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Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations: A Review

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Structural Durability & Health Monitoring 2025年第1期19卷 25-54页

作者： Chao Zhang Shang-Xi Lai Hua-Ping Wang School of Civil Engineering and mechanics Lanzhou UniversityLanzhou730000China Key Laboratory of Special Functional materials and Structural Design Ministry of EducationLanzhou UniversityLanzhou730000China

Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the ***,it is particularly signiﬁcant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientiﬁc basis for structural damage identiﬁcation and dynamic model modiﬁ*** view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and brieﬂy describes how to identify structural damages based on the derived modal *** paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),brieﬂy describes damage identiﬁcation methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artiﬁcial intelligence(AI)methods in the direction of modal parameter recognition and damage identiﬁcation is further *** on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identiﬁcation methods are given to provide scientiﬁc references for the optimized design and functional upgrading of SHM systems.

关键词： Structural health monitoring data information modal parameters damage identiﬁcation AI method

Independent modal variable structure fuzzy active vibration control of thin plates laminated with photostrictive actuators

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Chinese Journal of Aeronautics 2013年第2期26卷 350-356页

作者： He Rongbo Zheng Shijie Institute of Smart materials and structures State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics School of Electrical Information Anhui University of Technology

Photostrictive actuators can produce photodeformation strains under illumination of ultraviolet lights. They can realize non-contact micro-actuation and vibration control for elastic plate structures. Considering the switching actuation and nonlinear dynamic characteristics of photostrictive actuators, a variable structure fuzzy active control scheme is presented to control the light intensity applied to the actuators. Firstly, independent modal vibration control equations of photoelectric laminated plates are established based on modal analysis techniques. Then, the optimal light switching function is derived to increase the range of sliding modal area, and the light intensity self-adjusting fuzzy active controller is designed. Meanwhile, a continuous function is applied to replace a sign function to reduce the variable structure control （VSC） chattering. Finally, numerical simulation is carried out, and simulation results indicate that the proposed control strategy provides better performance and control effect to plate actuation and control than velocity feedback control, and suppresses vibration effectively.

关键词： Fuzzy active control Independent modal Photostrictive actuators Thin plate vibration Variable structure

“Cut-and-paste” method for the rapid prototyping of soft electronics

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Science China(Technological Sciences) 2019年第2期62卷 199-208页

作者： YANG XiangXing HUANG YiFu DAI ZhaoHe BARBER Jamie WANG PuLin LU NanShu department of Electrical and Computer Engineering the University of Texas at Austin Center for mechanics of Solids Structures and Materials Department of Aerospace Engineering and Engineering Mechanicsthe University of Texas at Austin Stretch Med Inc. department of Biomedical Engineering the University of Texas at Austin Texas materials Institute the University of Texas at Austin

Unlike wafer-based rigid electronics, soft electronics have many unique advantages including thinness, flexibility, stretchability,conformability, lightweight, large area, as well as low cost. As a result, they have demonstrated many emerging capabilities in healthcare devices, soft robotics, and human-machine interface. Instead of conventional microfabrication, there is an evergrowing interest in the freeform or digital manufacture of soft electronics. This review provides a survey for a cost-and timeeffective subtractive manufacturing process called the "cut-and-paste" method. It employs a mechanical cutter plotter to form patterns on various electronically functional membranes such as sheets of metals, functional polymers, and even two-dimensional(2D) materials, supported by a temporary tape. The patterned membranes can then be pasted on soft substrates such as medical tapes or even human skin. This process is completely dry and desktop. It does not involve any rigid wafers and is hence capable of making large-area electronics. The process can be repeated to integrate multiple materials on a single *** circuits(ICs) and rigid components can be added through a "cut-solder-paste" process. Multilayer devices can also be fabricated through lamination. We therefore advocate that the "cut-and-paste" method is a very versatile approach for the rapid prototyping of soft electronics for various applications.

关键词： cut-and-paste subtractive manufacture epidermal electronics electronic tattoos 2D materials

mechanics of flexible and stretchable piezoelectrics for energy harvesting

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Science China(Physics,mechanics & Astronomy) 2015年第9期58卷 39-51页

作者： CHEN Ying LU BingWei OU DaPeng FENG Xue department of Engineering mechanics Tsinghua University Center for mechanics and materials Tsinghua University

As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on Zn O and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.

关键词： piezoelectric effect energy harvesting flexible electronics stretchable electronics

Mechanical properties and shape memory behavior of 4D printed functionally graded cellular structures

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Science China(Technological Sciences) 2023年第12期66卷 3522-3533页

作者： ZENG ChengJun LIU LiWu ZHAO Wei LIU ZhengXian XIN XiaoZhou LIU YanJu LENG JinSong department of Astronautical Science and mechanics Harbin Institute of TechnologyHarbin 150001China Center for Composite materials and structures Harbin Institute of TechnologyHarbin 150080China

The properties of functionally graded(FG) cellular structures vary spatially, and the varying properties can meet the requirements of different working environments. In this study, we fabricated FG cellular structures with shape memory effect by 4D printing and evaluated the compressive performance and shape memory behavior of these structures with temperature through experimental analysis and finite element simulations. The results show that the maximum energy absorption gradually decreases but the compressive modulus gradually increases with increasing gradient parameters. Moreover, the finite element simulations also show that the compressive deformation mode of the structure shifts from uniform to non-uniform deformation with increasing gradient parameters. The compressive modulus and compressive strength of 4D printed FG structures decrease with increasing temperature due to the influence of the shape memory polymer, and they exhibit outstanding shape recovery capability under high-temperature stimulus. The proposed 4D printed FG structures with such responsiveness to stimulus shed light on the design of intelligent energy-absorbing devices that meet specific functional requirements.

关键词： functionally graded structures 4D printing shape memory polymers energy absorption cellular structures

Phosphate Glass Fibre Composites for Bone Repair

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Journal of Bionic Engineering 2009年第4期6卷 318-323页

作者： Andrew J.Parsons Ifty Ahmed Papia Haque Ben Fitzpatrick Muhammad I.K.Niazi Gavin S.Walker Chris D.Rudd Division of materials Mechanics & StructuresFaculty of EngineeringUniversity of NottinghamNottingham NG7 2RDUK

We investigate high-modulus degradable materials intended to replace metals in biomedical *** are typically composites comprising a polylactide(PLA)matrix reinforced with phosphate glass fibres,which provide reinforcement similar to E-glass but are entirely degradable in water to produce,principally,calcium *** have made composites using a variety of fibre architectures,from non-woven random mats to unidirectional fibre *** properties in the region of 30 GPa modulus and 350 MPa strength have been achieved-directly comparable to quoted values for human cortical *** collaboration with other groups we have begun to consider the development of foamed systems with structures mimicking cancellous bone and this has shown significant *** fibres in these foamed structures provide improved creep resistance and reinforcement of the pore *** date the materials have exhibited excellent cellular responses in vitro and further studies are due to include consideration of the surface character of the materials and the influence of this on cell interaction, both with the composites and the glass fibres themselves,which show promise as a standalone porous scaffold.

关键词： biocomposites phosphate glass PLA porous bone repair

Improving the thermal shock resistance of ceramics by crack arrest blocks

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Science China(Technological Sciences) 2016年第6期59卷 913-919页

作者： WANG Yan Wei XIA Biao SU Hong Hong CHEN Hang FENG Xue Applied mechanics Laboratory Department of Engineering Mechanics Tsinghua University Center for mechanics and materials Tsinghua University department of Engineering mechanics Chongqing University

Ceramics used in the high temperature environment are inevitably subjected to sudden temperature change, which may lead to catastrophic thermal shock failure due to the intrinsic brittleness of ceramics. In this paper, an experimental platform is designed to realize the in-situ observation during the thermal shock experiments. Experimental results show that all the cracks initiate from one of the edge midpoints and propagate to another one for square specimens. Such experimental observation is consistent with the maximum tensile stress zone with the maximum temperature gradient given by the finite element method(FEM). The different crack modes resulting from different heating rates after thermal shock experiments are observed and analyzed. Comparison between different clamping methods is conducted to study the effects of boundary conditions on the thermal shock experiments. Furthermore, in order to improve the thermal shock performance of alumina ceramics, crack arrest blocks are added near the edge midpoint. The thickness, shape and arrangement of the blocks are systematically investigated to understand the mechanism of improvement of thermal shock resistance.

关键词： thermal shock ultra-high temperature ceramics crack arrest blocks in-situ dynamic observation

Dynamic crushing behavior and energy absorption of hybrid auxetic metamaterial inspired by Islamic motif art

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Applied Mathematics and mechanics(English Edition) 2023年第3期44卷 345-362页

作者： Ruilan TIAN Huaitong GUAN Xuhao LU Xiaolong ZHANG Huanan HAO Wenjie FENG Guanglei ZHANG department of Engineering mechanics Hebei Key Laboratory of Mechanics of Intelligent Materials and StructuresShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Auxetic honeycomb structures are promising metamaterials with outstanding mechanical properties,and can be potentially used in energy absorption *** this study,a novel modified re-entrant hybrid auxetic metamaterial inspired by Islamic motif art is designed by integrating four-pointed double re-entrant motifs with symmetric semi-hexagonal unit cells to achieve a high energy absorption capacity(EAC).Theoretical analyses and numerical simulations are performed to examine the dynamic crushing behavior of the four-pointed double re-entrant combined structure(FDRCS).The developed finite element models(FEMs)are validated by the experiments under quasi-static *** deformation mode and stress-strain curves are further studied under low,medium,and high crushing *** theoretically predicted plateau stress of the FDRCS under different crushing velocities is consistent with the numerical simulation *** crushing stress and the EAC of the FDRCS are influenced by the geometric parameters and crushing *** FDRCS exhibits a negative Poisson's ratio(NPR),owing to the four-point re-entrant structure(RES).Moreover,the specific energy absorption(SEA)of these structures is higher than that of nonauxetic hexagonal and auxetic re-entrant structures,owing to the generation of more plastic hinges that dissipate more energy during dynamic crushing.

关键词： re-entrant honeycomb auxetic hybrid metamaterial energy-absorption dynamic crushing

A semi-analytical solution for electric double layers near an elliptical cylinder

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Acta Mechanica Sinica 2018年第1期34卷 62-67页

作者： Xiaoyun Dai Zhenghua Qian Jiashi Yang State Key Laboratory of mechanics and Control of Mechanical structures/College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics department of Mechanical and materials Engineering University of Nebraska-Lincoln

A theoretical analysis on the electric double layer formed near the surface of an infinite cylinder with an elliptical cross section and a prescribed electric potential in an ionic conductor was performed using the linearized Gouy–Chapman theory. A semi-analytical solution in terms of the Mathieu functions was obtained. The distributions of the electric potential, cations, anions, and electric field were calculated. The effects of various physical and geometric parameters were examined. The fields vary rapidly near the elliptical boundary and are nearly uniform at far field. Electric field concentrations were found at the ends of the semi-major and semi-minor axes of the ellipse. These concentrations are sensitive to the physical and geometric parameters.

关键词： Elliptical cylinder Electric double layer Semi-analytical solution Electric field concentration