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Numerical Simulation-Based Analysis of the Impact of Overloading on Segmentally Assembled Bridges
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作者 Donghui Ma Wenqi Wu +4 位作者 Yuan Li Lun Zhao yingchun cai Pan Guo Shaolin Yang 《Structural Durability & Health Monitoring》 EI 2024年第5期663-681,共19页
Segmentally assembled bridges are increasinglyfinding engineering applications in recent years due to their unique advantages,especially as urban viaducts.Vehicle loads are one of the most important variable loads acti... Segmentally assembled bridges are increasinglyfinding engineering applications in recent years due to their unique advantages,especially as urban viaducts.Vehicle loads are one of the most important variable loads acting on bridge structures.Accordingly,the influence of overloaded vehicles on existing assembled bridge structures is an urgent concern at present.This paper establishes thefinite element model of the segmentally assembled bridge based on ABAQUS software and analyzes the influence of vehicle overload on an assembled girder bridge struc-ture.First,afinite element model corresponding to the target bridge is established based on ABAQUS software,and the load is controlled to simulate vehicle movement in each area of the traveling zone at different times.Sec-ond,the key cross-sections of segmental girder bridges are monitored in real time based on the force character-istics of continuous girder bridges,and they are compared with the simulation results.Finally,a material damage ontology model is introduced,and the structural damage caused by different overloading rates is compared and analyzed.Results show that thefinite element modeling method is accurate by comparing with on-site measured data,and it is suitable for the numerical simulation of segmental girder bridges;Dynamic sensors installed at 1/4L,1/2L,and 3/4L of the segmental girder main beams could be used to identify the dynamic response of segmental girder bridges;The bottom plate of the segmental girder bridge is mostly damaged at the position where the length of the precast beam section changes and the midspan position.With the increase in load,damage in the direction of the bridge develops faster than that in the direction of the transverse bridge.Thefindings of this study can guide maintenance departments in the management and maintenance of bridges and vehicles. 展开更多
关键词 Segmentally assembled bridge dynamic response moving loads OVERLOADING structural damage finite element analysis
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Life-Cycle Bearing Capacity for Pre-Stressed T-beams Based on Full-Scale Destructive Test
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作者 Yushan Ye Tao Gao +4 位作者 Liankun Wang Junjie Ma yingchun cai Heng Liu Xiaoge Liu 《Structural Durability & Health Monitoring》 EI 2025年第1期145-166,共22页
To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concret... To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity. 展开更多
关键词 Pre-stressed T-beams whole process destructive test bearing capacity verification coefficient
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Fine Characterization and Analysis of Drying Strain of the ELM Board via DIC Technology
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作者 Yuanchu Liu Xiaodong Zhu +5 位作者 Zhengmin Jin Yingying Liu Qingjian Wei Bonan Liang yingchun cai Jingyao Zhao 《Journal of Renewable Materials》 SCIE EI 2023年第2期567-580,共14页
In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the... In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the temperature of 40℃and 80℃is detected via digital image correlation technology.Hence,the difference between tangential and radial strain at surface and core layers was denoted.The results showed that strain distribution in the width direction of the board is uneven.Moreover,a large drying shrinkage strain occurs at the near-core layer,while the maximum strain difference reaches 4.08%.Hence,the surface of the board is cracked along the thickness direction.The radial strain of the board is higher than the tangential strain in the early stage of drying,while these strains are reversed in the later stage of drying.The temperature is related to the difference between the tangential and radial strains of the elm board.These differences at the core layer are larger than those of the surface layer.The conducted research results provide a theoretical basis for process optimization. 展开更多
关键词 Digital image correlation technology drying strain fine characterization moisture content distribution
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Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis
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作者 Xiaoran Jia Jingyao Zhao yingchun cai 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期205-213,共9页
The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport ... The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating. Its advantages compared with the conventional models include: (1) Each independent vari- able has a separate control equation and is solved inde- pendently by converting the partial differential equation into a difference equation with the finite volume method; (2) The calculated data from different parts of the specimen can be displayed in the evolution curves, and the change law of the,parameters can be better described. After analyzing the calculated results, most of the important phenomena observed during RF/V drying were adequately described by this model. 展开更多
关键词 Bulk flow Mathematical model Numerical analysis RF/V drying transfer mechanism
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Waring-Goldbach Problem: One Square and Nine Biquadrates
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作者 Xiaodong Lü yingchun cai 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2019年第2期273-284,共12页
In this paper it is proved that every sufficiently large even integer N satisfying one of the congruence conditions N ≡ 10, 58, 130, or 178(mod 240) may be represented as the sum of one square and nine fourth powers ... In this paper it is proved that every sufficiently large even integer N satisfying one of the congruence conditions N ≡ 10, 58, 130, or 178(mod 240) may be represented as the sum of one square and nine fourth powers of prime numbers. 展开更多
关键词 Waring-Goldbach PROBLEM HARDY-LITTLEWOOD METHOD
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Chen's Theorem with Small Primes
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作者 Yingjie LI yingchun cai 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2011年第3期387-396,共10页
Let N be a sufficiently large even integer.Let p denote a prime and P2 denote an almost prime with at most two prime factors.In this paper,it is proved that the equation N = p + P2(p ≤ N0.945) is solvable.
关键词 Chen's Theorem Sieve method Mean value theorem
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A Remark on Chen’s Theorem (Ⅱ)
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作者 yingchun cai 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2008年第6期687-698,共12页
Let p denote a prime and P2 denote an almost prime with at most two prime factors. The author proves that for sufficiently large x,∑p≤x p+2=P2 1〉1.13Cx/log^2x,where the constant 1.13 constitutes an improvement of ... Let p denote a prime and P2 denote an almost prime with at most two prime factors. The author proves that for sufficiently large x,∑p≤x p+2=P2 1〉1.13Cx/log^2x,where the constant 1.13 constitutes an improvement of the previous result 1.104 due to J. Wu. 展开更多
关键词 Chen's theorem SIEVE Mean value theorem
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