Section Width Research Articles

Slab Reinforcement Contributions to Negative Moment Strength of Reinforced Concrete T-Beam with High Strength Steel at Exterior Beam-Column Joints

Previous studies have revealed that the contribution of slab reinforcement to the T-beam flexural strength in negative moment regions are not negligible for the seismic capacity design. An effective slab width (i.e., effective width of flanged section) has been proposed, within which the slab reinforcement needs to be included in the calculation of the beam nominal flexural strength in negative moment regions. These studies mainly focused on the cases using normal-strength steel in moment resisting frames. However, recently high-strength steel has been widely used in reinforced concrete moment resisting frames in high seismic regions to avoid congestion near beam-column joints. The use of high-strength steel may affect the beam stiffness due to the fact that it will require less amount of reinforcement, and result in a different normal stress distribution compared to the case with normal-strength steel. Therefore, this paper investigates the slab reinforcement contribution to the flexural strength of the reinforced concrete T-beam designed with high-strength steel in negative moment regions at exterior beam-column joints, for which nonlinear pushover analyses were conducted. Beam reinforcement grade was considered as a primary parameter with several other design variables including slab thickness, height, and span length of the beam. Analytical results show that the use of high-strength steel can result in a wider effective slab width than the case of normal-strength steel for calculating the beam nominal flexural strength under the negative moment. Based on these results, new design equations were proposed.

Justification of the parameters of pulling sections of units with transverse channels

BACKGROUND: In modern harvesting technologies, the main technological operation is mechanized crops pulling. The flax-pulling machine with transverse band-disc channels is the most promising. However, the basic design parameters of pulling sections are not justified sufficiently, the peculiarities of their layout are not considered, the processes of moving plants through sections and pulling short-stemmed flax are not sufficiently studied, which reduces the effectiveness of its use.
 AIMS: Theoretical and experimental justification of the parameters and operation modes of pulling sections of the device with transverse band-disc channels.
 METHODS: Experimental studies to justify the parameters and operation modes of experimental pulling machines were carried out according to known and developed methods, and the assessment of flax products was carried out according to current GOST standards. The influence of the velocity of the unit and the width of the grip of pulling sections on the indicators of the agrotechnical and technological assessment of the operation of pulling device was determined.
 RESULTS: Dependences for determining the design parameters of a pulling section and the minimum height of plant stand suitable for mechanized harvesting were obtained, the conditions for finishing and moving plants in the zone of fixed guides were established. The structures of the experimental pulling machines were used to assess the unit velocity, the effect of the width of a pulling section and the elimination of the separation of technological currents of plants during processing on improving agrotechnical performance and increasing the yield and number of long fiber. The frame elements of the TLN-1.9P unit, are placed above the pull pulleys, and the operating width of a section is 0.38 m. In the TLN-1.9M and the TLN-1.9K units, they are located behind the pull pulleys, with the operating width of a section of 0.35 and 0.31 m respectively. As a result, the flax straw had higher quality indicators: 1.5 numbers for the TLN-1.9M and the TLN-1.9K and 1.25 numbers for the TLN-1.9P; the average yield of long fiber of these units was 13.41, 13.1 and 12.59% respectively.
 CONCLUSIONS: When assembling pulling machines with transverse band-disc channels, the elements of the frame structure should be positioned behind pulling drums, technical solutions should be used to ensure the kinematic operation mode equal to one, with the operating width of a section of 0.31 m for harvesting seed breeding and 0.35 m for harvesting commercial crops.

Približni proračun kružnih AB stupova uz pomoć nomograma

Calculating the reinforcement of circular reinforced concrete (RC) columns involves not only the dual nonlinearity of the geometry and material but also the nonlinearity of the section width. Accurate solutions require iterative calculations. To develop the calculation method manually, the model column method was proposed to compute the second-order effect of the columns, and the strain method was used to calculate the ultimate strength of the sections analytically. The nomograms required to calculate the reinforcing steel content of the columns without iterations were obtained. The nomogram for calculating the section bearing capacity and reinforcing steel has three parameters (axial force, bending moment, and mechanical ratio of the reinforcing steel). Further, the nomogram for calculating the column bearing capacity and reinforcing steel has five parameters (axial force, bending moment, curvature, slenderness ratio, and mechanical ratio of the reinforcing steel), and the relationship between the five parameters can be expressed in a plan, which makes the application convenient. Finally, the calculation results of the nomograph were compared with those of the existing approximate calculation formulas and exact numerical methods, and the accuracy of the nomograms was verified.

Heat transfer performance investigation of rotating U-channel supercritical pressure hydrocarbon fuel with intermediate connection section

To meet the challenge of the high temperatures faced by hypersonic vehicle electricity provision turbine blades, the blades are cooled with hydrocarbon fuel. For reducing the friction loss and improving the thermal performance, this paper designs and investigates the fuel flow mechanism and heat transfer law in the rotating channel with and without intermediate connection section. The results show that the channel with intermediate connection sections can reduce the friction coefficient of hydrocarbon fuel under rotating conditions and enhance the thermal performance. The connection section width H = 2D channel exhibits the best thermal performance and the lowest coefficient of friction. Compared to the channel without intermediate connection section, the thermal performance of the channel with connection section width H = 2 D is maximally enhanced by 3.71 times and the friction coefficient is maximally reduced by 98.9%. Compared to stationary, the thermal performance of the channel with a width of connection section H = 2 D is maximally enhanced by 10.78 times in rotating. Connecting sections will gradually replace 180° top turning sections. When the inlet temperature increases, the thermal performance of the channel can be improved by decreasing the width of the intermediate connecting section.

Experimental study and numerical simulation on shear behavior of steel and concrete composite beam with molybdenum tailing

To improve the flexural performance of steel–concrete composite beams and alleviate the problem of sand depletion caused by the application of concrete structures, this paper proposes a new type of steel-molybdenum tailings concrete composite beam. In order to further study the shear performance of the new type of steel-molybdenum tailings concrete composite beam, this paper couples molybdenum tailings replacement ratio (0%, 50%, and 100%) and shear span ratio (1 and 2) as research parameters, designs a total of six 1:2 scaled composite beam models, and conducts monotonic loading tests to study the failure process, failure mode, ultimate bearing capacity, deformation, and local strain of some typical measuring points of the new composite beam. The steel and concrete composite beam with the molybdenum tailing has the similar mechanical behavior for each ratio of the shear span to the effective depth with that of the steel and concrete composite beam. In addition, they have a little difference in the failure processes for each ratio of the shear span to the effective depth, whereas they show typical diagonal compression failure mode for the ratio of the shear span to the effective depth is equal to 1 and the representative shear-compression failure mode for the ratio of shear span to effective depth is 2, and have no obvious difference in failure mode for each ratio of the shear span to the effective depth. Their shear resistance mechanism is basically the same. Furthermore, based on the validated finite element model, this paper conducted a parameter extension analysis. The finite element results show that: The ultimate load bearing capacity of the steel and concrete composite beam with molybdenum tailing varies significantly with the beam section size (beam section width and beam depth), reinforcement ratio, and the ratio of the shear span to the effective depth; Whereas it has little relation to the steel plate thickness. This provides the necessity and feasibility to use the steel and concrete composite beam with the molybdenum tailing in engineering practice. The proposed equation in this study is based on the previous researches and the simulated and test results. The proposed equation is rigorous and thorough and the predicted results are highly accurate and effective.

Optimization of Rectangular and Box Sections in Oblique Bending and Eccentric Compression

The article presents a solution to the problem of finding the optimal ratio of the height of the cross-section to the width for a rectangular and box-shaped section in the case of oblique bending and eccentric compression. Optimization is performed according to the strength criterion, and for the case of oblique bending of a rectangular beam, a solution was also obtained from the condition of a minimum full deflection. For a rectangular section, the solution is made analytically, and for a box section, numerically using the MATLAB environment and the Optimization Toolbox package. As a numerical method of nonlinear optimization, the interior point method is used. To simplify the solution, the box section is assumed to be thin-walled, i.e. it is assumed that the wall thickness is significantly less than the height and width of the cross section. An estimate of the error of such an assumption is also performed. It has been established that in the case of oblique bending of a rectangular beam, when optimizing according to the strength criterion, the optimal ratio of the cross-sectional height to width is equal to the cotangent of the angle between the force plane and the vertical axis, and when optimizing according to the rigidity criterion, it is the square root of the cotangent of this angle. In the case of eccentric compression of a rectangular beam with eccentricities in two planes, the optimal ratio of the height of the cross section to the width is equal to the ratio of the eccentricity along the vertical and horizontal axes. For a box-shaped section, graphs of the change in optimal parameters depending on the angle between the force plane and the vertical axis in the case of oblique bending, as well as depending on the ratio of eccentricities along the axes in the case of eccentric compression, are plotted.

Assessment of reliability for subterranean corroded pipelines in cold regions using Monte Carlo method and BP neural network

Due to the complexity and instability of the environment in which the buried oil pipeline is located in cold regions, the corrosion of the outer wall of the pipeline often occurs, and the corrosion poses a serious threat to the safety of the pipeline. In order to ensure the safe operation of buried oil pipelines, it is particularly urgent to study the reliability of operating pipelines. In this paper, the external temperature field and soil effect were taken into account, and the finite element method was used to calculate and analyze the results. The fitted formula which can predict the failure pressure of buried corroded pipeline was obtained. After that, the reliability of buried corroded pipelines was studied by using Monte Carlo method and BP neural network. The results show that the fitted formula for predicting the failure pressure of pipelines is more accurate than traditional code. The corrosion depth has the most significant impact on the reliability of pipelines, being 1.85 times that of the corrosion length. The impact of corrosion width, burial depth, frost-heaving rate, and length of the frost-heaving section on the reliability of corroded pipelines is relatively small. The frost-heaving section within 5000 mm can play a certain positive role in the reliability of corroded pipelines.

EXPERIMENTAL CHARACTERISATION OF THE WAKE OF A BOTTOM-MOUNTED TWO TANDEM OF CYLINDERS PLACED IN A HIGH VELOCITY AREA

Following the development of renewable marine energies, the characterization of areas with strong marine currents has become necessary. The Normandy coasts (France) are among the sites suitable for the installation of tidal turbine parks because they have significant energy potential. Projects to install machines in these sites raise questions about various factors affecting the performance of the turbines that would be placed there.
 We are currently working on the understanding of the mechanisms leading to the generation of ambient flow turbulence on the seabed. More particularly, we are interested in the impact of the complexity of the bathymetry on the organization of the wake generated. To simplify the modeling of the bathymetry of the seabed, we use generic cylindrical obstacles of rectangular section. The obstacles are placed on the bottom of the study area of ​​the Hydrodynamic Tunnel of the LUSAC laboratory and occupy its entire width. Measurements are made using Particle Image Velocimetry (PIV-2D) for a velocity flow of 3 m/s.
 In a first time, in a previous contribution, was evaluated the impact of the ratio between the Height and the Width (H/W) of the cross section of the cylinder on the organization of the near wake. Indeed, the average velocity fields obtained for six different obstacles, highlighted the modification of the organization of the flow topology. The variation of this ratio H/W leads to the modification of the length of the average vortex formation zone, implies the presence of two or even three average recirculation zones in the near wake of the cylinder and leads to the possible presence of a recirculation zone average placed upstream of the cylinder.
 Nevertheless, in the seabed the structures are not isolated. In the contrary, on the seabed we can observe successions of structures anchored on the funds, leading to the interaction of a structure with the wake generated upstream by another one structure. The experimental study with the characterization of the flow around a tandem of “long” cylindrical obstacles of square section (side H). The distance between these two cylinders is equal to 2H.
 As expected, in the present study, it can be observed the modifications of the topology of the mean flow and the distribution of the turbulent kinetic energy. Indeed, the interaction between the mean recirculation, generated downstream each cylinder, is shown.

Pair Production of Heavy Charged Gauge Bosons in pp Collisions at LHC

Abstract Two oppositely charged new heavy gauge boson pair production at the Large Hadron Collider (LHC), is presented in this paper. These bosons are known as W ′ boson due to the reason that it is the heavy version of Standard Model’s weak force carrier, the W boson. The production cross section and decay width in proton-proton (pp) collision at s = 8 TeV are calculated for different masses and coupling strengths of W ′ . Efficiencies for different signal regions and branching ratios for different decay channels are computed. In this study, the pair production ( W ′ + W ′ − ) is considered in emerging new physics as a result of pp collision at s = 8 TeV at the LHC with final state containing two tau (τ) leptons and two neutrinos (each W ′ decay to τ and its neutrino). The event selection efficiency similar to the CMS experiment is used for the mass of W ′ to set lower limits for different coupling strengths of W ′ and, the obtained results are presented in this work. For heavy gauge bosons, when coupling strength is similar to that of Standard Model’s W boson, the mass of W ′ below 445 GeV are excluded at a confidence level of 95%.

Modeling the load carrying capacity of corroded reinforced concrete compression bending members using explainable machine learning

Corrosion of reinforcement can lead to a decrease in the load carrying capacity of reinforced concrete structures and affect their safety. Therefore, accurate evaluation of the ultimate load carrying capacity is crucial for the maintenance and reinforcement of corroded reinforced concrete structures. In this paper, based on experimental research data of 192 corroded reinforced concrete compression bending members, data-driven analysis was conducted using ANN, SVM, RF, and AdaBoost algorithms to establish the relationship between the influencing factors of the load carrying capacity and their ultimate load carrying capacity. The input variables include the section width of the member, section height of the member, length of member, yield strength of reinforcement, diameter of longitudinal reinforcement, compressive strength of concrete, thickness of concrete cover, hoop diameter, original eccentricity, corrosion rate and the ultimate load carrying capacity is the output variable. Additionally, this study innovatively utilizes the Shapley additive explanations (SHAP) method to enhance the interpretability of the ML models, overcoming the "black box" issue associated with ML methods. Furthermore, the performance of the ML models is compared with theoretical formulas. The results indicate that the ML models exhibit good predictive performance, with higher accuracy than thetheoretical calculation formulas. And the predictive performance of ensemble learning models (RF, AdaBoost) is better than that of single learning models (ANN, SVM). The newly developed hybrid ML model is likely to become a new choice for dealing with the load carrying capacity problem of corroded reinforced concrete compression bending members.

Experimental investigation and design consideration on pull-through capacity of a C-shaped purlin section

A small-scale experimental study was carried out to investigate the pull-through failure of the C-shaped Cold-Formed Steel (CFS) roof purlin sections subjected to wind uplift force. The parameters investigated to comprehend the pull-through behavior of roof purlin are thickness, web depth, flange width of the CFS purlin section, and size of the screw head diameter. The test specimens experienced two different modes of pull-through failure (rupture and bearing) along with the prying effect. It was observed that the pull-through failure mode transitions from rupture of the purlin section around the screw fastener in 1 mm thickness to bearing type in 2 mm and 3 mm thicknesses. The test results were compared with existing design limits and previous studies from the literature which concluded that the existing elastic design approach for the service limit state is unconservative. Hence, a suitable design limit to predict the critical pull-through capacity of C-shaped roof purlins under high wind load is proposed. Additionally, reliability studies were carried out to determine the resistance and safety factors for the proposed design equations. The suggested design specifications are applicable and conservative for the material strength in the range of 350 MPa.

Development of mathematical models to predict the load-carrying capacity of tractor tires on rigid surface

Objective: The objective of this study was to develop the load-carrying capacity models of tractor tires on the rigid surface for both, radial and bias tires. Material and Methods: In order to develop functions, two tire constructional variables (section width and overall diameter), inflation pressure, and forward speed for the load-carrying capacity model were considered. The models developed in the literature for the load-carrying capacity of tires on rigid and soil surfaces were built on some limited data and as a result of this, the predominant variable and contribution of other variables still remain unknown. This study has the widest range of tractor tire sizes (width and diameter). The load-carrying capacity models developed in this study were verified with the theoretical models and experimental measurement values in the literature. Results: As a result of the study, it was found that the appropriate mathematical models were in non-linear (power) form and the coefficient of determination of the models was greater than 0.95. Conclusion: The models were verified against published data in the literature and found that the predictions from the models are in good agreement with the measured values.

Study on the Performance of Polyurea Anti-Seepage Spray Coating for Hydraulic Structures

The surfaces of hydraulic structures are vulnerable to damage and cracking, which can result in high-pressure reservoir water entering cracks and endangering the safety of the structures. Therefore, it is necessary to strengthen the anti-seepage treatment and protection on the surfaces of the structures. In this paper, we explore the tensile and high-water-pressure breakdown resistance properties of polyurea coating material. To do so, we independently designed and manufactured a high-water-pressure breakdown test device for coating. Our experimental results indicated that the thickness of the polyurea coating decreased with an increase in elongation. Furthermore, we found that the breakdown resistance of the polyurea coating was related to the coating thickness and the bottom free section width. We then fitted the stress–strain curve obtained from the experimental test using the Ogden constitutive model. Based on this, we numerically simulated the high-water-pressure breakdown performance of the polyurea coating using the finite element software ABAQUS 2022. We obtained the relationships among maximum displacement, free section width, and coating thickness under high water pressure. Our numerical findings indicated that the vertical displacement of the midpoint increased linearly with width in the case of the same coating thickness under water pressure load. Conversely, for the same free section width, the vertical displacement decreased with increasing coating thickness.

Reshape of the Bistable and Multistable Properties of Conical Structures Through Integrated Modification of Local Cross Section

Abstract Multistable structures can maintain multiple steady states without additional loads. However, the presence of geometric and material nonlinearities in multistable structures adds complexity and difficulty to their optimal design. In this paper, a novel method is proposed to achieve multistability in conical structures by local cross-section modification. A conical multistable structure with varying cross section is designed based on this method. The finite element model considering the nonlinear large deformation mechanics and rubber material’s hyperelasticity was established for analyzing the multistable properties and meanwhile verified by experiments. The influence of geometric parameters of the cross section (thickness, width, and position) on the multistabilities (number, distribution, and snapping threshold) was analyzed. The steady-state number can be effectively used to redesign the multistable properties by local reinforcement. It is also observed that the quasi-zero stiffness region of the force–displacement curve can be extended by 61.7% compared to the original conical structure. Moreover, the optimized QZS structure allows for an actively designable stepped dynamic response under forced vibration.

A Novel Design of Permanent Magnets for the Air Gap Magnetic Field of Hollow-Cup Motor

Spacecraft motors are often driven with trapezoidal phase currents to achieve higher output torque. For hollow cup motors (HCM) driven by trapezoidal wave currents, parallel magnetised permanent magnet (PM) motors produce an air gap magnetic field (AMF) waveform which is significantly different from the trapezoidal wave, causing the motor to generate noise or vibration. The existing control optimisation method or structure improvement design method is difficult to directly apply to HCM due to its large gas gap. In this paper, according to the fundamental theory of a constant magnetic field, the AMF of HCM is analysed using the equivalent surface current method (ESCM) and its mathematical model is established. The analytical expression of the AMF is solved, and the influencing parameters of the AMF are clarified. The structural design of the HCM with eccentric PMs sintered with high-performance NdFeB is further improved. On this basis, a prototype motor is designed. Simulation results show that the structure can effectively increase the width of the flat section of the AMF and make the AMF close to an ideal trapezoidal wave (ITW). Experiments verify the correctness of the method.

3-D Numerical Simulation of Seismic Response of the Induced Joint of a Subway Station

In recent times, induced joints have been set along the length of subway stations in order to avoid disordered cracking of the main structures occurring due to temperature stress, concrete shrinkage, creep, or uneven foundation settlement. At present, the use of induced joints in subway station structures is mainly based on engineering experience. The seismic response of induced joints has not yet been well explained, much less mastered. In this study, a 3-D numerical model of a subway station incorporating certain sorts of induced joints is established systematically. Then, the seismic response of those induced joints applied in different positions and various forms has been studied under different seismic waves by varying the spectral characteristics and peak acceleration values of the waves. The results show that the horizontal relative sliding displacement of the structures on both sides of an induced joint increases gradually from bottom to top along the structure of the subway station. While the vertical sliding displacements that occur along the section width are larger at both ends of the induced joints than in the middle. What is more, with an increase in seismic intensity, the horizontal relative sliding displacement becomes larger, while the vertical displacement becomes even smaller. In addition, the relative sliding displacement can be reduced by increasing the residual longitudinal reinforcement ratio of the induced joint. Furthermore, it is discovered that the setting of key grooves at the bottom plate of the induced joint section has a certain effect on controlling the horizontal relative sliding displacement, as well as a significant effect on preventing the vertical relative dislocation of the structures on both sides of the induced joint.

Features of the Peribiliary Glands of the Extrahepatic Biliary Tract in the Elderly and Long-Living Individuals

The aim of the study was to analyse histologically and morphometrically the peribiliary glands of the extrahepatic biliary tract in the elderly and long-living people.Material and methods. The study included wholemounts of the gallbladder, the cystic, hepatic and common bile ducts obtained from the corpses of both sexes aged 22 to 35 years (n=16) and older than 76 years (n=39). Macro-microscopy was used to evaluate the number, localization, sizes and shape of the glands, the area of the lumen of the excretory duct orifices, the area of the initial section of the glands, the number of initial (terminal) parts and the proportion of epithelial parenchyma in their composition.Results. With age, there is a decreased proportion of "complexly branched" glands with a significant number of initial sections and excretory ducts of the 1st order. The proportion of "simple" glands, with one initial section increases to 70.2–78.3% in the senile age, while it is 41.0–52.1% in people of mature age. In long-living people, there is an increased number (up to 70–85%) of glands with ampullar extensions of the common excretory duct. The total number, density of gland localization, the length and width of the initial section of the peribiliary glands tend to decrease from the period of mature age to longevity. In senile age, the size and quantitative parameters of the glands stabilize, and do not modify in long-living people.Conclusion. The results of the morphological analysis demonstrate that there is no progression of involutive changes in the peribiliary glands of the extrahepatic biliary tract from senile age to the period of longevity. In some cases, long-living individuals manifest compensatory-adaptive reactions, such as an increased severity of the epithelial parenchymal component in the composition of the glands and an increased proportion of glands with an ampullar expansion of the common excretory duct.

Justification of the Value of Air Flow Pressure for Transportation of Plant Material

The article is devoted to the analysis of the process of loading plant mass into the assembly chamber, carried out due to the energy of the air flow generated by the fan and the kinetic energy imparted to it by the rotor blades. Theoretical calculations performed using experimental data from the literature devoted to the study of hay-straw material pneumatic transport are presented. These calculations made it possible to determine the approximate range of the air flow for the developed hay transportation method. To determine the air pressure loss, the balance of resistance to the movement of air and material in the air duct was considered according to the Bernoulli equation for an elementary section. As a result of aerodynamic studies, the following was revealed: the dependence of the air flow velocity along the section width on the distance to the loader at different fan rotor speeds. Curves of distribution of velocities having the form of a parabola with a vertex in the middle of the air duct and the dependence of the velocities on the rotor speed were experimentally established. The obtained experimental data made it possible to evaluate the theoretical prerequisites, the possibility of using the Bernoulli equation in the calculations of transportation through the air duct of the loader

Оптимизация сжатых деревянных стоек переменного сечения по критерию максимума критической нагрузки

The article presents a numerical and analytical solution to the problem of optimizing compressed rods according to the criterion of the maximum critical load with a possible loss of stability in two planes. We consider a wooden bar of rectangular cross section, the height of which varies according to a linear law, and the width is constant. The calculation is performed in an elastic formulation. A constraint on the constancy of the rod mass is introduced. Variable parameters are the ratio of the minimum section height to the maximum, as well as the ratio of the section width to the maximum height. Numerical search for the optimal solution is performed in the MATLAB environment using the method of sequential quadratic programming. It has been established that the use of rods with a cross-sectional height that varies linearly along the length is effective only if the rod is fixed in at least one of the planes according to the “pinched-free end” scheme. It has been established that the increase in the critical load when using rods with a linearly varying cross-sectional height can be up to 22%.

Machine Learning Models for Ecofriendly Optimum Design of Reinforced Concrete Columns

CO2 emission is one of the biggest environmental problems and contributes to global warming. The climatic changes due to the damage to nature is triggering a climate crisis globally. To prevent a possible climate crisis, this research proposes an engineering design solution to reduce CO2 emissions. This research proposes an optimization-machine learning pipeline and a set of models trained for the prediction of the design variables of an ecofriendly concrete column. In this research, the harmony search algorithm was used as the optimization algorithm, and different regression models were used as predictive models. Multioutput regression is applied to predict the design variables such as section width, height, and reinforcement area. The results indicated that the random forest algorithm performed better than all other machine learning algorithms that have also achieved high accuracy.