC layer || discontinuous silicides || coarse-grained TiC layer. 2. The matrix of SiCf/Ti60 precursor wires contains α-Ti (∼ 1.9 μm), S2 (∼ 50 nm), and β-Ti (∼ 50 nm), in the matrix, β-Ti is precipitated from α-Ti, and HIP makes α-Ti, S2, and β-Ti grow to ∼ 2.4 μm, ∼ 200 nm, and ∼ 300 nm, respectively. 3. There are 〈0001〉//axial direction (AD) and 〈10−10〉//AD fiber textures in the matrix of the precursor wires, and HIP makes the matrix undergo a plastic deformation dominated by dislocation slip, and the pole density of the two kinds of textures are both increased.

Growth characteristics and wear properties of micro-arc oxidation coating on Ti-6Al-4V with different laser texture shapes

Poor wear properties severely limit the field of application and service life of titanium alloys. Three kinds of textures (dimple, groove and mesh) were prepared by laser texturing technique and compounded with micro-arc oxidation treatment to improve the tribological properties of titanium alloys in this study. The coatings' morphology, structure, and composition were characterized, and their antiwear properties were analyzed. The results show that the proportion of rutile phase in the coating increases with increasing textured area rate and that the textured edge coating has higher Si and P content, with increased thickness and densities. In terms of friction properties, the dimpled texture shows the best friction properties when textured alone, with a 28.6 % decrease in the average coefficient of friction compared to the substrate; in contrast, the meshed texture shows the best friction properties after the micro-arc oxidation treatment, with a 76.2 % decrease in the average coefficient of friction compared to the substrate. Studies have shown that laser texturing can reduce wear by retaining abrasive debris. However, laser texturing alone does not provide a significant increase in hardness at the edge location, which is more susceptible to damage during wear, leading to more severe wear. The “tip effect” encourages the growth of a micro-arc oxide layer, and the resulting hardness of the layer helps protect the texture structure from damage. The synergistic effect of the texture and the rough, hard structural features of the coating itself enhances the wear resistance of the composite coating.

Investigations for vibration and friction torque behaviors of thrust ball bearing with self-driven textured guiding surface

In order to improve the starved lubrication condition of rolling bearings, three kinds of textures, namely dimple, groove texture, and gradient groove texture, were developed on the guiding surface of thrust ball bearings in this study. The results show that gradient groove texture has the one-way self-driving function of liquid droplets. The root mean square (RMS) value of vibration acceleration of gradient groove textured bearing (GGB) decreased by 49.1% and the kurtosis decreased by 24.6% compared with non-textured bearing (NB) due to the directional spreading effect of gradient groove textures on oil. The frequency domain analysis showed that the textures mainly suppressed the medium and high-frequency energy of bearing vibration, and the GGB was reduced the most with 65.3% and 48%, respectively. In addition, whether the grease is sufficiently sheared has a large impact on the oil guiding effect, and the friction torque of GGB could decrease by 10.5% compared with NB in the sufficiently sheared condition. Therefore, the gradient groove texture with oil self-driven effect on the guiding surface of rolling bearing can effectively improve the lubrication condition of the bearing and thus reduce the bearing vibration and friction torque, which has a promising application prospect.

Effect of pre-solution treatment on the texture and the mechanical properties of hot-extruded Mg-2.6Nd-0.55Zn-0.5Zr alloys

This work realized the texture tailor of Mg-2.6Nd-0.55Zn-0.5Zr (wt.%) alloy sheets via the hot extrusion on the billets subjected to different solution times from 0 h to 16 h. The solution treatment of 530 °C could effectively dissolve the coarse Mg12Nd particles. But abundant small second phase particles again developed after hot extrusion owing to the solid solution decline of Nd in magnesium matrix and the strain induced precipitation. The occurrence of dynamic recrystallization during hot extrusion improved the microstructure homogeneity and refined the grain sizes to 4.2–5.7 μm. Additionally, the activations of basal slip, prismatic slip and pyramidal <c+a> slip together promoted the development of double peak basal texture in the hot-extruded sheets. However, this kind of texture was weakened by the particle-stimulated nucleation recrystallization and its weakening degree gradually decreased with the prolongation of solution time. This made the sheet with the long solution time more likely retain the strong deformation basal texture. Such strong basal texture increased the activation fraction of prismatic slip along the extrusion direction (ED), producing the higher yield stress and the lower uniform elongation. Influenced by this, the anisotropies in the yield stress and the uniform elongation between the ED and the transverse direction (TD) were obviously weakened. Besides, the activation of tension twinning greatly increased the uniform elongation and decreased the yield stress.

4. Exercises for Piano and their Role in the Pedagogical Activity of Vitalii Sechkin

Abstract In the article, the author analyses the role of technical exercises used in his pedagogical activity by Vitaly Sechkin, remarkable pianist and professor, Honoured Artist of Ukraine. He paid particular attention to the development of the technical skills of his students, for which he used various exercises and virtuoso etudes. A detailed characteristic is made of the particularities of C.-L. Hanon’s and J. Brahms’s sets of exercises, which pursue similar objectives - the development of finger speed, the freedom to execute different kinds of texture, assimilation of tonalities. The professor’s favourite exercises and his methodical recommendations are mentioned as well.

Investigation of the Tribological Properties of Different Textured Lead Bronze Coatings under Severe Load Conditions

The purpose of this paper is to investigate the variation in the coefficient of friction (CoF) and also the wear in a lead bronze coating under different texture conditions. The tribological tests were performed using a tribometer with pin on disk configuration. Several kinds of textures, realised by a surface laser texturing, were tested by varying the diameter, depth, and density of the dimples under severe working conditions. The innovative aspect concerns the behaviour of the textured lead bronze coating and the lubrication conditions when the sample is subjected to extreme load conditions. Confocal microscopies and SEM (Scanning Electron Microscopy)/EDS (Energy Dispersive X-Ray Spectroscopy) analyses were performed to evaluate the texture behaviour and also the surface deterioration of the coating. The results show that the application of texture processing leads to an improvement in the tribological properties of the coating. By analysing separately the variation of the different geometric parameters of the dimples, it has been shown that the best results are obtained with a diameter of 50 μm, a density of 5%, and a depth of 5 μm.

Deep Texture Exemplar Extraction Based on Trimmed T-CNN

Texture exemplar has been widely used in synthesizing 3D movie scenes and appearances of virtual objects. Unfortunately, conventional texture synthesis methods usually only emphasized on generating optimal target textures with arbitrary sizes or diverse effects, and put little attention to automatic texture exemplar extraction. Obtaining texture exemplars is still a labor intensive task, which usually requires carefully cropping and post-processing. In this paper, we present an automatic texture exemplar extraction based on Trimmed Texture Convolutional Neural Network (Trimmed T-CNN). Specifically, our Trimmed T-CNN is filter banks for texture exemplar classification and recognition. Our Trimmed T-CNN is learned with a standard ideal exemplar dataset containing thousands of desired texture exemplars, which were collected and cropped by our invited artists. To efficiently identify the exemplar candidates from an input image, we employ a selective search algorithm to extract the potential texture exemplar patches. We then put all candidates into our Trimmed T-CNN for learning ideal texture exemplars based on our filter banks. Finally, optimal texture exemplars are identified with a scoring and ranking scheme. Our method is evaluated with various kinds of textures and user studies. Comparisons with different feature-based methods and different deep CNN architectures (AlexNet, VGG-M, Deep-TEN and FV-CNN) are also conducted to demonstrate its effectiveness.

Миллий маданий концепт тушунчаси

Лингвокультурологиянинг асосий бирлиги маданий концептдир. Маданий концепт бу ментал бирлик бўлиб, онгдаги ментал ва психик ресурслар бирликларини ифодалашга ҳизмат қилувчи, ҳамда инсон тажрибаси ва билимларини акс эттирувчи информацион тузилма (Е.С.Кубрякова), маданиятнинг асосий бирлиги (В.И.Карасик), инсон онгидаги маданиятнинг ҳужайраси (Ю.С.Степанов). Концептга бўлган лисоний-маданий ёндашув концептни маданиятнинг таянч бирлиги сифатида қабул қилишни тақозо этади ва маълум бир маданият учун муҳим бўлган тушунчаларни ўзида акс эттиради.&#x0D; Концептнинг тузилиши мураккаб. Ю.С.Степанов концептнинг уч таркибий қатламини ажратади: (1) асосий, бош белги; (2) қўшимча, ёки бир неча кўшимча, “пассив" белгилар: (3) ташқи, лисоний шаклда акс эттириладиган, одатда, умуман эътиборга олинмайдиган ички шаклни. Олимларнинг кўпчилиги (С.Г. Воркачев, В.И. Карасик, Маслова В.А.), концептнинг мураккаб тузилма эканлигини қайд этишади ва уни асосини куйидагилар ташкил этади деб таъкидлайдилар: 1) маъно; 2) образ; 3) қадриявий.&#x0D; Концепт тузилишидаги конституентлар концепт майдонини ёки концептосферани ҳосил қилади. Миллий концептосфера - бу конкрет миллат учун характерли ҳисобланган концептларнинг йиғиндисидир, Концепт ўзида концептуал бўлак, элементларни тақдим этади. Унинг элементлари конкрет коммуникатив жараёнларда ўзларини намоён килади.&#x0D; Fire/Water концептларининг лексик сатҳда вербаллашувини таҳлил қилиш натижасида биз қуйилагиларни аниқладик:&#x0D; 1) Fire/Water концепти лексик сатҳда лексик бирликлар, синонимлар ва антонимлар, қўшма сўзларда орқали ифодаланади;&#x0D; 2) ‘Fire’ концептининг ядровий концептуал маънолари қўйидагилардан ташкил топади: а) олов – иссиқлик ва ёритиш қуроли; б) олов – офат, улим, халокат, синов, азоб, ҳавф; в) олов – ёнғин; г) олов – хис туйғу;&#x0D; ‘Water’ концептининг ядровий концептуал маънолари қўйидагилардан ташкил топади: а) сув – таъмсиз, рангсиз ва хидсиз суюқлик; б) сув – водород ва кислороддан ташкил топган; в) сув – ичимлик суви ва сув таъминотини амалга оширувчи система; г) сув – индустрияда қўлланувчи модда.&#x0D; 3) ўрганилган барча тил бирликларда асосан олов концептининг иккита концептуал маъноси ифодаланади: а) олов – ёнғин; б) олов – уруш қўроли, отиш қўроли. Сув концепти эса асосан а) бефойда ва б) сув – офат маъноларини ўзида мужассам этади.&#x0D; ‘Fire’ концептининг фразеологик бирликларда вербаллашувини таҳлил қилиш натижасида fire компонентли фразеологик бирликларда асосан Fire концептининг образлилик ва қадриявий қисмлари ўз ифодасини топишини кўриш мумкин. Ижобий эстетик баҳо қўйидаги концепуал белгиларда ўз аксини топган: олов бу 1) ижобий ҳис туйғулар (севги, дўстлик, ёктириш); 2) интилувчанлик, тиришқоқлик; 3) мотивация қўроли. Салбий эстетик баҳо вайронагарчилик, ёнғин, уруш тушунчаларини ифодаловчи тил бирикмаларинингконцептуал белгиларида ўз аксини топган. Олов бу 1) ёнғин, офат, халокат; 2) уруш ва отишқўроли; 3) салбий хис-туйғулар: жаҳлдорлик; 4) қийин синов, азоб; 5) вақт танқислиги; 6) танқид қўроли ва хк.&#x0D; ‘Water’ компонентли фразеологик бирликларда, сув 1) ҳаётдаги турли вазиятларни ифодаловчи хосса; 2) бошқа суюқликларга нисбатан фойдасиз ва арзон; 3) муқаддас суюқлик сифатида изоҳланади. Шу билан бирга, сув ва олов вайронагарчилик, табиий офат каби концептуал белгиларни ўз семантикасида акс этади.&#x0D; Шундай қилиб, инглиз лингвомаданиятида олов асосан салбий буёқдорликга эга бўлиб, вайронагарчилик, азоб, уруш, ёнғин каби тушунчалар билан боғлиқ. Бу оловнинг табиий офат эканлиги, чўғ олганда уни тўхтатиб бўлмаслиги, уруш қўроллари асосан ўтга алоқадорлиги (ўқ, снаряд, пушка, бомба) билан боғлиқ. Олов тушунчасининг инсон хис-туйғулари билан боғлиқ эканлиги, кишининг физиологик хусусиятлари билан боғлиқ (инсоннинг жаҳли чиққанда, уялганда, севиб қолганда қизариши, бадан хароратининг кўтарилиши ва ҳк.).

Texture and microstructure evolution of 321 austenitic stainless steel ultra-thin strip during asynchronous rolling

This paper studied the evolution of texture and microstructure of 321 austenitic stainless steel ultra-thin strip during asynchronous rolling. Experimental results show that during the process of asynchronous rolling, the martensitic structure mainly forms such kinds of texture, as {111} <110> Z texture, {111} <112> Y texture, {001} <110> R-CubeND texture, {112} <110> Cu texture, and {110} <110> Goss texture. With the increase of deformation, the strengths of {111} <112> Y texture, {001} <110> R-CubeND texture, {112} <110> Cu texture, and {110} <110> Goss texture increase first and then decrease. In the early stage of rolling, dislocation slip is the main plastic deformation, followed by deformation twins in the high strain region, which prevents further dislocation slip. When the rolling pressure rate is greater than 50%, the deformation induces rapid growth in the content of the martensite, with the continued nucleation and growth of the deformation twins.

A robust weakly supervised learning of deep Conv-Nets for surface defect inspection

Automatic defect detection is a challenging task owing to the complex textured background with non-uniform intensity distribution, weak differences between defects and background, diversity of defect types, and high cost of annotated samples. In order to solve these challenges, this paper proposes a novel end-to-end defect classification and segmentation framework based on weakly supervised learning of a convolutional neural network (CNN) with attention architecture. Firstly, a novel end-to-end CNN architecture integrating the robust classifier and spatial attention module is proposed to enhance defect feature representation ability, which significantly improves the classification accuracy. Secondly, a new spatial attention class activation map (SA-CAM) is proposed to improve segmentation adaptability by generating more accurate heatmap. Moreover, for different surface texture, SA-CAM can significantly suppress the background’s inference and highlight defect area. Finally, the proposed weakly supervised learning framework is trained using only global image labels and devoted to two main visual recognition tasks: defect samples classification and area segmentation. At the same time, it is robust to complex backgrounds. Results of the experiments verify the generalization of the proposed method on three distinct datasets with different kinds of textures and backgrounds. In the classification tasks, the proposed method improves accuracy by 0.66–25.50%. In the segmentation tasks, the proposed method improves accuracy by 5.49–7.07%.

Effects of process parameters on the mechanical properties of additively manufactured Zr–1Mo alloy builds

In order to solve the artifact problem in magnetic resonance images, a low magnetic Zr–1Mo(wt%) alloy with high mechanical performance was successfully fabricated by laser powder bed fusion (L-PBF) using gas-atomized Zr–1Mo alloy powder. The as-built Zr–1Mo alloy showed superior strength and elongation compared to the as-cast Zr–1Mo alloy due to grain refinement and the inexistence of large casting defects. The microstructure of L-PBF-processed Zr–1Mo alloy builds was not sensitive to process parameters. On the other hand, morphology and distribution of defects, interstitials concentration, and crystallographic orientation comprehensively influenced the mechanical properties of the builds. Increasing interstitials concentration caused by increasing energy density render to increasing strength. Large pores caused by balling effect lead to a severe decrease of both strength and ductility of builds using high energy density (over 70.3 J·mm−3) and high scanning speed (1050/1200 mm·s−1). On the contrary, spherical pores possessing several microns in size has much less effect on mechanical properties than the large-size pores. There are two kinds of texture({1 1 0}α texture and {1 1 0}α+{1 0 2}α bi-texture) were confirmed in this study. {1 1 0}α texture contributed to the slight increase of elongation with increasing energy density in low scanning speed case (600/750 mm·s−1) and the superior elongation of low scanning speed specimens compare to that of high scanning speed specimens in medium energy density range (about 48 J·mm−3). From the viewpoints of the ultimate tensile strength(UTS) and elongation, it was found that an energy density of 84.4 mm·s−1 with a scanning speed of 600 mm·s−1 is preferable for the L-PBF-processed Zr–1Mo alloy in this study. These experimental results may provide direct guidelines regarding the applicability of Zr–1Mo alloy fabricated by L-PBF for biomedical applications.

Infrared and Visible Image Fusion Based on the Total Variational Model and Adaptive Wolf Pack Algorithm

The purpose of image fusion is to merge a substantial amount of information, such as contour, texture and intensity distribution information from original images, with a fusion image. To retain a considerable amount of the fusion image while retaining the texture details of the source image and maintaining the edge of the source image, this paper proposes an improved infrared and visible image fusion algorithm that is based on total variation. First, source infrared and visible light images and a difference image were decomposed by a total variation model, and their respective cartoon and texture components were acquired. A fitness function was solved according to the entropy, standard deviation and edge similarity of the infrared and visible light images. The optimal combination weight of various kinds of texture and cartoon components was sought via a wolf pack intelligence optimization algorithm to acquire the final fusion results with high-quality contrast ratio and edge details. The experimental results indicate that the proposed method not only can preserve edge contour information about the original image but also can effectively retain its texture detail information. The method is superior to the traditional multiscale and sparse representation fusion method with regard to various indicators, such as subjective visual effect, mutual information, gradient information, structural similarity and visual sensitivity.

Study on Friction and Lubrication Characteristics of Surface with Unidirectional Convergence Texture

In order to study the influence of texture on the wear and lubrication performance of the surface of the tools, three kinds of textures with unidirectional convergence morphology were processed on the surface of the samples, and each texture was designed with different area occupancy ratios. Simulation analysis shows that, owing to the reflow and convection effect of liquid in the texture, the lubricating film flowing through the textured surface has a high hydrodynamic pressure value, and the semicircular ring texture is the most prominent. By comparing the friction coefficient, when the area occupancy ratio of texture on the surface is 10%, the surface of the samples with different morphology has the lowest coefficient of friction; the friction coefficient of the semicircular ring textured surface is especially very low. Surface textures reduce the direct contact area between the friction pairs, and generate dynamic pressure lubrication and secondary lubrication, so that the surface friction coefficient of the samples is obviously reduced. The surfaces of the non-textured samples have abrasive wear and contact fatigue wear, and the surfaces of the textured samples have adhesive wear, abrasive wear, and cavitation.

Evaluation of Twinning Behavior in Rolling of Mg Alloys with Three Kinds of Textures by a Generalized Schmid Factor

In this work, we statistically investigate the texture effect on twinning behavior in rolling of an AZ31 Mg alloy by electron backscatter diffraction technique and evaluate it by a generalized Schmid factor (GSF). The results show that twinning nucleation and area fraction are promoted significantly with the c-axis of grains rotating from the transverse direction to the rolling direction. More importantly, twin propensity and the selection of twin variants can be well explained by the GSF that is calculated based on an estimated stress state for rolling. The present results provide some insights into controlling the microstructure and texture of Mg alloys by rolling processes.

Unsupervised color texture segmentation based on multi-scale region-level Markov random field models

In the field of color texture segmentation, region-level Markov random field model (RMRF) has become a focal problem because of its efficiency in modeling the large-range spatial constraints. However, the RMRF defined on a single scale cannot describe the un-stationary essence of the image, which highly limits its robustness. Hence, by combining wavelet transformation and the RMRF model, we present a multi-scale RMRF (MsRMRF) model in wavelet domainin this paper. In the Bayesian framework, the proposed model seamlessly integrates the multi-scale information stemmed from both the original image and the region-level spatial constraints. Therefore, the new model can accurately describe the characteristics of different kinds of texture. Based on MsRMRF, an unsupervised segmentation algorithm is designed for segmenting color texture images. Both synthetic color texture images and remote sensing images are employed in the comparative experiments, and the experimental results show that the proposed method can obtain more accurate segmentation results than the competitors.

Tribological properties of WS2 coatings deposited on textured surfaces by electrohydrodynamic atomization

WS2 coating additive and surface micro texturing were investigated in order to improve the tribological properties of the cemented carbide tool surfaces. Laser surface texturing technology (LST) was employed to fabricate three kinds of textures (dimple array, line array and four-leaf clover array) on cemented carbide surfaces. Characterizations such as micromorphology, surface roughness, wettability of the surfaces with different micro-textures were examined. Electrohydrodynamic atomization technology (EHDA) was used to deposit WS2 coatings on the substrate surfaces. The influence of the atomization parameters (flow rate, operating voltage and atomizing distance) on the characteristics of deposited coatings was examined. Uniform and dense coating, with a thickness of ~20 μm, was produced under the optimized conditions. The friction and wear properties of textured surfaces before and after depositing WS2 coatings were evaluated by reciprocating sliding friction tests. The coating-substrate adhesion was evaluated by scratch tests. The results show that the friction and wear properties would be improved by EHDA deposited WS2 coating or micro-textures, and the samples combined with deposited WS2 coatings and textured surfaces exhibited the best efficiency. Additionally, laser surface micro-texturing can improve the coating-substrate adhesion strength and then prolong the wear life of WS2 coatings.

Automatic texture exemplar extraction based on global and local textureness measures

Texture synthesis is widely used for modeling the appearance of virtual objects. However, traditional texture synthesis techniques emphasize creation of optimal target textures, and pay insufficient attention to choice of suitable input texture exemplars. Currently, obtaining texture exemplars from natural images is a labor intensive task for the artists, requiring careful photography and significant postprocessing. In this paper, we present an automatic texture exemplar extraction method based on global and local textureness measures. To improve the efficiency of dominant texture identification, we first perform Poisson disk sampling to randomly and uniformly crop patches from a natural image. For global textureness assessment, we use a GIST descriptor to distinguish textured patches from non-textured patches, in conjunction with SVM prediction. To identify real texture exemplars consisting solely of the dominant texture, we further measure the local textureness of a patch by extracting and matching the local structure (using binary Gabor pattern (BGP)) and dominant color features (using color histograms) between a patch and its sub-regions. Finally, we obtain optimal texture exemplars by scoring and ranking extracted patches using these global and local textureness measures. We evaluate our method on a variety of images with different kinds of textures. A convincing visual comparison with textures manually selected by an artist and a statistical study demonstrate its effectiveness.

Numerical simulation and experimental investigation on friction and wear behaviour of micro-textured cemented carbide in dry sliding against TC4 titanium alloy balls

The model of ball-on-disk test was established and three kinds of textures with different geometric characteristics were designed on the surface of the cemented carbide disk. The optimal geometric characteristic of texture was obtained by finite element analysis. The hole-textures of different parameters were processed on the surface of the cemented carbide disk by laser machining. The effects of texture and lubricant on friction and wear behaviour were analysed by comparing four different cemented carbide disks through the ball-on-disk contrast tests. Ball-on-disk orthogonal tests were carried out to obtain the best geometric parameters of the hole-texture. The results of numerical simulation showed that the wear depth of the hole-texture disk was the smallest among all three different textured disks. The results of contrast tests showed that the texture filled with lubricant could effectively improve the friction and wear of cemented carbide disk in dry sliding against TC4 titanium alloy balls. It was found that the adhesion of the surface textured cemented carbide disk was the most serious and the adhesion of the surface textured cemented carbide disk with lubricant filled into the textures was the lowest among four tested samples, which indicated that the texture could significantly increase the adhesion of titanium alloy to the surface of cemented carbide disk, while the solid lubricant could effectively reduce it. Meanwhile, the main effect mechanisms of textures were also discussed. In addition, the best geometric parameters of the texture were determined to be 100 μm in diameter, 80 μm in depth and 600 μm in spacing through orthogonal tests. It was also found that the spacing had the greatest effect on the friction coefficient and the wear volume, and the friction coefficient and the wear volume decreased with the increasing of the spacing.

Influence of Different Micro-Imprints to Fatigue Life of Components

Abstract To improve tribological properties of components, different kinds of textures are added to their surfaces. Although the added imprints or craters are only few tens of micrometers wide and a few micrometers deep, they form an initial crack from which a fatigue crack may propagate. In this article, a numerical approach for calculating the fatigue life of a body with present micro-imprints with standard finite-element software will be presented. The objective is to show how the imprint shape and its manufacturing process influences the fatigue life. The considered specimens are round bodies that were made from Boehler K890 microclean cold-working steel. Three shapes of the imprints are studied: the imprints produced by a Vickers pyramid and a Rockwell cone and a half-spherical crater void produced by a laser device. The flat-surface round body served as a reference. The imprint shape and its manufacturing process is also considered. For this reason, a simulation of impression of Vickers and Rockwell indenters is simulated first, which is followed by a numerical fatigue-life prediction. In this manner, the residual stresses from the imprinting process are considered during the fatigue-life prediction. For the laser-induced craters and the reference body, only the fatigue life is numerically predicted. Because the material inhomogeneities are much smaller than the geometrical ones, the calculated fatigue lives for different texturing represent the fatigue-life reduction caused by the applied textures. To validate the presented numerical approach, the calculated fatigue lives are compared to the experimentally determined.

$\mathcal {H}$ Distribution for Multilook Polarimetric SAR Data

Polarimetric synthetic aperture radar (PolSAR) is an advanced imaging radar system, for which the acquired data provide not only the information of each channel but also the correlation between channels. To fully utilize and accurately model the multilook PolSAR data, a novel compound distribution, named the $\mathcal {H}$ distribution, is proposed based on the generalized Fisher distribution ( $\text{G}\mathcal {F}\text{D}$ ). Specifically, the $\text{G}\mathcal {F}\text{D}$ introduces a power parameter to the ordinary Fisher distribution. With one more free parameter, the $\text{G}\mathcal {F}\text{D}$ is flexible and versatile enough to characterize different kinds of texture. Then, by assuming the generalized-Fisher-distributed texture and the Wishart-distributed speckle, the $\mathcal {H}$ distribution is derived, whose closed-form expression is obtained with the help of Fox’s H-function. As such, the $\mathcal {H}$ distribution has a compact form and is conveniently applied to practical problems, such as modeling and classification of PolSAR data. The effectiveness of this method is tested by modeling the multilook PolSAR data and performing image classification. The experimental results demonstrate that the $\mathcal {H}$ distribution is a flexible and effective way to model multilook PolSAR data.