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Fusion of structural damage identification results from different test scenarios and evaluation indices in structural health monitoring

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STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL 2021年第5期20卷 2540-2565页

作者： Li, X. Y. Lin, S. J. Law, S. S. Lin, Y. Z. Lin, J. F. Jinan Univ Sch Mech & Bldg Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China Jinan Univ Sch Mech & Bldg Engn Guangzhou Peoples R China Chongqing Univ Sch Civil Engn Chongqing Peoples R China Shenzhen Acad Disaster Prevent & Reduct China Earthquake Adm Ctr Safety Monitoring Engn Struct Shenzhen 518003 Peoples R China

There are many existing algorithms and damage indices that can effectively meet the engineering need in damage diagnosis. However, all of them (except those with an exact formulation) are based on certain assumptions with approximations, and their performances depend on the combination of test parameters, for example, type, number, and location of excitations and sensors;identification algorithm adopted;and environmental noise effect. Results obtained from different combinations of these test parameters are different and they may be mathematically biased or contradicting. Existing practice adopts the general indication of result for further maintenance decisions or by subjective screening the results with engineering sense. This article demonstrates the possibility to have a better design of the structural health monitoring system where the benefits of different damage indices and evaluation methodologies can be reaped via the fusion of the identified results. The scenario for discussion is the vibration-based damage localization problem. The change in mode shape in the modal domain and change in the covariance of impulse response function change in the time domain are selected as damage indices for the illustration. An exact form of the covariance of impulse response function is also proposed for this purpose. The demonstration is conducted via a simulated truss structure, an experimental beam, and 280 days valid recorded data from an in-service suspension bridge deck. Different measurements are analyzed to produce large number of identified results for reducing traffic excitation effect, the temperature effect, and so on, and to enhance the structural damage information in the final set of results. Experiences in handling the structural health monitoring data for monitoring the movement of a structural joint before and after a typhoon are also presented. The proposed strategy does not need a mathematical model of the structure, but this leads to heavy sensor requi

关键词： Damage identification acceleration Bayesian fusion covariance mode shape structural health monitoring damage localization

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Dynamics of a Gaussian and Non-Gaussian Vibration Excited Discrete Product Packaging System with Hyperbolic Tangent Nonlinearity

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SSRN 2023年

作者： Yang, Song-Ping Deng, Pei-Chang Wang, Zhi-Wei Packaging Engineering Institute College of Packaging Engineering Jinan University Zhuhai519070 China MOE Key Laboratory of Disaster Forecast and Control in Engineering School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China Key Laboratory of Product Packaging and Logistics of Guangdong Higher Education Institutes Jinan University Zhuhai519070 China

This paper reveals the dynamical properties of a Gaussian and non-Gaussian vibration excited multi-degree-of-freedom (MDOF) discrete product packaging system (DPPS) with hyperbolic tangent nonlinearity base on a more systematic acceleration response analysis. Firstly, the product package considering multiple critical components is modeled as a general model of MDOF DPPS, centered around the opposite designed purpose with the similar multiple tuned mass damper (MTMD) model, in which the hyperbolic tangent nonlinearity is rarely considered, then approximate solution theory is established to effectively predicate the acceleration response spectrum of the hyperbolic tangent MDOF DPPS under Gaussian random vibration. Secondly, Hermite polynomial is adopted to simulate non-Gaussian vibration excitation, and verified by the actual road excitation signal. On this basis, the non-Gaussian random vibration analysis method is introduced to analyze the acceleration non-Gaussian stochastic response of the system, the sensitivity of the response to the external excitation and system parameters is discussed. Finally, the reliability analysis via the first-passage distribution of the acceleration stochastic response is given. Approximate solution theory can effectively predict acceleration response spectrum of the system under Gaussian random vibration. The proposed non-Gaussian vibration analysis approach can conveniently reproduce actual non-Gaussian vibration excitation and analyze the dynamic properties, the investigation provides a guidance for packaging vibration absorption design. © 2023, The Authors. All rights reserved.

关键词： Reliability analysis

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Bond behavior between recycled macro fibers and ultra-high-performance concrete matrix: Tests and property characterization

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JOURNAL OF BUILDING engineering 2024年 95卷

作者： You, X. M. Xu, Y. B. Fan, Y. C. Zou, Q. Q. Fu, Bing Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Harbin Inst Technol Sch Astronaut Harbin 150001 Peoples R China Southern Univ Sci & Technol Dept Ocean Sci & Engn Shenzhen 518055 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

A green and cost-efficient ultra-high-performance concrete (UHPC) has been proposed using discrete macro fibers recycled from waste glass fiber reinforced polymer (GFRP). The tensile properties of such composites are significantly affected by the macro fiber/UHPC bond properties. However, there is very little work characterizing the bond properties of the macro fiber/UHPC interface. Furthermore. lack of study focused on the methods for macro fiber surface treatment and their effects on macro fiber/UHPC interfacial bonding. Therefore, the present study first carried out pullout tests in two series consisting of 128 pullout specimens. Series 1 aimed to characterize the bond behavior of the macro fiber/UHPC interface, while Series 2 aimed to investigate the effect of surface-modifying agents on macro fiber/UHPC interfacial bonding. The results demonstrated that the bond strength increased from 19.3 to 20.9 MPa when the embedded length of the 8 mm-wide fiber increased from 5 to 10 mm. The modification of neutral Nano SiO2 (NNS) enhanced the bond strength by up to 20.5 %, while alkaline Nano SiO2 (ANS) and silane coupling agent (SCA) showed a negative effect on bond strength. Then, the shear-lag theory was utilized for predicting the pull force-slip curves of the fibers embedded in UHPC, and then the bond parameters of the interfaces were obtained through an inverse analysis. A good agreement is exhibited with integral absolute error (IAE) from 4.5 % to 10.5 % between predicted results and test results.

关键词： Glass fiber reinforced polymer composites Ultra -high -performance concrete Recycling Macro fibers Interfacial bond

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A general continuum damage model for soft composites

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JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2023年第1期175卷

作者： Zhan, Lin Wang, Siyu Qu, Shaoxing Steinmann, Paul Xiao, Rui Zhejiang Univ Dept Engn Mech State Key Lab Fluid Power & Mechatron Syst Key Lab Soft Machines & Smart Devices Zhejiang Pro Hangzhou 310027 Peoples R China Jinan Univ Coll Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Friedrich Alexander Univ Erlangen Nuremberg Inst Appl Mech Egerland Str 5 D-91058 Erlangen Germany

Soft composites, including filled rubbers, nanocomposite gels, double network hydrogels, and multiple network elastomers, all exhibit stress-softening behavior in loading-unloading cycles, also denoted as the Mullins effect. Though qualitatively this damage behavior shows similar features, the details still vary with material types. In this work, we provide a general approach towards modeling the Mullins effect for soft composites based on continuum damage mechanics. We start with formulating a one-dimensional damage model. A logarithmic damage variable is employed, while a damage potential function is adopted to obtain the evolution law for the damage variable. We then extend the one-dimensional damage model to three-dimensions. The eight-chain type micro-macro transition is used to formulate an isotropic damage model. An anisotropic damage model is constructed based on the full network model, while a new micro-macro mapping is used to determine the micro stretch from the macro deformation. With this new mapping, the full network model appears in a consistent format in that the free energy, dissipation, and stress are respectively given by the average of their directional micro counterparts. In the current approach, two constitutive functions need to be determined: the elastic free energy density and the stored energy limit. Simple forms of these two constitutive functions are provided with only a small set of model parameters. The resulting models are then successfully applied to describe the stress response in loading-unloading cycles and the anisotropic response of predeformed materials for different kinds of soft composites.

关键词： Mullins effect Continuum damage mechanics Micro-macro mapping Anisotropic damage model Soft composites

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Experiment Research on Emergency Stop Vibrations of key Components in the Friction Vertical Lifting System

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SHOCK AND VIBRATION 2022年第0期2022卷

作者： Peng, Qifeng Xu, Peng Li, Yukun Yuan, Hong Xue, Zhangna Yang, Jinchuan China Univ Petr East China Coll Pipeline & Civil Engn Qingdao 266580 Peoples R China Jinan Univ Sch Mech & Construction Engn Key Lab Disaster Forecast & Control Engn MOE Guangzhou 510632 Peoples R China

In order to analyze emergency stop vibration of the friction vertical lifting system under different loads, a loading experiment was carried out, and the longitudinal vibration characteristics of the carriage, frame, and steel rope were measured during the emergency braking process of an elevator. Accordingly, it is found that the load mass does not affect the peak deceleration value of the car frame and the wire rope during downwards emergency stop. Then, vertical vibration is explored using the time-varying vibration analysis theory. The obtained results show that when analyzing the vibration of objects on both sides of the traction wheel, the deceleration of the wire rope on both sides of the traction wheel are not equal, and the influence of the pressure change during the traction-wheel friction should be considered in calculations. This article may provide a reference to calculate the steel rope tension of the elevator and mine hoist.

关键词： Wheels

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Fault structure, seismicity, and magmatism of the Littoral Fault zone, northern South China sea: Insights from high-resolution seismic reflection data

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MARINE AND PETROLEUM GEOLOGY 2024年 160卷

作者： Zhang, Yanxin Ye, Xiuwei Wan, Kuiyuan Lv, Zuoyong Wen, Genggeng Xu, Shunshan Guangdong Earthquake Agcy CEA Key Lab Earthquake Monitoring & Disaster Mitig Guangzhou 510070 Peoples R China Guangdong Sci & Technol Collaborat Innovat Ctr Ear Guangzhou 510070 Peoples R China Urban Earthquake Safety Lab MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510070 Peoples R China Chinese Acad Sci South China Sea Inst Oceanol CAS Key Lab Ocean & Marginal Sea Geol Guangzhou 510301 Peoples R China Southern Marine Sci & Engn Guangdong Lab Guangzhou Guangzhou 511458 Peoples R China Univ Nacl Autonoma Mexico Ctr Geociencias Queretaro 76230 Mexico

Four destructive M7+ earthquakes and 18 M6+ earthquakes demonstrate that the Littoral Fault Zone (LFZ) is one of the most seismically active regions in the offshore area of South China. However, the location, geometry, and structural characteristics of the LFZ, which spans over 1000 km, have not been properly examined. In this study, we investigate the precise position of the LFZ offshore East Guangdong (EGD) and map the fault structure using recently acquired high-resolution multi-channel seismic (MCS) reflection data. The LFZ consists of an array of normal faults that collectively form a terraced sidewall fault zone linked to the continental rifting of the South China Sea (SCS). This fault zone is approximately 35-75 km wide and runs parallel to the shoreline. The primary faults of the LFZ EGD segment correlate to a high-gravity gradient zone and serve as the northern boundary of the Zhu-I Depression. During the syn-rift phase, the LFZ experienced significant intra-plate deformation, resulting in fault throws of up to 1000 m. This deformation was locally influenced by pre-existing structures, giving rise to a listric geometry at depth. In the post-rift period, the LFZ exhibited inherited activity along its rift-related faults. The presence of growth fault structures suggests that the LFZ remained active throughout the Cenozoic, with numerous active faults extending practically to the seafloor. The negative flower structure confirms the strikeslip character of the LFZ, which is influenced by the modern tectonic stress field. Intense multi-phase Cenozoic magmatism, including igneous intrusion, volcanism, and lava flows, has been detected in the offshore area of Nan'ao Island. The frequent earthquakes in the study area are primarily attributed to far-field stress release resulting from the subduction of the Philippine Sea Plate beneath the Eurasian Plate. Additionally, the intense magmatism weakens crustal structures, further facilitating stress release and the frequ

关键词： Littoral Fault zone Active fault Magmatism Multi-channel seismic profile Northern South China sea

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Structural damage detection based on modal feature extraction and multi-objective optimization method for steel structures

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FRONTIERS IN MATERIALS 2022年 9卷

作者： Chen, Zepeng Zhao, Di Chen, Zhou Wang, Wenxue Foshan Univ Sch Transportat & Civil Engn & Architecture Foshan Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China Kyushu Univ Res Inst Appl Mech Fukuoka Japan

Model updating based on intelligent algorithms has achieved great success in structural damage detection (SDD). But the appropriate selection of objective functions remains unclear and becomes an obstacle to applying the methods to real-world steel structures. In this paper, a multi-objective identification method based on modal feature extraction and linear weight sum was proposed, and the best weight values to gain the best solution were also determined. A hybrid particle swarm optimization (HPSO) was selected as a solver to update structural parameters for accurate SDD results. First of all, six single objective functions based on modal feature extraction were considered, and numerical simulations show that the one based on MTMAC indicator exhibits certain superiority over the other. In order to provide a fair comparison among different objective functions, a quantified indicator named damage vector consistency (DVC) is also defined, which describes the consistency between identified result and the assumed one. After that, a multi-objective identification method is formulated by linearly combining an MTMAC-based objective function and another selected single objective function. Different weight values were also investigated to find out the best solution for accurate SDD. Three numerical simulations were conducted, including a simply-supported beam, a two-story steel frame, and a 31-bar plane truss. Their SDD results verify the applicability of the proposed multi-objective optimization method. Some relative discussions are also described in detail.

关键词： structural damage detection (SDD) modal feature extraction multi-objective optimization damage vector consistency steel structures

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Theoretical analysis and finite element simulation of pipeline structure in liquefied soil

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HELIYON 2021年第7期7卷 e07480页

作者： Yang, Chunsheng Li, Shanqing Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

A mechanical analysis model for the floating of buried pipelines in soil liquefaction areas is established in this paper. In order to improve the inherent defects of the elastic foundation beam method based on the Winkler model and increase the calculation accuracy, the Pasternak model is introduced and the interaction between soil and spring is considered. A mechanical analysis method for buried pipelines in liquefaction zone considering axial load is proposed in present paper. According to the Pasternak model and the deflection curve differential equation, the pipe bending deformation curve equation and the deformation coordination equation are derived. The analytical calculation method of the pipe mechanical response is established. A new method of the mechanical analysis of the floating of buried pipelines in the liquefaction zone is provided. The mechanical response of the pipeline under the conditions of different pipeline parameters and liquefaction zone length is analyzed. The reliability of the analysis method in this paper is verified by the comparison of finite element method (FEM). Considering that the previous researches of scholars mainly focused on straight pipes, there are few studies on the pipe structure nodes in liquefied soil. The mechanical properties of the three-way pipe structure in the soil liquefaction zone are analyzed by the finite element method (FEM). The influence of pipe diameter, wall thickness, liquefied soil density, transition zone length, buried depth, and pipeline internal pressure on the mechanical response of the pipeline is analyzed.

关键词： Buried pipeline Liquefied soil Pasternak model Pipeline node Mechanical response

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Free Vibration of Axially Moving Functionally Graded Nanoplates Based on the Nonlocal Strain Gradient Theory

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INTERNATIONAL JOURNAL OF ACOUSTICS AND VIBRATION 2020年第4期25卷 587-596页

作者： Li, Cheng Wang, P. Y. Luo, Q. Y. Li, S. Soochow Univ Sch Rail Transportat Dept Vehicle Engn Suzhou 215131 Jiangsu Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Using the nonlocal strain gradient theory, we explore vibration behaviours of initially bidirectional tensioned functionally graded nanoplates with axial speed. The governing equation of motion can be obtained based on the differential type of nonlocal strain gradient constitutive relation, which characters the dynamics of nanostructures containing kinematic relation. The simply supported boundary constraints on four sides are considered and subsequently the numerical results are determined. It shows that natural frequencies of axially moving nanoplates decrease when increasing the axial speed and the nonlocal parameter. Hence the nonlocal and kinematic factors cause the natural frequencies to decrease or, weaken the equivalent bending rigidity. On the other hand, natural frequencies increase with an increase in the axial tension and material characteristic scale. Hence the strain gradient and tensile stress factors cause the natural frequencies to increase or, strengthen the equivalent bending rigidity. In addition, the natural frequencies get higher with a larger aspect ratio of the functionally graded nanoplate. The larger one between the nonlocal parameter and the material characteristic scale plays a dominant role in the softening and stiffening mechanisms of the nonlocal strain gradient effect. In case of the same magnitude of the nonlocal parameter and the material characteristic scale, the softening and hardening phenomena disappear. The equivalent bending rigidity neither increases nor decreases in such a situation, and its value degenerates to the classical one.

关键词： Natural frequencies

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Flexural Performance of Layered Macro Fiber Reinforced Concrete Short Beams

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SSRN 2022年

作者： Yuan, Hong Fu, Xiao-Hui Fan, Ya-Chen Fu, Bing Zou, Qi-Qi School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China MOE Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou510632 China Department of Ocean Science and Engineering Southern University of Science and Technology Shenzhen518055 China

Fiber-reinforced polymer (FRP) composites have been increasingly used in various sectors, which inevitably results in an increasing amount of FRP waste to be dealt with. A recent study conducted by the author’s group explored a novel mechanical recycling method to process GFRP waste into small slender elements (referred to as "macro fibers") for reinforcing concrete, leading to so called "macro fibre reinforced concrete" (i.e., MFRC). The macro fibres recycled from waste FRP composites bridge the cracks in concrete and mitigate their development, thus enhancing the flexural strength and toughness of MFRC flexural members. However, the macro fibres have a negligible effect on the compressive properties of MFRC, which implies that the macro fibres in the compressive zone cannot be efficiently utilized. As motivated by the concept of the layered structure, this paper presents an experimental investigation on the flexural performance of the layered beams with the MFRC bottom layer and PC (plain concrete) top layer, expecting to improve the utilization of the incorporated macro fibres. The investigated test parameters include the height of the bottom layer as well as the macro fiber content in the bottom layer. The test results show that the application of layer structure effectively enhances the utilization of macro fibers and hence promotes the future technological application of the proposed mechanical recycling method. © 2022, The Authors. All rights reserved.

关键词： Fibers

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