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The Burst Time Duration in Micropillar Deformation

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Chinese Physics Letters 2014年第2期31卷 83-86页

作者：张旭尚福林 state key laboratory for strength and vibration of mechanical structures School of Aerospace Xi'an Jiaotong University Xi'an 710049

Plastic flow of single crystal micropillars proceeds through a sequence of intermittent burst slips. The burst time durations are investigated based on an extended theoretical model which incorporates the observed power-law distribution of burst sizes in compression experiments of micropillars. The results show that the burst time durations exhibit a powerlaw behavior with an exponential cutoff, suggesting the same scaling behaviors as the burst sizes. In addition, the predicted scaling exponent is found to converge to a value of -1.6. It is demonstrated that our results are consistent with the experimental data.

关键词： Single crystals

Numerical Analysis of Electromagneto-mechanical Coupling Dynamic Response of a Typical Tokomak Structure

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Plasma Science and Technology 2013年第3期15卷 252-256页

作者：刘天彦袁振圣李勇陈振茂武文晶裴翠祥 state key laboratory for strength and vibration of mechanical structures School of AerospaceXi'an Jiaotong University Graduate school of engineering The University of Tokyo

In an effort to simulate the dynamic behavior of a non-ferromagnetic conducting structure with consideration of the magnetic damping effect, a finite element code is developed, which is based on the reduced vector potential （At） method, the step-by-step integration algorithm and a time-partitioned strategy. An additional term is introduced to the conventional governing equations of eddy current problems to take into account the velocity-induced electric field corre- sponding to the magnetic damping effect. The TEAM-16 benchmark problem is simulated using the proposed method in conjunction with the commercial code ANSYS. The simulation results indicate that the proposed method has better simulation accuracy, especially in the presence of a high-intensity external magnetic field.

关键词： plasma disruption electromagneto-mechanical coupling magnetic damping tokomak structure numerical analysis

Self-sensing magnetic actuators of bilayer hydrogels

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International Journal of Smart and Nano Materials 2023年第4期14卷 496-509页

作者： Shengyuan Zhang Huangsan Wei Jingda Tang state key laboratory for strength and vibration of mechanical structures School of Aerospace EngineeringXian Jiaotong UniversityXi'anChina

Hard magnetic soft robots have been widely used in biomedical *** these applications,it is crucial to sense the movement of soft robots and their interaction with target ***,we propose a strategy to fabricate a self-sensing bilayer actuator by combining magnetic and ionic conductive *** magnetic hydrogel containing NdFeB particles exhibits rapid response to magnetic field and achieve bending ***,the polyacrylamide(PAAm)hydrogel with lithium chloride(LiCl)allows for the sensing of *** bending behavior of the bilayer under magnetic field is well captured by theoretical and simulated ***,the bilayer strain sensor shows good sensitivity,stability and can endure a wide-range cyclic stretching(0-300%).These merits qualify the self-sensing actuator to monitor the motion signals,such as bending of fingers and grasping process of an intelligent *** subject to an external magnetic field,the gripper can grab a cube and sense the resistance change simultaneously to detect the object *** work may provide a versatile strategy to integrate actuating and self-sensing ability in soft robots.

关键词： hard magnetic soft robots bilayer structure ionic conductive hydrogel selfsensing

Chemo-mechanical coupling effect in the high-temperature oxidation of metal materials: A review

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Science China(Technological Sciences) 2019年第8期62卷 1246-1254页

作者： WANG HaiLong YU WenShan SHEN ShengPing school of Civil engineering Chang 'an University Xi'an 710061 China state key laboratory for strength and vibration of mechanical structures Shaanxi Engineering Laboratory for Vibration Control of Aerospace Structures School of Aerospace Engineering Xi'an Jiaotong University Xi'an 710049 China

The metal materials are susceptible to be oxidized when they are exposed to the complex and harsh environments, especially at the elevated temperature. The development of corresponding chemo-mechanical coupling theory is indispensable in theoretically and numerically predicting the material properties reduction and failures due to the oxidation. In this paper, we review the historical sketch of the coupling theory of chemical reactions and mechanics in the high-temperature oxidation of metal materials. The oxidation results in the stress generation while the generated stress in turn affects the chemical reaction rate and the diffusion process of the reactants. It is therefore a complex chemo-mechanical coupling problem. This review begins with the discussion of the diffusion-controlled oxidation, and then discusses the stress-dependent diffussion during the oxidation and the oxide growth induced stress, and ends with the discussion of interaction between chemical reactions and stress. This review of chemo-mechanical coupling literature is not exhaustive;we review much of the fundamental literature and draw comparisons of coupling theory development in the filed of metal oxidation.

关键词： oxidation diffusion growth stress chemo-mechanical coupling metal

几何非线性条件下微纳米梁型谐振器的非线性支撑损失

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Acta Mechanica Sinica 2024年第3期40卷 165-175页

作者：马程中王检耀史柯文孔子文杨伟东陈思宇国凤林 school of Naval Architecture Ocean and Civil Engineering(State Key Laboratory of Ocean Engineering)Shanghai Jiao Tong UniversityShanghai200240China school of aerospace engineering and Applied Mechanics Tongji UniversityShanghai200092China Department of engineering Mechanics Tsinghua UniversityBeijing100084China

作为微纳米机械谐振器主要的能量耗散源之一,支撑损失主要采用未考虑中面拉伸效应的线性理论进行研究.然而该理论却无法适用于大挠度非线性振动状态谐振器的支撑损失.为此,我们研究了考虑几何非线性和轴向预拉力的两端固支微梁谐振器处... 详细信息

作为微纳米机械谐振器主要的能量耗散源之一,支撑损失主要采用未考虑中面拉伸效应的线性理论进行研究.然而该理论却无法适用于大挠度非线性振动状态谐振器的支撑损失.为此,我们研究了考虑几何非线性和轴向预拉力的两端固支微梁谐振器处于面内弯曲振动模式时的支撑损失,旨在准确模拟大挠度振动下高性能谐振器的支撑损失.本文不仅考虑了支撑结构与谐振器连接区域受中面拉伸产生的正应力作用而引起的支撑损失,也考虑了受剪应力作用而引起的支撑损失,并且理论结果与有限元模拟以及文献中实验结果一致.另外,本文还研究了轴向预拉力对谐振器非线性振动特性的影响,并讨论了谐振器的振幅、长高比以及轴向预拉力对支撑损失的影响.理论结果表明,相比于线性振动状态下谐振器的支撑损失,由谐振器大变形振动产生的中面拉伸效应会引起更大的支撑损失,并且会随非线性振幅的增大而增大.本文提出的非线性支撑损失模型有望对评估非线性振动谐振器的支撑损失以及阐明支撑损失随非线性振幅增大的现象提供理论指导.

关键词： Support loss Micro/nano beam resonator Geometric nonlinearity Axial pre-tension

Shear response of β-SiC bulk dependent on temperature and strain rate

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Acta Mechanica Solida Sinica 2017年第2期30卷 137-144页

作者： Liang Wang Qunfeng Liu Wenshan Yu Shengping Shen state key laboratory for strength and vibration of mechanical structures School of Aerospace Xi'an Jiaotong University Xi'an 710049 PR China

The shear responses of β-SiC are investigated using molecular dynamics simulation with the Tersoff interatomic potential. Results show a clear decreasing trend in critical stress,fracture strain and shear modulus as temperature increases. Above a critical temperature, β-SiC bulk just fractures after the elastic deformation. However, below the critical temperature, an interesting pattern in β-SiC bulk emerges due to the elongation of Si-C bonds before fracture. Additionally, the shear deformation of β-SiC at room temperature is found to be dependent on the strain rate. This study may shed light on the deformation mechanism dependent on temperature and strain rate.

关键词： β-SiC Fracture Temperature effect Strain rate Shear deformation

A Computational Investigation of the Group Effect of Pits on the Ultimate strength of Steel Plates

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China Ocean engineering 2018年第6期32卷 665-674页

作者： FU Qiang FANG Hui WU Ren-xia YU Xue-hui LI Hua-jun Institute of Coastal and Offshore engineering School of Engineering Ocean University of China state key laboratory for strength and vibration of mechanical structures School of Aerospace Engineering Xi'an Jiaotong University

In this work, we focus on assessing the group effect of localized corrosion on the ultimate strength of the marine structural plates and study the load-deformation behaviors of plates of various slenderness and uniaxial ***, we investigate different corroded patterns from a single circular pit to 25 circular pits distributed over the plate and carry out hundreds of nonlinear finite element simulations by combining the number, depth, distribution of pits with imperfections and slenderness of plate. The distribution of multiple pits causes scattering of stress concentration on the plate, then the plastic section of plate changes with wider distribution of damage simultaneously. The ultimate strength arises when un-loading zone comprised of the yielding strips and holes extends across the plate. It can be concluded that the corroded condition defined as group effect of pits manipulates the deformation state and the loading capacity of plate at the ultimate strength mode that coincides with the proportion of effective loading area and section in the process of post-buckling. To validate the effect of pits group, we perform the numerical experiments of the post-buckling of steel plates containing pits in a row with different orientation.

关键词： group effect localized corrosion post-buckling ultimate strength

Experimental study of solid-liquid origami composite structures with improved impact resistance

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 118-123页

作者： Shuheng Wang Zhanyu Wang Bei Wang Zhi Liu Yunzhu Ni Wuxing Lai Shan Jiang Yong An Huang AML Department of Engineering MechanicsLaboratory of Flexible Electronics TechnologyTsinghua UniversityBeijing 100084China Institute of Advanced Structure Technology Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and StructuresBeijing Institute of TechnologyBeijing 100081China Hangzhou Institute of Technology Xidian UniversityHangzhou 311200China Nanjing Research Institude of Electronics Technology Nanjing 210039China The Institute of engineering Thermophysics Chinese Academy of SciencesBeijing 100190China state key laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

In this paper,a liquid-solid origami composite design is proposed for the improvement of impact *** this design strategy,Kresling origami composite structures with different fillings were designed and fabricated,namely air,water,and shear thickening fluid(STF).Quasi-static compression and drop-weight impact experiments were carried out to compare and reveal the static and dynamic mechanical behavior of these *** results from drop-weight impact experiments demonstrated that the solid-liquid Kresling origami composite structures exhibited superior yield strength and reduced peak force when compared to their empty ***,the Kresling origami structures filled with STF exhibited significantly heightened yield strength and reduced peak *** example,at an impact velocity of 3 m/s,the yield strength of single-layer STF-filled Kresling origami structures increased by 772.7%and the peak force decreased by 68.6%.This liquid-solid origami composite design holds the potential to advance the application of origami structures in critical areas such as aerospace,intelligent protection and other important *** demonstrated improvements in impact resistance underscore the practical viability of this approach in enhancing structural performance for a range of applications.

关键词： Solid-liquid design Origami structure Impact resistance Shear thickening fluid

Numerical study on the electromechanical behavior of dielectric elastomer with the influence of surrounding medium

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International Journal of Smart and Nano Materials 2016年第1期7卷 52-68页

作者： Kun Jia Tongqing Lu state key laboratory for strength and vibration of mechanical structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’anChina

The considerable electric-induced shape change,together with the attributes of lightweight,high efficiency,and inexpensive cost,makes dielectric elastomer,a promising soft active material for the realization of actuators in broad ***,a number of prototype devices have been demonstrated in the past few years,the further development of this technology necessitates adequate analytical and numerical ***,previous the-oretical studies always neglect the influence of surrounding *** to the large deformation and nonlinear equations of states involved in dielectric elastomer,finite element method(FEM)is anticipated;however,the few available formulations employ homemade codes,which are inconvenient to *** aim of this work is to present a numerical approach with the commercial FEM package COMSOL to investigate the nonlinear response of dielectric elastomer under electric *** influence of surrounding free space on the electric field is analyzed and the corresponding electric force is taken into account through an electric surface traction on the circumstances *** employ-ing Maxwell stress tensor as actuation pressure,the mechanical and electric governing equations for dielectric elastomer are coupled,and then solved simultaneously with the Gent model of stain energy to derive the electric induced large deformation as well as the electromechanical *** finite element imple-mentation presented here may provide a powerful computational tool to help design and optimize the engineering applications of dielectric elastomer.

关键词： Dielectric elastomer electromechanical coupling finite element method Maxwell stress tensor