摘要：
Utilizing xanthate in bulk flotation of Cu-Mo sulfide ores is inevitable, but the implication of xanthate on the flotation of molybdenite fines is barely understood. In this study, the influence of sodium butyl xanthate (SIBX) on the flotation of molybdenite fines and the interaction mechanism was comprehensively investigated by micro-flotation tests, contact angle, adsorption capacity, electrochemical tests, atomic force microscopy (AFM), Fourier Transform Infrared Spectrometer (FTIR), X-ray Photoelectron Spectroscopy (XPS) and density functional theory (DFT) calculations. Micro-flotation tests indicated that SIBX significantly enhanced the flotation of molybdenite fines across a wide pH range. Contact angle, adsorption capacity, Tafel curves, AFM, FTIR and XPS results suggested both xanthate and dixanthogen species adsorbed on molybdenite surfaces, thus improving the hydrophobicity of both edges and faces. Rest potential measurements clarified dixanthogen species dominated on faces while xanthate ions prevailed on edges. DFT calculations elucidated dixanthogen physically adsorbed (−66.06 kJ/mol) on faces while xanthate chemisorbed (−235.62 kJ/mol) on edges via the hybridization of two S atoms within SIBX with two Mo atoms to form highly covalent bonds. This work first clearly unveiled the anisotropic adsorption mechanism of SIBX species on faces and edges, significantly improving the flotation efficiency of molybdenite fines.
期刊：
Reliability Engineering & System Safety,2024年244 ISSN：0951-8320
通讯作者：
Wang, L
作者机构：
[Wang, Lei; Hu, Zhuo] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.;[Beer, Michael; Dang, Chao; Hu, Zhuo] Leibniz Univ Hannover, Inst Risk & Reliabil, Callinstr 34, Hannover 30167, Germany.;[Beer, Michael] Univ Liverpool, Inst Risk & Uncertainty, Liverpool L69 7ZF, England.;[Beer, Michael] Tongji Univ, Int Joint Res Ctr Resilient Infrastructure, Shanghai 200092, Peoples R China.;[Beer, Michael] Tongji Univ, Int Joint Res Ctr Engn Reliabil & Stochast Mech, Shanghai 200092, Peoples R China.
通讯机构：
[Wang, L ] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.
关键词：
Bayesian active learning;Small failure probability;Gaussian process;Importance ball sampling;Parallel computing
摘要：
Bayesian active learning methods have emerged for structural reliability analysis, showcasing more attractive features compared to existing active learning methods. The parallel adaptive Bayesian quadrature (PABQ) method, as a representative of them, allows to efficiently assessing small failure probabilities but faces the problem of empirically specifying several important parameters. The unreasonable parameter settings could lead to the inaccurate estimates of failure probability or the non -convergence of active learning. This study proposes a refined PABQ (R-PABQ) method by presenting three novel refinements to overcome the drawbacks of PABQ. Firstly, a sequential population enrichment strategy is presented and embedded into the importance ball sampling technique to solve the computer memory problem when involving large sample population. Secondly, an adaptive determination strategy for radius is developed to automatically adjust the sampling region during the active learning procedure. Lastly, an adaptive multi -point selection method is proposed to identify a batch of points to enable parallel computing. The effectiveness of the proposed R-PABQ method is demonstrated by four numerical examples. Results show that the proposed method can estimate small failure probabilities (e.g., 10-7 similar to 10-9) with superior accuracy and efficiency over several existing active learning reliability methods.
摘要：
Mechanisms responsible for the caving of the strata overlying Chengchao Iron Mine were investigated by analyzing in situ deformation monitoring results and the distinctive engineering geological conditions. The results indicated that waste rocks caved from the overlying host strata and the large-scale sliding rocks at the footwall near the goaf continuously flow towards the caved zone when surrounding rocks of goaf are relatively broken. As a result, a large air gap does not generally form above the caved zone. In this case, the strata overlying the goaf do not globally cave upwards to the surface on a large scale. Instead, they cave in a direction in which the rock is weak and soft and thus form locally caved pipelines within the overlying strata. That is, pipe caving occurs in the overlying strata which results in collapse sinkholes in the ground surface that have a punctate distribution. The continuous flow of large-scale sliding rock masses towards the caved zone can effectively slow down the occurrence of pipe caving. More importantly, rocks surrounding a caved pipeline will cave continuously with excavation of orebodies. However, this caving tends to decrease or completely stop after a certain period of time. This is mainly due to a change in the location of the underground orebody being excavated or because the flow in the caving channel has become blocked. Pipe caving has become a caving mode that is typically encountered in strata overlying the metal ore in mines excavated through sublevel caving with no sill pillars.
摘要：
Circular targets, as one of typical image features, are widely used in image -based measurement, such as photogrammetry, displacement sensing, and vibration monitoring. However, its positioning accuracy is usually sensitive to intensity changes in ambient lighting, particularly in outdoor applications and long-term monitoring scenarios. In this paper, a speckle -based circular target (SbCT) is introduced as a solution to the sensitivity of localization accuracy of traditional circular targets in illumination variation environment. By incorporating a speckle pattern on the circular target and utilizing digital image correlation method, the SbCT achieves insensitivity to illumination variations when an appropriate correlation function is chosen. This enables accurate and reliable measurements even in lighting varying environment. This paper initially outlines the design strategy of the SbCT and demonstrates its extraction procedure. Subsequently, simulations are conducted to analyze the positioning accuracy of SbCT under linearly varying illumination situations. Additionally, experiments are performed to study the accuracy and robustness of SbCT with the comparison to concentric circular targets under different lighting variation cases. The results from both simulation and experiment demonstrate the illumination robustness of SbCT, of which the stability is better than 0.01 pixel. According to the displacement tracking experiment, the relative error obtained by SbCT is smaller than 0.2%. Therefore, it can be concluded that SbCT is an illumination -robust feature, offering automatic recognition and accurate localization performance even in illumination varying situations.
摘要：
In this work, the geopolymerization process was simulated by molecular dynamics based on the NaOH-activated metakaolin system. The structural changes and reaction kinetics during geopolymerization were systematically studied. The results show that the layered structure of MK was gradually destroyed, and the SiO4 and AlO4 monomers were formed. These monomers then reacted with each other to form the network-structured geopolymer. The Alumunum was dissolved prior to silicon and preferentially participated in geopolymerization reaction. The Al3+ acted as a charge-balanced ion to attract the surrounding oxygen linked to Si, making the O-Si-O bond smaller. This study provides a theoretical basis for understanding the reaction kinetics and mechanism of geopolymerization.
通讯机构：
[Guo, W ] C;Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;Natl Engn Res Ctr High Speed Railway Construct Tec, Changsha 410075, Peoples R China.
摘要：
This paper proposes a gradient descent based restoration method of track irregularity. Based on the theory of asymmetric chord-reference method (CRM), the restoration of track irregularity is described as an optimization problem for an underdetermined linear system. Gradient descent method is employed to solve this optimization problem, where a quadratic cost function considering penalization is used. To evaluate the performance of the proposed method, an inspection trolley was setup and used in a field test on a scaled bridge model. Comparison between the proposed method and level measurement validates a good accuracy of gradient descent based restoration method. Compared with traditional method which needs a specially designed inverse filter, the proposed method has a clear physical meaning, which only needs configuration of asymmetric CRM and measured chord reference value to establish the optimization model. This suggests that gradient descent method has good operability in the field test. And the repeatability assessment reveals that the proposed method has a good track irregularity restoration reproduction capacity.
期刊：
Journal of Fluids and Structures,2024年125:104085 ISSN：0889-9746
通讯作者：
Yan Han
作者机构：
School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China;[Yan Han; Jun Song; Peng Hu] Key Laboratory of Bridge Engineering Safety Control by Department of Education, Changsha University of Science & Technology, Changsha 410114, China;[C.S. Cai] Department of Bridge Engineering, School of Transportation, Southeast University, Nanjing, 211189, China;[Kai Li] School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China<&wdkj&>Key Laboratory of Bridge Engineering Safety Control by Department of Education, Changsha University of Science & Technology, Changsha 410114, China
通讯机构：
[Yan Han] K;Key Laboratory of Bridge Engineering Safety Control by Department of Education, Changsha University of Science & Technology, Changsha 410114, China
摘要：
To estimate nonlinear flutter response of long-span bridges, this study established a method for identifying full set of amplitude-dependent flutter derivatives (FDs) from free vibration wind tunnel tests. Taking a typical double-deck truss bridge as a Case study, the amplitude-dependent FDs of the bridge deck at the whole wind speed regime are identified and cross-validated based on large-amplitude free vibration wind tunnel tests of its single degree of freedom (SDOF) torsional and 2DOF vertical-torsional section models. The influential mechanism of vertical DOF on nonlinear flutter was revealed by quantitatively comparing the nonlinear aerodynamic damping of the SDOF and 2DOF systems. The amplitude-dependent FDs are then used to calculate the nonlinear flutter responses of the 2D bridge section and a prototype long-span suspension bridge (1650m) with four main cables based on developed 2D and 3D nonlinear flutter analysis methods. Finally, the influence of structural parameters and 3D effects on nonlinear flutter are quantified and discussed. The results show that the 2DOF system has a lower critical wind speed and higher torsional stable amplitudes compared with the SDOF system since the participation of vertical DOF introduces the negative coupled aerodynamic damping to the system. The aerodynamic nonlinearity becomes stronger and stronger as the wind speed increases and it mainly leads to the significant amplitude dependence of the uncoupled aerodynamic damping, which is the key factor to cause the limit cycle oscillation (LCO)-type of flutter. While the coupled aerodynamic damping appears to be a relatively linear damping with weak amplitude-dependence within the studied wind speed and it mainly plays the role of reducing the stability of the system. The 3D effects of the vibrating bridge deck will reduce the system stability mainly by increasing the negative uncoupled aerodynamic damping. Therefore, the amplitudes of nonlinear flutter will be seriously underestimated if the 3D effects are ignored.
摘要：
As important load-bearing structures, suspension cables have been widely used in suspension bridges, engineering ropeways, cable suspension systems and other special equipment. Their dynamic problems have always been a research hotspot. Especially for complex cable systems such as engineering ropeways and cable lifting equipment, there will be moving loads acting on multi-span continuous friction-slip cable structures, resulting in nonlinear coupled vibration. Therefore, few scholars have studied how to calculate the nonlinear coupling vibration effect between such moving loads and multi-span continuous cables considering friction slip. Therefore, this paper proposes the use of the combination of the direct stiffness method and the Newmark-beta integration method to solve the nonlinear system of equations of motion, which can be derived from the coupled vibration response between the moving load and the main cable. The corresponding calculation program is prepared. Combined with the dynamic load test and simulation results of engineering cases, the correctness and reasonableness of the coupled vibration equations and the program can be verified through comparative analysis. The results show that the calculation results of the self-programmed program are in good agreement with the dynamic load test results, in which the maximum error of the vertical displacement in the span is -4.40% and 0.86%, and the error of the static calculation reaches -13.90%. The impact effect is more obvious when hoisting the weight out of the pulling cable, in which the impact coefficient of the main cable can be up to 2.0. The impact coefficient of the deviation of the cable tower is 4.0. During the traveling process of the moving load, the vertical downward deflection of the main cable at the action point is the largest, and the upward deflection is in the region of 0.2 similar to 0.8L from the action point.
作者机构：
[Yonghao Chu] School of Civil Engineering, Changsha University of Science and Technology, China;Hunan Provincial Key Laboratory of Green Construction and Maintenance of Bridges and Buildings, Changsha University of Science and Technology, China;[Haohui Xin] Department of Civil Engineering, School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, China;[Yuping Zhang; Jun He] School of Civil Engineering, Changsha University of Science and Technology, China<&wdkj&>Hunan Provincial Key Laboratory of Green Construction and Maintenance of Bridges and Buildings, Changsha University of Science and Technology, China
通讯机构：
[Jun He] S;School of Civil Engineering, Changsha University of Science and Technology, China<&wdkj&>Hunan Provincial Key Laboratory of Green Construction and Maintenance of Bridges and Buildings, Changsha University of Science and Technology, China
摘要：
Since temperature effect on steel-concrete composite beam varies significantly across different regions, this study aims to investigate the regional differences and zoning of temperature action values due to solar exposure on steel-concrete composite beams. A steel-concrete composite beam for cable-stayed bridge in Guangdong province of China was taken as a practical engineering case to investigate its temperature field through field monitoring and numerical simulation. The measured temperature values demonstrated a good correlation with the results obtained from the finite element analysis, indicating the accuracy of the performed finite element method. The maximum vertical positive temperature difference (Tv) of steel-concrete composite beam was obtained by thermal analysis using the validated finite element model. The representative value (Td) of vertical temperature difference in steel-concrete composite beam was determined through extrapolation using generalized extreme value distribution function. The representative value of temperature difference (Td) in the 50-year return period of the maximum vertical positive temperature difference in steel-concrete composite beams is 17.61 °C. In addition, the representative values of vertical temperature difference in steel-concrete composite beams were preliminarily determined in 371 major cities of China. A calculation formula considering correlation between temperature difference and meteorological parameters was proposed to calculate the representative value of the temperature difference. Using the proposed formula, the temperature difference of steel-concrete composite beams in Chinese various regions were preliminarily divided into five regions. This study can provide a reference for the improvement of temperature values for steel-concrete composite beam bridges.
摘要：
This paper introduces an asynchronous-pouring-construction (APC) technology for long-span prestressed concrete (PC) box girder bridges with corrugated steel webs (CSWs). The technology makes full use of the CSWs to support the hanging basket. The top slabs, bottom slabs and CSWs are divided into multiple independent working platforms to improve the construction efficiency. In present study, the authors conducted a theoretical analysis of the deflection in PC girder bridges with CSWs using APC technology. A simplified deflection calculation model was developed on the basis of the principle of section equivalence for different segment division. Consequently, a series of theoretical formulas was proposed considering additional shear deflection induced by bending moments. These formulas could be utilised to calculate the configuration and the total deflection of the bridge during APC process, facilitating the pre-camber application to eliminate the deflection and to ensure the closure of the bridge. Moreover, parallel finite element analyses (FEA) and field monitoring tests were conducted to validate the simplified calculation method. The comparison results showed that the calculated deflections using the simplified method agreed well with the FEA and test results. The proportion of shear deflection in the total deflection ranged from 17% to 39% from the forward movement of basket to the pouring slabs, the shear deflection could not be negligible. The segments' length had large effect on the deflection of the CSWs with 50 mm at the maximum cantilever state in this bridge case study, and the deflection induced by the pouring concrete of the slabs accounted for approximately 70% of the total deflection. The additional shear deformation due to bending moment at the end of area A (composite section with both concrete top and bottom slabs and CSWs) was basically the same as that in area B (composite section with bottom slab and CSWs). Therefore, the simplified method which takes into account the additional shear deformation of the segments in area A without considering area B was able to satisfy the engineering accuracy. In short, in comparison to traditional analytical methods and FEA, the proposed method could predict the deflection more efficient within accept accuracy.
摘要：
The existing calculation process of the cantilever cast arch-cable force has a poor fit with the actual process, leading to the lack of good parameter corrections. To improve the overall control quality of the linearity and stress of the arch ring, there is an urgent need for a solution method with higher flexibility and better practicability. Combined with the existing research results, this study proposes a multi-loop nesting algorithm. The algorithm decomposes the whole construction process into individual subsystem control modules, and sets the control indexes of stress and displacement in individual control modules. Subsequently, the analysis and calculation of other modules are completed according to the construction sequence until structure closure. Finally, we determine whether the overall construction control indexes meet the requirements. According to the findings, the results obtained by this algorithm meet the design requirements, and its applicability is verified. Compared with other algorithms, the algorithm is more effective in controlling the stress and deformation of the arch ring during the construction process. This algorithm solves the dispersion between structural systems in previous calculations and has more flexible parameter and control index settings. Additionally, the calculation control idea of this algorithm can be further extended to the construction control of the "cable-beam" cantilever structure.
通讯机构：
[Zhang, JM ] C;Changsha Univ Sci & Technol, Sch Comp & Commun Engn, Changsha 410114, Peoples R China.
关键词：
Object tracking;Cross-correlation;Transformer;Decoupled head
摘要：
The fusion of the template and search region features plays a significant role in deep learningbased trackers. In Siamese -based trackers, different cross -correlation operations are commonly used to fuse features, which cannot obtain global connections. On the other hand, transformerbased trackers use attention mechanism to fuse features, which cannot suppress the interference of distractors in the background. Furthermore, existing trackers use regression and classification heads with the same structure, which leads to lack a deeper understanding of these two different tasks. To address these problems, we firstly propose a feature enhancement -fusion network (FEFN) based on cross -correlation and transformer, with two Encoders that employ self -attention and a Decoder that removes cross -attention to adapt to the tracking task. Using the FEFN to combine the advantages of Siamese -based and transformer -based trackers, our tracker establishes global connections while effectively suppressing the distractors. We also propose a novel decoupled head, designing a spatial sensitive classification head and a global information sensitive regression head, which helps the context -aware tracker locate the target more accurately. Our proposed tracker obtains 0.710 of AO, 0.814 of SR0.5 and 0.657 of SR0.75 on the GOT -10k test set, and achieves real-time requirement at 36.99FPS.
作者机构：
[Yusong Pan; Pan Wu] Department of Engineering Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China;[Shuaiqi Fan] School of Mechanics and Construction Engineering, Jinan University, West Huangpu Avenue 601, Guangzhou 510632, China;[Xulong Peng] School of Civil Engineering, Changsha University of Science & Technology, Changsha, Hunan 410114, China;Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, 1037 Luoyu Road, Wuhan 430074, China;[Ziguang Chen] Department of Engineering Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China<&wdkj&>Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, 1037 Luoyu Road, Wuhan 430074, China
通讯机构：
[Xulong Peng] S;[Ziguang Chen] D;Department of Engineering Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China<&wdkj&>Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, 1037 Luoyu Road, Wuhan 430074, China<&wdkj&>School of Civil Engineering, Changsha University of Science & Technology, Changsha, Hunan 410114, China
摘要：
Pores are a key type of concerns in additive manufacturing technology. They can significantly affect materials’ fatigue resistance and fatigue crack growth in the structures. In this paper, an intermediately-homogenized (IH) peridynamic (PD) fatigue crack model is introduced for simulating the fatigue crack growth in porous materials. The effect of micro-scale heterogeneity on fatigue failure is preserved in the IH-PD model, where stochastically-generated pre-damage matches materials’ porosity. The PD J-integral, a key parameter used to connect the fatigue simulation and the experimental measurements, is calculated under different porosities, and the independence of PD J-integral on its integration path is verified. Then, the PD fatigue crack model combined with the IH-PD material model is applied to study the dependence of the crack path and growth rate on porosity in compact tension alloy samples. The normalized fatigue life between experimental measurements and numerical results is compared. The normalized fatigue life-porosity relationship calculated from the IH-PD fatigue model matches the average trend of the experimental measurements.
摘要：
In Singapore's hot tropical climate, phase change materials (PCMs) hold significant promise for year-round passive cooling solutions in buildings. However, the narrow diurnal temperature range of 24-32 degrees C poses a great challenge for pure PCMs with poor thermal conductivity to undergo complete melting-freezing cycles. Herein, we tested two composite PCMs in a self-designed thermal box: (1) paraffin RT28HC/graphene nanoplatelets (GNP-PCMs) and (2) paraffin RT28HC/copper foam (CF-PCMs). The passive cooling performance of the composite PCMs was evaluated based on their charging power at 32 degrees C and discharging power at 24 degrees C. The focus is on convection heat transfer between the composite PCMs and ambient air, with considering various factors, including GNPs content (0.1-0.9 wt%), CF pore density (40 pores per inch (PPI) and 70 PPI), airflow rate (natural convection and forced convection), and orientation (horizontal and vertical). The results indicate that a minimum temperature range of 26.6-30.3 degrees C is necessary for complete melting-freezing cycles. The effect of GNPs content is more sensitive to orientation, whereas the effect of CF pore density is more affected by airflow rate. In all cases, the CF-PCMs exhibit superior temperature uniformity than the GNP-PCMs. Under forced convection, the charging power and discharging power of pure PCM reached a maximum of 110.8 and 163.5 W/m2, respectively. The addition of GNPs enhanced the charging power and discharging power of pure PCM by up to 14.2 % and 10.2 %, respectively. Moreover, the incorporation of CF boosted the charging power and discharging power of pure PCM by up to 75.1 % and 64.3 %, respectively.
期刊：
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS,2024年21:1-5 ISSN：1545-598X
作者机构：
[Yinshuo Li; Wenkai Lu; Cao Song] Department of Automation and the Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, China;[Zhuo Jia] School of Civil Engineering, Changsha University of Science and Technology, Changsha, China
摘要：
Magnetic inversion aims to estimate the subsurface susceptibility distribution from surface magnetic anomaly data. Recently, supervised deep learning (DL) methods have been widely utilized in lots of geophysical fields including magnetic inversion. However, these methods rely heavily on synthetic training data, whose performance is limited since the synthetic data are not independently and identically distributed with the field data. Thus, we proposed to realize magnetic inversion by self-supervised learning. The proposed self-supervised knowledge-driven method for 3-D magnetic inversion (SSKMI) learns on the target field data by a closed loop of the inversion and forward models. Given that the parameters of the forward model are preset, SSKMI can optimize the inversion model by minimizing the difference between observed and re-estimated surface magnetic anomalies. Besides, there is a knowledge-driven module in the proposed inversion model, which makes the DL-based method more explicable. Meanwhile, comparative experiments demonstrate that the knowledge-driven module can accelerate the training and achieve better results. Since magnetic inversion is an ill-pose task, SSKMI proposed to constrain the inversion model by a guideline from a well log, seismic waves, or electromagnetic signals. The experimental results demonstrate that the proposed method is a reliable magnetic inversion method with outstanding performance.
摘要：
The mechanical performance of carbon fiber reinforced polymer (CFRP) is a crucial parameter influencing the effectiveness of CFRP reinforcement. The addition of nano-toughening agents to the resin matrix can effectively enhance the mechanical properties of CFRP. This paper investigates the influence of nano-SiO2 and MWCNTs content (0.2, 0.4, and 0.6 wt%) as well as their blending ratios (1:3, 1:1, 3:1) on the tensile properties of CFRP plates using the vacuum assisted resin infusion molding (VARIM) process. Additionally, an assessment is conducted to evaluate how the tensile performance of CFRP plates affects the CFRP plate/steel interface performance.The results indicate that the resin viscosity increases with the addition of nano-toughening agents, with the resin viscosity experiencing a respective increase of 32.9% and 92.7% when incorporating 0.6 wt% nano-SiO2 or MWCNTs compared to pure resin. The inclusion of nano-toughening agents enhances the tensile strength of CFRP plates, with a more pronounced effect observed when adding 0.4 wt% nano-SiO2 or MWCNTs, resulting in respective increases of 41.5% and 31.5% compared to pure CFRP plates. When nano-SiO2 and MWCNTs are mixed, the tensile performance of the CFRP plate is inferior to that of plates with the same individual nano-toughening agents content. This is attributed to the excessively high viscosity of the resin matrix during mixing, hindering complete infiltration of carbon fibers. Therefore, in the manufacturing process of CFRP plates using the VARIM technique, it is advisable to consider resins with lower viscosity. Additionally, the utilization of CFRP plates with superior tensile performance contributes to enhanced CFRP/steel interface properties, although the tensile performance of CFRP plates does not alter the bonding slip curve of CFRP/steel double-lap joint specimens.
摘要：
To investigate the effects of compaction (K), rock content (RC), and wet-dry cycle (WD) on the road performance of carbonaceous mudstone soil-rock mixtures (CMSRM), orthogonal tests were designed to measure the unconfined compressive strength (UCS) and California bearing ratio (CBR). The correlation degree of K, RC, and WD with the UCS and CBR of CMSRM was investigated using orthogonal theory and grey correlation theory. Based on multivariate nonlinear regression analysis, mathematical models of the road performance of CMSRM were built. The results show that the UCS and CBR of CMSRM were positively correlated with K and negatively correlated with the WD. With increasing RC, UCS increased at first and then decreased, while CBR increased continuously. The failure modes of CMSRM change from tensile failure to shear failure as the K increases under uniaxial compression. The RC and WD affect the structural integrity of the failed samples. Combining the results of range analysis, variance analysis, and grey relational analysis, the most significant influence on the UCS is K, and the most significant influence on the CBR is RC. It is recommended to select 94%–96% for K and 40%–60% for RC in engineering.
作者：
Zhenhao Zhang Aff.M.ASCE;Yu Liu;Lei Wang M.ASCE*;Wenbiao Li;Gao Ma
期刊：
ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering,2024年10(2):04024007 ISSN：2376-7642
通讯作者：
Lei Wang M.ASCE
作者机构：
[Gao Ma] Associate Professor, College of Civil Engineering, Hunan Univ., Lushan South Rd., Changsha 410082, China.;[Wenbiao Li] Postgraduate Student, School of Civil Engineering, Changsha Univ. of Science and Technology, 960 Wanjiali South Rd., Changsha 410114, China.;[Yu Liu] Postgraduate Student, School of Civil Engineering, Changsha Univ. of Science and Technology, 960 Wanjiali South Rd., Changsha 410114, China;[Zhenhao Zhang Aff.M.ASCE] Professor, School of Civil Engineering, Changsha Univ. of Science and Technology, 960 Wanjiali South Rd., Changsha 410114, China;[Lei Wang M.ASCE] Professor, School of Civil Engineering, Changsha Univ. of Science and Technology, 960 Wanjiali South Rd., Changsha 410114, China
通讯机构：
[Lei Wang M.ASCE] P;Professor, School of Civil Engineering, Changsha Univ. of Science and Technology, 960 Wanjiali South Rd., Changsha 410114, China
摘要：
Based on the stochastic process multiple threshold crossings analysis formula, the impact of structural response random process crossing-threshold duration on structural fatigue reliability is studied, which was not involved in fatigue reliability analysis before. This paper considers the type of structural stress stochastic processes with Wiener characteristics in engineering and establishes a novel method considering the random response crossing-threshold duration for fatigue reliability evaluation. The fatigue cumulative damage considering random response crossing-threshold duration is derived analytically based on the assumption that cumulative damage is linear to crossing-threshold duration. This study makes the fatigue reliability analysis closer to the reality.
作者机构：
National-Local Joint Laboratory of Engineering Technology for Long-Term Performance Enhancement of Bridges in Southern District, Changsha University of Science & Technology, Changsha 410114, China;[Jing Liu; Jian Cui; Yang Liu; Naiwei Lu; Honghao Wang] Key Laboratory of Bridge Engineering Safety Control by Department of Education, School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China;Author to whom correspondence should be addressed.;[Guodong Wang] National-Local Joint Laboratory of Engineering Technology for Long-Term Performance Enhancement of Bridges in Southern District, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Key Laboratory of Bridge Engineering Safety Control by Department of Education, School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
通讯机构：
[Guodong Wang] N;National-Local Joint Laboratory of Engineering Technology for Long-Term Performance Enhancement of Bridges in Southern District, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Key Laboratory of Bridge Engineering Safety Control by Department of Education, School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Multiple fatigue cracks are generally present in practical engineering due to the existence of welding; the size and number of cracks of orthotropic steel bridge decks are greatly uncertain. The component failure conditions caused by these cracks may have correlations. Currently, it is still a challenging issue to develop a physical model of multiple fatigue crack propagation in bridge decks and perform a fatigue reliability assessment, which is also the motivation that drives the innovation of this study. A fatigue reliability evaluation method is presented for orthotropic steel bridge decks, considering the coupling effect of multiple cracks and the randomness of vehicle loading. A numerical simulation method for multifatigue crack growth is developed by combining the ABAQUS and FRANC3D programs. The equivalent crack depth under different spacing and depths of collinear cracks is calculated by using numerical simulation and the multicrack equivalent characterization method. The critical damage accumulation function of multiple fatigue cracks is established using linear elastic fracture mechanics. Subsequently, the critical damage accumulation function of multiple fatigue cracks is established based on linear elastic fracture mechanics. In order to solve the time-consuming problem of traditional Monte Carlo method, the iHL-RF method and AK-MCS method are developed for fatigue reliability analysis. The results show that compared with the single-crack model, the fatigue reliability of orthotropic steel deck will be crucially reduced considering the coupling effect of double cracks. The MCS, iHL-RF and AK-MCS methods can effectively solve the fatigue reliability analysis problem. Compared with the MCS method, the reliability calculation time based on AK-MCS method is significantly reduced. The AK-MCS method-based method reduces the time for calculating the reliability of orthotropic steel decks by 50% compared with the iHL-RF method. The reliability analysis of orthotropic steel deck bridge based on AK-MCS method is proved to be efficient and accurate.
