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Scaling law of launch velocity in laser-induced microparticle impact testing

Science China(Physics,mechanics & Astronomy) 2025年第5期68卷 151-163页

作者： Yiping Song Zhoupeng Gu Minqiang Jiang Qiuyun Yin Chenguang Huang Xianqian Wu Anhui Institute of Optics and Fine Mechanics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Science Island Branch University of Science and Technology of ChinaHefei 230026China Key Laboratory of Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

Laser-induced microparticle impact testing(LIPIT)is a useful method for measuring the dynamic mechanical behavior of materials under ultra-high strain rates by accelerating and launching a single microparticle at high *** is important to establish a scaling law for the laser-induced microparticle launching system to optimize its configurations and improve the achievable velocity of the *** this study,the physical process of laser-induced microparticle launching is analyzed.A scaling law for the launch system is obtained by dimensional *** influence of dominant dimensionless parameters on the dimensionless velocity of the microparticle is then assessed by numerical *** results show that the dimensionless launch velocity of the microparticle increases with increasing dimensionless energy and dimensionless time of the laser pulse and with decreasing dimensionless thickness of metal and elastomer films and the dimensionless mass of the ***,the dimensionless formulas for predicting the velocity of the microparticle of the launch system with thick-metal-film and thin-metal-film configurations are determined,*** study promotes the understanding of the launch mechanisms of LIPIT and provides a guideline for optimizing its configuration to achieve a wide range of impact velocities of the microparticles.

关键词： laser-induced microparticle impact testing scaling law launch velocity dimensional analysis numerical simulation

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Rock fracture mechanism of buffer blasting with cushion layer at the borehole bottom

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 325-334页

作者： Xinguang Zhu Chenxi Ding Zhe Sui Hong Su Xu Guo School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Chemical and Blasting Engineering Anhui University of Science and TechnologyHuainan 232001China

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock *** involves analyses of the evolution patterns of blasting stress,characteristics of crack distribution,and rock fracture features in the ***,blasting model experiments were carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock *** experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock ***,the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the continuum-discontinuum element method(CDEM)and the Landau explosion source model,with varying thicknesses of bottom cushion *** numerical simulation results indicate that with increasing cushion thickness,the absorption of energy generated by the explosion becomes more pronounced,resulting in fewer cracks in the bottom rock *** illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

关键词： bottom cushion layer blasting crack propagation continuum-discontinuum element method dynamic stress intensity factor

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Synthesis ofδ-MnO_(2)via ozonation routine for low temperature formaldehyde removal

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Journal of Environmental Sciences 2025年第1期147卷 642-651页

作者： Guijun Fan Yacong Guo Shaohua Chai Le Zhang Jian Guan Guojun Ma Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China College of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science and Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 361021China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Petrochemical Engineering&Environment Zhejiang Ocean UniversityZhoushan 316022China

Nowadays,it is still a challenge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle the long-living indoor air ***,δ-MnO_(2)is successfully synthesized by a facile ozonation strategy,where Mn^(2+)is oxidized by ozone(O_(3))bubble in an alkaline *** presents one of the best catalytic properties with a low 100%conversion temperature of 85℃for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr).As a comparison,more than 6 times far longer oxidation time is needed if O3 is replaced by O_(2).Characterizations show that ozonation process generates a different intermediate of tetragonalβ-HMnO_(2),which would favor the quick transformation into the final productδ-MnO_(2),as compared with the relatively more thermodynamically stable monoclinicγ-HMnO_(2)in the O_(2)***,HCHO is found to be decomposed into CO_(2)via formate,dioxymethylene and carbonate species as identified by room temperature insitu diffuse reflectance infrared fourier transform *** these results show great potency of this facile ozonation routine for the highly activeδ-MnO_(2)synthesis in order to remove the HCHO contamination.

关键词： δ-MnO_(2) Ozone oxidation HCHO oxidation In-situ DRIFTS

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Semantic Scene Completion via Semantic-Aware Guidance and Interactive Refinement Transformer

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IEEE Transactions on Circuits and systems for Video Technology 2025年第5期35卷 4212-4225页

作者： Xiao, Haihong Kang, Wenxiong Liu, Hao Li, Yuqiong He, Ying South China University of Technology School of Automation Science and Engineering Guangzhou510641 China South China University of Technology School of Automation Science and Engineering School of Future Technology Guangzhou510641 China Pazhou Laboratory Guangzhou510335 China Nanyang Technological University College of Computing and Data Science Jurong West 639798 Singapore Institute of Mechanics Chinese Academy of Sciences Key Laboratory for Mechanics in Fluid Solid Coupling Systems Beijing100190 China

Predicting per-voxel occupancy status and corresponding semantic labels in 3D scenes is pivotal to 3D intelligent perception in autonomous driving. In this paper, we propose a novel semantic scene completion framework that can generate complete 3D volumetric semantics from a single image at a low cost. To the best of our knowledge, this is the first endeavor specifically aimed at mitigating the negative impacts of incorrect voxel query proposals caused by erroneous depth estimates and enhancing interactions for positive ones in camera-based semantic scene completion tasks. Specifically, we present a straightforward yet effective Semantic-aware Guided (SAG) module, which seamlessly integrates with task-related semantic priors to facilitate effective interactions between image features and voxel query proposals in a plug-and-play manner. Furthermore, we introduce a set of learnable object queries to better perceive objects within the scene. Building on this, we propose an Interactive Refinement Transformer (IRT) block, which iteratively updates voxel query proposals to enhance the perception of semantics and objects within the scene by leveraging the interaction between object queries and voxel queries through query-to-query cross-attention. Extensive experiments demonstrate that our method outperforms existing state-of-the-art approaches, achieving overall improvements of 0.30 and 2.74 in mIoU metric on the SemanticKITTI and SSCBench-KITTI-360 validation datasets, respectively, while also showing superior performance in the aspect of small object generation. © 1991-2012 IEEE.

关键词： 3D modeling

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High-velocity impact response of shear thickening fluid-filled sandwich lattice panels

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Composites Part B: Engineering 2025年 299卷

作者： Gu, Z.P. Yue, J.Z. Huang, C.G. Wu, X.Q. Key Laboratory of Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences Beijing100190 China School of Engineering Science University of Chinese Academy of Sciences Beijing100049 China Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China

This study investigates the impact response of sandwich panels with lattice truss cores (SPLTC), filled with shear-thickening fluids (STF), under various impact velocities using fluid-structure interaction (FSI) simulations. A constitutive model for STF, which accounts for bulk compressibility and nonlinear, strain-rate-dependent viscosity at high strain rates, is developed and validated through laser-shock experiments. The shock response of SPLTC with different fillers at impact velocities ranging from 50 to 200 m/s is analyzed using FSI simulations. The results show that STF-filled SPLTC (SPLTC-STF) significantly improves shock resistance and energy dissipation, absorbing 1.6 times more energy than the empty SPLTC. Additionally, the effect of STF thickening properties on the shock behavior of SPLTC-STF is analyzed, revealing that higher STF viscosity reduces deformation, enhances energy absorption, and increases buckling resistance. A two-stage energy dissipation process is identified, consisting of the shock wave attenuation stage and the FSI dissipation stage. While the specific energy absorption (SEA) increases with STF viscosity, it decreases beyond a critical viscosity threshold due to reduced fluidity and weaker FSI effects. These findings underscore the potential of SPLTC-STF for impact-protection applications and highlight the importance of optimizing STF parameters for maximum energy absorption. © 2025 Elsevier Ltd

关键词： Sandwich structures

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Explosive fragmentation of brittle granular materials

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Engineering Fracture mechanics 2025年 321卷

作者： Zhang, Chuanshan Feng, Chun Zhou, Jun Xue, Kun State Key Laboratory of Explosive Science and Safety Protections Beijing Institute of Technology Beijing100081 China Beijing Aerospace Institute for Metrology and Measurement Technology No. 1 Nan Da Hong Men Road Beijing100076 China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Chinese Academy of Science Beijing100190 China

This study experimentally investigates the dynamic fragmentation behaviors of brittle granular materials subjected to explosive loadings, employing a concentric shell configuration. The setup consisted of a high-explosive sphere surrounded by a densely packed shell of dry glass spheres. To minimize reflection enhancement, the particle shells were confined within thin-walled glass casings, effectively simulating air-exposed conditions. This configuration allowed rarefaction waves reflected from the outer surface of the particle shell to significantly influence particle fragmentation, particularly in thinner shells. A specialized fragment-collecting apparatus was designed to prevent collision-induced damage to particle fragments, enabling the recovery of most fragments with preserved post-test morphologies following the explosion tests. A comprehensive analysis was conducted on the breakage extent and pulverization degree of the fragmented brittle particles, utilizing metrics such as breakage index, fragmentation volume fraction, and fractal dimension. These parameters exhibited significant variations as the particle shell thickness increased from a dimension comparable to the explosive radius to several times that radius. Notably, the thinnest particle shell underwent near-total particle crushing, evidenced by a fractal dimension of up to 3.2, indicating intense fractal crushing. When the shell thickness increased to 3.75 times the explosive radius, the fragmentation volume fraction was nearly halved, and the fractal dimension decreased significantly. These variations in fragmentation behaviors highlight the impact of divergent blast waves, which impart transient explosive loadings with rapidly decaying overpressures on the particles. The experimental results elucidate the relationship between explosive fragmentation and transient explosive loadings, providing estimations for the radii of pulverized and fractured spherical zones. Particles fragmented by explosive loa

关键词： Fractal dimension

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Investigation on transonic flutter active auppression with CFD-Based ROMs

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Science China(Physics,mechanics & Astronomy) 2015年第1期58卷 107-116页

作者： NIE XueYuan YANG GuoWei ZHANG MingFeng Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences

The calculation of accurate unsteady aerodynamic forces is critical in the analysis of aeroelastic problems,however the efficiency is low because of high computational costs of the computational fluid dynamics(CFD)***,direct integrated CFD and computational structural dynamics(CSD)technique is unsuitable for the analysis of ASE and the flutter active suppression in state-space form.A reduced-order model(ROM)based on Volterra series was developed using CFD calculation and used to predict the flutter coupled with the *** closed-loop control systems designed by the sliding mode control(SMC)and linear quadratic Gaussian(LQG)control were constructed with ROM/CSD to suppress the AGARD 445.6wing *** detailed implementation of the two control approaches is presented,and the flutter suppression effectiveness is discussed and *** results indicate that SMC method can make the controlled object response decay to the stable equilibrium more rapidly and has better control effects than the LQG control.

关键词： reduced order model aeroelasticity linear quadratic Gaussian control sliding mode control active flutter suppression

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Effect of perforation on flow past a conic cylinder at Re=100:vortex-shedding pattern and force history

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Acta Mechanica Sinica 2018年第2期34卷 238-256页

作者： L.M.Lin X.F.Zhong Y.X.Wu Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences

The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, *** angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance *** regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented.

关键词： Vortex shedding pattern fluid forces Flow control Conical shroud Perforation

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Frame-invariance in finite element formulations of geometrically exact rods

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Applied Mathematics and mechanics(English Edition) 2016年第12期37卷 1669-1688页

作者： Peinan ZHONG Guojun HUANG Guowei YANG Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of Sciences

This article is concerned with finite element implementations of the three- dimensional geometrically exact rod. The special attention is paid to identifying the con- dition that ensures the frame invariance of the resulting discrete approximations. From the perspective of symmetry, this requirement is equivalent to the commutativity of the employed interpolation operator I with the action of the special Euclidean group SE（3）, or I is SE（3）-equivariant. This geometric criterion helps to clarify several subtle issues about the interpolation of finite rotation. It leads us to reexamine the finite element for- mulation first proposed by Simo in his work on energy-momentum conserving algorithms. That formulation is often mistakenly regarded as non-objective. However, we show that the obtained approximation is invariant under the superposed rigid body motions, and as a corollary, the objectivity of the continuum model is preserved. The key of this proof comes from the observation that since the numerical quadrature is used to compute the integrals, by storing the rotation field and its derivative at the Gauss points, the equiv- ariant conditions can be relaxed only at these points. Several numerical examples are presented to confirm the theoretical results and demonstrate the performance of this al- gorithm.

关键词： geometrically exact rod finite element method interpolation equivariance frame invariance

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On the degradation of granular materials due to internal erosion

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Acta Mechanica Sinica 2015年第5期31卷 685-697页

作者： Xiaoliang Wang Jiachun Li Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of Sciences

A new state-based elasto-plastic constitutive relationship along with the discrete element model is established to estimate the degradation of granular materials due to internal *** essential effects of internal erosion such as the force network damage and relaxation are proposed and then incorporated into the constitutive relationship to formulate internal erosion impacts on the mechanical behavior of granular *** manifestations in the degradation of granular materials,such as reduction of peak strength and dilatancy are predicted by the modified constitutive relationship in good agreement with the discrete element method（DEM）*** particular,the sudden reduction of stress for conspicuous mass erosion in a high stress state is captured by force network damage and the relaxation *** is concluded that the new modified constitutive relationship is a potential theory to describe the degradation of granular materials due to internal erosion and would be very useful,for instance,in the prediction and assessment of piping disaster risk during the flood season.

关键词： Internal erosion Degradation Granular materials Discrete element method

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