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12 pages, 2260 KiB

Open AccessArticle

Deformation Evolution Law of Surfacing Welding on Thin Bending Plates Based on the Three-Dimensional Thermal Digital Image Correlation Method

by Xiqiang Ma, Nan Guo, Fang Yang, Chunyang Liu and Zhiqiang Guan

Coatings 2022, 12(8), 1084; https://doi.org/10.3390/coatings12081084 - 31 Jul 2022

Cited by 3 | Viewed by 1201

Abstract

Surfacing on the surface of thin metal bending plates will cause significant deformation, and current numerical simulation and experimental methods cannot fully and truly reflect the deformation state of the bending plate. In this paper, a non-contact detection method based on the three-dimensional [...] Read more.

Surfacing on the surface of thin metal bending plates will cause significant deformation, and current numerical simulation and experimental methods cannot fully and truly reflect the deformation state of the bending plate. In this paper, a non-contact detection method based on the three-dimensional (3D) thermal digital image correlation (DIC) method is proposed. The proposed method can be used for the 3D full-field dynamic measurement of metal thin bending plate surfaces. In addition, the evolution law of in-plane and out-of-plane deformation of thin bending plates during surfacing welding and cooling was studied. Moreover, the influence of curvature on the shrinkage deformation of thin bending plate weld was explored, and the correlation between the curvature of thin bending plates and the weld shrinkage was established. Results show that the proposed detection method based on the 3D thermal DIC method can rapidly and accurately detect bending deformation online. The out-of-plane deformation of the surfacing welding of the thin bending plate transits from the disk to the saddle. Furthermore, the curvature of the thin bending plate is inversely proportional to the transverse shrinkage of the weld bead. After the curvature reaches a certain value, it has little effect on the longitudinal shrinkage of the weld bead. This detection method solves the problem of welding deformation simulation verification, truly clarifies the law of welding dynamic deformation, and provides a theoretical basis for welding lightweight manufacturing. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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15 pages, 3450 KiB

Open AccessArticle

Modeling Technology of Bonded Particle Model for Gold Ore and Its Validation Based on Drop Weight Test

by Xiao Wang, Xiqiang Ma, Mian Zhang, Yuanyuan Huang, Zhiqiang Guan and Jishun Li

Coatings 2022, 12(6), 731; https://doi.org/10.3390/coatings12060731 - 25 May 2022

Viewed by 1499

Abstract

In recent years, studies have focused mainly on the selection of appropriate parameters for ore crushing technology to achieve optimal distributions of particle sizes. The control of particle sizes in mineral processing plays a significant role in improving mineral separation efficiency. The discrete [...] Read more.

In recent years, studies have focused mainly on the selection of appropriate parameters for ore crushing technology to achieve optimal distributions of particle sizes. The control of particle sizes in mineral processing plays a significant role in improving mineral separation efficiency. The discrete element method (DEM) is an effective numerical simulation method for studying the process of mineral crushing, which can deal with the problem of deformation and movement of discontinuities, that is, the problem of cracks caused by mineral crushing, which is difficult to be solved by traditional continuum mechanics simulation methods. Additionally, the transformation of a mechanical model from continuum to discontinuum mechanics can be realized simply and effectively, so the discrete element method has obvious advantages in the simulation of mineral crushing. However, the accuracy of the DEM simulation is highly dependent on the mathematical models used. In this paper, methodologies for selecting particle sizes and inter-particle bond energy are proposed based on the results of the drop weight test carried out in the laboratory. Particle sizes and inter-particle bond energy are the key parameters for bonded particle model used in discrete element simulation. The suitable parameters proposed by methodologies were applied to construct the bonded particle model for the ore, and its particle size distribution was obtained by simulating the impact crushing process using DEM. The particle size distributions obtained from both the DEM simulation and the drop weight test were in good agreement. The average errors under the three impact energies were 1.96%, 3.31%, and 1.66%, which indicated that the modeling technique proposed in this paper can represent the crushing characteristics of ore materials and improve the accuracy of the DEM simulation. It lays the foundation for guiding the reasonable selection of grinding process parameters and mill equipment. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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11 pages, 2088 KiB

Open AccessArticle

Mechanically Enhanced Self-Stratified Acrylic/Silicone Antifouling Coatings

by Jingjing Xue, Li Wang, Yong Fan, Jianing Xu, Jie Zhao, Limei Tian and Wenbo Du

Coatings 2022, 12(2), 232; https://doi.org/10.3390/coatings12020232 - 11 Feb 2022

Cited by 8 | Viewed by 2522

Abstract

Great attention has been paid to silicone-based fouling-release coatings (FRCs) in the realm of maritime antifouling due to their highly efficient and eco-friendly properties, but many challenges remain for developing a silicone-based FRC that improves its adhesion performance without reducing the antifouling property. [...] Read more.

Great attention has been paid to silicone-based fouling-release coatings (FRCs) in the realm of maritime antifouling due to their highly efficient and eco-friendly properties, but many challenges remain for developing a silicone-based FRC that improves its adhesion performance without reducing the antifouling property. Herein, a non-toxic silicone-based FRC has been developed by integrating acrylic resin (AR) with a silicon resin (PDMS) to spontaneously form a self-stratified AR/PDMS coating. The AR/PDMS antifouling coating still has the same fouling-release performance but improved adhesion strength (from 0.4 to 2.0 MPa) in comparison with pristine PDMS. Moreover, the antifouling coating has proven to be extremely stable in different environments (such as pH, heating, and ultraviolet exposure). The study provides a facile and convenient self-stratified strategy to develop antifouling coatings, contributing to environmentally friendly coatings in marine applications. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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15 pages, 8063 KiB

Open AccessArticle

The Tribological Adaptability for Ventral Scales of Dinodon rufozonatum in Dry/Wet/Rough Environments

by Song Hu, Ge Shi, Qinggang Guo, Long Zheng, Luquan Ren and Chao Su

Coatings 2022, 12(1), 20; https://doi.org/10.3390/coatings12010020 - 24 Dec 2021

Viewed by 1909

Abstract

The ventral scales of Dinodon rufozonatum were investigated to understand the outstanding tribological adaptability in various environments. The coefficient of friction (COF) of ventral scales was measured and changed with the contact conditions. It was discovered that the COF of scales under water-lubrication [...] Read more.

The ventral scales of Dinodon rufozonatum were investigated to understand the outstanding tribological adaptability in various environments. The coefficient of friction (COF) of ventral scales was measured and changed with the contact conditions. It was discovered that the COF of scales under water-lubrication conditions (WLC) was larger than that under dry conditions (DC). More interestingly, the COF increased first and then decreased as the substrate roughness reduced. The abrasion marks on scales were then observed. The results indicated that the scales in DC wore more gently than that in WLC. Moreover, the degree of wear reduced with the decrease of substrate roughness. The frictional performance of ventral scales enabled the snakes to move more efficiently, quickly, and flexibly in multiple environments. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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20 pages, 10326 KiB

Open AccessArticle

Study on the Drag Reduction Characteristics of the Surface Morphology of Paramisgurnus dabryanus Loach

by Liyan Wu, Jiaqi Wang, Guihang Luo, Siqi Wang, Jianwei Qu, Xiaoguang Fan and Cuihong Liu

Coatings 2021, 11(11), 1357; https://doi.org/10.3390/coatings11111357 - 03 Nov 2021

Cited by 8 | Viewed by 1917

Abstract

The drag reduction design of underwater vehicles is of great significance to saving energy and enhancing speed. In this paper, the drag reduction characteristics of Paramisgurnusdabryanus loach was explored using 3D ultra-depth field microscopy to observe the arrangement of the scales. Then, [...] Read more.

The drag reduction design of underwater vehicles is of great significance to saving energy and enhancing speed. In this paper, the drag reduction characteristics of Paramisgurnusdabryanus loach was explored using 3D ultra-depth field microscopy to observe the arrangement of the scales. Then, a geometric model was established and parameterized. A simulated sample was processed by computer numerical control (CNC) machining and tested through using a flow channel bench. The pressure drop data were collected by sensors, and the drag reduction rate was consequently calculated. The test results showed that the drag reduction rate of a single sample could reach 23% at a speed of 1.683 m/s. Finally, the experimental results were verified by numerical simulation and the drag reduction mechanism was explored. The boundary layer theory and RNG k-ε turbulence model were adopted to analyze the velocity contour, pressure contour and shear force contour diagrams. The numerical simulation results showed that a drag reduction effect could be achieved by simulating the microstructure of scales of the Paramisgurnusdabryanus loach, showing that the results are consistent with the flow channel experiment and can reveal the drag reduction mechanism. The bionic surface can increase the thickness of boundary layer, reduce the Reynolds number and wall resistance. The scales disposition of Paramisgurnusdabryanus loach can effectively reduce the surface friction, providing a reference for future research on drag reduction of underwater vehicles such as ships and submarines. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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7 pages, 2262 KiB

Open AccessArticle

Theoretical Investigation on the Friction Behavior of Bio-Inspired Hard-Soft-Integrated Materials

by Mi Wang, Wei Yang, Hao Cui, Shu-Chen Yang, Zhen-Ning Liu and Guo-Long Lu

Coatings 2021, 11(11), 1296; https://doi.org/10.3390/coatings11111296 - 26 Oct 2021

Cited by 3 | Viewed by 1398

Abstract

Structural biological materials with integrated soft and hard phases are ubiquitous in nature. Over recent decades, bio-inspired hard-soft-integrated materials (BHSIMs) have shown excellent mechanical properties of drag reduction and abrasion resistance. This work is proposed to investigate the friction behaviors of BHSIMs via [...] Read more.

Structural biological materials with integrated soft and hard phases are ubiquitous in nature. Over recent decades, bio-inspired hard-soft-integrated materials (BHSIMs) have shown excellent mechanical properties of drag reduction and abrasion resistance. This work is proposed to investigate the friction behaviors of BHSIMs via theoretical modeling, numerical simulation and experimental verification. First, the mathematical model of the friction process was established based on the classic adhesive friction theory. Then, a range of factors in the friction process were examined by simulation and the respective friction coefficients were discussed. Subsequently bio-inspired materials with integrated soft and hard layers were prepared by 3D printing and their friction coefficients were measured by experiments, which had verified the results of theoretical analyses. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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15 pages, 4036 KiB

Open AccessArticle

Study on the Structural Characteristics of Bird Necks and Their Static Motion Features in the Sagittal Plane

by Jiajia Wang, Wenfeng Jia, Fu Zhang, Xiqiang Ma, Zhaomei Qiu, Zhihui Qian, Luquan Ren, Zhijun Guo and Yakun Zhang

Coatings 2021, 11(10), 1228; https://doi.org/10.3390/coatings11101228 - 09 Oct 2021

Cited by 3 | Viewed by 2275

Abstract

The necks of birds that possess complex structures, graceful curves, and flexible movements are perfect natural motion actuators. Studying their structural features, mechanic characteristics, and motion rules can provide valuable references for imitating such actuators and motion functions artificially. Previous studies have analyzed [...] Read more.

The necks of birds that possess complex structures, graceful curves, and flexible movements are perfect natural motion actuators. Studying their structural features, mechanic characteristics, and motion rules can provide valuable references for imitating such actuators and motion functions artificially. Previous studies have analyzed the influence of two-dimensional motion geometric features and anatomical structure of the neck on motion efficiency and motion stability. However, the mechanism of motion flexibility from the perspective of neck structure has not been investigated. This study investigates the general law of the relationship between the structural parameters and motion characteristics of birds’ necks using tomography technology and 3D reconstruction technology. The results show that the structural characteristics of geese and ducks are similar, and there are significant differences in joint motion characteristics. Geese obtains complex neck postures through active intervertebral joints and highly flexible facet joints and possesses higher neck flexibility than ducks. This study provides a generic measuring method for obtaining birds’ cervical spinal vertebral structural dimensional parameters and offers a new theoretical concept for bionic robotic structural design and manufacture. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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13 pages, 3615 KiB

Open AccessArticle

Durable and Superhydrophobic Aluminium Alloy with Microscale Hierarchical Structures and Anti-Drag Function Inspired by Diving Bell Spider

by You Chen, Zijing Quan, Yuhan Sun, Deqiang Chi, Delei Liu, Liang Zhou, Junqiu Zhang, Zhengzhi Mu, Ze Wang, Bo Li, Shichao Niu, Zhiwu Han and Luquan Ren

Coatings 2021, 11(10), 1146; https://doi.org/10.3390/coatings11101146 - 22 Sep 2021

Cited by 4 | Viewed by 2532

Abstract

Coating materials with special surface wettability are widely applied in marine paint systems used in the naval industry to reduce the corrosion and viscous drag of seawater. However, traditional coatings are inefficient and limited, either by poor durability or insufficient anti-drag capacity. Here, [...] Read more.

Coating materials with special surface wettability are widely applied in marine paint systems used in the naval industry to reduce the corrosion and viscous drag of seawater. However, traditional coatings are inefficient and limited, either by poor durability or insufficient anti-drag capacity. Here, inspired by the diving bell spider, a bionic superhydrophobic coating with multiscale hierarchical architecture was successfully prepared on the surface of aluminium alloy. It possesses excellent mechanical abrasion durability, chemical durability, and low adhesion. Remarkably, the water contact angles could remain over 150.9° after more than 15 abrasion cycles or strong acid/alkali conditions. In addition, the impacting water droplet lifted off the surface of bionic superhydrophobic aluminium alloy (BSAA) within 13 ms, illustrating an excellent low adhesion property. In fact, when the BSAA is immersed in water, it could absorb bubbles and form a gas membrane. The existence of the gas membrane could prevent water and anaerobic organisms from contacting and even corroding the BSAA. Meanwhile, the gas membrane acts as a lubricant and significantly deceases friction at the solid–liquid interface, reducing the drag for BSAA. The BSAA proposed in this work has broad application prospects, such as medical devices, microfluidic chips, gas separation and collection in water. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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13 pages, 4703 KiB

Open AccessArticle

Coupled Superhydrophilic PMMA Film with Inverted Pyramid Microstructures for Antireflection and Antifogging Properties

by Xiaoming Feng, Guizhong Tian, Shichao Niu and Honggen Zhou

Coatings 2021, 11(9), 1107; https://doi.org/10.3390/coatings11091107 - 14 Sep 2021

Cited by 1 | Viewed by 2183

Abstract

Transparent substrates with antifogging and antireflection ability are of extreme significance for optical devices, because they alleviate performance loss and maintenance costs. Here, we reported that a multifunctional film, with excellent mechanical properties, can be fabricated on the PMMA surface via the micro-transfer [...] Read more.

Transparent substrates with antifogging and antireflection ability are of extreme significance for optical devices, because they alleviate performance loss and maintenance costs. Here, we reported that a multifunctional film, with excellent mechanical properties, can be fabricated on the PMMA surface via the micro-transfer printing method. In particular, the synergistic effect of the inverted pyramid microstructure and SiO₂ nanoparticles gives the film excellent antireflective, superhydrophilic and antifogging properties, and the silica sol firmly adheres to the PMMA substrate via the silane coupling agent, which exhibits an encouraging prospect of practical applications from lenses for personal and sports eyewear to transparent displays and sensors, etc. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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12 pages, 4928 KiB

Open AccessArticle

Corrosion Behavior of NiTi Alloys Fabricate by Selective Laser Melting Subjected to Femtosecond Laser Shock Peening

by Long Ma, Wanqing Li, Yongzhi Yang, Yuanxue Ma, Kai Luo, Bochao Jia, Zezhou Xu and Zhenglei Yu

Coatings 2021, 11(9), 1078; https://doi.org/10.3390/coatings11091078 - 06 Sep 2021

Cited by 6 | Viewed by 2341

Abstract

NiTi alloys are commonly used in many fields such as aerospace, mechanical engineering due to their excellent mechanical properties and shape memory effect. In recent years, the emergence of selective laser melting (SLM) technology provides a new method for the preparation of NiTi [...] Read more.

NiTi alloys are commonly used in many fields such as aerospace, mechanical engineering due to their excellent mechanical properties and shape memory effect. In recent years, the emergence of selective laser melting (SLM) technology provides a new method for the preparation of NiTi parts. But the surface corrosion failure of SLM-NiTi is the most common problem. This paper mainly focuses on the research of femtosecond laser shock peening of the surface of SLM-NiTi alloy to improve the corrosion resistance. Selecting different scanning space (1 μm, 3 μm, 5 μm, 10 μm), and analyze the surface morphology of the material through the OM, SEM, EDS and white light interferometer, and investigate the surface nanohardness and corrosion resistance through nanoindentation and electrochemical testing. The research results show that part of the TiO₂ is formed under different scanning spaces, and part of NiO is formed when the scanning space is 1μm. At the same time, it is found that the sample under the condition of 10 μm has the most excellent corrosion resistance and nanohardness. The nanohardness reaches 1303 ± 40 HV and the corrosion current density reaches 1.45 ± 0.1 × 10⁻⁹ A·cm⁻². Proper femtosecond laser treatment can effectively improve the surface strength and corrosion resistance of the NiTi alloys. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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12 pages, 1521 KiB

Open AccessArticle

Effects of Pine Bark Extract on Physicochemical Properties and Biological Activity of Active Chitosan Film by Bionic Structure of Dragonfly Wing

by Kang Wan, Mengdi Cong, Xu Teng, Miao Feng, Lili Ren and Liyan Wang

Coatings 2021, 11(9), 1077; https://doi.org/10.3390/coatings11091077 - 06 Sep 2021

Cited by 4 | Viewed by 1764

Abstract

Bionic and active films based on chitosan were developed with the bionic structure of dragonfly wings incorporating pine bark extract (PBE). Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, and water vapor permeability were measured. Antioxidant activity of [...] Read more.

Bionic and active films based on chitosan were developed with the bionic structure of dragonfly wings incorporating pine bark extract (PBE). Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, and water vapor permeability were measured. Antioxidant activity of the films was characterized by DPPH free radical scavenging activity. The interaction between chitosan and PBE was explored by attenuated total reflectance Fourier transform infrared spectrometry, X-ray diffraction, and differential scanning calorimetry. The results indicated that the addition of PBE gave rise to the films greater opacity, redness, and darker appearance. Compared with pure chitosan film, the thickness, opacity, mechanical properties, and oxidation resistance of the bionic chitosan–PBE film increased, and the water vapor permeability decreased. The films based on chitosan incorporated PBE and with the bionic structure of dragonfly wings can potentially be applied to food packaging. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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Review

Jump to: Research

28 pages, 10083 KiB

Open AccessReview

Cross-Scale Biological Models of Species for Future Biomimetic Composite Design: A Review

by Wenda Song, Zhengzhi Mu, Zhiyan Zhang, Yufei Wang, Handong Hu, Zhe Ma, Liewei Huang, Ze Wang, Binjie Zhang, Yujiao Li, Shuang Zhang, Bo Li, Junqiu Zhang, Shichao Niu, Zhiwu Han and Luquan Ren

Coatings 2021, 11(11), 1297; https://doi.org/10.3390/coatings11111297 - 26 Oct 2021

Cited by 6 | Viewed by 3049

Abstract

The rise in structural performance requirements in engineering is driving the research and development of stronger, stiffer, and lighter materials. However, most traditional artificial materials are unable to meet the needs of modern industrial and technological development. In fact, multifarious creatures in nature [...] Read more.

The rise in structural performance requirements in engineering is driving the research and development of stronger, stiffer, and lighter materials. However, most traditional artificial materials are unable to meet the needs of modern industrial and technological development. In fact, multifarious creatures in nature are further ahead in their use of structural materials. There is a fairly limited selection of natural structural materials at ambient temperatures. They usually consist of hard and soft phases arranged in a complex hierarchy with characteristic dimensions ranging from nanoscale to macroscale. The resulting materials usually show a nearly perfect combination of strength and toughness integrated with lightweight characteristics. This is exactly what is required of engineering materials. In this review, different biological materials were divided into the following types in terms of structural elements: 1D fibrous structures, 2D layered structures, 3D cellular structures and heterogeneous interface structures. For each structural element, corresponding structure components and mechanical properties of typical organisms were well described. Abundant sophisticated models of natural biological structures were discussed contrastively. The purpose of this review was to summarize the excellent properties of multi-dimensional biological models with cross-scale features and to reveal the relationship between structure characteristics and function mechanism, which could provide valuable references for the design and optimization of a future biomimetic composite with high mechanical performance. This review is anticipated to not only inspire novel biomimetic design but also offer a window for the deep understanding of existing outstanding structural composites in diversified species, which could provide continuous innovative power for composite renovation in many engineering fields. Full article

(This article belongs to the Special Issue Mechanical Bionic and Bio-Inspired Interface Materials)

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