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Anti-sparse representation for structural model updating using l∞ norm regularization

STRUCTURAL engineering AND MECHANICS 2020年第4期75卷 477-485页

作者： Luo, Ziwei Yu, Ling Liu, Huanlin Chen, Zexiang Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Finite element (FE) model based structural damage detection (SDD) methods play vital roles in effectively locating and quantifying structural damages. Among these methods, structural model updating should be conducted before SDD to obtain benchmark models of real structures. However, the characteristics of updating parameters are not reasonably considered in existing studies. Inspired by the l(infinity) norm regularization, a novel anti-sparse representation method is proposed for structural model updating in this study. Based on sensitivity analysis, both frequencies and mode shapes are used to define an objective function at first. Then, by adding l(infinity) norm penalty, an optimization problem is established for structural model updating As a result, the optimization problem can be solved by the fast iterative shrinkage thresholding algorithm (FISTA). Moreover, comparative studies with classical regularization strategy, i.e. the l(2) norm regularization method, are conducted as well. To intuitively illustrate the effectiveness of the proposed method, a 2-DOF spring-mass model is taken as an example in numerical simulations. The updating results show that the proposed method has a good robustness to measurement noises. Finally, to further verify the applicability of the proposed method, a six-storey aluminum alloy frame is designed and fabricated in laboratory. The added mass on each storey is taken as updating parameter. The updating results provide a good agreement with the true values, which indicates that the proposed method can effectively update the model parameters with a high accuracy.

关键词： structural model updating l(infinity) norm regularization anti-sparse representation sensitivity analysis

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A hybrid ant lion optimizer with improved Nelder-Mead algorithm for structural damage detection by improving weighted trace lasso regularization

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ADVANCES IN STRUCTURAL engineering 2020年第3期23卷 468-484页

作者： Chen, Chengbin Yu, Ling Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou Guangdong Peoples R China

Structural damage detection is the kernel technique in deploying structural health monitoring. The structural damage-detection technique using heuristic algorithms has been developed at an astounding pace over the past years. However, some existing structural damage-detection methods are prone to easily fall into the local optimum and to be unstable when they are applied to complex structures. In order to make full use of advantages of heuristic algorithms and overcome abovementioned shortcomings, a hybrid algorithm, which combines the ant lion optimizer with an improved Nelder-Mead algorithm, is proposed to solve the constrained optimization problem of complex structural damage detection. First, an objective function is established for damage identification using structural modal parameters, that is, frequencies and mode shapes. The solution to the objective function is accurately attained by a newly improved weighted trace lasso which can improve the computing performance and stability of procedure and reduce randomness of weighted coefficients. After assessing the computing performance of the proposed hybrid algorithm using three classical mathematical benchmark functions, two structural damage-detection numerical simulations and a laboratory verification are then conducted to fully assess the structural damage-detection capability of the proposed method. Meanwhile, the equivalent element stiffness-reduction model is introduced to estimate the real damage severities of cracks which are created in laboratory structures and to compare with the structural damage-detection results by the proposed method. The illustrated results show that the proposed hybrid algorithm can locate damage and quantify damage severity more accurately and stably with a good robustness to noise.

关键词： ant lion optimizer with an improved Nelder-Mead algorithm equivalent element stiffness-reduction model improved weighted trace lasso sparse regularization structural damage detection

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Experimental and numerical study on extended endplate beam-column joints after high temperature to resist progressive collapse

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JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH 2024年 219卷

作者： Guo, Zhan Yang, Kai Xing, Zhiquan Nie, Zhenhua Chen, Yu Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Fuzhou Univ Coll Civil Engn Fuzhou 350118 Peoples R China

This paper presents experimental and numerical investigations on the collapse -resisting behavior of extended endplate beam -column joints after high temperatures. The failure patterns and structural responses of extended endplate (EP) joints after high temperature to resist progressive collapse were first described, and then the effects of fire temperature and temperature duration on their collapse resistance mechanisms were also analyzed in detail. The test results demonstrate that all specimens withdrew from work owing to the serious deformation of endplate bolt holes or the brittle fracture of high -strength bolts, resulting in the catenary mechanisms of EP joints not being adequately developed. Compared with previous studies, it is shown that the fire temperature exerts the most significant effects on the carrying capacities and deformability of EP joints, and the collapse resistance of corresponding assemblies is most sensitive to the fire temperature. However, the temperature durations have an insignificant influence on the development of flexural mechanism resistance, especially for those after 600 degrees C and 800 degrees C. Moreover, the corresponding refined FE models in consideration of the damage and fracture of ductile metals have been established to reproduce the structural response of specimens after high temperature. To improve the post -fire collapse -resisting performance of assemblies, both the lateral plate reinforcement and welding reinforcement methods were proposed and compared with the assistance of validated FE models. From a practical viewpoint, the reinforcement with lateral plates is determined as a superior technique for post -fire EP joints against progressive collapse.

关键词： Extended endplate (EP) joints High temperature Progressive collapse Push -down tests Numerical simulation

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A novel WOA-based structural damage identification using weighted modal data and flexibility assurance criterion

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STRUCTURAL engineering AND MECHANICS 2020年第4期75卷 445-454页

作者： Chen, Zexiang Yu, Ling Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Structural damage identification (SDI) is a crucial step in structural health monitoring. However, some of the existing SDI methods cannot provide enough identification accuracy and efficiency in practice. A novel whale optimization algorithm (WOA) based method is proposed for SDI by weighting modal data and flexibility assurance criterion in this study. At first, the SDI problem is mathematically converted into a constrained optimization problem. Unlike traditional objective function defined using frequencies and mode shapes, a new objective function on the SDI problem is formulated by weighting both modal data and flexibility assurance criterion. Then, the WOA method, due to its good performance of fast convergence and global searching ability, is adopted to provide an accurate solution to the SDI problem, different predator mechanisms are formulated and their probability thresholds are selected. Finally, the performance of the proposed method is assessed by numerical simulations on a simply-supported beam and a 31-bar truss structures. For the given multiple structural damage conditions under environmental noises, the WOA-based SDI method can effectively locate structural damages and accurately estimate severities of damages. Compared with other optimization methods, such as particle swarm optimization and dragonfly algorithm, the proposed WOA-based method outperforms in accuracy and efficiency, which can provide a more effective and potential tool for the SDI problem.

关键词： structural damage identification whale optimization algorithm constrained optimization problem objective function flexibility assurance criterion

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Alternating iterative method for moving force identification 10

Alternating iterative method for moving force identification

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10th International Conference on Bridge Maintenance, Safety and Management (IABMAS)

作者： Liu, H. L. Li, C. Yu, L. Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China State Key Lab Hlth & Safety Bridge Struct Wuhan Peoples R China

ISBN: (纸本)9780429279119;9780367232788

Moving force identification (MFI) has attracted increasing attentions in recent years. However, the MFI results obtained from the existing methods are inaccurate under measurement noises. One of reasons is fact that the characteristics of moving forces are not properly explored. To fix the problem, a novel MFI method is proposed by combining an alternating iterative method (AIM) and regularizations here. Firstly, each of moving forces is decomposed into constant force and time varying force components respectively. The prior knowledge that time-varying force component usually fluctuates around constant force component is then adopted. Rather than convex optimization problem, a semi-convex constrained estimation problem is defined and solved by the AIM. Numerical simulations on MFI in a simply supported beam are conducted to assess its effectiveness. The results show that the proposed method can provide a higher MFI accuracy than the truncated generalized singular value decomposition method and the prior knowledge is reasonable.

关键词： Iterative methods

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Propagation Characteristics of Flexural Wave in One-Dimensional Phononic Crystals Based on Lattice Dynamics Model

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Journal of Applied Mathematics and Physics 2022年第5期10卷 1416-1431页

作者： Hao Wu Youdi Kuang School of Mechanics and Construction Engineering MOE Key Laboratory of Disaster Forecast and Control in Engineering Jinan University Guangzhou China School of Civil Engineering and Architecture Wuyi University Jiangmen China

In this paper, we establish discrete flexural lattice chain models of Bragg and locally resonant phononic crystals by setting mass defect atoms and local resonant elements on the flexural lattice chain. The bandgap characteristics of flexural wave in phononic crystals are studied by establishing the governing equations of the model. The results from models show that with the change of the mass ratio of defective atoms to normal atoms, the bandgap of the flexural wave produced by Bragg scattering shows a certain rule. When the local resonant bandgap and Bragg scattering bandgap are close to each other, the two bandgaps will be coupled to form a wider flexural wave bandgap. The effect of axial strain on bending wave propagation is only the shift of bandgap position. The effect of material damping on the propagation of a bending wave is only energy dissipation at high frequency. In addition, we use finite element simulation to calculate the bandgap of flexural wave in phononic crystals with mass defects, and the results are consistent with lattice chain model. This shows that lattice chain model can effectively guide the bandgap design of phononic crystals. This comprehensive study may help to elucidate the rule of bandgap generation of flexural wave in one-dimensional phononic crystals.

关键词： Phononic Crystals Local Resonance Bragg Scattering Damping Strain Flexural Wave

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Study on Band Gap Characteristics of Boat-Shaped Phononic Crystal

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Journal of Applied Mathematics and Physics 2022年第12期10卷 3693-3699页

作者： Jia Xu Yabing Li Youdi Kuang School of Mechanics and Construction Engineering MOE Key Laboratory of Disaster Forecast and Control in Engineering Jinan University Guangzhou China School of Civil Engineering and Architecture Wuyi University Jiangmen China

In this paper, we analyze the two-dimensional Boat-shaped structure based on the finite element method. We calculated its energy band structure and vibration transmission properties and found that the structure has band gaps at both high and low frequencies. Compared with common traditional two- dimensional phononic crystals, the boat-shaped phononic crystal has the advantage of larger bandgap design and modulation parameter space due to their structural complexity. In order to obtain better bandgap characteristics, we studied the influence of four key parameters, such as the rod length and the angle between the rods, on the bandgap. The results show that: for low frequency band gaps, the width of the band gap can be effectively changed by changing the size of the angle between the rods while rod length greatly affects the bandgap position;for high band gaps, the length of rods has a large effect on the band gap position. These laws have guiding significance for the bandgap regulation of boat-shaped phononic crystal.

关键词： Phononic Crystal Band Gap Boat-Shaped Finite Element Simulation

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Effect of filter material and porosity on the energy storage capacity characteristics of diesel particulate filter thermoelectric conversion mobile energy storage system

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ENERGY 2023年 283卷

作者： Zhao, Xiaohuan Jiang, Jiang Mao, Zhengsong Jinan Univ Int Energy Coll Energy & Elect Res Ctr Zhuhai Campus Zhuhai 519070 Peoples R China Yuchai Synland Technol Co Ltd Nanning 530007 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Jinan Univ Minist Educ China Sch Mech & Construct Engn Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

The thermal energy generated by the diesel particulate filter (DPF) is converted into electrical energy through the thermoelectric generator (TEG) and stored in a mobile battery power energy storage (MBPE) system. The filter material and porosity directly affect the regeneration temperature of the DPF, which in turn affects the thermoelectric conversion capability of the thermoelectric module (TEM). This study explores the energy storage capacity characteristics for the DPF-TEG of the MBPES system at a regeneration temperature of 923 K. The filter materials considered are cordierite, mullite and SiC with porosities of 0.4, 0.45, 0.5, 0.55, 0.6, 0.65 and 0.7. The maximum output power and thermoelectric conversion efficiency are analyzed. The thermal input power for the SiC filter is approximately 2.4 times and 1.8 times than that of the cordierite filter and the mullite filter. As the porosity increases from 0.4 to 0.7, the output current for the DPF-TEG of the MBPES system with the 3 filter materials ranges from 0.66 A to 2.11 A. The output voltage changes from 50.62 V to 161.98 V. The maximum output power varies from 33.36 W to 341.59 W and the conversion efficiency rises from 0.88% to 2.72%.

关键词： Diesel particulate filter DPF Mobile battery power energy storage system Thermoelectric module Filter material Porosity

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Progressive Failure Analysis of Laminates with Embedded Wrinkle Defects Based on an Elastoplastic Damage Model

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MATERIALS 2020年第10期13卷 2422页

作者： Ning, Zhi Hua Huo, Guan Liang Liu, Ren Huai Wu, Wei Lin Xie, Jia Ming Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Out-of-plane wrinkling has a significant influence on the mechanical performance of composite laminates. Numerical simulations were conducted to investigate the progressive failure behavior of fiber-reinforced composite laminates with out-of-plane wrinkle defects subjected to axial compression. To describe the material degradation, a three-dimensional elastoplastic damage model with four damage modes (i.e., fiber tensile failure, matrix failure, fiber kinking/splitting, and delamination) was developed based on the LaRC05 criterion. To improve the computational efficiency in searching for the fracture angle in the matrix failure analysis, a high-efficiency and robust modified algorithm that combines the golden section search method with an inverse interpolation based on an existing study is proposed. The elastoplastic damage model was implemented in the finite-element code Abaqus using a user-defined material subroutine in Abaqus/Explicit. The model was applied to the progressive failure analysis of IM7/8552 composite laminates with out-of-plane wrinkles subjected to axial compressive loading. The numerical results showed that the compressive strength prediction obtained by the elastoplastic damage model is more accurate than that derived with an elastic damage model. The present model can describe the nonlinearity of the laminate during the damage evolution and determine the correct damage locations, which are in good agreement with experimental observations. Furthermore, it was discovered that the plasticity effects should not be neglected in laminates with low wrinkle levels.

关键词： elastoplastic damage model wrinkle defect progressive failure analysis fiber kinking fracture plane

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Comparative studies on Structural Damage Detection using different kinds of Objective Functions based on Modal Data

Comparative studies on Structural Damage Detection using dif...

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International Conference on Intelligent Transportation, Big Data & Smart City (ICITBS)

作者： Zepeng Chen Di Zhao School of Transportation and Civil Engineering & Architecture Foshan University Foshan China MOE Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou China

In order to investigate the ability of different objective functions based on modal data for SDD problems, six objective functions are defined and a comparison study is presented in this paper. To make a fair comparison, a quantified index name damage vector consistency is defined to describe the consistency between the identified damage vector factor and the assume one. Simply-supported beam with 10 finite elements is simulated which provides modal data generation and damage cases simulation. The percentage of DVC equaling to 100% in the all 100 times is also calculated which shows the objective function based on MTMAC is the best one for SDD.

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