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Ultrafast laser-chemical modification hybrid fabrication of hydrostatic bearings with a superhydrophobicity solid-liquid interface

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Science China(Technological Sciences) 2024年第3期67卷 696-708页

作者： GUO MingHui rong youmin HUANG Yu FENG XiaoLin HU HaiDong WU CongYi ZHANG GuoJun State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Faculty of Engineering and Life Sciences Universiti Selangor Bestari JayaSelangor 45600Malaysia

Oil film vortex severely reduces the stability of hydrostatic bearings. A solid-liquid interface with drag and slip properties can weaken the oil film vortex of the bearing. Here, a combined picosecond laser ablation and chemical modification method is proposed to prepare surfaces with microbulge array structure on 6061 aluminum alloy substrates. Because of the low surface energy of the perfluorododecyltriethoxysilane modification and the bulge geometry of the microbulge array structure, the surface shows excellent superhydrophobicity. The optimum contact angle in air for water is 164°, and that for oil is 139°. Two surfaces with “lotus-leaf effect” and “rose-petal effect” were obtained by controlling the processing parameters. The drag reduction properties of superhydrophobic surfaces were systematically investigated with slip lengths of 22.26 and 36.25 μm for deionized water and VG5 lubricant, respectively. In addition, the superhydrophobic surface exhibits excellent mechanical durability and thermal stability. The proposed method provides a new idea for vortex suppression in hydrostatic bearings and improves the stability of bearings in high-speed operation.

关键词： superhydrophobicity surface ultrafast laser drag reduction solid-liquid interface microbulge array structure

基于粒子群算法确定热源参数的EH40/316L高功率激光焊接温度场模拟

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焊接学报 2024年第1期45卷 31-39,I0005页

作者：徐加俊黄禹王璐荣佑民华中科技大学武汉430074 广东华中科技大学工业技术研究院东莞518052

焊接瞬态温度场对焊接残余应力与变形模拟结果具有重要的影响,为提高EH40/316L高功率激光焊接的温度场模拟精度,开发了用于热源模型经验参数优化的智能计算方法.该方法利用MATLAB软件随机生成热源模型的经验参数,调用ANSYS软件执行焊接... 详细信息

焊接瞬态温度场对焊接残余应力与变形模拟结果具有重要的影响,为提高EH40/316L高功率激光焊接的温度场模拟精度,开发了用于热源模型经验参数优化的智能计算方法.该方法利用MATLAB软件随机生成热源模型的经验参数,调用ANSYS软件执行焊接温度场模拟的APDL命令,并在计算完成后返回结果数据,然后通过借助粒子群算法的群体智能和进化智能的优点,根据预测结果生成新的热源经验参数,进行迭代计算,直至预测结果为最优结果;同时,为提高收敛速度,将有限元几何模型简化为原模型的1/5.基于该方法,开展了10个热源模型经验参数优化案例的计算,并根据优化结果分析了热源模型的参数敏感性.结果表明,该方法实现了温度场的准确预测,其中10个优化案例的平均计算时间为30.3 h,最大、最小和平均预测误差分别为2.84%,2.06%和2.16%;同时,由预测误差和热源经验参数的响应曲面可知,两者之间具有复杂的非线性关系,其数学函数为多谷函数.

关键词：高功率激光焊接异种钢焊接温度场模拟热源参数优化粒子群算法

Laser cutting of thermoplastic film:Mechanism and processing technology

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Science China(Technological Sciences) 2022年第9期65卷 2068-2078页

作者： WU CongYi rong youmin HUANG Yu ZHANG GuoJun State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

The mechanism of ultraviolet(UV) nanosecond laser cutting of thermoplastic films and the influence of process parameters on process quality are systematically *** photothermal effect plays a dominant role in the interaction between the UVnanosecond laser and thermoplastic *** this photothermal reaction,a heat source with the focal point as the core is formed,around which a thermal carbonization layer,a thermal melting layer,and a thermal expansion layer are formed in order from the inside to the *** them,the thermal carbonization layer is not prevalent,and the thermal melting layer and thermal expansion layer are *** process quality can be adjusted by adjusting the cutting speed,the laser power,and the repetition number of cuts to regulate the process of heat generation and heat *** the effective range,the faster the cutting speed and the lower the laser power,the smaller the kerf width and heat-affected zone(HAZ) *** a certain range,the depth of kerf can be increased by increasing the repetition number of cuts.

关键词： laser cutting thermoplastic film mechanism process parameters

Lattice Boltzmann study on the effects of surface nanostructure on wettability with application in laser scanning fabrication of superhydrophobic surfaces

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Science China(Technological Sciences) 2023年第11期66卷 3197-3205页

作者： HUANG Hao GUO MingHui WU CongYi rong youmin HUANG Yu ZHANG GuoJun State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Nanostructured surfaces with dimensions on a scale of a few millimeters exhibit remarkable *** geometry of these nanostructures considerably affects their ***,determining the optimal geometry is challenging due to the abundance of geometry parameters and the difficulty in numerically describing their effects on wettability at the mesoscopic *** addition,the fabrication of nanostructured surfaces with precise geometries is *** establish a lattice Boltzmann method(LBM)model to address these *** use the model to gain mesoscopic insights into the interaction between droplets and *** model can accurately reproduce contact angles(CAs)on various nanostructured surfaces and enables investigation of the effects of nanostructure geometry on *** optimize the geometry of the nanostructures using the insights provided by the LBM model on the wettability *** analysis indicates that cones with dimensions of 40μm in width and 33μm in height exhibit the highest *** successfully fabricate a superhydrophobic surface with the desired geometry via laser scanning,achieving a CA of 163°.We believe that this approach,which combines the LBM model and laser manufacturing,will enable a better understanding of the wettability mechanism and provide a high-performance approach for fabricating superhydrophobic surfaces.

关键词： wettability lattice Boltzmann method nanostructure laser scanning

Revealing the interaction mechanism of pulsed laser processing with the application of acoustic emission

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Frontiers of Optoelectronics 2023年第2期16卷 91-101页

作者： Weinan Liu youmin rong Ranwu Yang Congyi Wu Guojun Zhang Yu Huang State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

The mechanisms of interaction between pulsed laser and materials are complex and indistinct,severely infuencing the stability and quality of laser *** paper proposes an intelligent method based on the acoustic emission(AE)technique to monitor laser processing and explore the interaction *** validation experiment is designed to perform nanosecond laser dotting on foat *** parameters are set diferently to generate various outcomes:ablated pits and irregular-shaped *** the signal processing stage,we divide the AE signals into two bands,main and tail bands,according to the laser processing duration,to study the laser ablation and crack behavior,*** parameters extracted by a method that combines framework and frame energy calculation of AE signals can efectively reveal the mechanisms of pulsed laser *** main band features evaluate the degree of laser ablation from the time and intensity scales,and the tail band characteristics demonstrate that the cracks occur after laser *** addition,from the analysis of the parameters of the tail band very large cracks can be efciently *** intelligent AE monitoring method was successfully applied in exploring the interaction mechanism of nanosecond laser dotting foat glass and can be used in other pulsed laser processing felds.

关键词： Laser dotting Acoustic emission Monitoring Laser ablation Cracks

Analysis and comparison of laser cutting performance of solar float glass with different scanning modes

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Frontiers of Mechanical Engineering 2021年第1期16卷 97-110页

作者： Wenyuan LI Yu HUANG youmin rong Long CHEN Guojun ZHANG Zhangrui GAO State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China HG Farley Laserlab Cutting Welding System Engineering Co. Ltd.Wuhan 430223China

Cutting quality and efficiency have always been important indicators of glass laser *** scanning modes have two kinds,namely,the spiral and concentric circle scanning *** modes can achieve high-performance hole cutting of thick solar float glass using a 532-nm nanosecond *** mechanism of the glass laser cutting under these two different scanning modes has been *** experiments are conducted to explore the effect of machining parameters on cutting efficiency and quality under these two scanning *** indicate that compared with the spiral scanning mode,the minimum area of edge chipping(218340µm)and the minimum Ra(3.01µm)in the concentric circle scanning mode are reduced by 9.4%and 16.4%***,the best cutting efficiency scanning mode is 14.2%faster than that in the spiral scanning *** best parameter combination for the concentric circle scanning mode is as follows:Scanning speed:2200 mm/s,number of inner circles:6,and circle spacing:0.05 *** parameter combination reduces the chipping area and sidewall surface roughness by 8.8%and 9.6%respectively at the same cutting efficiency compared with the best spiral processing *** range of glass processing that can be achieved in the concentric circle scanning mode is wider than that in the spiral *** analyses of surface topography,white spots,microstructures,and sidewall surface element composition are also *** study concluded that the concentric circle scanning mode shows evident advantages in the performance of solar float glass hole cutting.

关键词： laser cutting solar float glass scanning mode surface quality cutting efficiency

Dimethicone-aided laser cutting of solar rolled glass

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Frontiers of Mechanical Engineering 2021年第1期16卷 111-121页

作者： Wenyuan LI Guojun ZHANG Long CHEN Yu HUANG youmin rong Zhangrui GAO State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China HG Farley Laserlab Cutting Welding System Engineering Co. Ltd.Wuhan 430223China

Solar rolled glass,with one micro-structure surface and another roughness surface,can cause diffuse refraction of the focused laser spot,and this phenomenon restricts the application of laser *** this study,laser cutting of solar rolled glass with a thickness of 2.5 mm was successfully achieved with the help of dimethicone to ensure laser *** was coated on the top surface of the rolled glass processing zone,and a bottom–up multilayer increment with the spiral line was applied to control the cutting *** viscosity values of dimethicone were *** showed that surface quality increased as the viscosity increased until a certain threshold was reached;afterward,the surface quality decreased or directly caused the cutting to *** minimum surface roughness(3.26µm)of the processed surface(chipping:Width≤113.64µm,area 215199µm)was obtained when the dimethicone viscosity and laser pulse frequency were 1000 mm/s and 43 kHz(power 25.4 W),*** micro-defects on the processed surface were few,and the edge chipping width and depth of the laser processed surface were small.

关键词： laser cutting solar rolled glass dimethicone viscosity surface quality

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激光焊接速度对匙孔行为影响的试验分析

应用激光 2018年第6期38卷 959-962页

作者：李敏荣佑民江汉大学光电化学材料与器件教育部重点实验室湖北武汉430056 江汉大学化学与环境工程学院湖北武汉430056 华中科技大学机械科学与工程学院湖北武汉430074

选取耐高温石英玻璃作为观测介质,试验研究了焊接速度对动态匙孔及焊缝质量的影响行为。首先,瞬态匙孔存在波动行为,其1.0、1.5和2.0m/min不同焊接速度下的平均深度分别为4.57、4.98和2.01mm;其次,随着焊接速度的增加,焊缝上宽度从2.1、... 详细信息

选取耐高温石英玻璃作为观测介质,试验研究了焊接速度对动态匙孔及焊缝质量的影响行为。首先,瞬态匙孔存在波动行为,其1.0、1.5和2.0m/min不同焊接速度下的平均深度分别为4.57、4.98和2.01mm;其次,随着焊接速度的增加,焊缝上宽度从2.1、1.2至0.7mm逐渐变窄;进一步,1.5m/min和2.0m/min焊接速度下焊缝微观组织出现鳞状奥氏体;最后,在给定的三种不同焊接速度下,焊接速度1.5m/min情况下的匙孔动态行为更有助于获得好的焊缝形貌和可接受的微观组织。

关键词：激光焊接匙孔动态行为焊缝形貌微观组织

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基于声发射信号的纳秒激光划片轮廓监测

应用激光 2023年第3期43卷 150-155页

作者：王淼峥荣佑民华中科技大学机械科学与工程学院湖北武汉430074

针对Al5083纳秒激光划片过程中产生沟槽和凸起两种轮廓的问题,研究了不同工艺参数下产生轮廓与映射声信号的关系。开展Al5083薄板纳秒紫外脉冲激光划片试验,观察轮廓的微观形貌,探究轮廓形成机制;采集声发射信号,小波包变换后分析声信... 详细信息

针对Al5083纳秒激光划片过程中产生沟槽和凸起两种轮廓的问题,研究了不同工艺参数下产生轮廓与映射声信号的关系。开展Al5083薄板纳秒紫外脉冲激光划片试验,观察轮廓的微观形貌,探究轮廓形成机制;采集声发射信号,小波包变换后分析声信号的差异性,并开展支持向量机分析。微观观测结果表明,凸起轮廓的成形机制包括熔融金属溅出受阻和凝固时产生的大量气孔。声信号分析结果显示,沟槽轮廓对应的小波包分解系数的方差和包络面积显著高于凸起轮廓;以小波包分解后的频谱为特征向量,添加标签后使用高斯核支持向量机分类,分类准确度达92.57%,验证了小波包变换和支持向量机的结合在基于声信号的轮廓监测中的可行性,为构建基于声发射的激光划片监测系统提供可行的技术路径。

关键词：激光划片声发射小波包变换支持向量机