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SSRN 2023年

作者： Zhang, Wen-Hua MOE Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou510632 China School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China

The development of contact theories for film are valuable for high-precision machining and measurement. Herein, based on the constitutive equations and potential theory method, accurate contact mechanics theories of films under common indenter loading are established, where the film structures are "film with two free boundaries" and "film/rigid substrate". The displacement and stress at arbitrary position can be obtained with the exact solutions, which are represented by elementary functions. It is convenient for engineers applicating the theories when addressing contact problem of films. The influence of substrate effects and film parameters on contact radius and indentation depth was analyzed. It is found that Poisson’s ratio has little influence on indentation curves, which is mainly affected by the elastic modulus. An effective method for measurement of film material parameters is presented. With numerical software platforms, the analytic algorithm could be transformed into numerical codes and be integrated in special software. © 2023, The Authors. All rights reserved.

关键词： Constitutive equations

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Structural damage detection based on SSA with CI and sensitivity analysis 10

Structural damage detection based on SSA with CI and sensiti...

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

作者： Wang, X. E. Liu, H. L. Yu, L. Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

ISBN: (纸本)9780429279119;9780367232788

This paper proposes a novel structural damage detection (SDD) approach by using salp swarm algorithm (SSA) combined with cosine-based indicator (CI) and sensitivity analysis on mode shape and frequency under environmental noises. The SDD problem is first converted into a mathematical constrained optimization problem while structural damage is assumed as stiffness reduction in finite element analysis. Then an objective function is defined based on the novel CI damage indicator and the changes in frequencies for effectively improving the SDD accuracy and efficiency by the sensitivity analysis of more complex structures. Finally, the SDD problem is solved by the aid of SSA. Numerical simulations on a twostory frame structure and experimental verifications on a three-story steel frame structure are both conducted to assess the performance of the proposed approach. The results show that the proposed approach can effectively locate structural damages and quantify damage extents with an exact detection accuracy and a faster efficiency.

关键词： Sensitivity analysis

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Multi-morphology TPMS structures with multi-stage yield stress platform and multi-level energy absorption: Design, manufacturing, and mechanical properties

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engineering STRUCTURES 2023年第1期294卷

作者： Xi, Huifeng Zhou, Zicong Zhang, Haohua Huang, Shiqing Xiao, Heng Jinan Univ Sch Machan & Construct Engn MOE Key Lab Disaster Forecast & Control Engn West Huangpu Ave 601 Guangzhou 510632 Peoples R China

Multi-morphology TPMS structures have recently gained increased attention in many areas because they exhibit even more advantageous and desired properties than traditional TPMS structures with uniform unit. However, the connections between the different morphology TPMS and their mechanical properties have not been extensively investigated. In this study, the connection function when designing multi-morphology TPMS was characterized, and the multi-morphology TPMS could be manufactured by 3D printing technology. A good agreement between experimental and simulation results was achieved. According to compression test results, it was found that the multi-morphology TPMS structures have multi-stage yield platform and multi-level energy absorption differently from conventional TPMS. More closely, energy absorption capacity of N-G TPMS structure is better than P-G TPMS structure and P-N TPMS structure, and the deformation and energy absorption of multimorphology TPMS structures can be designed for impact protection requirement.

关键词： Multi-morphology TPMS 3D printing technology Mechanical properties Multi-stage yield platform Energy absorption

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Analytical Study of Seismic Demand and Fragility of Piping Systems in the Reticulated Shell Structures 26th

Analytical Study of Seismic Demand and Fragility of Piping S...

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26th Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2023

作者： Li, Fengze Zhi, Xudong Zhu, Enchun Wang, Duozhi Zhang, Rong School of Civil Engineering Harbin Institute of Technology Harbin China Key Lab of Structures Dynamic Behaviour and Control of the Ministry of Education Harbin Institute of Technology Harbin China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration Harbin China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency Management Harbin China

ISBN: (纸本)9789819733965

The large-span spatial hub structure is an important urban lifeline project with complex structure form and many types of internal non-structural components. As one of the main non-structural components, the safety of the piping system is important to ensure the normal use of the overall function of the large span hub structure. Once damage occurs to the piping system under the action of earthquake, it will affect the traffic operation and urban rescue, resulting in incalculable casualties and property damage. To assess the impact of diverse connection locations on the piping system’s response, this study investigates acceleration and response amplification factors at various positions within the reticulated shell structure. Through this analysis, we underscore the critical need to consider the spatial coupling effect for the piping system within the reticulated shell structure. In this study, the seismic response and damage modes of the internal piping system in a prevalent type of reticulated shell structures are investigated. This is achieved by establishing a coupled finite element model of the reticulated shell structure and the piping system. Three distinct damage modes of the piping system and their corresponding computational signs are identified, facilitating the creation of fragility curves for the piping system. The results highlight significant variation in the damage degree of the piping system at different locations. Additionally, past studies have shown a notable probability of damage to piping systems, even under very slight ground shaking, emphasizing the necessity for careful consideration. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Shells (structures)

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A two-stage approach for structural damage detection using MSE and ALO-INM 10

A two-stage approach for structural damage detection using M...

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

作者： Chen, C. B. Luo, Z. W. Yu, L. Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

ISBN: (纸本)9780429279119;9780367232788

The locations of structural damages are normally unknown in practical engineering, and using the swarm intelligent (SI) algorithm-based structural damage detection (SDD) approach requires evaluation of the objective function for the total population in each iteration, which is time-consuming. In this study, a twostage (TS) SDD approach based on the modal strain energy (MSE) and the ALO-INM algorithm is proposed to solve these problems of the original ALO-INM-based method. At first, the potential structural damages are located by calculating the MSE change ratio (MSECR) values. These damaged elements will be further analyzed to identify and quantify the damage extents using the ALO-INM algorithm. Finally, the effectiveness of the proposed TSALO-INM approach is verified using numerical simulations of a 20-element simply supported beam. The results show that the proposed approach can accurately locate damages and quantify damage extents more precisely than the original approach, and its computational efficiency is also greatly improved.

关键词： Computational efficiency

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A method of coating analysis based on cylindrical indenter loading on coated structure

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ACTA MECHANICA 2023年第5期234卷 2223-2267页

作者： Huang, Shi-Qing Tang, Pan-Jun Hou, Peng-Fei Zhang, Wen-Hua Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Chinese Acad Sci GBA Branch Aerosp Informat Res Inst Guangzhou 510700 Peoples R China Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Peoples R China Hunan Univ Dept Engn Mech Changsha 410082 Peoples R China

The most common coated structure contact problems include spherical, conical and cylindrical contact. The evaluation of mechanical performance for coating structures has always been a very important issue in the field of mechanics and materials;due to the too small proportion between the thickness of the coating and the substrate, the deviation of traditional evaluation methods becomes unacceptable. Indentation technology is the basis for analysis, measurement, and the standardized application of coating structures. The research object of this paper is cylindrical contact, which is one part of building the theoretical framework of contact mechanics of coating structures. In the paper, an accurate and efficient general theory of the frictional cylindrical contact problem for the coated structure is presented. The general solutions are expressed in the form of harmonic functions. 3D exact solutions of a transversely isotropic elasticity coated structure under frictional cylindrical punch contact are derived, based on the general solution and the boundary conditions. The theory is proposed in two cases, including the frictionless contact and the frictional contact. By contrast with existing theories (obtained in this paper by degradation), the numerical calculations show the good convergence, high accuracy, efficiency, and stability. The difference of stress singularity analysis between Finite Element Method (FEM) and the presented theory is explained, which shows the theory's validity and applicability. This analytical theory plays an important role in boundary stress singularity analysis. The finite element comparison shows that the analytical theory plays an important role in boundary stress singularity analysis and further, proves the validity and applicability of this theory. In the numerical analysis, the influence of coating thickness on interface stress is shown, the distribution forms of stress and displacement are given, and the influence of material paramete

关键词： Finite element method Coating

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Notes on micro-continua exhibiting quantum effects

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Applied Mathematics and Mechanics(English Edition) 2020年第10期41卷 1597-1598页

作者： Heng XIAO College of Mechanics and Construction Engineering MOE Lab of Disaster Forecast and Control in EngineeringJinan UniversityGuangzhou 510632China

1 Uniqueness concerning exact linearization Most recently[1–2],the Schr¨odinger equation governing the quantum effects has been shown to be derivable as exact linearization from the following nonlinear field equ... 详细信息

关键词： quantum exact linearization

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Structural model updating based on l₂ and l_∞ norm regularizations 10

Structural model updating based on <i>l</i><sub>2</sub> and ...

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

作者： Luo, Z. W. Yu, L. Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

ISBN: (纸本)9780429279119;9780367232788

For structural damage detection (SDD), an accurate finite element (FE) model plays a vital role to evaluate structural states. Due to the ill-posedness of structural model updating problems, regularization methods have been introduced to obtain stable solutions. However, the l(q) (0 < q <= 1) norm regularization methods have strong constraint effects so they are not suitable for structural model updating. In this paper, based on properties of regularization methods, the l(infinity) norm regularization is adopted for model updating. Both l(2) and l(infinity) norm penalties are respectively chosen to define objective functions for comparative studies. Some numerical simulations in spring-mass model and simply supported beam are conducted to verify their effectiveness. The results show that the l(infinity) norm regularization has good performances in model updating problems when design variables in many elements have same order in magnitude, while the l(2) norm regularization is suitable to update stiffness changes in magnitudes for contiguous elements.

关键词： Damage detection

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Strengthening layer with nano-twins in titanium alloy induced by laser surface re-melting: Mechanism of high strength and ductility

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MATERIALS CHARACTERIZATION 2023年第1期196卷

作者： Li, Kunmao Liu, Xiaochun Liu, Yujing Wu, Xiang Zhang, Wencai Yang, Junjie Li, Wei Zhou, Shengfeng Jinan Univ Inst Adv Wear & Corros Resistance & Funct Mat MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Changsha Univ Sci & Technol Coll Mat Sci & Engn Inst Met Sect 2 960 Wanjiali RD S Changsha 410004 Hunan Peoples R China Jinan Univ Affiliated Hosp 1 Dept Orthoped Guangzhou 510632 Peoples R China Chongqing Univ State Key Lab Mech Transmiss Chongqing 400044 Peoples R China

To increase the strength of titanium (Ti) alloys, severe plastic deformation techniques are usually adopted to refine their grain structure, but these methods have long processing cycle, high cost, and easily result in the oxidized of Ti alloys. This work proposes a strategy of laser surface re-melting (LSR) as-cast TC4-1Cu alloy, which can refine its grain into-63 nm at relatively lower costs and short manufacturing cycle. By forming a thin strengthening layer with a thickness of-60 mu m, the yield strength and tensile strength of the as-cast TC4-1Cu alloy are increased by 28% and 35%, respectively. More importantly, the {10-11} nano-twinned system is activated due to the tensile stress, thereby accommodating plastic strain. These improvements in properties are attributed to the surface strengthening layer with nano-twins and the homogenized elemental distribution, which can provide important implications for studying how to address the strength-ductility trade-off in as-cast Ti alloys.

关键词： Titanium alloy Laser surface re-melting (LSR) Nanostructured surface layer Nano-twins Mechanical properties

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A Novel Improved Dragonfly Algorithm-Based Structural Damage Identification Approach Using Flexibility Assurance Criterion and Trace Lasso

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INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 2024年第13期24卷 2450144-2450144页

作者： Chen, Zepeng Zhao, Di Liu, Qitian Zhang, Zhiyu Yu, Ling Foshan Univ Sch Transportat & Civil Engn & Architecture Foshan Peoples R China Jinan Univ Guangzhou MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Jinan Peoples R China

Aiming to enhance the accuracy, stability, and noise robustness of swarm intelligence-based algorithms for structural damage identification (SDI), a novel improved dragonfly algorithm (IDA) is proposed. The IDA integrates the dragonfly algorithm (DA) with three key strategies including enhanced Levy flight, optimal solution bidirectional search, and greedy preservation. These strategies are introduced to enhance the exploration capability of the original DA and improve the IDA's capacity to obtain global optima. An objective function is defined using frequency change ratio and flexibility assurance criterion (FAC). Additionally, trace sparse regularization is also incorporated into the objective function since most of the damages in structures tend to be sparsely distributed, so that a sparse result is ensured to improve SDI accuracy. To evaluate the performance of the proposed algorithm, a comparison of the original DA and IDA is conducted using four benchmark functions. The results demonstrate that the proposed algorithm achieves improved convergent rate and accuracy. Furthermore, numerical simulations are performed on a 10-element simply-supported beam and a 31-element planar truss to validate the effectiveness and efficiency of the proposed algorithm in SDI. Significantly, the utilization of IDA instead of DA leads to a substantial reduction in the average calculated relative error for the truly damaged element within the considered damage cases of the simply-supported beam, decreasing from 13.05% to 6.15%. Moreover, an experimental simply-supported beam structure with several assumed damage cases is fabricated in the laboratory. The experimental results further confirm the robustness and capability of the proposed method in real-world SDI applications.

关键词： Structural damage identification (SDI) improved dragonfly algorithm (IDA) flexibility assurance criterion (FAC) trace sparse regularization model updating

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