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Multi-layer quasi-zero-stiffness meta-structure for high-efficiency vibration isolation at low frequency

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1189-1208页

作者： Jiahao ZHOU Jiaxi ZHOU Hongbin PAN Kai WANG Changqi CAI guilin wen College of Mechanical and Vehicle Engineering Hunan University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body The Ministry of Science and Technology School of Mechanical Engineering Zhejiang Sci-Tech University School of Mechanical Engineering Yanshan University

An easily stackable multi-layer quasi-zero-stiffness(ML-QZS) meta-structure is proposed to achieve highly efficient vibration isolation performance at low ***, the distributed shape optimization method is used to design the unit cel, i.e., the single-layer QZS(SL-QZS) meta-structure. Second, the stiffness feature of the unit cell is investigated and verified through static experiments. Third, the unit cells are stacked one by one along the direction of vibration isolation, and thus the ML-QZS meta-structure is constructed. Fourth, the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted, and the dynamic responses are obtained from the equations of motion, and verified by finite element(FE) simulations. Finally, a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing, and the vibration isolation performance is evaluated experimentally. The results show that the vibration isolation performance substantially enhances when the number of unit cells increases. More importantly, the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly stacked. Hence, the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency.

关键词： quasi-zero stiffness (QZS) meta-structure high efficiency low frequency vibration isolation O328 34C15 74P10

用于振动模态可操纵性的克拉尼图形拓扑优化设计

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Acta Mechanica Sinica 2024年第4期40卷 172-184页

作者：薛亮文桂林 Fengwen Wang Niels LPedersen School of Mechanical Engineering Yanshan UniversityQinhuangdao066004China Department of Civil and Mechanical Engineering Solid MechanicsTechnical University of DenmarkKgs.Lyngby2800Denmark Body Hunan UniversityChangsha410082China

经典克拉尼图形(Chladni patterns,CP)是特征向量的视觉表示,在振动分析、乐器设计、粒子操纵和分离等领域中具有广泛的应用.均质结构通常会表现出高度规则化的CP,这限制它们的应用场景.因此,实现面向应用来逆向设计结构的CP是非常重要... 详细信息

经典克拉尼图形(Chladni patterns,CP)是特征向量的视觉表示,在振动分析、乐器设计、粒子操纵和分离等领域中具有广泛的应用.均质结构通常会表现出高度规则化的CP,这限制它们的应用场景.因此,实现面向应用来逆向设计结构的CP是非常重要的,而这可以通过使用拓扑优化来实现CP的逆向设计.本研究提出了一种使用基于密度的拓扑优化算法来设计结构CP的方法.优化列式中,给出了描述图形的指标函数,并以最小化特征向量和目标CP之间的误差构建了优化目标.数值结果表明,所提出的方法可以为指定的单阶或多阶CP生成新颖的材料分布.这表明了本文所提出的方法能够实现CP的精确定制设计,进一步为面向应用的需求提供了更多选择.

关键词：定制设计面向应用逆向设计指标函数特征向量拓扑优化可操纵性振动模态

A quasi-zero-stiffness isolator with a shear-thinning viscous damper

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Applied Mathematics and Mechanics(English Edition) 2022年第3期43卷 311-326页

作者： guilin wen Yu LIN Junfeng HE School of Mechanical and Electrical Engineering Guangzhou UniversityGuangzhou 510006China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004Hebei ProvinceChina

Quasi-zero-stiffness(QZS)vibration isolators have been widely studied,because they show excellent high static and low dynamic stiffnesses and can effectively solve low-frequency and ultralow-frequency ***,traditional QZS(T-QZS)vibration isolators usually adopt linear damping,owing to which achieving good isolation performance at both low and high frequencies is difficult.T-QZS isolators exhibit hardening stiffness characteristics,and their vibration isolation performance is even worse than that of linear vibration isolators under a large excitation ***,this study proposes a QZS isolator with a shear-thinning viscous damper(SVD)to improve the vibration isolation performance of the T-QZS *** force-velocity relation of the SVD is obtained,and a dynamic model is established for the *** dynamic responses of the system are solved using the harmonic balance method(HBM)and the Runge-Kutta *** vibration isolation performance of the system is evaluated using force transmissibility,and the isolator parameters are *** results show that compared with the T-QZS isolators,the proposed QZS-SVD isolator achieves the lower initial vibration isolation frequency and peak value,and exhibits better vibration isolation performance at medium and high ***,the proposed isolator can withstand a large excitation amplitude in the effective vibration isolation range.

关键词： quasi-zero-stiffness(QZS)isolator shear-thinning viscous damper(SVD) vibration isolation force transmissibility

镉基MOFs材料的合成、表征及催化降解染料废水

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西北大学学报（自然科学版） 2024年第2期54卷 230-239页

作者：文桂林王静蕊刘道富童悦王尧宇淮南师范学院化学与材料工程学院安徽淮南232038 西北大学化学与材料科学学院陕西西安710127

工业废水处理对于维护生态平衡、实现可持续发展具有重要意义,研究开发新的污水处理剂,实现污染物催化降解是从根本上解决废水问题的有效方案。基于此,从晶体工程原理出发,以选材广泛、结构可调的MOFs材料为研究对象,通过选用亚甲基双... 详细信息

工业废水处理对于维护生态平衡、实现可持续发展具有重要意义,研究开发新的污水处理剂,实现污染物催化降解是从根本上解决废水问题的有效方案。基于此,从晶体工程原理出发,以选材广泛、结构可调的MOFs材料为研究对象,通过选用亚甲基双羟萘酸(H_(2)pam)和2,5-双(4-吡啶基)-1,3,4-噻二唑(bpt)作为构件,成功制备了一例MOFs材料,即[Cd(bpt)(H_(2)O)4]n·n(pam)·2nH_(2)O(MOF-1)。结构分析和性能表征说明,MOF-1具有一维共价链状和复杂的超分子构型,其合成方法简单、品质好,且形貌较为单一,尺寸为0.5~2μm;主体框架在310℃以下稳定存在并具有较好的化学稳定性,在强酸和中性水溶液中可保持完整形貌不少于60 d和163 d;呈现明亮的绿色荧光,可在较宽温度范围内作为分子发光温度计。催化降解工业染料废水的模拟研究显示,MOF-1材料的禁带宽度E_(g)=2.85 eV,带隙值小,对罗丹明B的脱色率达到了85.94%,可显著降解。因此,MOF-1材料是一种具有较大比较优势的染料污水处理剂。

关键词： MOFs材料晶体结构理化性能染料降解

Synthesis and Evaluation of Microporous Metal Organic Frameworks for Light Hydrocarbon Adsorption

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China Petroleum Processing & Petrochemical Technology 2022年第4期24卷 120-128页

作者： wen guilin Li Ying Li Jianzhe Li Qingrun Zhang Hongxing Xiao Anshan Tao Bin State Key Laboratory of Safety and Control for Chemicals SINOPEC Research Institute of Safety Engineering Co.Ltd.Qingdao 266101China

Five microporous MOFs were synthesized and their static adsorption properties for light hydrocarbons were experimentally investigated at 298 K and 150 *** the five MOFs,HKUST-1 and Ni(bdc)(ted)0.5 exhibited much higher uptakes of ethane and propane than PCN-250,UiO-66,and *** experiments were carried out at 298 K and atmospheric pressure on HKUST-1 and two commercially used ***-1 exhibited a much lower dynamic than static adsorption ***,HKUST-1 and the two traditional adsorbents could effectively separate binary(ethane/propane)and ternary(ethane/propane/toluene)mixtures.

关键词： light hydrocarbons metal-organic frameworks adsorption breakthrough curve adsorption selectivity

Suppression of grazing-induced instability in single degree-of-freedom impact oscillators

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Applied Mathematics and Mechanics(English Edition) 2019年第1期40卷 97-110页

作者： Shan YIN guilin wen Xin WU School of Mechanical and Electric Engineering Guangzhou University State Key Laboratory of Advanced Design and Manufacture for Vehicle Body Hunan University School of Mechanical Engineering Hunan Institute of Engineering

As a typical non-smooth bifurcation, grazing bifurcation can induce instability of elementary near-grazing impact periodic motion in impact oscillators. In this paper,the stability for near-grazing period-one impact motion to suppress grazing-induced instabilities is analyzed, based on which, a control strategy is proposed. The commonly-used leading order zero time discontinuity mapping is extended to a higher order one to aid the perturbation analysis of the characteristic equation. It is shown that the degenerate grazing bifurcation can eliminate the singular term in the characteristic equation, leading to bounded eigenvalues. Based on such a precondition, the bounded eigenvalues are further restricted inside the unit circle, and a continuous transition between non-impact and controlled impact motion is observed. One discrete feedback controller that changes the velocity of the oscillator based on the selected Poincar′e sections is adopted to demonstrate the control procedure.

关键词： grazing-induced instability higher order discontinuity mapping eigenvalue perturbation degenerate grazing bifurcation

A Crystal-Plasticity Cyclic Constitutive Model for the Ratchetting of Polycrystalline Material Considering Dislocation Substructures

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Acta Mechanica Solida Sinica 2020年第2期33卷 268-280页

作者： Xuehong Ren Shaopu Yang guilin wen wenjie Zhao State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

A crystal-plasticity cyclic constitutive model of polycrystalline material considering intra-granular heterogeneous dislocation substructures,in terms of three dislocation categories:mobile dislocations,immobile dislocations in the cell interiors and in the cell walls,is proposed based on the existing microscopic and macroscopic experimental *** multiplication,annihilation,rearrangement and immobilization of dislocations on each slip system are taken as the basic evolutionary mechanism of the three dislocation categories,and the cross-slip of screw dislocations is viewed as the dynamic recovery mechanism at room *** slip resistance associated with the isotropic hardening rule results from the interactions of dislocations on the slip ***,a modified nonlinear kinematic hardening rule and a rate-dependent flow rule at the slip system level are employed to improve the predictive capability of the model for ratchetting *** predictive ability of the developed model to uniaxial and mul-tiaxial ratchetting in macroscopic scale is verified by comparing with the experimental results of polycrystalline 316L stainless *** ratchetting in intra-granular scale which is obviously dependent on the crystallographic orientation and stress levels can be reasonably predicted by the proposed model.

关键词： Ratchetting Dislocation substructures Crystal plasticity Polycrystalline materials Constitutive model

Fractional-order visco-plastic constitutive model for uniaxial ratcheting behaviors

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Applied Mathematics and Mechanics(English Edition) 2019年第1期40卷 49-62页

作者： wenjie ZHAO Shaopu YANG guilin wen Xuehong REN State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University State Key Laboratory of Mechanical Behavior in Traffic Engineering Structure and System Safety Shijiazhuang Tiedao University

This paper proposes a novel unified visco-plastic constitutive model for uniaxial ratcheting behaviors. The cyclic deformation of the material presents remarkable time-dependence and history memory phenomena. The fractional(fractional-order)derivative is an efficient tool for modeling these phenomena. Therefore, we develop a cyclic fractional-order unified visco-plastic(FVP) constitutive model. Specifically, within the framework of the cyclic elasto-plastic theory, the fractional derivative is used to describe the accumulated plastic strain rate and nonlinear kinematic hardening rule based on the Ohno-Abdel-Karim model. Moreover, a new radial return method for the back stress is developed to describe the unclosed hysteresis loops of the stress-strain *** capacity of the FVP model used to predict the cyclic deformation of the SS304 stainless steel is verified through a comparison with the corresponding experimental data found in the literature(KANG, G. Z., KAN, Q. H., ZHANG, J., and SUN, Y. F. Timedependent ratcheting experiments of SS304 stainless steel. International Journal of Plasticity, 22(5), 858–894(2006)). The FVP model is shown to be successful in predicting the rate-dependent ratcheting behaviors of the SS304 stainless steel.

关键词： cyclic visco-plastic constitutive fractional derivative fractional-order uni-fied visco-plastic(FVP)model rate-dependent ratcheting

Efficient,high-resolution topology optimization method based on convolutional neural networks

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Frontiers of Mechanical Engineering 2021年第1期16卷 80-96页

作者： Liang XUE Jie LIU guilin wen Hongxin WANG State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China Center for Research on Leading Technology of Special Equipment School of Mechanical and Electric EngineeringGuangzhou UniversityGuangzhou 510006China

Topology optimization is a pioneer design method that can provide various candidates with high mechanical ***,high resolution is desired for optimum structures,but it normally leads to a computationally intractable puzzle,especially for the solid isotropic material with penalization(SIMP)*** this study,an efficient,high-resolution topology optimization method is developed based on the super-resolution convolutional neural network(SRCNN)technique in the framework of *** involves four processes,namely,refinement,path extraction and representation,nonlinear mapping,and image *** computational efficiency is achieved with a pooling strategy that can balance the number of finite element analyses and the output mesh in the optimization process.A combined treatment method that uses 2D SRCNN is built as another speed-up strategy to reduce the high computational cost and memory requirements for 3D topology optimization *** examples show that the high-resolution topology optimization method using SRCNN demonstrates excellent applicability and high efficiency when used for 2D and 3D problems with arbitrary boundary conditions,any design domain shape,and varied load.

关键词： topology optimization convolutional neural network high resolution density-based