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Hypervelocity impact induced shock acoustic emission waves for quantitative damage evaluation using in situ miniaturized piezoelectric sensor network

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Chinese Journal of Aeronautics 2019年第5期32卷 1059-1070页

作者： Menglong LIU Qiang WANG Qingming ZHANG Renrong LONG Fangsen CUI zhongqing su Institute of High Performance Computing A*STAR (Agency for Science Technology and Research) School of Automation Nanjing University of Posts and Telecommunications State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Institute of High Performance Computing (A*STAR Agency for Science Technology and Research) Department of Mechanical Engineering The Hong Kong Polytechnic University

Manmade debris and natural meteoroids, travelling in the Low Earth Orbit at a speed of several kilometers per second, pose a severe safety concern to the spacecraft in service through the HyperVelocity Impact(HVI). To address this issue, an investigation of shock Acoustic Emission(AE) waves induced by HVI to a downscaled two-layer Whipple shielding structure is performed,to realize a quantitative damage evaluation. Firstly a hybrid numerical model integrating smoothparticle hydrodynamics and finite element is built to obtain the wave response. The projectiles, with various impact velocities and directions, are modelled to impact the shielding structure with different thicknesses. Then experimental validation is carried out with built-in miniaturized piezoelectric sensors to in situ sense the HVI-induced AE waves. A quantitative agreement is obtained between numerical and experimental results, demonstrating the correctness of the hybrid model and facilitating the explanation of obtained AE signals in experiment. Based on the understanding of HVI-induced wave components, assessment of the damage severity, i.e., whether the outer shielding layer is perforated or not, is performed using the energy ratio between the regions of ‘‘high frequency" and ‘‘low frequency" in the acquired AE signals. Lastly, the direct-arrival fundamentalsymmetric wave mode is isolated from each sensing signal to be input into an enhanced delay-andsum algorithm, which visualizes HVI spots accurately and instantaneously with different sensor network configuration. All these works demonstrate the potential of quantitative, in situ, and real time HVI monitoring using miniaturized piezoelectric sensor network.

关键词： Acoustic Emission(AE) Damage detection Hypervelocity impact Piezoelectric sensor Whipple shielding assembly

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Observation of an acoustic non-Hermitian topological Anderson insulator

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Science China(Physics,Mechanics & Astronomy) 2023年第9期66卷 57-62页

作者： Zhongming Gu He Gao Haoran Xue Di Wang Jiamin Guo zhongqing su Baile Zhang Jie Zhu Institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore Centre for Disruptive Photonic Technologies Nanyang Technological UniversitySingapore 637371Singapore

The interaction of band topology and disorder can give rise to intriguing *** paradigmatic example is the topological Anderson insulator,whose nontrivial topology is induced in a trivial system by *** this study,we investigate the efect of purely non-Hermitian disorders on topological systems using a one-dimensional acoustic lattice with coupled ***,we construct a theoretical framework to describe the non-Hermitian topological Anderson insulator phase solely driven by disordered loss ***,the complete evolution of non-Hermitian disorder-induced topological phase transitions,from an initial trivial phase to a topological Anderson phase and finally to a trivial Anderson phase,is revealed experimentally using both bulk and edge ***,topological modes induced by non-Hermitian disorders to be immune to both weak Hermitian and non-Hermitian *** findings pave the way for future research on disordered non-Hermitian systems for novel wave manipulation.

关键词： topological Anderson insulator non-Hermitian systems topological edge states

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含分层复合材料层合板的接触阻尼特性

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振动与冲击 2019年第24期38卷 8-17,47页

作者：何意肖毅苏众庆同济大学航空航天与力学学院上海200092 香港理工大学机械工程系香港999077

阻尼响应是用于识别分层损伤的高敏感动态参数。分层板的阻尼包括材料阻尼和接触阻尼两部分:基于应变能法,计算了复合材料材料阻尼;基于静-动摩擦一体化能量损耗模型,计算了一阶模态下分层界面接触阻尼;采用有限元软件Abaqus建立了分层... 详细信息

阻尼响应是用于识别分层损伤的高敏感动态参数。分层板的阻尼包括材料阻尼和接触阻尼两部分:基于应变能法,计算了复合材料材料阻尼;基于静-动摩擦一体化能量损耗模型,计算了一阶模态下分层界面接触阻尼;采用有限元软件Abaqus建立了分层板有限元模型(FEMs),借助罚刚度法引入界面法向接触刚度,同时运用等效黏性阻尼引入接触阻尼参数,分析了分层层合板动态响应;采用自由衰减试验测量了不同分层尺寸和厚度方向位置板件的动态参数。结果表明,分层比例越大,层合板的一阶模态阻尼上升越多,其中接触阻尼起主要作用。试验结果与有限元结果吻合较好,验证了有限元模型的合理性和准确性。

关键词：复合材料层合板分层损伤有限元分析接触阻尼罚刚度法

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基于振动疲劳试验的复合材料螺栓连接预紧力松弛特性

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复合材料学报 2016年第1期33卷 163-173页

作者：张振肖毅刘彦清苏众庆同济大学航天航空与力学学院上海200092 香港理工大学机械工程系

在强迫弯曲振动试验的基础上,建立了基于模态参数(共振频率和阻尼比)表征螺栓连接结构动态性能的分析方法和试验测试手段;通过施加不同初始预紧力和激振频率,探究碳纤维/环氧复合材料螺栓连接预紧力松弛的时变行为及其影响因素。结果表... 详细信息

在强迫弯曲振动试验的基础上,建立了基于模态参数(共振频率和阻尼比)表征螺栓连接结构动态性能的分析方法和试验测试手段;通过施加不同初始预紧力和激振频率,探究碳纤维/环氧复合材料螺栓连接预紧力松弛的时变行为及其影响因素。结果表明:在10h振动疲劳过程中,螺栓初始预紧力越小,激振频率越大,连接件预紧力松弛程度越大;振动疲劳损伤会导致连接结构刚度衰退、阻尼增加;复合材料螺栓连接松弛受到材料黏弹性以及界面摩擦的共同影响,其中约50%的松弛是由复合材料黏弹性效应引起的。

关键词：复合材料结构螺栓连接预紧力松弛振动疲劳阻尼比长期耐久性

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基于模糊理论和AHP的高速列车端部舱设计方案评价

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大连交通大学学报 2015年第2期36卷 30-34页

作者：马思群王一丰苏众庆董小鹏大连交通大学交通运输学院辽宁大连116028 香港理工大学深圳研究院广东深圳518057 厦门大学信息科学与技术学院光波技术研究所福建厦门361005

为了使企业在面对多种结构相似的设计方案,能做出正确,合理的选择,提出了基于模糊理论和层次分析法的某型动车组端部舱设计方案的评价研究.为辅助工程师进行设计方案的选择,在综合考虑制造成本、强度、抗疲劳性能的基础上,构建了设计方... 详细信息

为了使企业在面对多种结构相似的设计方案,能做出正确,合理的选择,提出了基于模糊理论和层次分析法的某型动车组端部舱设计方案的评价研究.为辅助工程师进行设计方案的选择,在综合考虑制造成本、强度、抗疲劳性能的基础上,构建了设计方案的综合评价指标体系;借助模糊数学理论,利用中值法确定评价因素与评价集的隶属度,利用层次分析法确定因素权重,对动车组端部舱三种设计方案分别进行模糊综合评价,从中获得最优设计方案.实践表明,所建立的评价体系可以快速获得客观综合评价结果,能为企业设计方案的择优选择提供依据.

关键词：动车组端部舱模糊理论 AHP

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First-principles calculations of elasticity of minerals at high temperature and pressure

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Science China Earth Sciences 2016年第6期59卷 1107-1137页

作者： WU zhongqing WANG WenZhong Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space ScienceUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory Mengcheng 233527China

The elasticity of minerals at high temperature and pressure （PT） is critical for constraining the composition and temperature of the Earth＇s interior and understand better the deep water cycle and the dynamic Earth. First-principles calcula- tions without introducing any adjustable parameters, whose results can be comparable to experimental data, play a more and more important role in investigating the elasticity of minerals at high PT mainly because of （1） the quick increasing of computational powers and （2） advances in method. For example, the new method reduces the computation loads to one-tenth of the traditional method with the comparable precise as the traditional method. This is extraordinarily helpful because first-principles calculations of the elasticity of minerals at high PT are extremely time-consuming. So far the elasticity of most of lower mantle minerals has been investigated in detail. We have good idea on the effect of temperature, pressure, and iron concentration on elasticity of main minerals of the lower mantle and the unusual softening in bulk modulus by the spin crosso- ver of iron in ferropericlase. With these elastic data the lower mantle has been constrained to have 10-15 wt% ferropericlase, which is sufficient to generate some visible effects of spin crossover in seismic tomography. For example, the spin crossover causes that the temperature sensitivity of P wave at the depth of -1700 km is only a fraction of that at the depth of -2300 kin. The disruptions of global P wave structure and of P wave image below hotspots such as Hawaii and Iceland at similar depth are in consistence with the spin crossover effect of iron in ferropericlase. The spin crossover, which causes anomalous ther- modynamic properties of ferropericlase, has also been found to play a control role for the two features of the large low shear velocity provinces （LLSVPs）： the sharp edge and high elevation up to 1000 km above core-mantle boundary. All these results clearly su

关键词： Mantle temperature Mantle composition Composition of Earth's core Ab initio method

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Impact Analysis of Microscopic Defect Types on the Macroscopic Crack Propagation in Sintered Silver Nanoparticles

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 441-458页

作者： zhongqing Zhang Bo Wan Guicui Fu Yutai su Zhaoxi Wu Xiangfen Wang Xu Long School of Reliability and Systems Engineering Beihang UniversityBeijing100191China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China China Aerospace Components Engineering Center Beijing100098China

Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional ***,the material reliability is significantly affected by various microscopic *** this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and *** dynamics(MD)simulations are employed to observe the failure evolution of different microscopic *** dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation *** the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain *** impact of defect types on the failure process is also ***,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale *** validity of the crack propagation model is confirmed through tensile ***,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD *** findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.

关键词： Sintered silver nanoparticles defect types microscopic defect evolution macroscopic crack propagation molecular dynamics simulation cohesive zone model

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改进U-Net芯片X线图像焊缝气泡缺陷检测方法

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华中科技大学学报（自然科学版） 2022年第6期50卷 104-110页

作者：李可吴忠卿吉勇宿磊江南大学机械工程学院江苏无锡214122 江南大学江苏省食品先进制造装备技术重点实验室江苏无锡214122 中国电子科技集团第五十八研究所江苏无锡214000

针对传统图像处理算法的芯片缺陷检测方法难以实现缺陷的精确提取且泛化性较差的问题,提出了结合空间注意力机制(SAM)、空间金字塔池化(SPP)、移动端神经网络(Mobile-Net)和密集条件随机场(DCRF)改进经典UNet芯片X线图像焊缝气泡缺陷的... 详细信息

针对传统图像处理算法的芯片缺陷检测方法难以实现缺陷的精确提取且泛化性较差的问题,提出了结合空间注意力机制(SAM)、空间金字塔池化(SPP)、移动端神经网络(Mobile-Net)和密集条件随机场(DCRF)改进经典UNet芯片X线图像焊缝气泡缺陷的检测方法(DSSMob-U-Net).首先,针对经典U-Net网络特征提取能力不足、泛化性较差的问题,引入Mobile-Net作为U-Net的主干特征提取网络,提高网络获取缺陷形状和位置信息的能力,并减少网络的参数量,降低模型对训练样本量的要求;其次,在Mobile-Net的低维特征提取部分引入空间注意力机制,并在特征提取后引入空间金字塔池化,提升网络对图像高、低维特征的提取能力,解码后针对解码器上采样层导致的特征信息丢失问题,在分类完成后引入密集条件随机场,结合像素点的像素值和所属类别信息对像素的分类结果重新评估,进一步提高分割精度;最后,在芯片缺陷数据集上进行实验,验证了DSSMob-U-Net模型的有效性,并与其他常用的语义分割网络进行比较,结果表明该模型具有更好的检测性能.

关键词：缺陷检测机器视觉语义分割空间注意力密集条件随机场

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Semisynthesis and biological evaluation of platensimycin and platencin analogues

Semisynthesis and biological evaluation of platensimycin and...

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中国化学会第十二届全国天然有机化学学术会议

作者： Youchao Deng Meng su Xingyun Liu zhongqing Wen Yuling Li Dingding Kang Xinxin Ji Ben Shen Yanwen Duan Yong Huang Xiangya International Academy of Translational Medicine at Central South University Departments of Chemistry and Molecular Medicine and Natural Products Library Initiative at The Scripps Research InstituteThe Scripps Research Institute Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery

The high yield fermentative production of complex microbial natural products and their subsequent facile organic transformation have resulted in many affordable antibiotics to humans and ***(PTM) and platencin(PTN) are newly-discovered and potent inhibitors of bacterial fatty acid synthases,which exhibited excellent antibacterial activities against drug-resistant *** both PTM and PTN had to be continuously infused into mice in order to achieve therapeutic efficacy against Staphylococcus aureus infection,new analogues with proper pharmacokinectics are keenly *** semisynthesis of over 100 analogues of PTM and PTN have been achieved in the past years,based on our pilot-scale production of PTM and *** of the analogues showed impressive antibacterial activities or improved *** above studies suggested a few new design principles to diversify the privileged PTM and PTN molecular scaffolds and improve their bioavailability,in order to advance them into clinics.

关键词： Platensimycin Platencin Semisynthesis antibiotics

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多孔水凝胶研究进展

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化学进展 2007年第4期19卷 485-493页

作者：卢国冬燕青芝宿新泰刘中清葛昌纯北京科技大学特种陶瓷粉末冶金研究室北京100083

水凝胶是亲水性而又不溶于水的高分子聚合物材料,因其独特的吸水、保水和仿生特性而受到材料科学和生物医学工作者的关注。将多孔结构引入水凝胶可以极大地提高其溶胀率、溶胀速率和刺激敏感性。本文结合作者实验室开展的波聚合法制备... 详细信息

水凝胶是亲水性而又不溶于水的高分子聚合物材料,因其独特的吸水、保水和仿生特性而受到材料科学和生物医学工作者的关注。将多孔结构引入水凝胶可以极大地提高其溶胀率、溶胀速率和刺激敏感性。本文结合作者实验室开展的波聚合法制备多孔水凝胶的研究工作,较全面地介绍了国内外多孔水凝胶材料的研究现状及其在生物医药领域的应用,并对其发展前景进行了展望。

关键词：水凝胶多孔结构成孔机理溶胀性

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