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Automated Tunnel Point Cloud Segmentation and Extraction Method

APPLIED SCIENCES-BASEL 2025年第6期15卷 2926-2926页

作者： Wang, Zhe Zhu, Zhenyi Wu, Yong Hong, Qihao Jiang, Donglai Fu, Jinbo Xu, Sifa Zhejiang Univ Technol Coll Civil Engn Hangzhou 310014 Peoples R China Zhejiang Key Lab Intelligent Control Transit Infra Hangzhou 310007 Peoples R China Zhejiang Huadong Surveying & Engn Safety Technol C Hangzhou 311500 Peoples R China

To address the issue of inaccurate tunnel segmentation caused by solely relying on point cloud coordinates, this paper proposes two algorithms, GuSAC and TMatch, along with a ring-based cross-section extraction method to achieve high-precision tunnel lining segmentation and cross-section extraction. GuSAC, based on the RANSAC algorithm, introduces a minimum spanning tree to reconstruct the topological structure of the tunnel design axis. By using a sliding window, it effectively distinguishes between curved and straight sections of long tunnels while removing non-tunnel structural point clouds with normal vectors, thereby enhancing the lining boundary features and significantly improving the automation level of tunnel processing. At the same time, the TMatch algorithm, which combines cluster analysis and Gaussian Mixture Models (GMMs), achieves accurate segmentation of tunnel rings and inner ring areas and further determines the tunnel cross-section position based on this segmentation result to complete the cross-section extraction. Experimental results show that the proposed method achieves a segmentation accuracy of up to 95% on a standard tunnel point cloud dataset. Compared with traditional centerline extraction methods, the proposed cross-section extraction method does not require complex parameter settings, provides more stable positioning, and demonstrates high practicality and robustness.

关键词： tunnel structure disease analysis RANSAC algorithm sliding window fitting clustering segmentation Gaussian mixture model scalar field

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A Spatiotemporal-Adaptive-Network-Based Method for Predicting Axial Forces in Assembly Steel Struts with Servo System of Foundation Pits

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APPLIED SCIENCES-BASEL 2025年第5期15卷 2343-2343页

作者： Liu, Weiwei Sheng, Jianchao Zhou, Jian Fu, Jinbo Yao, Wangjing Chang, Kuan Wang, Zhe Zhejiang Univ Dept Civil Engn Hangzhou 310058 Peoples R China China Construct First Grp Construct & Dev Co Ltd Beijing 100102 Peoples R China Zhejiang Univ Technol Coll Civil Engn Hangzhou 310007 Peoples R China Zhejiang Key Lab Intelligent Control Transit Infra Hangzhou 310007 Peoples R China Zhejiang Univ Res Ctr Coastal & Urban Geotech Engn Hangzhou 310058 Peoples R China

The axial force in assembly steel struts with servo systems is a critical indicator of stability in foundation pit support systems. Due to its high sensitivity to temperature variations and direct influence on the lateral deformation of the foundation pit enclosure structure, accurate prediction is essential for safety monitoring and early warning. This study proposes a novel method for predicting the axial force in assembly steel struts with servo systems based on a spatiotemporal adaptive network. The method begins by feeding historical axial force data from multiple steel struts into an LSTM network to extract temporal sequence features. A self-attention mechanism is then employed to capture the global dependencies within the axial force data, enhancing the feature representation. Concurrently, a convolutional neural network (CNN) is utilized to extract local spatial features. Additionally, excavation depth and excavated soil stratification data are processed through convolutional operations to derive stratification-related features. Subsequently, the temporal and spatial features of axial force are fused with stratification-related features derived from excavation data and further refined through a CNN, enabling more accurate predictions. Validation using deep foundation pit data from a metro station in zhejiang Province demonstrated the method's reliability and improved performance across multiple metrics compared to the existing approaches.

关键词： deep excavation axial force prediction deep excavation safety early warning neural network model

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Comparative numerical study on the impact resistance of Z-pin reinforced and unreinforced composite laminates

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POLYMER COMPOSITES 2025年第5期46卷 4197-4211页

作者： Zhao, Guozhi Li, Mengjia Gao, Ying Zhao, Yuan Chen, Puhui Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Nanjing 210016 Peoples R China Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & Ma Jinhua 321004 Peoples R China Zhejiang GBF Co Ltd Jinhua Peoples R China

Compared with the common numerical analysis of out-of-plane low-velocity impact (LVI) of composite laminates, this paper established a finite element model (FEM) for out-of-plane LVI of unreinforced laminates and Z-pin-reinforced laminates. The mechanical response and damage morphology of the model after impact at energies of 5, 10, 30, and 50 J were verified with experiments. Through mechanical response research, it was found that the numerical analysis models of LVI of unreinforced and Z-pin-reinforced laminates have higher prediction accuracy for maximum impact force, maximum displacement, and energy absorption of the laminate. The simulation results showed that the Z-pin reinforced laminates had higher impact force and lower maximum displacement compared to the unreinforced laminates. From the LVI simulation, it was observed that the damage morphology of the laminate's surface and interior indicated minor fiber damage, which correlated well with the fiber damage observed in the experiments. In contrast, matrix damage played a dominant role during the impact, leading to extensive damage. This extensive damage occurred due to the loss of the stress transfer medium caused by matrix damage, which subsequently resulted in fiber *** Comparison of simulated and experimental mechanical response Criteria for determining the initiation of matrix/fiber damage Simulation analysis of Z-pin reinforced laminates Intra-laminar fiber/matrix damage and inter-laminar delamination

关键词： delamination finite element analysis impact behavior laminate Z-pin

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Unlocking the potential of N-doped porous Carbon: Facile synthesis and superior CO2 adsorption performance

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SEPARATION AND PURIFICATION TECHNOLOGY 2024年 333卷

作者： Shao, Jiawei Wang, Junting Yu, Qiyun Yang, Fanhui Demir, Muslum Altinci, Osman Cem Umay, Ahmet Wang, Linlin Hu, Xin Zhejiang Normal Univ Minist Educ Adv Catalysis Mat Key Lab Jinhua 321004 Zhejiang Peoples R China Bogazici Univ Dept Chem Engn Istanbul Turkiye TUBITAK Marmara Res Ctr Mat Inst TR-41470 Gebze Turkiye Osmaniye Korkut Ata Univ Dept Chem Engn TR-80000 Osmaniye Turkiye Osmaniye Korkut Ata Univ Dept Environm Protect & Control Technol Osmaniye Turkiye Zhejiang Normal Univ Coll Engn Key Lab Urban Rail Transit Intelligent Operat & M Jinhua 321004 Zhejiang Peoples R China

Porous carbon derived from bio-based sources is highly regarded as a promising adsorbent material, attributed to its exceptional CO2 uptake performance and favorable CO2/N2 selectivity. In this study, we employed a one-step chemical activating technique to fabricate self-heteroatom-doped porous carbon utilizing chitosan as a carbon precursor and KOH as chemical activating reagent. Subsequent activation processes resulted in the porous carbons possessing an excess amount of nitrogen functionality and advanced textural feature. Remarkably, a high CO2 capture amount of 4.40 mmol/g was accomplished at 25 degrees C and 1 bar, accompanied by a significant CO2/N2 selectivity of 21 for the dual gas blend. The gas adsorption mechanisms were thoroughly discussed, elucidating the factors contributing to the exceptional performance. The superior adsorption and separation capabilities, enhanced recyclability and effective dynamic adsorption capability, establish this N-enriched carbon as a potential adsorbent for CO2 uptake. The present work presents a novel approach for designing high-performance carbon-based CO2 adsorbents.

关键词： Porous carbons N-doping CO2 adsorption Biomass

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Investigation into defect image segmentation algorithms for galvanised steel sheets under texture backgrounds

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INSIGHT 2023年第9期65卷 492-500页

作者： Pan, Rui Gao, Wei Zuo, Yunbo Wu, Guoxin Chen, Yuda Zhejiang Normal Univ Coll Engn Key Lab Urban Rail Transit Intelligent Operat & M Jinhua 321004 Zhejiang Peoples R China Maanshan Iron & Steel Co Ltd Ctr Technol Maanshan 243000 Peoples R China Beijing Informat Sci & Technol Univ Mech Elect Engn Sch Key Lab Measurement & Control Mech & Elect Syst Beijing 100101 Peoples R China

Image segmentation is a significant step in image analysis and computer vision. Many entropy-based approaches have been presented on this topic. Among them, Tsallis entropy is one of the best-performing methods. In this paper, the surface defect images of galvanised steel sheets were studied. A two-dimensional asymmetric Tsallis cross- entropy image segmentation algorithm based on chaotic bee colony algorithm optimisation was used to investigate the segmentation of surface defects under complex texture backgrounds. On the basis of Tsallis entropy threshold segmentation, a more concise expression form was used to define the asymmetric Tsallis cross-entropy in order to reduce the calculation complexity of the algorithm. The chaotic algorithm was combined with the artificial bee colony (ABC) algorithm to construct the chaotic bee colony algorithm, so that the optimal threshold of Tsallis entropy could be quickly identified. The experimental results showed that compared with the maximum Shannon entropy algorithm, the calculation time of this algorithm decreased by about 58% and the threshold value increased by about (26%, 54%). Compared with the two-dimensional Tsallis cross-entropy algorithm, the calculation time of this algorithm decreased by about 35% and about 20% was improved in the g-axis direction only. Compared with the two-dimensional asymmetric Tsallis cross-entropy algorithm, the calculation time of this algorithm decreased by about 30% and the threshold values of the two algorithms were almost the same. The algorithm proposed in this paper can rapidly and effectively segment defect targets, making it a more suitable method for detecting surface defects in factories with a rapid production pace.

关键词： galvanised steel sheets surface defect detection image filtering image segmentation texture features

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Investigation into Defect Image Segmentation Algorithms for Galvanized Steel Sheets Under Texture Background

Investigation into Defect Image Segmentation Algorithms for ...

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International Conference of The Efficiency and Performance Engineering Network (TEPEN)

作者： Pan, Rui Chen, Yuda Wu, Guoxin Xu, Xiaoli Beijing Informat Sci & Technol Univ Key Lab Measurement & Control Mech & Elect Syst T Beijing 100101 Peoples R China Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & M Jinhua 321004 Zhejiang Peoples R China Zhejiang Normal Univ Coll Engn Jinhua 321004 Zhejiang Peoples R China

ISBN: (纸本)9783031261954;9783031261930;9783031261923

Galvanized steel sheets have been widely used due to their excellent corrosion resistance and sound formability, but their surface defects can severely affect their performance, so it is of immense significance to identify them effectively and accurately. This paper selected the images of surface defects of galvanized steel sheets as the research objects, investigated the segmentation of surface defects under complex texture backgrounds, and offered an optimized two-dimensional asymmetric Tsallis cross entropy image segmentation algorithm based on Chaotic Bee Colony Algorithm. On the basis of Tsallis cross entropy threshold segmentation algorithm, a simpler expression was adopted to define the asymmetric Tsallis cross entropy in order to reduce its calculation complexity;chaotic algorithm and Artificial BeeColonyAlgorithmwere combined to construct Chaotic Bee Colony Algorithm, so that the optimal threshold of Tsallis entropy could be searched quickly. The experimental results showed that compared with other commonly used threshold segmentation algorithms, the algorithm proposed by this paper could rapidly and effectively segment defect targets, a more suitable method of detecting surface defects for factories with a rapid production pace.

关键词： Galvanized steel sheets Surface defect detection Image filtering Image segmentation Texture features

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Joint iterative state and parameter estimation for bilinear systems with autoregressive noises via the data filtering

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ISA TRANSACTIONS 2024年 147卷 337-349页

作者： Liu, Siyu Wang, Yanjiao Ding, Feng Alsaedi, Ahmed Hayat, Tasawar Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & Ma Jinhua 321004 Peoples R China Jiangnan Univ Sch Internet Things Engn Key Lab Adv Proc Control Light Ind Minist Educ Wuxi 214122 Peoples R China Guangdong Univ Technol Sch Automat Guangzhou 510006 Peoples R China Hubei Univ Technol Sch Elect & Elect Engn Wuhan 430068 Peoples R China King Abdulaziz Univ Dept Math Jeddah 21589 Saudi Arabia

This paper proposes a novel iterative algorithm for the joint state and parameter estimation of bilinear state- space systems disturbed by colored noise. Estimating the states and parameters of such systems is challenging due to their nonlinearity and greater number of parameters compared to linear systems. Our method is to modify the Kalman filtering appropriately to estimate the unknown states of bilinear systems. Once the unknown states are estimated, we develop the Kalman filtering -based multi -innovation gradient -based iterative (KF-MIGI) algorithm for parameter estimation. To further improve estimation accuracy and cope with colored noises, we introduce a data filtering -based KF-MIGI algorithm that uses an adaptive filter to filter input-output data. Additionally, we compare the gradient -based iterative algorithm and the stochastic gradient algorithm. The effectiveness of the proposed algorithm is demonstrated through numerical examples.

关键词： Data filtering State estimation Bilinear system Parameter estimation State-space model Multi-innovation identification theory

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A numerical study of the influence of Z-pin parameters on the elastic properties of laminates

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POLYMERS & POLYMER COMPOSITES 2021年第9期29卷 1390-1402页

作者： Li, Mengjia Chen, Puhui Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & M 688 Yingbin Ave Jinhua 321004 Zhejiang Peoples R China Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct 29 Yudao St Nanjing 210016 Peoples R China

A finite element model with periodic boundary conditions was developed to investigate the influence of different Z-pin parameters including diameter, spacing, and insertion angle of Z-pin on the elastic properties of composite laminates. Benchmark tests were carried out to verify the FE model and a series of parametric analyses were subsequently performed. In general, all the elastic moduli, excluding the through-thickness modulus (E-z ), decreased while E-z increased nonlinearly with increasing Z-pin diameter and decreasing spacing. The reduction of E-y (transverse modulus) was approximately 40% of that of E-x (longitudinal modulus), while the reduction of G(xy) is similar to that of E-x . Besides, G(xz) and G(yz) were reduced by approximately half of the reduction of G(xy) . Although the impact of insertion angle was obvious on E-z , it was negligible on the other five moduli.

关键词： Z-pin composite laminate elastic modulus Poisson’ s ratio finite element analysis

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Improving the impact damage resistance of composite laminates using CNF/Z-pin multi-scale toughening

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THIN-WALLED STRUCTURES 2023年第1期189卷

作者： Zhao, Guozhi Li, Mengjia Li, Xiping Zheng, Jiajia Zhang, Ziang Hu, Zhonglue Zhao, Yuan Chen, Puhui Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & Ma Jinhua 321004 Peoples R China Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Nanjing 210016 Peoples R China

This paper investigated the effect of CNF (carbon nanofibre)/Z-pin multi-scale synergistic reinforcement on improving the impact damage resistance of carbon fiber-reinforced composite laminates. The out-of-plane low-velocity impact response of unreinforced, CNF-reinforced, Z-pin-reinforced and CNF/Z-pin multi-scale synergistic reinforced laminates were investigated. The use of CNF concurrently with Z-pin can not only eliminate the incapability of Z-pin in improving the damage resistance at low energy (damage initiation) but can also synergistically maximize the improvement of the impact resistance at high energy (damage propagation). At 50 J impact energy, the damaged area of CNF, Z-pin and CNF/Z-pin reinforced laminates were reduced by 10.3%, 29.5% and 34.8%.

关键词： CNF-reinforced Multi-scale synergistic reinforced Z-pin Impact behavior Damage mechanics

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Exploration of failure mechanisms in a novel basalt fiber-reinforced phthalonitrile composite under extreme temperature conditions

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COMPOSITES COMMUNICATIONS 2024年 52卷

作者： Zhao, Guozhi Li, Mengjia Hu, Chaokang Xu, Jiayang Zhejiang Normal Univ Key Lab Urban Rail Transit Intelligent Operat & Ma Jinhua 321004 Peoples R China Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Nanjing 210016 Peoples R China Zhejiang GBF Co Ltd Jinhua 321004 Peoples R China

As composites become increasingly prevalent in aerospace structures, their resistance to high temperatures in extreme environments has captured the attention of numerous scholars. This paper discussed the development of a new basalt fiber-reinforced phthalonitrile matrix (BFRPN) composite, examining its mechanical performance across a spectrum of temperatures, including -55 degrees C low-temperature dry state (CTD), 23 degrees C room-temperature dry state (RTD), 250 degrees C, 350 degrees C, and 450 degrees C. The reliability of the mechanical properties was assessed by calculating the B-basis value. Additionally, optical and scanning electron microscope (SEM) photos were employed to analyze the damage morphology and elucidate the failure mechanisms at both high and low temperatures. The study revealed that the BFRPN composites maintained functional integrity from -55 degrees C to 350 degrees C. For representative unnotched plate tensile (UPT) and unnotched plate compression (UPC) specimens, the retention of UPT strength and UPC strength stayed above 100 % and 83 % respectively. At 450 degrees C, the retention rate of UPT strength consistently exceeds 78 %, while the matrix undergoes significant oxidative decomposition, with delamination being the main observed damage mode.

关键词： Basalt fiber Phthalonitrile Failure mechanism B -basis value High temperature

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