A hybrid fiber-reinforced polymer(HFRP)continuous sucker rod,comprising a carbon fiber-reinforced polymer(CFRP)core layer,a glass fiber-reinforced polymer(GFRP)winding layer,and a GFRP coating layer(CFRP:GFRP=2:3),has...A hybrid fiber-reinforced polymer(HFRP)continuous sucker rod,comprising a carbon fiber-reinforced polymer(CFRP)core layer,a glass fiber-reinforced polymer(GFRP)winding layer,and a GFRP coating layer(CFRP:GFRP=2:3),has been developed and widely used in oilfield extraction due to its lower specific gravity,enhanced corrosion resistance,and superior strength.However,HFRP rod joints and their adjacent sections are prone to multi-mode failures,including fracture,debonding,and cracking.Due to the complexity of joint structure and the coupling of tension,bending,and torsion,the failure mechanism is unclear.To address this issue,a dual-scale failure assessment methodology for HFRP rods was proposed,utilizing both macro and meso finite element models(FEM).This methodology was validated through tensile and bending experiments,which yielded critical loads for theφ22 mm HFRP rod:a tensile load of 340.2 kN,a torque of 132.3 N m,and a bending moment of 1192.4 N m.Additionally,a comprehensive FEM of the joint was established,which identified potential failure points at the necking of the rotary joint,resin adhesive and the HFRP rod cross-section at the first groove tip.These failure modes closely matched the experimental observations.Furthermore,the simulation results show that stress concentration at the joint reduced the tensile,bending,and torsional strengths of the HFRP rod to 61%,12%,and 82%of their original values,respectively.The effects of bending moments and torque on the tensile strength of HFRP rods were subsequently explored,leading to the development of an equivalent fatigue assessment method for HFRP rod joints.This method,based on the fatigue characteristics of HFRP rods and joint components,reveals that the primary cause of joint failure is the susceptibility of both the joint and the HFRP rod to bending moments and torque induced by dynamic buckling of the sucker rod string(SRS).Using this method,the fatigue ultimate axial force of theφ22 mm HFRP joint was determined to be 91.5 kN,with corresponding fatigue ultimate torque and bending moment under an axial force of 62.4 kN being 89.3 N m and 71.5 N m,respectively.Finally,a design method incorporating a concentrated weighting strategy for HFRP-steel mixed rods was proposed to enhance their service life,and its effectiveness was demonstrated through on-site testing.展开更多
Recent experiments have found that a liquid crystal elastomer(LCE)rod supported in the middle can rotate continuously under horizontal illumination due to the combined impacts of gravity and light-fueled lateral bend-...Recent experiments have found that a liquid crystal elastomer(LCE)rod supported in the middle can rotate continuously under horizontal illumination due to the combined impacts of gravity and light-fueled lateral bend-ing deformation.Similar to traditional gravity-driven systems,it is constrained by the direction of gravity and cannot be applied in microgravity environments.This study introduces a lateral constraint to a liquid crystal elastomer rod system,enabling self-rotation under lighting from any direction,including horizontal and vertical illumination.Through theoretical modeling,the results indicate that the system can steadily rotate under the combined impacts of lateral forces and vertical illumination.Factors like thermal energy flux,thermal conduc-tivity coefficient,the LCE rod length,contraction coefficient,and friction coefficient affect the angular velocity of the self-rotation.The numerical computations align closely with the experimental data.Our proposed steadily self-rotating system features a simple structure with constant self-rotation.It operates independently of gravity direction,making it an excellent choice for special environments,such as the microgravity conditions on the Moon.The lateral constraint strategy presented in this study offers a general approach to expanding the applica-tions of gravity-driven self-sustained motion,with promising potential,especially in microgravity settings,where its versatility under varying lighting conditions could yield valuable insights.展开更多
Accurate measurement of anchor rod length is crucial for ensuring structural safety in tunnel engineering,yet conventional destructive techniques face limitations in efficiency and adaptability to complex underground ...Accurate measurement of anchor rod length is crucial for ensuring structural safety in tunnel engineering,yet conventional destructive techniques face limitations in efficiency and adaptability to complex underground environments.This study presents a novel wireless instrument based on the standing wave principle to enable remote,non-destructive length assessment.The system employs a master-slave architecture,where a handheld transmitter unit initiates measurements through robust 433 MHz wireless communication,optimized for signal penetration in obstructed spaces.The embedded measurement unit,integrated with anchor rods during installation,utilizes frequency-scanning technology to excite structural resonances.By analyzing standing wave characteristics,anchor length is derived from a calibrated frequency-length relationship.Power management adopts a standby-activation strategy to minimize energy consumption while maintaining operational readiness.Experimental validation confirms the system effectively measures anchor lengths with high precision and maintains reliable signal transmission through thick concrete barriers,demonstrating suitability for tunnel deployment.The non-destructive approach eliminates structural damage risks associated with traditional pull-out tests,while wireless operation enhances inspection efficiency in confined spaces.Thiswork establishes a paradigmfor embedded structural healthmonitoring in tunneling,offering significant improvements over existing methods in safety,cost-effectiveness,and scalability.The technology holds promise for broad applications in mining,underground infrastructure,and geotechnical engineering.展开更多
The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods w...The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.展开更多
In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,th...In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,the average output power of the fundamental laser at 1064 nm reaches as high as 20.98 W at a repetition rate of 50 Hz with a maximum single pulse energy of 419.6 mJ,corresponding to a maximum optical conversion efficiency of 38.8%and a slope efficiency of 41%.展开更多
h-BN rods modified low-carbon alumina-carbon(Al_(2)O_(3)-C)refractories were prepared,and the effect of h-BN rod addition on the high-temperature properties was investigated and compared with commercial h-BN flake,car...h-BN rods modified low-carbon alumina-carbon(Al_(2)O_(3)-C)refractories were prepared,and the effect of h-BN rod addition on the high-temperature properties was investigated and compared with commercial h-BN flake,carbon black,and carbon nanotubes additives.The results demonstrated that Al_(2)O_(3)-C refractories containing h-BN rods exhibited optimal high-temperature service performances,including 25%higher hot modulus of rupture,21.3%higher thermal shock strength residual ratio,20.9%lower in oxidation and 44.3%less in slag corrosion,compared to the counterpart specimens without additives.Moreover,benefiting from the synergistic enhancement of the rod-like h-BN and in-situ generated SiC whiskers,the high-temperature service performances of h-BN rods containing specimens outperformed counterpart specimens containing commercial h-BN flake,carbon black,and carbon nanotubes,respectively.展开更多
The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computatio...The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.展开更多
Nuclear energy is a vital source of clean energy that will continue to play an essential role in global energy production for future generations.Nuclear fuel rods are core components of nuclear power plants,and their ...Nuclear energy is a vital source of clean energy that will continue to play an essential role in global energy production for future generations.Nuclear fuel rods are core components of nuclear power plants,and their safe utilization is paramount.Due to its inherent high radioactivity,indirect neutron radiography(INR)is currently the only viable technology for irradiated nuclear fuel rods in the field of energy production.This study explores the experimental technique of indirect neutron computed tomography(INCT)for radioactive samples.This project includes the development of indium and dysprosium conversion screens of different thicknesses and conducts resolution tests to assess their performance.Moreover,pressurized water reactor(PWR)dummy nuclear fuel rods have been fabricated by self-developing substitute materials for cores and outsourcing of mechanical processing.Experimental research on the INR is performed using the developed dummy nuclear fuel rods.The sparse reconstruction technique is used to reconstruct the INR results of 120 pairs of dummy nuclear fuel rods at different angles,achieving a resolution of 0.8 mm for defect detection using INCT.展开更多
The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault lo...The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system.展开更多
Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensi...Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.展开更多
In the production of the sucker rod well, the dynamic liquid level is important for the production efficiency and safety in the lifting process. It is influenced by multi-source data which need to be combined for the ...In the production of the sucker rod well, the dynamic liquid level is important for the production efficiency and safety in the lifting process. It is influenced by multi-source data which need to be combined for the dynamic liquid level real-time calculation. In this paper, the multi-source data are regarded as the different views including the load of the sucker rod and liquid in the wellbore, the image of the dynamometer card and production dynamics parameters. These views can be fused by the multi-branch neural network with special fusion layer. With this method, the features of different views can be extracted by considering the difference of the modality and physical meaning between them. Then, the extraction results which are selected by multinomial sampling can be the input of the fusion layer.During the fusion process, the availability under different views determines whether the views are fused in the fusion layer or not. In this way, not only the correlation between the views can be considered, but also the missing data can be processed automatically. The results have shown that the load and production features fusion(the method proposed in this paper) performs best with the lowest mean absolute error(MAE) 39.63 m, followed by the features concatenation with MAE 42.47 m. They both performed better than only a single view and the lower MAE of the features fusion indicates that its generalization ability is stronger. In contrast, the image feature as a single view contributes little to the accuracy improvement after fused with other views with the highest MAE. When there is data missing in some view, compared with the features concatenation, the multi-view features fusion will not result in the unavailability of a large number of samples. When the missing rate is 10%, 30%, 50% and 80%, the method proposed in this paper can reduce MAE by 5.8, 7, 9.3 and 20.3 m respectively. In general, the multi-view features fusion method proposed in this paper can improve the accuracy obviously and process the missing data effectively, which helps provide technical support for real-time monitoring of the dynamic liquid level in oil fields.展开更多
The umbilical cable is a vital component of subsea production systems that provide power,chemical agents,control signals et al.,and its requirement for reliability is exceedingly high.However,as the umbilical cable is...The umbilical cable is a vital component of subsea production systems that provide power,chemical agents,control signals et al.,and its requirement for reliability is exceedingly high.However,as the umbilical cable is a composite structure comprising multiple functional units,the reliability analysis of such cables involves numerous parameters that can impact calculation efficiency.In this paper,the reliability analysis of a new kind of umbilical cable with carbon fiber rod under tension is analyzed.The global dynamic analytical model is first established to determine the maximum tension load,then the local analytical model of umbilical cable including each unit are constructed by finite element method(FEM).Based on the mechanical analytical model,the reliability of umbilical cable under tension load is studied using response surface method(RSM)and Monte Carlo method.During the calculation process,a new tangent plane sampling method to calculate the response surface function(RSF)is proposed in this paper,which could make sampling points faster come close to the RSF curve,and it is proved that the calculation efficiency increases about 33%comparing with traditional method.展开更多
In this paper,we review computational approaches to optimization problems of inhomogeneous rods and plates.We consider both the optimization of eigenvalues and the localization of eigenfunctions.These problems are mot...In this paper,we review computational approaches to optimization problems of inhomogeneous rods and plates.We consider both the optimization of eigenvalues and the localization of eigenfunctions.These problems are motivated by physical problems including the determination of the extremum of the fundamental vibration frequency and the localization of the vibration displacement.We demonstrate how an iterative rearrangement approach and a gradient descent approach with projection can successfully solve these optimization problems under different boundary conditions with different densities given.展开更多
As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary ...As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary to conduct flow analysis.In this study,numerical simulations of the flow field around a 330 kV cylindrical lightning rod with different diameters were performed using the SST k-ωmodel.The flow patterns in different segments of the lightning rod at the same reference wind speed(wind speed at a height of 10 m)and the flow patterns in the same segment at different reference wind speeds were investigated.The variations of lift coefficient,drag coefficient,and vorticity distribution were obtained.The results showed that vortex shedding phenomena occurred in all segments of the lightning rod,and the strength of vortex shedding increased with decreasing diameter.The vorticity magnitude and the root mean square magnitudes of the lift coefficient and drag coefficient also increased accordingly.The time history curves of the lift coefficient and drag coefficient on the surface of the lightning rod exhibited sinusoidal patterns with a single dominant frequency.For the same segment,as the wind speed increased in a certain range,the root mean square values of the lift coefficient and drag coefficient decreased,while their dominant frequencies increased.Moreover,there was a proportional relationship between the dominant frequencies of the lift coefficient and drag coefficient.The findings of this study can provide valuable insights for the refined design of lightning rods with similar structures.展开更多
An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characte...An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.展开更多
目的 :探讨应用Smiley face rod固定系统治疗L5椎弓峡部裂的临床疗效。方法:2016年1月~2017年6月,我科采用Smiley face rod固定系统节段内固定植骨融合治疗腰椎峡部裂患者18例,男13例,女5例,年龄28.2±3.2岁(25~32岁),术前平均病程...目的 :探讨应用Smiley face rod固定系统治疗L5椎弓峡部裂的临床疗效。方法:2016年1月~2017年6月,我科采用Smiley face rod固定系统节段内固定植骨融合治疗腰椎峡部裂患者18例,男13例,女5例,年龄28.2±3.2岁(25~32岁),术前平均病程为16.3±5.7个月(7~24个月)。峡部裂节段均位于L5。术后3个月、1年时进行随访,对患者进行疼痛视觉模拟评分(visual analogue scale,VAS)及Oswestry功能障碍指数(Oswestry disability index,ODI)评定,评价其临床治疗效果。行X线、CT等检查,分析术前和术后L5/S1椎间活动度变化及椎间不稳发生率变化情况,并评价患者术后植骨融合情况。结果:手术时间平均90.0±24.1min,术中出血量平均140±15ml。平均随访18.5±5.0个月(12~24个月)。术前VAS评分为7.3±2.5分,ODI为(67.0±15.1)%;术后3个月时分别为3.0±1.2分和(17.2±4.5)%,较术前明显改善(P<0.05);术后1年时分别为1.0±0.6分和(9.1±5.3)%,较术后3个月时进一步改善(P<0.05)。术前L5/S1间隙活动度为13.1°±2.1°,存在腰椎不稳或小于Ⅰ度滑脱者共15例(83.3%,15/18);术后1年时分别为9.3°±1.6°和2例(11.1%,2/18),两者之间存在统计学差异(P<0.05)。术后1年时随访患者峡部裂均获得骨性愈合。结论 :应用Smiley face rod固定系统治疗L5椎弓峡部裂具有创伤小、对神经干扰少、恢复正常的解剖结构、提高椎间稳定性的优点。展开更多
基金the Fundamental Research Funds for the Central Universities under Grant no.24CX02019Athe Opening Fund of National Engineering Research Center of Marine Geophysical Prospecting and Exploration and Development Equipment under Grant no.24CX02019A。
文摘A hybrid fiber-reinforced polymer(HFRP)continuous sucker rod,comprising a carbon fiber-reinforced polymer(CFRP)core layer,a glass fiber-reinforced polymer(GFRP)winding layer,and a GFRP coating layer(CFRP:GFRP=2:3),has been developed and widely used in oilfield extraction due to its lower specific gravity,enhanced corrosion resistance,and superior strength.However,HFRP rod joints and their adjacent sections are prone to multi-mode failures,including fracture,debonding,and cracking.Due to the complexity of joint structure and the coupling of tension,bending,and torsion,the failure mechanism is unclear.To address this issue,a dual-scale failure assessment methodology for HFRP rods was proposed,utilizing both macro and meso finite element models(FEM).This methodology was validated through tensile and bending experiments,which yielded critical loads for theφ22 mm HFRP rod:a tensile load of 340.2 kN,a torque of 132.3 N m,and a bending moment of 1192.4 N m.Additionally,a comprehensive FEM of the joint was established,which identified potential failure points at the necking of the rotary joint,resin adhesive and the HFRP rod cross-section at the first groove tip.These failure modes closely matched the experimental observations.Furthermore,the simulation results show that stress concentration at the joint reduced the tensile,bending,and torsional strengths of the HFRP rod to 61%,12%,and 82%of their original values,respectively.The effects of bending moments and torque on the tensile strength of HFRP rods were subsequently explored,leading to the development of an equivalent fatigue assessment method for HFRP rod joints.This method,based on the fatigue characteristics of HFRP rods and joint components,reveals that the primary cause of joint failure is the susceptibility of both the joint and the HFRP rod to bending moments and torque induced by dynamic buckling of the sucker rod string(SRS).Using this method,the fatigue ultimate axial force of theφ22 mm HFRP joint was determined to be 91.5 kN,with corresponding fatigue ultimate torque and bending moment under an axial force of 62.4 kN being 89.3 N m and 71.5 N m,respectively.Finally,a design method incorporating a concentrated weighting strategy for HFRP-steel mixed rods was proposed to enhance their service life,and its effectiveness was demonstrated through on-site testing.
基金supported by the University Natural Science Research Project of Anhui Province(Grant Nos.2022AH040042 and 2022AH020029)the National Natural Science Foundation of China(Grant No.12172001)+1 种基金Anhui Provincial Natural Science Foundation(Grant No.2208085Y01)the Housing and Urban-Rural Development Science and Technology Project of Anhui Province(Grant No.2022-YF069).
文摘Recent experiments have found that a liquid crystal elastomer(LCE)rod supported in the middle can rotate continuously under horizontal illumination due to the combined impacts of gravity and light-fueled lateral bend-ing deformation.Similar to traditional gravity-driven systems,it is constrained by the direction of gravity and cannot be applied in microgravity environments.This study introduces a lateral constraint to a liquid crystal elastomer rod system,enabling self-rotation under lighting from any direction,including horizontal and vertical illumination.Through theoretical modeling,the results indicate that the system can steadily rotate under the combined impacts of lateral forces and vertical illumination.Factors like thermal energy flux,thermal conduc-tivity coefficient,the LCE rod length,contraction coefficient,and friction coefficient affect the angular velocity of the self-rotation.The numerical computations align closely with the experimental data.Our proposed steadily self-rotating system features a simple structure with constant self-rotation.It operates independently of gravity direction,making it an excellent choice for special environments,such as the microgravity conditions on the Moon.The lateral constraint strategy presented in this study offers a general approach to expanding the applica-tions of gravity-driven self-sustained motion,with promising potential,especially in microgravity settings,where its versatility under varying lighting conditions could yield valuable insights.
基金supported in part by the Natural Science Foundation of Gansu Province(Nos.20JR10RA614,22YF7GA182,22JR11RA042,22JR5RA1006,24CXGA024)the National Natural Science Foundation of China under Grant 61804071.
文摘Accurate measurement of anchor rod length is crucial for ensuring structural safety in tunnel engineering,yet conventional destructive techniques face limitations in efficiency and adaptability to complex underground environments.This study presents a novel wireless instrument based on the standing wave principle to enable remote,non-destructive length assessment.The system employs a master-slave architecture,where a handheld transmitter unit initiates measurements through robust 433 MHz wireless communication,optimized for signal penetration in obstructed spaces.The embedded measurement unit,integrated with anchor rods during installation,utilizes frequency-scanning technology to excite structural resonances.By analyzing standing wave characteristics,anchor length is derived from a calibrated frequency-length relationship.Power management adopts a standby-activation strategy to minimize energy consumption while maintaining operational readiness.Experimental validation confirms the system effectively measures anchor lengths with high precision and maintains reliable signal transmission through thick concrete barriers,demonstrating suitability for tunnel deployment.The non-destructive approach eliminates structural damage risks associated with traditional pull-out tests,while wireless operation enhances inspection efficiency in confined spaces.Thiswork establishes a paradigmfor embedded structural healthmonitoring in tunneling,offering significant improvements over existing methods in safety,cost-effectiveness,and scalability.The technology holds promise for broad applications in mining,underground infrastructure,and geotechnical engineering.
基金supported by the general project of the National Natural Science Foundation of China(No.52071042)Chongqing Natural Science Foundation Project,China(Nos.CSTB2023NSCQ-MSX0079,cstc2021ycjh-bgzxm0148)Graduate Student Innovation Program of Chongqing University of Technology,China(No.gzlcx20232008).
文摘The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.
基金supported by the Nanjing University of Posts and Telecommunications Foundation,China(Grant Nos.JUH219002 and JUH219007)the Key R&D Program of Shandong Province,China(Grant No.2021CXGC010202)。
文摘In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,the average output power of the fundamental laser at 1064 nm reaches as high as 20.98 W at a repetition rate of 50 Hz with a maximum single pulse energy of 419.6 mJ,corresponding to a maximum optical conversion efficiency of 38.8%and a slope efficiency of 41%.
基金support from the National Natural Science Foundation of China(Grant Nos.52072274,52272021,U23A20559 and 52232002)the Open Foundation of State Key Laboratory of Advanced Refractories(No.SKLAR202207)+1 种基金the Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials(Wuhan University of Science and Technology,WKDM202201)the Open/Innovation Foundation of Hubei Three Gorges Laboratory(SK232006).
文摘h-BN rods modified low-carbon alumina-carbon(Al_(2)O_(3)-C)refractories were prepared,and the effect of h-BN rod addition on the high-temperature properties was investigated and compared with commercial h-BN flake,carbon black,and carbon nanotubes additives.The results demonstrated that Al_(2)O_(3)-C refractories containing h-BN rods exhibited optimal high-temperature service performances,including 25%higher hot modulus of rupture,21.3%higher thermal shock strength residual ratio,20.9%lower in oxidation and 44.3%less in slag corrosion,compared to the counterpart specimens without additives.Moreover,benefiting from the synergistic enhancement of the rod-like h-BN and in-situ generated SiC whiskers,the high-temperature service performances of h-BN rods containing specimens outperformed counterpart specimens containing commercial h-BN flake,carbon black,and carbon nanotubes,respectively.
基金supported by Shanghai 2021“Science and Technology Innovation Action Plan”:Social Development Science and Technology Research Project(Grant No.21DZ1202703).
文摘The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.
基金supported in part by the National Key R&D Program of China (No. 2022YFA1604002)the Sichuan Postdoctoral Research Program (No. TB2022035)+1 种基金the Nuclear Energy Development Research Program of Chinathe Scientific Research and Innovation Team Program of Sichuan University of Science and Engineering (No. SUSE652A001)
文摘Nuclear energy is a vital source of clean energy that will continue to play an essential role in global energy production for future generations.Nuclear fuel rods are core components of nuclear power plants,and their safe utilization is paramount.Due to its inherent high radioactivity,indirect neutron radiography(INR)is currently the only viable technology for irradiated nuclear fuel rods in the field of energy production.This study explores the experimental technique of indirect neutron computed tomography(INCT)for radioactive samples.This project includes the development of indium and dysprosium conversion screens of different thicknesses and conducts resolution tests to assess their performance.Moreover,pressurized water reactor(PWR)dummy nuclear fuel rods have been fabricated by self-developing substitute materials for cores and outsourcing of mechanical processing.Experimental research on the INR is performed using the developed dummy nuclear fuel rods.The sparse reconstruction technique is used to reconstruct the INR results of 120 pairs of dummy nuclear fuel rods at different angles,achieving a resolution of 0.8 mm for defect detection using INCT.
基金the National Key Research and Development Program of China under Grant 2021YFB3301300the National Natural Science Foundation of China under Grant 62203213+1 种基金the Natural Science Foundation of Jiangsu Province under Grant BK20220332the Open Project Program of Fujian Provincial Key Laboratory of Intelligent Identification and Control of Complex Dynamic System under Grant 2022A0004.
文摘The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system.
文摘Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.
基金supported by the National Natural Science Foundation of China under Grant 52325402, 52274057, 52074340 and 51874335the National Key R&D Program of China under Grant 2023YFB4104200+1 种基金the Major Scientific and Technological Projects of CNOOC under Grant CCL2022RCPS0397RSN111 Project under Grant B08028。
文摘In the production of the sucker rod well, the dynamic liquid level is important for the production efficiency and safety in the lifting process. It is influenced by multi-source data which need to be combined for the dynamic liquid level real-time calculation. In this paper, the multi-source data are regarded as the different views including the load of the sucker rod and liquid in the wellbore, the image of the dynamometer card and production dynamics parameters. These views can be fused by the multi-branch neural network with special fusion layer. With this method, the features of different views can be extracted by considering the difference of the modality and physical meaning between them. Then, the extraction results which are selected by multinomial sampling can be the input of the fusion layer.During the fusion process, the availability under different views determines whether the views are fused in the fusion layer or not. In this way, not only the correlation between the views can be considered, but also the missing data can be processed automatically. The results have shown that the load and production features fusion(the method proposed in this paper) performs best with the lowest mean absolute error(MAE) 39.63 m, followed by the features concatenation with MAE 42.47 m. They both performed better than only a single view and the lower MAE of the features fusion indicates that its generalization ability is stronger. In contrast, the image feature as a single view contributes little to the accuracy improvement after fused with other views with the highest MAE. When there is data missing in some view, compared with the features concatenation, the multi-view features fusion will not result in the unavailability of a large number of samples. When the missing rate is 10%, 30%, 50% and 80%, the method proposed in this paper can reduce MAE by 5.8, 7, 9.3 and 20.3 m respectively. In general, the multi-view features fusion method proposed in this paper can improve the accuracy obviously and process the missing data effectively, which helps provide technical support for real-time monitoring of the dynamic liquid level in oil fields.
基金Financial support for this research was provided by the National Natural Science Foundation of China (Grant No.52222111)。
文摘The umbilical cable is a vital component of subsea production systems that provide power,chemical agents,control signals et al.,and its requirement for reliability is exceedingly high.However,as the umbilical cable is a composite structure comprising multiple functional units,the reliability analysis of such cables involves numerous parameters that can impact calculation efficiency.In this paper,the reliability analysis of a new kind of umbilical cable with carbon fiber rod under tension is analyzed.The global dynamic analytical model is first established to determine the maximum tension load,then the local analytical model of umbilical cable including each unit are constructed by finite element method(FEM).Based on the mechanical analytical model,the reliability of umbilical cable under tension load is studied using response surface method(RSM)and Monte Carlo method.During the calculation process,a new tangent plane sampling method to calculate the response surface function(RSF)is proposed in this paper,which could make sampling points faster come close to the RSF curve,and it is proved that the calculation efficiency increases about 33%comparing with traditional method.
基金supported by the DMS-1853701supported in part by the DMS-2208373.
文摘In this paper,we review computational approaches to optimization problems of inhomogeneous rods and plates.We consider both the optimization of eigenvalues and the localization of eigenfunctions.These problems are motivated by physical problems including the determination of the extremum of the fundamental vibration frequency and the localization of the vibration displacement.We demonstrate how an iterative rearrangement approach and a gradient descent approach with projection can successfully solve these optimization problems under different boundary conditions with different densities given.
基金supported by State Grid Ningxia Electric Power Co.,Ltd.under Grant 5229CG220006Natural Science Foundation of Ningxia Province under Grant 2022AAC03629.
文摘As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary to conduct flow analysis.In this study,numerical simulations of the flow field around a 330 kV cylindrical lightning rod with different diameters were performed using the SST k-ωmodel.The flow patterns in different segments of the lightning rod at the same reference wind speed(wind speed at a height of 10 m)and the flow patterns in the same segment at different reference wind speeds were investigated.The variations of lift coefficient,drag coefficient,and vorticity distribution were obtained.The results showed that vortex shedding phenomena occurred in all segments of the lightning rod,and the strength of vortex shedding increased with decreasing diameter.The vorticity magnitude and the root mean square magnitudes of the lift coefficient and drag coefficient also increased accordingly.The time history curves of the lift coefficient and drag coefficient on the surface of the lightning rod exhibited sinusoidal patterns with a single dominant frequency.For the same segment,as the wind speed increased in a certain range,the root mean square values of the lift coefficient and drag coefficient decreased,while their dominant frequencies increased.Moreover,there was a proportional relationship between the dominant frequencies of the lift coefficient and drag coefficient.The findings of this study can provide valuable insights for the refined design of lightning rods with similar structures.
文摘An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.
文摘目的 :探讨应用Smiley face rod固定系统治疗L5椎弓峡部裂的临床疗效。方法:2016年1月~2017年6月,我科采用Smiley face rod固定系统节段内固定植骨融合治疗腰椎峡部裂患者18例,男13例,女5例,年龄28.2±3.2岁(25~32岁),术前平均病程为16.3±5.7个月(7~24个月)。峡部裂节段均位于L5。术后3个月、1年时进行随访,对患者进行疼痛视觉模拟评分(visual analogue scale,VAS)及Oswestry功能障碍指数(Oswestry disability index,ODI)评定,评价其临床治疗效果。行X线、CT等检查,分析术前和术后L5/S1椎间活动度变化及椎间不稳发生率变化情况,并评价患者术后植骨融合情况。结果:手术时间平均90.0±24.1min,术中出血量平均140±15ml。平均随访18.5±5.0个月(12~24个月)。术前VAS评分为7.3±2.5分,ODI为(67.0±15.1)%;术后3个月时分别为3.0±1.2分和(17.2±4.5)%,较术前明显改善(P<0.05);术后1年时分别为1.0±0.6分和(9.1±5.3)%,较术后3个月时进一步改善(P<0.05)。术前L5/S1间隙活动度为13.1°±2.1°,存在腰椎不稳或小于Ⅰ度滑脱者共15例(83.3%,15/18);术后1年时分别为9.3°±1.6°和2例(11.1%,2/18),两者之间存在统计学差异(P<0.05)。术后1年时随访患者峡部裂均获得骨性愈合。结论 :应用Smiley face rod固定系统治疗L5椎弓峡部裂具有创伤小、对神经干扰少、恢复正常的解剖结构、提高椎间稳定性的优点。
