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Analytical solution for longitudinal deformation of shield tunnel induced by overcrossing tunnelling considering circumferential joints
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作者 Zhiwei Zhang Rongzhu Liang +4 位作者 Zhongchao Li Cheng Kang MHEl Naggar Mingzhao Xiao Wenbing Wu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第9期2355-2374,共20页
This paper presents a new analytical solution for assessing the longitudinal deformation of shield tunnel associated with overcrossing tunnelling in consideration of circumferential joints.A simplified longitudinal be... This paper presents a new analytical solution for assessing the longitudinal deformation of shield tunnel associated with overcrossing tunnelling in consideration of circumferential joints.A simplified longitudinal beam-spring model(SLBSM)is established to model the longitudinal behaviours of shield tunnel,which can consider the opening and dislocation between segmental rings simultaneously.Then,the existing tunnel is treated as the SLBSM resting on the elastic foundation.The state equations including tunnel displacements and internal forces are constructed to solve the discontinuous deformation of circumferential joint-segmental ring.The feasibility of the proposed solution is verified through three well-documented cases.The predictions from the proposed method are also compared with other analytical methods.It is found that the proposed method can well capture the deformation of tunnel segmental rings and joints,where the rigid displacement mainly occurs in the segmental rings while the rotation and dislocation occur in the circumferential joints.Some dominant parameters are also analysed to explore the effects on existing tunnel deformation,including the rotation stiffness and shearing stiffness of joints,the skew angle and the clearance between new and old tunnels. 展开更多
关键词 Overcrossing tunnelling Shield tunnel circumferential joints Longitudinal beam-spring model(LBSM) Opening DISLOCATION
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Prognostic Value of Feature-Tracking Circumferential Strain in Dilated Cardiomyopathy Patients with Severely Reduced Ejection Fraction Incremental to Late Gadolinium Enhancement 被引量:7
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作者 Shcng-lei SHU Jing WANG +6 位作者 Cheng WANG Feng ZHU Yu-xi JIA Lan ZHANG Xiao-yue ZHOU Tian-jing ZHANG Chuan-sheng ZHENG 《Current Medical Science》 SCIE CAS 2021年第1期158-166,共9页
Myocardial fiber deformation measurements have been reported to be associated with adverse outcomes in patients with acute heart failure and those with myocardial infarction.However,few studies have addressed the prog... Myocardial fiber deformation measurements have been reported to be associated with adverse outcomes in patients with acute heart failure and those with myocardial infarction.However,few studies have addressed the prognostic value of global circumferential strain(GCS)in dilated cardiomyopathy(DCM)patients with severely impaired systolic function.This study aimed to evaluate the prognostic value of cardiac magnetic resonance(CMR)-derived GCS in DCM patients with severely reduced ejection.Consecutive DCM patients with severely reduced ejection fraction(EF<35%)who underwent CMR were included.GCS was calculated from CMR cine images.The clinical endpoint was a composite of all-cause mortality,heart transplantation,implantable cardioverter defibrillator(ICD)implantation and aborted sudden cardiac death(SCD).A total of 129 patients with a mean EF of 15.33%(11.36%–22.27%)were included.During a median follow-up of 518 days,endpoint events occurred in 50 patients.Patients with GCS≥the median(−5.17%)had significantly reduced event-free survival as compared with those with GCS<the median(P<0.01).GCS was independently associated with adverse events after adjusting for clinical and imaging risk factors including extent of late gadolinium enhancement(LGE)(P<0.05).Adding GCS into the model including the extent of LGE resulted in significant improvements in the C-statistic(from 0.706 to 0.742;P<0.05)with a continuous net reclassification improvement(NRI)of 29.71%.It was concluded that GCS derived from CMR could be useful for risk stratification in DCM patients with severely reduced EF,which may increase common imaging risk factors including LGE. 展开更多
关键词 cardiac magnetic resonance imaging circumferential strain PROGNOSIS late gadolinium enhancement dilated cardiomyopathy
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Analytical computation of support characteristic curve for circumferential yielding lining in tunnel design 被引量:5
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作者 Kui Wu Zhushan Shao +2 位作者 Mostafa Sharifzadeh Siyuan Hong Su Qin 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第1期144-152,共9页
Circumferential yielding lining is able to tolerate controlled displacements without failure,which has been proven to be an effective solution to large deformation problem in squeezing tunnels.However,up to now,there ... Circumferential yielding lining is able to tolerate controlled displacements without failure,which has been proven to be an effective solution to large deformation problem in squeezing tunnels.However,up to now,there has not been a well-established design method for it.This paper aims to present a detailed analytical computation of support characteristic curve(SCC)for circumferential yielding lining,which is a significant aspect of the implementation of convergence-confinement method(CCM)in tunnel support design.Circumferential yielding lining consists of segmental shotcrete linings and highly deformable elements,and its superior performance mainly depends on the mechanical characteristic of highly deformable element.The deformation behavior of highly deformable element is firstly investigated.Its whole deforming process can be divided into three stages including elastic,yielding and compaction stages.Especially in the compaction stage of highly deformable element,a nonlinear stress-strain relationship can be observed.For mathematical convenience,the stress-strain curve in this period is processed as several linear sub-curves.Then,the reasons for closure of circumferential yielding lining in different stages are explained,and the corresponding accurate equations required for constructing the SCC are provided.Furthermore,this paper carries out two case studies illustrating the application of all equations needed to construct the SCC for circumferential yielding lining,where the reliability and feasibility of theoretical derivation are also well verified.Finally,this paper discusses the sensitivity of sub-division in element compaction stage and the influence of element length on SCC.The outcome of this paper could be used in the design of proper circumferential yielding lining. 展开更多
关键词 Squeezing ground circumferential yielding lining Highly deformable element Support characteristic curve(SCC) Analytical method
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Fracture mechanism of a cylindrical shell cut by circumferential detonation collision 被引量:3
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作者 He-yang Xu Wei-bing Li +4 位作者 Wen-bin Li Qing Zhang Ya-jun Wang Xiao-wen Hong Ying Yang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第5期1650-1659,共10页
The failure mechanism of a cylindrical shell cut into fragments by circumferential detonation collision was experimentally and numerically investigated.A self-designed detonation wave regulator was used to control the... The failure mechanism of a cylindrical shell cut into fragments by circumferential detonation collision was experimentally and numerically investigated.A self-designed detonation wave regulator was used to control the detonation and cut the shell.It was found that the self-designed regulator controlled the fragment shape.The macrostructure and micro-characteristics of fragments revealed that shear fracture was a prior mechanism,the shell fractured not only at the position of detonation collision,but the crack also penetrated the shell at the first contact position of the Chapmen-Jouguet(C-J)wave.The effects of groove number and outer layer thickness on the fracture behavior were tested by simulations.When the thickness of the outer layer was 5e18 mm,it has little effect on fragmentation of the shell,and shells all fractured at similar positions.The increase of the groove number reduced the fracture possibility of the first contact position of the C-J wave.When the groove number reached 7 with a 10 mm outer layer(1/4 model),the fracture only occurred at the position of detonation collision and the fragment width rebounded. 展开更多
关键词 Detonation wave circumferential detonation collision Fracture mechanism Fragmentation control
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Numerical Perspective of Second-Harmonic Generation of Circumferential Guided Wave Propagation in a Circular Tube 被引量:2
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作者 李明亮 邓明晰 +2 位作者 朱武军 高广健 项延训 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第12期81-85,共5页
The effect of second-harmonic generation (SHG) by primary (fundamental) circumferential guided wave (CGW) propagation is investigated from a numerical standpoint. To enable that the second harmonic of the primar... The effect of second-harmonic generation (SHG) by primary (fundamental) circumferential guided wave (CGW) propagation is investigated from a numerical standpoint. To enable that the second harmonic of the primary CGW mode can accumulate along the circumferential direction, an appropriate mode pair of primary and double frequency CGWs is chosen. Finite element simulations and evaluations of nonlinear CGW propagation are analyzed for the selected CGW mode pair. The numerical simulations performed directly demonstrate that the response of SHG is completely generated by the desired primary CGW mode that satisfies the condition of phase velocity matching at a specific driving frequency, and that the second harmonic of the primary CGW mode does have a cumulative effect with circumferential angles. The numerical perspective obtained yields an insight into the complicated physical process of SHG of primary CGW propagation unavailable previously. 展开更多
关键词 of on MODE Numerical Perspective of Second-Harmonic Generation of circumferential Guided Wave Propagation in a Circular Tube in SHG is for that
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Performance comparison for oil-water heat transfer of circumferential overlap trisection helical baffle heat exchanger 被引量:2
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作者 王伟晗 程道来 +1 位作者 刘涛 刘颖昊 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第10期2720-2727,共8页
The performance tests were conducted on oil–water heat transfer in circumferential overlap trisection helical baffle heat exchangers with incline angles of 12°, 16°, 20°, 24° and 28°, and com... The performance tests were conducted on oil–water heat transfer in circumferential overlap trisection helical baffle heat exchangers with incline angles of 12°, 16°, 20°, 24° and 28°, and compared with a segmental baffle heat exchanger. The results show that the shell side heat transfer coefficient h_o and pressure drop Δp_o both increase while the comprehensive index h_o/Δp_o decreases with the increase of the mass flow rate of all schemes. And the shell side heat transfer coefficient, pressure drop and the comprehensive index ho/Δpo decrease with the increase of the baffle incline angle at a certain mass flow rate. The average values of shell side heat transfer coefficient and the comprehensive index h_o/Δp_o of the 12° helical baffled scheme are above 50% higher than those of the segmental one correspondingly, while the pressure drop value is very close and the ratios of the average values are about 1.664 and 1.596, respectively. The shell-side Nusselt number Nu_o and the comprehensive index Nu_o·Eu_(zo)^(-1) increase with the increase of Reynolds number of the shell side axial in all schemes, and the results also demonstrate that the small incline angled helical scheme has better comprehensive performance. 展开更多
关键词 performance experiments helical baffled heat exchangers circumferential overlap of baffles incline angle of baffle heat transfer enhancement
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GUIDED CIRCUMFERENTIAL WAVES IN DOUBLE-WALLED CARBON NANOTUBES 被引量:2
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作者 Zhang Huiling Yin Xiaochun 《Acta Mechanica Solida Sinica》 SCIE EI 2007年第2期110-116,共7页
A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotu... A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotube has been taken into account in the model. The dispersion curves of the guided circumferential wave propagation are studied, and some dispersion characteristics are illustrated by comparing with those of single-walled carbon nanotubes. It is found that in double-walled carbon nanotubes, the guided circumferential waves will propagate in more dispersive ways. More interactions between neighboring wave modes may take place. In particular, it has been found that a couple of wave modes may disappear at a certain frequency and that, while a couple of wave modes disappear, another new couple of wave modes are excited at the same wave number. 展开更多
关键词 carbon nanotube guided circumferential waves continuum mechanics van der Waals force dispersion equation mode disappearance and excitation
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Study of circumferential resection margin in patients with middle and lower rectal carcinoma 被引量:2
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作者 Ze-Yu Wu Jin Wan +8 位作者 Jing-Hua Li Gang Zhao Lin Peng Yuan Yao Jia-Lin Du Quan-Fang Liu Zhi-Du Wang Zhi-Ming Huang Hua-Huan Lin 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第24期3380-3383,共4页
AIM: To clarify the relationship between circumferential resection margin status and local and distant recurrence as well as survival of patients with middle and lower rectal carcinoma. The relationship between circum... AIM: To clarify the relationship between circumferential resection margin status and local and distant recurrence as well as survival of patients with middle and lower rectal carcinoma. The relationship between circumferential resection margin status and clinicopathologic characteristics of middle and lower rectal carcinoma was also evaluated. METHODS: Cancer specimens from 56 patients with middle and lower rectal carcinoma who received total mesorectal excision at the Department of General Surgery of Guangdong Provincial People's Hospital were studied. A large slice technique was used to detect mesorectal metastasis and evaluate circumferential resection margin status. RESULTS: Local recurrence occurred in 12.5% (7 of 56 cases) of patients with middle and lower rectal carcinoma. Distant recurrence occurred in 25% (14 of 56 cases) of patients with middle and lower rectal carcinoma. Twelve patients (21.4%) had positive circumferential resection margin. Local recurrence rate of patients with positive circumferential resection margin was 33.3% (4/12), whereas it was 6.8% (3/44) in those with negative circumferential resection margin (P = 0.014). Distant recurrence was observed in 50% (6/12) of patients with positive circumferential resection margin; conversely, it was 18.2% (8/44) in those with negative circumferential resection margin (P = 0.024). Kaplan-Meier survival analysis showed significant improvements in median survival (32.2 ± 4.1 mo, 95% CI: 24.1-40.4mo vs 23.0 ± 3.5 mo, 95% CI: 16.2-29.8 mo) for circumferential resection margin-negative patients over circumferential resection margin-positive patients (log-rank, P < 0.05). 37% T3 tumors examined were positive for circumferential resection margin, while only 0% T1 tumors and 8.7% T2 tumors were examined as circumferential resection margin. The difference between these three groups was statistically significant (P = 0.021). In 18 cancer specimens with tumor diameter ≥ 5 cm 7 (38.9%) were detected as positive circumferential resection margin, while in 38 cancer specimens with a tumor diameter of < 5 cm only 5 (13.2%) were positive for circumferential resection margin (P = 0.028). CONCLUSION: Our findings indicate that circumferential resection margin involvement is significantly associated with depth of tumor invasion and tumor diameter. The circumferential resection margin status is an important predictor of local and distant recurrence as well as survival of patients with middle and lower rectal carcinoma. 展开更多
关键词 Middle and lower rectal carcinoma circumferential resection margin PROGNOSIS
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Enhancement effect of cumulative second-harmonic generation by closed propagation feature of circumferential guided waves 被引量:1
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作者 Guang-Jian Gao Ming-Xi Deng +1 位作者 Ning Hu Yan-Xun Xiang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第2期301-308,共8页
On the basis of second-order perturbation approximate and modal expansion approach,we investigate the enhancement effect of cumulative second-harmonic generation(SHG)of circumferential guided waves(CGWs)in a circular ... On the basis of second-order perturbation approximate and modal expansion approach,we investigate the enhancement effect of cumulative second-harmonic generation(SHG)of circumferential guided waves(CGWs)in a circular tube,which is inherently induced by the closed propagation feature of CGWs.An appropriate mode pair of primary-and double-frequency CGWs satisfying the phase velocity matching and nonzero energy flux is selected to ensure that the second harmonic generated by primary CGW propagation can accumulate along the circumference.Using a coherent superposition of multi-waves,a model of unidirectional CGW propagation is established for analyzing the enhancement effect of cumulative SHG of primary CGW mode selected.The theoretical analyses and numerical simulations performed directly demonstrate that the second harmonic generated does have a cumulative effect along the circumferential direction and the closed propagation feature of CGWs does enhance the magnitude of cumulative second harmonic generated.Potential applications of the enhancement effect of cumulative SHG of CGWs are considered and discussed.The theoretical analysis and numerical simulation perspective presented here yield an insight previously unavailable into the physical mechanism of the enhancement effect of cumulative SHG by closed propagation feature of CGWs in a circular tube. 展开更多
关键词 circumferential guided wave second-harmonic generation(SHG) enhancement effect of CUMULATIVE SHG CLOSED PROPAGATION FEATURE
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CIRCUMFERENTIAL EQUISPACED CURVES'S IMAGE DETECTION TECHNIQUE AND ITS APPLAICATION ON RIFLING ANGLE MEASUREMENT 被引量:1
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作者 ZhengJun ZhangWei ShiKeren 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第4期519-523,共5页
Aiming at the parameter detection of the circumferential equispaced curves,and on the background of the rifling parameter detection, a panoramic image based detectiontechnique is proposed, which employs the panoramic ... Aiming at the parameter detection of the circumferential equispaced curves,and on the background of the rifling parameter detection, a panoramic image based detectiontechnique is proposed, which employs the panoramic image photographed by a tamper reflector and aCCD camera to detect the parameter of the circumferential equispaced curves. The effect of thesystem's off-center error, deflection error and pixel error on the parameter detection is analyzed,which shows that this technique make a good use of the property of the circumferential equispaced,and has a high power of anti off-center error and anti deflection error, resulting a high precisionat the parameter measurement on circumferential equispaced curves. 展开更多
关键词 Image detection Panoramic image circumferential equispaced curves Rifling
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Giant Circumferential Dyke Swarms on Earth: Possible Analogues of Coronae on Venus and Similar Features on Mars 被引量:2
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作者 Kenneth L.BUCHAN Richard E.ERNST 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期186-187,共2页
Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
关键词 Giant circumferential Dyke Swarms on Earth Possible Analogues of Coronae on Venus and Similar Features on Mars
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Experimental Observation of Cumulative Second-Harmonic Generation of Circumferential Guided Wave Propagation in a Circular Tube 被引量:2
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作者 邓明晰 高广健 李明亮 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第12期88-91,共4页
The experimental observation of cumulative second-harmonic generation of the primary circumferential guided wave propagation is reported. A pair of wedge transducers is used to generate the primary circumferential gui... The experimental observation of cumulative second-harmonic generation of the primary circumferential guided wave propagation is reported. A pair of wedge transducers is used to generate the primary circumferential guided wave desired and to detect its fundamental-frequency and second-harmonic amplitudes on the outside surface of the circular tube. The amplitudes of the fundamental waves and the second harmonics of the circumferential guided wave propagation are measured for different separations between the two wedge transducers. At the driving frequency where the primary and the double-frequency circumferential guided waves have the same linear phase velocities, the clear second-harmonic signals can be observed. The quantitative relationships between the second-harmonic amplitudes and circumferential angle are analyzed. It is experimentally verified that the second harmonics of primary circumferential guided waves do have a cumulative growth effect with the circumferential angle. 展开更多
关键词 LENGTH Experimental Observation of Cumulative Second-Harmonic Generation of circumferential Guided Wave Propagation in a Circular Tube
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Direct numerical simulation of turbulent flows through concentric annulus with circumferential oscillation of inner wall 被引量:1
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作者 Yichen YAO Chunxiao XU Weixi HUANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2018年第9期1267-1276,共10页
Periodic wall oscillations in the spanwise or circumferential direction can greatly reduce the friction drag in turbulent channel and pipe flows. In a concentric annulus, the constant rotation of the inner cylinder ca... Periodic wall oscillations in the spanwise or circumferential direction can greatly reduce the friction drag in turbulent channel and pipe flows. In a concentric annulus, the constant rotation of the inner cylinder can intensify turbulence fluctuations and enhance skin friction due to centrifugal instabilities. In the present study, the effects of the periodic oscillation of the inner wall on turbulent flows through concentric annulus are investigated by the direct numerical simulation(DNS). The radius ratio of the inner to the outer cylinders is 0.1, and the Reynolds number is 2 225 based on the bulk mean velocity Um and the half annulus gap H. The influence of oscillation period is considered. It is found that for short-period oscillations, the Stokes layer formed by the circumferential wall movement can effectively inhibit the near-wall coherent motions and lead to skin friction reduction, while for long-period oscillations, the centrifugal instability has enough time to develop and generate new vortices, resulting in the enhancement of turbulence intensity and skin friction. 展开更多
关键词 turbulence drag reduction circumferential oscillation Taylor vortex
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Study on mechanism of circumferential cracks in cold-region tunnels 被引量:2
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作者 ZHOU Lincong ZHENG Yifeng LI Zhong 《Global Geology》 2010年第2期75-78,共4页
There exists frost damage in cold-region tunnels. The circumferential cracks affect the function of tunnels. Using three-dimensional finite element method, the authors analyzed the mechanism of circumferential cracks ... There exists frost damage in cold-region tunnels. The circumferential cracks affect the function of tunnels. Using three-dimensional finite element method, the authors analyzed the mechanism of circumferential cracks in cold-region tunnels It is proved that the internal thermal stress in lining exceeds the tensile strength of concrete, which is the direct cause for circumferential cracks occurring. The laws of thermal stress in lining induced by parameters such as temperature drop, horizontal drag coefficient and length of lining are analyzed. The conclusions are valuable to the design and construction of cold-region tunnels considering the thermal stress. 展开更多
关键词 TUNNEL cold region circumferential crack temperature stress
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Response features of nonlinear circumferential guided wave on early damage in inner layer of a composite circular tube
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作者 Ming-Liang Li Liang-Bing Liu +4 位作者 Guang-Jian Gao Ming-Xi Deng Ning Hu Yan-Xun Xiang Wu-Jun Zhu 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第4期224-229,共6页
A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variation... A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variations in third-order elastic constants(TOECs)] in an inner layer of CCT are investigated. On the basis of the modal expansion approach, the second-harmonic field of primary CGW propagation can be assumed to be a linear sum of a series of double-frequency CGW(DFCGW) modes. The quantitative relationship of DFCGW mode versus the relative changes in the inner layer TOECs is then investigated. It is found that the changes in the inner layer TOECs of CCT will obviously affect the driving source of DFCGW mode and its modal expansion coefficient, which is intrinsically able to influence the efficiency of cumulative second-harmonic generation(SHG) by primary CGW propagation. Theoretical analyses and numerical simulations demonstrate that the second harmonic of primary CGW is monotonic and very sensitive to the changes in the inner layer TOECs of CCT, while the linear properties of primary CGW propagation almost remain unchanged. Our results provide a potential application for accurately characterizing the level of early damage in the inner layer of CCT through the efficiency of cumulative SHG by primary CGW propagation. 展开更多
关键词 circumferential GUIDED wave(CGW) early damage INNER LAYER of COMPOSITE circular tube secondharmonic generation(SHG)
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Transverse Vibration Analysis of Concentrated Mass-Loaded Thin Circular Plate Based on Strcutural Circumferential Periodicity
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作者 李德胜 张俊红 +1 位作者 李德华 毕凤荣 《Transactions of Tianjin University》 EI CAS 2015年第2期147-152,共6页
The structural circumferential periodicity of inertial excitation produced by concentrated mass was utilized to establish the mathematical model of thin circular plate carrying eccentric concentrated mass and to analy... The structural circumferential periodicity of inertial excitation produced by concentrated mass was utilized to establish the mathematical model of thin circular plate carrying eccentric concentrated mass and to analyze its transverse vibration. The fundamental frequency coefficient, natural frequency and mode shape function are determined by this method. A clamped thin circular plate was taken as an example to study the mass effect on the vibrating system.Comparison between the present results and published ones exhibits excellent agreement, which shows that the analytical method in this paper can be used to predict the transverse vibration parameters accurately. 展开更多
关键词 THIN CIRCULAR PLATE concentrated mass structural circumferential PERIODICITY TRANSVERSE vibration
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TORSIONAL BUCKLING OF SPHERICAL SHELLS UNDER CIRCUMFERENTIAL SHEAR LOADS
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作者 张音翼 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第4期87+89-93,共6页
By the aid of differential geometry analysis on the initial buckling of shell element, a set of new and exact buckling bifurcation equations of the spherical shells is derived. Making use of Galerkin variational metho... By the aid of differential geometry analysis on the initial buckling of shell element, a set of new and exact buckling bifurcation equations of the spherical shells is derived. Making use of Galerkin variational method, the general stability of the hinged spherical shells with the circumferential shear loads is studied. Constructing the buckling mode close to the bifurcation point deformations, the critical eigenvalues, critical load intensities and critical stresses of torsional buckling ranging from the shallow shells to the hemispherical shell are obtained for the first time. 展开更多
关键词 spherical shell buckling bifurcation equation circumferential shear load EIGENVALUE buckling critical value
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Abdominoperineal excision following preoperative radiotherapy for rectal cancer: Unfavorable prognosis even with negative circumferential resection margin
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作者 Lin Wang Guo-Li Gu +2 位作者 Zhong-Wu Li Yi-Fan Peng Jin Gu 《World Journal of Gastroenterology》 SCIE CAS 2014年第27期9138-9145,共8页
AIM: To evaluate whether an abdominoperineal excision (APE) is associated with increased local recurrence (LR) and shortened disease-free survival (DFS) in mid-low rectal cancer with a negative circumferential resecti... AIM: To evaluate whether an abdominoperineal excision (APE) is associated with increased local recurrence (LR) and shortened disease-free survival (DFS) in mid-low rectal cancer with a negative circumferential resection margin (CRM). 展开更多
关键词 Abdominoperineal excision Preoperative radiotherapy circumferential resection margin SURVIVAL
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Characterization of inner layer thickness change of a composite circular tube using nonlinear circumferential guided wave:A feasibility study
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作者 Ming-Liang Li Guang-Jian Gao Ming-Xi Deng 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第8期412-417,共6页
The feasibility of using the nonlinear effect of primary circumferential guided wave(CGW)propagation for characterizing the change of inner layer thickness of a composite circular tube(CCT)has been investigated.An app... The feasibility of using the nonlinear effect of primary circumferential guided wave(CGW)propagation for characterizing the change of inner layer thickness of a composite circular tube(CCT)has been investigated.An appropriate mode pair of the fundamental and double-frequency CGWs(DFCGWs)has been selected to enable the second harmonics of primary wave mode in the given CCT to accumulate along the circumferential direction.When changes in the inner layer thickness(described as the equivalent inner layer thickness)take place,the corresponding nonlinear CGW measurements are conducted.It is found that there is a direct correlation between change of equivalent inner layer thickness of the CCT and the relative acoustic nonlinearity parameter(Δβ)measured with CGWs propagating through one full circumference,and that the effect of second-harmonic generation(SHG)is very sensitive to change in the inner layer thickness.The experimental result obtained demonstrates the feasibility for quantitatively assessing the change of equivalent inner layer thickness in CCTs using the effect of SHG by primary CGW propagation. 展开更多
关键词 circumferential guided wave(CGW) second-harmonic generation(SHG) inner layer thickness composite circular tube
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Experimental analysis on effect of grouser circumferential angle on motion performance of lunar rover wheel
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作者 刘吉成 高海波 邓宗全 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第1期131-137,共7页
To guide the design of grouser parameters for lunar rover wheel,the effect analysis of circumferential angle of grousers on motion performance of a rigid wheel was conducted in a laboratory single-wheel test bed with ... To guide the design of grouser parameters for lunar rover wheel,the effect analysis of circumferential angle of grousers on motion performance of a rigid wheel was conducted in a laboratory single-wheel test bed with loose sand bin.All tests had been done at a free wheel sinkage.The circumferential angle was varied from 0°,5°,10°,15° to 20°.By the analysis and comparisons of tractive and steering performance between smooth wheels and wheels with different circumferential angle grousers,the results show that the drawbar pull(DP),driving torque(DT) and steering resistance moment(SRM) decrease slightly with the increasing circumferential angle.And chevron grousers are more beneficial to improve the tractive performance than herringbone grousers.In order to evaluate motion performance of wheels with grousers,the evaluation indexes of motion performance are introduced into the experimental results.The results reveal that the optimal circumferential angle is 0°,and the optimum value of wheel slip is 13% from the perspective of saving energy to the similar loose sand in the experiments. 展开更多
关键词 ROVER WHEEL circumferential angle chevron grouser herringbone grouser
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