Experimental and numerical study of buckling-restrained braces configured with out-of-plane eccentricity under cyclic loading

This study focuses on variations in the hysteretic behavior of buckling-restrained braces(BRBs)configured with or without out-of-plane eccentricity under cyclic loading.Quasi-static experiments and numerical simulations were carried out on concentrically and eccentrically loaded BRB specimens to investigate the mechanical properties,energy dissipation performance,stress distribution,and high-order deformation pattern.The experimental and numerical results showed that compared to the concentrically loaded BRBs,the stiffness,yield force,cumulated plastic ductility(CPD)coefficient,equivalent viscous damping coefficient and energy dissipation decreased,and the yield displacement and compression strength adjustment factor increased for the eccentrically loaded BRBs.With the existence of the out-of-plane eccentricity,the initial yield position changes from the yield segment to the junction between the yield segment and transition segment under a tensile load,while the initial high-order buckling pattern changes from a first-order C-shape to a secondorder S-shape under a compressive load.

3D modeling for effect of tool eccentricity on coupled thermal and material flow characteristics during friction stir welding

A novel three-dimensional numerical model is proposed to investigate the effect of tool eccentricity on the coupled thermal and material flow characteristics in friction stir welding(FSW) process.An asymmetrical boundary condition at the tool-workpiece interface,and the dynamic mesh technique are both employed for the consideration of the tool eccentricity during tool rotating.It is found that tool eccentricity induces the periodical variation of the heat densities both at the tool-workpiece interface and inside the shear layer,but the fluctuation amplitudes of the heat density variations are limited.However,it is demonstrated that tool eccentricity results in significant variation of the material flow behavior in one tool rotating period.Moreover,the material velocity variation at the retreating side is particularly important for the formation of the periodic characteristics in FSW.The modeling result is found to be in good agreement with the experimental one.

Failure process and monitoring data of an extra-large landslide at the Nanfen Open-pit Iron Mine

An extra-large landslide occurred on June 19,2021,on the footwall slope of the Nanfen Open-pit Iron Mine in Liaoning Province,China,with a volume of approximately 1.2×107 m3.To elucidate the causative factors,development process,and destructive mechanisms of this catastrophic landslide,comprehensive field tests,investigations,and laboratory experiments were conducted.Initially,the heavily weathered rock mass of the slope was intersected by faults and joint fissures,facilitating rainwater infiltration.Moreover,the landslide contained a substantial clay mineral with highly developed micro-cracks and micro-pores,exhibiting strong water-absorption properties.As moisture content increased,the rock mass underwent softening,resulting in reduced strength.Ultimately,continuous heavy rainfall infiltration amplified the slope's weight,diminishing the weak structural plane's strength,leading to fracture propagation,slip plane penetration,and extensive tensile-shear and uplift failure of the slope.The study highlights poor geological conditions as the decisive factor for this landslide,with continuous heavy rainfall as the triggering factor.Presently,adverse environmental factors persistently affect the landslide,and deformation and failure continue to escalate.Hence,it is imperative to urgently implement integrated measures encompassing slope reinforcement,monitoring,and early-warning to real-time monitor the landslide's deformation and deep mechanical evolution trends.

The Effect of Core Eccentricity on the Structural Behavior of Concrete Tall Buildings

The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were investigated.Three cases of main core locations are studied:centric(A),eccentric by one sixth(B)and one third(C)of building width.The three-dimensional finite element method has been used in conducting structural analysis through ETABS software.Gravity and lateral(wind and seismic)loadings are applied to all building cases.It has been concluded that the core location is the prime parameter governing the structural behavior of tall buildings.Although the first two cases(A,B)have acceptable and similar structural behaviors conforming to code limits,in the third case(C),the building behavior came beyond code limits.The author introduced remedial action by adding two secondary cores in the opposite direction of the main core(C-R)to restore the building behavior to the code limits.The results of this action were satisfactory.

Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis

基于Ansoft／Maxwell设置动态偏心故障，建立求解电机电感和磁链的有限元模型，通过仿真，证明了将感应电机动态偏心故障的特征频率经过简化后，同样适用于无刷直流电动机。基于Ansoft／Simplorer建立无刷直流电动机系统的仿真模型。在电机稳态运行下，对定子电流进行傅里叶分析，研究并建立基于定子电流监测动态偏心故障的仿真模型：动态偏心故障与特征频率的关系、动态偏心故障程度与特征频率幅值的关系。进而研究了无刷直流电动机稳态运行时转速波动对偏心故障监测的影响。仿真结果表明，转子偏心程度加大，特征频率的幅值增加。

An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

Anchoring eccentricity features and rectifying devices for resin grouted bolt/cable bolt

The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent.This paper reports on numerical simulation and laboratory experiments conducted to clarify the effect of eccentricity on the anchoring quality of the bolt and cable bolt,and to establish an effective solution strategy.The results reveal that the anchoring eccentricity causes unbalanced stress distribution and the uncoordinated deformation of the resin layer,which results in higher stress and greater deformation of the resin layer at the near side of the rod body.Additionally,as the degree of anchoring eccentricity increases,the effect becomes more significant,and the resin layer of the anchoring system becomes more likely to undergo preferential failure locally,which weakens the load-bearing performance of the anchoring system.This paper develops an innovative bolt anchoring rectifying device(B-ARD)and cable bolt anchoring rectifying device(C-ARD)on the basis of the structural characteristics of the bolt and cable bolt to better ensure the anchoring effect of them.The working effects of these two devices were verified in detailed experiments and analysis.The experimental results show that the anchoring rectifying devices(ARD)improve and ensure the anchoring concentricity of the bolt and cable bolt,which will help improve the supporting performance of them.The paper provides a convenient and effective method for improving the anchoring concentricity of the bolt and cable bolt,and provides a concept and reference for technical research on improving the effect of roof bolting.

QTL Mapping for Grain Size Traits Based on Extra-Large Grain Rice Line TD70

Grain size traits, including grain length, grain width and grain thickness, are controlled by quantitative trait loci （QTLs）. Many QTLs relating to rice grain size traits had been reported, but their control mechanisms have not yet been elucidated. A recombinant inbred line （RIL） population of 240 lines, deriving from a cross between TD70, an extra-large grain size japonica line with 80 g of 1000-grain weight, and Kasalath, a small grain size indica variety, were constructed and used to map grain size QTLs to a linkage map by using 141 SSR markers in 2010 and 2011. Five QTLs for grain length, six for grain width and seven for grain thickness were detected distributing over chromosomes 2, 3, 5, 7, 9 and 12. Seven QTLs, namely qGL3.1, qGW2, qGW2.2, qGW5.1, qGW5.2, qGT2.3 and qGT3.1, were detected in either of the two years and explained for 56.19%, 4.42%, 29.41%, 10.37%, 7.61%, 21.19% and 17.06% of the observed phenotypic variances on average, respectively. The marker interval RM1347-RM5699 on chromosome 2 was found common for grain length, grain width and grain thickness; qGL3.1 and qGT3.1 were mapped to the same interval RM6080-RM6832 on chromosome 3. All 18 QTL alleles were derived from the large grain parent TD70. Most of the QTLs mapped in the present study were found the same as the genes previously cloned （GW2, GS3 or qGL3, GW5 and GS5）, and several were the same as the QTLs （GS7 and qGL-7） previously mapped. Three QTLs, qGL2.2 on chromosome 2, qGW9 and qGT9 on chromosome 9, were first detected. These results laid a foundation for further fine mapping or cloning of these QTLs.

Load eccentricity effects on behavior of circular footings reinforced with geogrid sheets

In this paper, an experimental study for an eccentrically loaded circular footing, resting on a geogridreinforced sand bed, is performed. To achieve this aim, the steel model footing of 120 mm in diameterand sand in relative density of 60% are used. Also, the effects of depth of first and second geogrid layersand number of reinforcement layers （1e4） on the settlement-load response and tilt of footing undervarious load eccentricities （0 cm, 0.75 cm, 1.5 cm, 2.25 cm and 3 cm） are investigated. Test results indicatethat ultimate bearing capacity increases in comparison with unreinforced condition. It is observed thatwhen the reinforcements are placed in the optimum embedment depth （u/D ？0.42 and h/D ？0.42）, thebearing capacity ratio （BCR） increases with increasing load eccentricity to the core boundary of footing,and that with further increase of load eccentricity, the BCR decreases. Besides, the tilt of footing increaseslinearly with increasing settlement. Finally, by reinforcing the sand bed, the tilt of footing decreases at 2layers of reinforcement and then increases by increasing the number of reinforcement layers.

Strip Thickness Control of Cold Rolling Mill with Roll Eccentricity Compensation by Using Fuzzy Neural Network

In rolling mill, the accuracy and quality of the strip exit thickness are very important factors. To realize high accuracy in the strip exit thickness, the Automatic Gauge Control (AGC) system is used. Because of roll eccentricity in backup rolls, the exit thickness deviates periodically. In this paper, we design PI controller in outer loop for the strip exit thickness while PD controller is used in inner loop for the work roll actuator position. Also, in order to reduce the periodic thickness deviation, we propose roll eccentricity compensation by using Fuzzy Neural Network with online tuning. Simulink model for the overall system has been implemented using MATLAB/SIMULINK software. The simulation results show the effectiveness of the proposed control.

Extra-large Undersea Shield Tunnel in Composite Ground:Maliuzhou Traffic Tunnel in Zhuhai

1Project objective Extra-large shield tunnels have become the best choice for urban transportation tunnels due to the advantage of taking the best use of underground space.Hengqin Island in Zhuhai is a demonstration area to explore a new cooperation mode among Guangzhou,Hong Kong and Macao,which is also an important pivot of the 21st Century Maritime Silk Road.Thus,it takes an important role in serving Hong Kong and Macao and driving the economic development of the Pearl River Delta.However,as typhoons are frequent in Zhuhai,Hengqin Island will be isolated to the mainland when bridges are obstructed in typhoon seasons.Therefore,the bridges cannot satisfy the traffic demand to the island.The inconvenient transportation has a neglect influence on production and live of people on the island,which also affects the long term development of Hengqin Island.Apart from the two existed bridges,Maliuzhou Traffic Tunnel in Zhuhai is the third major link of Hengqin Island to the mainland,which will put an end to the"losing connectionM problem due to obstructing the bridges in typhoon seasons.This linkage is able to promote Zhuhai tourism exploitation and the long term development of the city,and also increase the security of peopled lives.Meanwhile,the construction of the Maliuzhou Traffic Tunnel has conquered the challenges in designing and building of the extra-large shield tunnel in composite ground and undersea circumstances.The designing methods and constructing approaches used in this project will provide theoretical supports and technical guarantees to similar projects.

Construction and stability of an extra-large section chamber in solid backfill mining

In solid backfill mining without gangue removal, the gangue is separated directly underground and backfilled into goaf. This necessitates the underground construction of an extra-large section chamber for separation equipments. For the construction of an extra-large section chamber in the Tangshan mine, we proposed an active support through a combination of bolting, anchor cables, lining, and a reinforced chamber floor by inverted arch pouring. ABAQUS software was used to analyze the surrounding rock deformation and the plastic zone development of the chamber under different excavation schemes.The best excavation scheme was determined, and the effectiveness of the combined supports was verified. In practice, the engineering installation showed good overall control of the movement of the surrounding rock, with roof-to-floor and side-to-side convergences of 154.6 and 77.5 mm, respectively,which meets the requirements for underground coal gangue separation.

Effect of the shaft eccentricity and rotational direction on the mixing characteristics in cylindrical tank reactors

Strategy of the shaft eccentricity is introduced to enhance the mixing characteristics in a flat bottomed cylindrical vessel without baffles. The mixing is ensured by a six-curved blade impeller. Three solutions which are models of food emulsions are used as working fluids. These solutions have a shear thinning behavior modeled by the power-law. The effects of fluid properties, stirring rates, impeller rotational direction and impeller eccentricity on the 3D flow fields and power consumption are investigated. Three values of impeller eccentricity are considered, namely 0%, 24% and 48% of the vessel diameter. It is found that the opposite clockwise rotational direction reduces the power consumption, compared with the clockwise rotational direction. Also, the obtained results show that an impeller placed at an eccentric position between 24% and 48% of the vessel diameter and at the third of the vessel height may ensure the best mixing characteristics.

FUZZY ECCENTRICITY AND GROSS ERROR IDENTIFICATION

The dominant and recessive effect made by exceptional interferer is analyzed in measurement system based on responsive character, and the gross error model of fuzzy clustering based on fuzzy relation and fuzzy equipollance relation is built. The concept and calculate formula of fuzzy eccentricity are defined to deduce the evaluation rule and function ofgruss error, on the base of them, a fuzzy clustering method of separating and discriminating the gross error is found, utilized in the dynamic circular division measurement system, the method can identify and eliminate gross error in measured data, and reduce measured data dispersity. Experimental results indicate that the use of the method and model enables repetitive precision of the system to improve 80% higher than the foregoing system, to reach 3.5 s, and angle measurement error is less than 7 s.

Multi-Panel Extra-Large Scale MIMO Based Joint Activity Detection and Channel Estimation for Near-Field Massive IoT Access

The extra-large scale multiple-input multiple-output(XL-MIMO)for the beyond fifth/sixth generation mobile communications is a promising technology to provide Tbps data transmission and stable access service.However,the extremely large antenna array aperture arouses the channel near-field effect,resulting in the deteriorated data rate and other challenges in the practice communication systems.Meanwhile,multi-panel MIMO technology has attracted extensive attention due to its flexible configuration,low hardware cost,and wider coverage.By combining the XL-MIMO and multi-panel array structure,we construct multi-panel XL-MIMO and apply it to massive Internet of Things(IoT)access.First,we model the multi-panel XL-MIMO-based near-field channels for massive IoT access scenarios,where the electromagnetic waves corresponding to different panels have different angles of arrival/departure(AoAs/AoDs).Then,by exploiting the sparsity of the near-field massive IoT access channels,we formulate a compressed sensing based joint active user detection(AUD)and channel estimation(CE)problem which is solved by AMP-EM-MMV algorithm.The simulation results exhibit the superiority of the AMP-EM-MMV based joint AUD and CE scheme over the baseline algorithms.

ECCENTRICITY CHANGE IN TUBE SINKING

The rectification of eccentricity was revealed to be more effective in tube sinking than drawing with a mandrel.The ratio of thickness to diameter of tube blank on both sides of thick and thin wall seems to be the principal influential factor in rectifying eccentricity.The greater the ini- tial outside diameter and the initial wall thickness difference are and the less the initial wall thickness of the tube blank is,the better the rectification is.

An alternative approach for computing seismic response with accidental eccentricity

Accidental eccentricity is a non-standard assumption for seismic design of tall buildings. Taking it into consideration requires reanalysis of seismic resistance, which requires either time consuming computation of natural vibration of eccentric structures or finding a static displacement solution by applying an approximated equivalent torsional moment for each eccentric case. This study proposes an alternative modal response spectrum analysis （MRSA） approach to calculate seismic responses with accidental eccentricity. The proposed approach, called the Rayleigh Ritz Projection-MRSA （RRP-MRSA）, is developed based on MRSA and two strategies： （a） a RRf＂ method to obtain a fast calculation of approximate modes of eccentric structures; and （b） an approach to assemble mass matrices of eccentric structures. The efficiency of RRP-MRSA is tested via engineering examples and compared with the standard MRSA （ST-MRSA） and one approximate method, i.e., the equivalent torsional moment hybrid MRSA （ETM-MRSA）. Numerical results show that RRP-MRSA not only achieves almost the same precision as ST-MRSA, and is much better than ETM-MRSA, but is also more economical. Thus, RRP-MRSA can be in place of current accidental eccentricity computations in seismic design.

New Bounds for Zagreb Eccentricity Indices

The Zagrebeccentricity indices are the eccentricity version of the classical Zagrebindices. The first Zagrebeccentricity index (E1(G)) is defined as sum of squares of the eccentricities of the vertices and the second Zagrebeccentricity index (E2(G)) is equal to sum of product of the eccentricities of the adjacent vertices. In this paper we give some new upper and lower bounds for first and second Zagreb eccentricity indices.

Eccentricity and thermoviscous effects on ultrasonic scattering from a liquid-coated fluid cylinder

Calculation of the scattered field of the eccentric scatterers is an old problem with numerous applications. This study considers the interaction of a plane compressional sound wave with a liquid-encapsulated thermoviscous fluid cylinder submerged in an unbounded viscous thermally conducting medium. The translational addition theorem for cylindrical wave functions, the appropriate wave field expansions and the pertinent boundary conditions are employed to develop a closed-form solution in the form of infinite series. The analytical results are illustrated with a numerical example in which the compound cylinder is insonified by a plane sound wave at selected angles of incidence in a wide range of dimensionless frequencies. The backscattered far-field acoustic pressure amplitude and the spatial distribution of the total acoustic pressure in the vicinity of the cylinder are evaluated and discussed for representative values of the parameters characterizing the system. The effects of incident wave frequency, angle of incidence, fluid thermoviscosity, core eccentricity and size are thoroughly examined. Limiting case involving an ideal com- pressible liquid-coated cylinder is considered and fair agreement with a well-known solution is established.

Effect of eccentric and inclined loading on the bearing capacity of strip footing placed on rock mass

This paper deals with the bearing capacity determination of strip footing on a rock mass in hilly area by considering the influence of inclined and eccentric loading. Applying the generalized HoekBrown failure criterion, the failure behavior of the rock mass is modeled with the help of the power cone programming in the lower bound finite element limit analysis framework. Using bearing capacity factor(Ns), the change in bearing capacity of the strip footing due to the occurrence of eccentrically inclined loading is presented. The variations of the magnitude of Ns are obtained by examining the effects of the Hoek-Brown rock mass strength parameters(uniaxial compressive strength(sci), disturbance factor(D), rock parameter(mi), and Geological Strength Index(GSI)) in the presence of different magnitudes of eccentricity(e) and inclination angle(λ) with respect to the vertical plane, and presented as design charts. Both the inclined loading modes, i.e., inclination towards the center of strip footing(+λ) and inclination away from the center of strip footing(-λ), are adopted to perform the investigation. In addition, the correlation between the input parameters and the corresponding output is developed by utilizing the artificial neural network(ANN). Additionally, from sensitivity analysis, it is observed that inclination angle(λ) is the most sensitive parameter. For practicing engineers, the obtained design equation and design charts can be beneficial to understand the bearing capacity variation in the existence of eccentrically inclined loading in mountain areas.